216 results on '"Parker KL"'
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2. Impaired follicle development and infertility in female mice lacking steroidogenic factor 1 in ovarian granulosa cells
- Author
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PELUSI, CARLA, Ikeda Y, Zubair M, Parker KL, Pelusi C, Ikeda Y, Zubair M, and Parker KL
- Published
- 2008
3. A comparison of iEMG activity between the medial and lateral heads of the gastrocnemius muscle during partial weight bearing plantarflexion contractions at varying loads.
- Author
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Fiebert IM, Spielholz NI, Applegate B, Crabtree FG, Martin LA, and Parker KL
- Abstract
The purpose of this study was to determine the differences between iEMG activity of the medial head (MH) and lateral head (LH) of the gastrocnemius of normal right legs during partial weight bearing isometric plantarflexion contractions under varying percentages of body weight (BW) and maximal contractions. Fifty-three healthy volunteers ranging in age from 18 to 35, with no history of right lower extremity injury or disease volunteered for this study. Each subject's age, height, weight, and medical history were recorded. A chronaximeter was used to identify the motor points of the MH and LH. After performing a 5-minute warm-up, surface electrodes were placed just distal to the motor point, and subjects were positioned on the sliding board of the Total Gym Therapy System. The percentage of BW used as resistance was determined by the angle of inclination of the slide board. The subjects were then directed to plantarflex to 20 degrees, with 8 second iEMG recordings, with a proprioceptive cue, under four conditions: 30%, isometric (1 trial). Paired t-tests concluded the MH consistently demonstrated a larger percent of total iEMG activity than the LH in the 30, 50, and 70% difference between iEMG activity of the MH and LH during the maximum isometric trial was not statistically significant (p= 0.2958). A repeated measures ANOVA and post-hoc analysis demonstrated the percent of total iEMG differences to be greater at the lighter loads (D30 > D50 > D70; p< 0.0001). These findings strongly suggest separate but complementary functions of the two heads of the gastrocnemius muscle. [ABSTRACT FROM AUTHOR]
- Published
- 2000
- Full Text
- View/download PDF
4. The effects of the standard rolling walker and two posterior rolling walkers on gait variables of normal children.
- Author
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Levangie PK, Brouwer J, McKeen SH, Parker KL, and Shelby KA
- Abstract
The purpose of this study was to determine the effects of the standard rolling walker (SRW) and two versions of the posteriorly placed posterior rolling walker on gait variables of a sample of normal children. The two versions of the posterior rolling walker included the two-wheeled model (PRW2) and the four-wheeled model (PRW4). Nineteen children aged six to eight years old from two suburban first and second grade classrooms comprised the sample. The footprint method of analysis was used to record and measure the variables of velocity, cadence, step length, stride length, base of support, and toe angle. Each child was initially recorded while walking unassisted, and then with the SRW, PRW2 and PRW4 presented in randomized order for a total of four trials per child. The mean values for each gait variable were obtained for each trial for each child. A Multiple Analysis of Variance with one repeated measure and Duncan Multiple Comparison Tests were used to analyze these data. Results indicated that use of a walker, regardless of model, changed normal (unassisted) gait in all variables measured except toe angle. Gait using the PRW4 most closely approximated unassisted gait. Results may have implications for clinicians both in setting the optimal level of function that might be expected from children using walkers, and in choosing among walker models for their patients. [ABSTRACT FROM AUTHOR]
- Published
- 1990
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5. Animal responses to environmental variation: Physiological mechanisms in ecological models of performance in deer (Cervidae)
- Author
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Tyler, NJC, Gregorini, Pablo, Parker, KL, and Hazlerigg, DG
- Published
- 2020
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6. Knockdown of the Non-canonical Wnt Gene Prickle2 Leads to Cerebellar Purkinje Cell Abnormalities While Cerebellar-Mediated Behaviors Remain Intact.
- Author
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Abbott PW, Hardie JB, Walsh KP, Nessler AJ, Farley SJ, Freeman JH, Wemmie JA, Wendt L, Kim YC, Sowers LP, and Parker KL
- Subjects
- Animals, Mice, Mice, Knockout, Mice, Inbred C57BL, Male, Behavior, Animal physiology, Disease Models, Animal, Gene Knockdown Techniques, Purkinje Cells metabolism, Purkinje Cells pathology, LIM Domain Proteins genetics, LIM Domain Proteins deficiency, Cerebellum metabolism, Cerebellum pathology
- Abstract
Autism spectrum disorders (ASD) involve brain wide abnormalities that contribute to a constellation of symptoms including behavioral inflexibility, cognitive dysfunction, learning impairments, altered social interactions, and perceptive time difficulties. Although a single genetic variation does not cause ASD, genetic variations such as one involving a non-canonical Wnt signaling gene, Prickle2, has been found in individuals with ASD. Previous work looking into phenotypes of Prickle2 knock-out (Prickle2
-/- ) and heterozygous mice (Prickle2-/+ ) suggest patterns of behavior similar to individuals with ASD including altered social interaction and behavioral inflexibility. Growing evidence implicates the cerebellum in ASD. As Prickle2 is expressed in the cerebellum, this animal model presents a unique opportunity to investigate the cerebellar contribution to autism-like phenotypes. Here, we explore cerebellar structural and physiological abnormalities in animals with Prickle2 knockdown using immunohistochemistry, whole-cell patch clamp electrophysiology, and several cerebellar-associated motor and timing tasks, including interval timing and eyeblink conditioning. Histologically, Prickle2-/- mice have significantly more empty spaces or gaps between Purkinje cells in the posterior lobules and a decreased propensity for Purkinje cells to fire action potentials. These structural cerebellar abnormalities did not impair cerebellar-associated behaviors as eyeblink conditioning and interval timing remained intact. Therefore, although Prickle-/- mice show classic phenotypes of ASD, they do not recapitulate the involvement of the adult cerebellum and may not represent the pathophysiological heterogeneity of the disorder., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)- Published
- 2024
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7. Commentary on New Guidance for Human Papillomavirus-Related Cancer Screening Among Sexual and Gender Minority Populations.
- Author
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Jackson SS and Parker KL
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- Humans, Health Disparate Minority and Vulnerable Populations, Human Papillomavirus Viruses, Minority Groups, Sexual Behavior, Male, Female, Early Detection of Cancer, Neoplasms
- Abstract
Competing Interests: The authors have declared they have no conflicts of interest.
- Published
- 2023
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8. Supra-second interval timing in bipolar disorder: examining the role of disorder sub-type, mood, and medication status.
- Author
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Ewald VAM, Trapp NT, Sarrett ME, Pace BD, Wendt L, Richards JG, Gala IK, Miller JN, Wessel JR, Magnotta VA, Wemmie JA, Boes AD, and Parker KL
- Abstract
Background: Widely reported by bipolar disorder (BD) patients, cognitive symptoms, including deficits in executive function, memory, attention, and timing are under-studied. Work suggests that individuals with BD show impairments in interval timing tasks, including supra-second, sub-second, and implicit motor timing compared to the neuronormative population. However, how time perception differs within individuals with BD based on disorder sub-type (BDI vs II), depressed mood, or antipsychotic medication-use has not been thoroughly investigated. The present work administered a supra-second interval timing task concurrent with electroencephalography (EEG) to patients with BD and a neuronormative comparison group. As this task is known to elicit frontal theta oscillations, signal from the frontal (Fz) lead was analyzed at rest and during the task., Results: Results suggest that individuals with BD show impairments in supra-second interval timing and reduced frontal theta power during the task compared to neuronormative controls. However, within BD sub-groups, neither time perception nor frontal theta differed in accordance with BD sub-type, depressed mood, or antipsychotic medication use., Conclusions: This work suggests that BD sub-type, depressed mood status or antipsychotic medication use does not alter timing profile or frontal theta activity. Together with previous work, these findings point to timing impairments in BD patients across a wide range of modalities and durations indicating that an altered ability to assess the passage of time may be a fundamental cognitive abnormality in BD., (© 2023. Springer-Verlag GmbH Germany, part of Springer Nature.)
- Published
- 2023
- Full Text
- View/download PDF
9. Violence and Related Health Outcomes in Sexual and Gender Minority Communities: Introduction to the Special Issue.
- Author
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Avila I, Patel S, Parker KL, and Whitton SW
- Subjects
- Humans, Sexual Behavior, Gender Identity, Violence, Outcome Assessment, Health Care, Sexual and Gender Minorities
- Abstract
Violence affects every community but is particularly prevalent among sexual and gender minority (SGM) people. Although research on violence within SGM populations is increasing, knowledge gaps remain that limit development of evidence-based policy, prevention, and intervention efforts to reduce the violence disparities the SGM community faces. In 2021, the National Institutes of Health (NIH) hosted a multiphase scientific workshop to identify and prioritize key research needs to further our understanding of violence affecting SGM communities and its health outcomes. In this perspective, we summarize the research needs identified. NIH supports this special issue as an outcome of the scientific workshop.
- Published
- 2023
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10. Neuropsychiatric outcomes following strokes involving the cerebellum: a retrospective cohort study.
- Author
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Muller Ewald VA, Deifelt Streese C, Bruss JE, Manzel K, Montilla LM, Gala IK, Tranel DT, and Parker KL
- Abstract
Introduction: Given the wide-ranging involvement of cerebellar activity in motor, cognitive, and affective functions, clinical outcomes resulting from cerebellar damage can be hard to predict. Cerebellar vascular accidents are rare, comprising less than 5% of strokes, yet this rare patient population could provide essential information to guide our understanding of cerebellar function., Methods: To gain insight into which domains are affected following cerebellar damage, we retrospectively examined neuropsychiatric performance following cerebellar vascular accidents in cases registered on a database of patients with focal brain injuries. Neuropsychiatric testing included assessment of cognitive (working memory, language processing, and perceptual reasoning), motor (eye movements and fine motor control), and affective (depression and anxiety) domains., Results: Results indicate that cerebellar vascular accidents are more common in men and starting in the 5th decade of life, in agreement with previous reports. Additionally, in our group of twenty-six patients, statistically significant performance alterations were not detected at the group level an average of 1.3 years following the vascular accident. Marginal decreases in performance were detected in the word and color sub-scales of the Stroop task, the Rey Auditory Verbal Learning Test, and the Lafayette Grooved Pegboard Test., Discussion: It is well established that the acute phase of cerebellar vascular accidents can be life-threatening, largely due to brainstem compression. In the chronic phase, our findings indicate that recovery of cognitive, emotional, and affective function is likely. However, a minority of individuals may suffer significant long-term performance impairments in motor coordination, verbal working memory, and/or linguistic processing., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Muller Ewald, Deifelt Streese, Bruss, Manzel, Montilla, Gala, Tranel and Parker.)
- Published
- 2023
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11. Supra-second interval timing in bipolar disorder: examining the role of disorder sub-type, mood, and medication status.
- Author
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Müller Ewald VA, Trapp NT, Sarrett ME, Pace BD, Wendt L, Richards JG, Gala IK, Miller JN, Wessel JR, Magnotta VA, Wemmie JA, Boes AD, and Parker KL
- Abstract
Background : Widely reported by bipolar disorder (BD) patients, cognitive symptoms, including deficits in executive function, memory, attention, and timing are under-studied. Work suggests that individuals with BD show impairments in interval timing tasks, including supra-second, sub-second, and implicit motor timing compared to the neuronormative population. However, how time perception differs within individuals with BD based on BD sub-type (BDI vs II), mood, or antipsychotic medication-use has not been thoroughly investigated. The present work administered a supra-second interval timing task concurrent with electroencephalography (EEG) to patients with BD and a neuronormative comparison group. As this task is known to elicit frontal theta oscillations, signal from the frontal (Fz) lead was analyzed at rest and during the task. Results : Results suggest that individuals with BD show impairments in supra-second interval timing and reduced frontal theta power compared during the task to neuronormative controls. However, within BD sub-groups, neither time perception nor frontal theta differed in accordance with BD sub-type, mood, or antipsychotic medication use. Conclusions : his work suggests that BD sub-type, mood status or antipsychotic medication use does not alter timing profile or frontal theta activity. Together with previous work, these findings point to timing impairments in BD patients across a wide range of modalities and durations indicating that an altered ability to assess the passage of time may be a fundamental cognitive abnormality in BD.
- Published
- 2023
- Full Text
- View/download PDF
12. Posterior Fossa Sub-Arachnoid Cysts Observed in Patients with Bipolar Disorder: a Retrospective Cohort Study.
- Author
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Ewald VAM, Purnell JR, Bruss JE, Barsotti EJ, Aldine AS, Mahachi KG, Wemmie JA, Magnotta VA, Boes AD, Parker KL, and Fiedorowicz JG
- Subjects
- Humans, Retrospective Studies, Magnetic Resonance Imaging methods, Cerebellum abnormalities, Cranial Fossa, Posterior, Arachnoid Cysts, Bipolar Disorder
- Abstract
Posterior fossa arachnoid cysts (PFACs) are rare congenital abnormalities observed in 0.3 to 1.7% of the population and are traditionally thought to be benign. While conducting a neuroimaging study investigating cerebellar structure in bipolar disorder, we observed a higher incidence of PFACs in bipolar patients (5 of 75; 6.6%) compared to the neuronormative control group (1 of 54; 1.8%). In this report, we detail the cases of the five patients with bipolar disorder who presented with PFACs. Additionally, we compare neuropsychiatric measures and cerebellar volumes of these patients to neuronormative controls and bipolar controls (those with bipolar disorder without neuroanatomical abnormalities). Our findings suggest that patients with bipolar disorder who also present with PFACs may have a milder symptom constellation relative to patients with bipolar disorder and no neuroanatomical abnormalities. Furthermore, our observations align with prior literature suggesting an association between PFACs and psychiatric symptoms that warrants further study. While acknowledging sample size limitations, our primary aim in the present work is to highlight a connection between PFACs and BD-associated symptoms and encourage further study of cerebellar abnormalities in psychiatry., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)
- Published
- 2023
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13. Editorial: Unravelling the complex and multifaceted role of the cerebellum in health and disease.
- Author
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Mathews PJ, Paradis AL, Cvetanovic M, Carlson ES, and Parker KL
- Abstract
Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
- Published
- 2023
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14. Plasma and cellular ivacaftor concentrations in patients with cystic fibrosis.
- Author
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Guimbellot JS, Ryan KJ, Anderson JD, Parker KL, Victoria Odom L, Rowe SM, and Acosta EP
- Subjects
- Aminophenols therapeutic use, Benzodioxoles therapeutic use, Cystic Fibrosis Transmembrane Conductance Regulator genetics, Cystic Fibrosis Transmembrane Conductance Regulator therapeutic use, Humans, Mutation, Cystic Fibrosis drug therapy, Quinolones therapeutic use
- Abstract
Access to cystic fibrosis transmembrane conductance regulator (CFTR) modulators has been gradually increasing for people with cystic fibrosis, the first of which was ivacaftor, a CFTR potentiator that is part of all clinically available modulator treatments. In this study, we hypothesized that the steady-state concentrations in blood and tissue are highly variable in patients taking ivacaftor in a real-world context, which may have an impact on the treatment approach. We collected nasal epithelial cells to estimate target site concentrations and blood samples to estimate pharmacokinetic parameters at a steady state. We found that patients on ivacaftor monotherapy have variable concentrations well above the maximal effective concentration and may maintain concentrations necessary for the clinical benefit even if dosing is reduced. We also are the first to provide detailed target site concentration data over time, which shows that tissue concentrations do not fluctuate significantly and do not correlate with plasma concentrations. These findings show that some patients may have higher-than-expected concentrations and may benefit from tailored dosing to balance clinical response with side effects or adherence needs., (© 2022 Wiley Periodicals LLC.)
- Published
- 2022
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15. Involvement of the cerebellum in migraine.
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Wang M, Tutt JO, Dorricott NO, Parker KL, Russo AF, and Sowers LP
- Abstract
Migraine is a disabling neurological disease characterized by moderate or severe headaches and accompanied by sensory abnormalities, e.g., photophobia, allodynia, and vertigo. It affects approximately 15% of people worldwide. Despite advancements in current migraine therapeutics, mechanisms underlying migraine remain elusive. Within the central nervous system, studies have hinted that the cerebellum may play an important sensory integrative role in migraine. More specifically, the cerebellum has been proposed to modulate pain processing, and imaging studies have revealed cerebellar alterations in migraine patients. This review aims to summarize the clinical and preclinical studies that link the cerebellum to migraine. We will first discuss cerebellar roles in pain modulation, including cerebellar neuronal connections with pain-related brain regions. Next, we will review cerebellar symptoms and cerebellar imaging data in migraine patients. Lastly, we will highlight the possible roles of the neuropeptide calcitonin gene-related peptide (CGRP) in migraine symptoms, including preclinical cerebellar studies in animal models of migraine., Competing Interests: AR is a consultant for Lundbeck, Amgen, Novartis, Eli Lilly, AbbVie, and Schedule 1 Therapeutics. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Wang, Tutt, Dorricott, Parker, Russo and Sowers.)
- Published
- 2022
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16. Incorporating a trauma-informed perspective in HIV-related research with transgender and gender diverse individuals.
- Author
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Allison SM, Parker KL, and Senn TE
- Subjects
- Gender Identity, Health Behavior, Humans, Social Stigma, HIV Infections epidemiology, HIV Infections psychology, Transgender Persons, Violence
- Published
- 2022
- Full Text
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17. The dorsal hippocampus' role in context-based timing in rodents.
- Author
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De Corte BJ, Farley SJ, Heslin KA, Parker KL, and Freeman JH
- Subjects
- Animals, Cues, Rats, Reward, Hippocampus, Rodentia
- Abstract
To act proactively, we must predict when future events will occur. Individuals generate temporal predictions using cues that indicate an event will happen after a certain duration elapses. Neural models of timing focus on how the brain represents these cue-duration associations. However, these models often overlook the fact that situational factors frequently modulate temporal expectations. For example, in realistic environments, the intervals associated with different cues will often covary due to a common underlying cause. According to the 'common cause hypothesis,' observers anticipate this covariance such that, when one cue's interval changes, temporal expectations for other cues shift in the same direction. Furthermore, as conditions will often differ across environments, the same cue can mean different things in different contexts. Therefore, updates to temporal expectations should be context-specific. Behavioral work supports these predictions, yet their underlying neural mechanisms are unclear. Here, we asked whether the dorsal hippocampus mediates context-based timing, given its broad role in context-conditioning. Specifically, we trained rats with either hippocampal or sham lesions that two cues predicted reward after either a short or long duration elapsed (e.g., tone-8 s/light-16 s). Then, we moved rats to a new context and extended the long cue's interval (e.g., light-32 s). This caused rats to respond later to the short cue, despite never being trained to do so. Importantly, when returned to the initial training context, sham rats shifted back toward both cues' original intervals. In contrast, lesion rats continued to respond at the long cue's newer interval. Surprisingly, they still showed contextual modulation for the short cue, responding earlier like shams. These data suggest the hippocampus only mediates context-based timing if a cue is explicitly paired and/or rewarded across distinct contexts. Furthermore, as lesions did not impact timing measures at baseline or acquisition for the long cue's new interval, our data suggests that the hippocampus only modulates timing when context is relevant., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Inc. All rights reserved.)
- Published
- 2022
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18. A limited cerebellar contribution to suprasecond timing across differing task demands.
- Author
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Heslin KA, Purnell JR, De Corte BJ, and Parker KL
- Subjects
- Animals, Brain, Cerebellar Nuclei, Cerebellum, Humans, Rats, Time Perception
- Abstract
The involvement of the cerebellum in suprasecond interval timing (i.e., timing in the seconds to minutes range) is controversial. A limited amount of evidence from humans, nonhuman primates, and rodents has shown that the lateral cerebellum, including the lateral cerebellar nucleus (LCN), may be necessary for successful suprasecond timing performance. However, many existing studies have pitfalls, such as limited timing outcome measures and confounded task demands. In addition, many existing studies relied on well-trained subjects. This approach may be a drawback, as the cerebellum is hypothesized to carry out ongoing error correction to limit timing variability. By using only experienced subjects, past timing studies may have missed a critical window of cerebellar involvement. In the experiments described here, we pharmacologically inactivated the rat LCN across three different peak interval timing tasks. We structured our tasks to address past confounds, collect timing variability measures, and characterize performance during target duration acquisition. Across these various tasks, we did not find strong support for cerebellar involvement in suprasecond interval timing. Our findings support the existing distinction of the cerebellum as a subsecond interval timing brain region. (PsycInfo Database Record (c) 2022 APA, all rights reserved).
- Published
- 2022
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19. A revision of Angolan species in the genus Pedioplanis Fitzinger (Squamata: Lacertidae), with the description of a new species.
- Author
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Parrinha D, Marques MP, Heinicke MP, Khalid F, Parker KL, Tolley KA, Childers JL, Conradie W, Bauer AM, and Ceraco LMP
- Subjects
- Animals, Cell Nucleus, Mitochondria, Phylogeny, Lizards genetics
- Abstract
The genus Pedioplanis reaches its northernmost limit in western Angola, where it is represented by three species, Pedioplanis benguelensis, P. haackei and P. huntleyi. The taxonomic status of P. benguelensis remains problematic, mainly due to the vague original description and the loss of the original type material. Here we provide a revision of the Angolan representatives of the genus, with the description of a new species, Pedioplanis serodioi sp. nov., from the lowlands of southwestern Angola. Phylogenetic analyses using a combination of mitochondrial (16S and ND2) and nuclear (RAG-1) markers, as well as morphological data, support the recognition of the new species. For purposes of nomenclatural stability, we designate a neotype for P. benguelensis and provide motivation to correct the spelling of the specific epithet to benguelensis. The clarification of the status of P. benguelensis and the description of a new species contribute to a better understanding of the taxonomy and biogeography of the genus Pedioplanis, as well as the general biogeographic context of southwestern Angola, adding to the growing evidence in favor of the recognition of this region as a hotspot of lizard diversity and endemism. An updated key to the genus is also provided.
- Published
- 2021
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20. Intersectionality in Public Health Research: A View From the National Institutes of Health.
- Author
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Alvidrez J, Greenwood GL, Johnson TL, and Parker KL
- Subjects
- Humans, Minority Groups, Research Design, United States, Health Status Disparities, Intersectoral Collaboration, National Institutes of Health (U.S.) organization & administration, Public Health, Research organization & administration, Socioeconomic Factors
- Published
- 2021
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21. Wave-like Patterns of Plant Phenology Determine Ungulate Movement Tactics.
- Author
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Aikens EO, Mysterud A, Merkle JA, Cagnacci F, Rivrud IM, Hebblewhite M, Hurley MA, Peters W, Bergen S, De Groeve J, Dwinnell SPH, Gehr B, Heurich M, Hewison AJM, Jarnemo A, Kjellander P, Kröschel M, Licoppe A, Linnell JDC, Merrill EH, Middleton AD, Morellet N, Neufeld L, Ortega AC, Parker KL, Pedrotti L, Proffitt KM, Saïd S, Sawyer H, Scurlock BM, Signer J, Stent P, Šustr P, Szkorupa T, Monteith KL, and Kauffman MJ
- Subjects
- Animals, Geographic Information Systems, Herbivory, Animal Migration physiology, Climate Change, Deer physiology, Ecosystem, Plant Development, Plant Physiological Phenomena, Plants metabolism
- Abstract
Animals exhibit a diversity of movement tactics [1]. Tracking resources that change across space and time is predicted to be a fundamental driver of animal movement [2]. For example, some migratory ungulates (i.e., hooved mammals) closely track the progression of highly nutritious plant green-up, a phenomenon called "green-wave surfing" [3-5]. Yet general principles describing how the dynamic nature of resources determine movement tactics are lacking [6]. We tested an emerging theory that predicts surfing and the existence of migratory behavior will be favored in environments where green-up is fleeting and moves sequentially across large landscapes (i.e., wave-like green-up) [7]. Landscapes exhibiting wave-like patterns of green-up facilitated surfing and explained the existence of migratory behavior across 61 populations of four ungulate species on two continents (n = 1,696 individuals). At the species level, foraging benefits were equivalent between tactics, suggesting that each movement tactic is fine-tuned to local patterns of plant phenology. For decades, ecologists have sought to understand how animals move to select habitat, commonly defining habitat as a set of static patches [8, 9]. Our findings indicate that animal movement tactics emerge as a function of the flux of resources across space and time, underscoring the need to redefine habitat to include its dynamic attributes. As global habitats continue to be modified by anthropogenic disturbance and climate change [10], our synthesis provides a generalizable framework to understand how animal movement will be influenced by altered patterns of resource phenology., Competing Interests: Declaration of Interests The authors declare no competing interests., (Copyright © 2020 Elsevier Inc. All rights reserved.)
- Published
- 2020
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22. Corrigendum to: State-dependent foraging by caribou with different nutritional requirements.
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Denryter K, Cook RC, Cook JG, Parker KL, and Gillingham MP
- Abstract
[This corrects the article DOI: 10.1093/jmammal/gyaa003.]., (© The Author(s) 2020. Published by Oxford University Press on behalf of the American Society of Mammalogists.)
- Published
- 2020
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23. State-dependent foraging by caribou with different nutritional requirements.
- Author
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Denryter K, Cook RC, Cook JG, Parker KL, and Gillingham MP
- Abstract
Foraging by animals is hypothesized to be state-dependent, that is, varying with physiological condition of individuals. State often is defined by energy reserves, but state also can reflect differences in nutritional requirements (e.g., for reproduction, lactation, growth, etc.). Testing hypotheses about state-dependent foraging in ungulates is difficult because fine-scale data needed to evaluate these hypotheses generally are lacking. To evaluate whether foraging by caribou ( Rangifer tarandus ) was state-dependent, we compared bite and intake rates, travel rates, dietary quality, forage selection, daily foraging time, and foraging strategies of caribou with three levels of nutritional requirements (lactating adults, nonlactating adults, subadults 1-2 years old). Only daily foraging times and daily nutrient intakes differed among nutritional classes of caribou. Lactating caribou foraged longer per day than nonlactating caribou-a difference that was greatest at the highest rates of intake, but which persisted even when intake was below requirements. Further, at sites where caribou achieved high rates of intake, caribou in each nutritional class continued foraging even after satisfying daily nutritional requirements, which was consistent with a foraging strategy to maximize energy intake. Foraging time by caribou was partially state-dependent, highlighting the importance of accounting for physiological state in studies of animal behavior. Fine-scale foraging behaviors may influence larger-scale behavioral strategies, with potential implications for conservation and management., (© The Author(s) 2020. Published by Oxford University Press on behalf of American Society of Mammalogists.)
- Published
- 2020
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24. Cerebellar D1DR-expressing neurons modulate the frontal cortex during timing tasks.
- Author
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Heskje J, Heslin K, De Corte BJ, Walsh KP, Kim Y, Han S, Carlson ES, and Parker KL
- Subjects
- Animals, Male, Rats, Long-Evans, Cerebellum physiology, Conditioning, Operant physiology, Frontal Lobe physiology, Neurons physiology, Receptors, Dopamine D1 physiology, Time Factors
- Abstract
Converging lines of evidence suggest that the cerebellum plays an integral role in cognitive function through its interactions with association cortices like the medial frontal cortex (MFC). It is unknown precisely how the cerebellum influences the frontal cortex and what type of information is reciprocally relayed between these two regions. A subset of neurons in the cerebellar dentate nuclei, or the homologous lateral cerebellar nuclei (LCN) in rodents, express D1 dopamine receptors (D1DRs) and may play a role in cognitive processes. We investigated how pharmacologically blocking LCN D1DRs influences performance in an interval timing task and impacts neuronal activity in the frontal cortex. Interval timing requires executive processes such as working memory, attention, and planning and is known to rely on both the frontal cortex and cerebellum. In our interval timing task, male rats indicated their estimates of the passage of a period of several seconds by making lever presses for a water reward. We have shown that a cue-evoked burst of low-frequency activity in the MFC initiates ramping activity (i.e., monotonic increases or decreases of firing rate over time) in single MFC neurons. These patterns of activity are associated with successful interval timing performance. Here we explored how blocking right LCN D1DRs with the D1DR antagonist SCH23390 influences timing performance and neural activity in the contralateral (left) MFC. Our results indicate that blocking LCN D1DRs impaired some measures of interval timing performance. Additionally, ramping activity of MFC single units was significantly attenuated. These data provide insight into how catecholamines in the LCN may drive MFC neuronal dynamics to influence cognitive function., Competing Interests: Declaration of Competing Interest We do not have any competing interests to report., (Copyright © 2019 Elsevier Inc. All rights reserved.)
- Published
- 2020
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25. A review of the African snake-eyed skinks (Scincidae: Panaspis) from Angola, with the description of a new species.
- Author
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Ceríaco LMP, Heinicke MP, Parker KL, Marques MP, and Bauer AM
- Subjects
- Angola, Animals, Phylogeny, Lizards
- Abstract
The genus Panaspis in Angola is represented by four species, most of them part of taxonomically and nomenclaturally challenging species-complexes. We present a taxonomic revision of the group in the region and describe one new species, Panaspis mocamedensis sp. nov., endemic to the lowland areas of the Namibe province, southwestern Angola. Phylogenetic analysis using a combination of mitochondrial (16S, cytb) and nucleares (RAG1, PDC) markers, as well as morphological and meristic data support the recognition of the new species. In addition, these data support the presence of nominotypical Panaspis cabindae, P. wahlbergi and P. maculicollis in Angola. Reexamination of the Angolan population of P. breviceps was based on morphological analysis, as no molecular data from Angola is available for this species. According to our results, this population likely represents the nominotypical form, but due to its complex taxonomic and nomenclatural history and the lack of molecular data, this population needs to be reconsidered when molecular data become available. The description of a new species and revision of the Angolan Panaspis contributes to a better understanding of the true species richness of the Angolan herpetofauna, as well as to understanding the major biogeographic patterns of the region. A key to Angolan Panaspis species is also presented.
- Published
- 2020
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26. Virtual Brain Projection for Evaluating Trans-skull Beam Behavior of Transcranial Ultrasound Devices.
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Brinker ST, Preiswerk F, McDannold NJ, Parker KL, and Mariano TY
- Subjects
- Humans, Magnetic Resonance Imaging methods, Reproducibility of Results, Transducers, Brain diagnostic imaging, Brain Mapping methods, Computer Simulation, Imaging, Three-Dimensional methods, Ultrasonography, Doppler, Transcranial methods
- Abstract
Focused ultrasound single-element piezoelectric transducers constitute a promising method to deliver ultrasound to the brain in low-intensity applications, but are subject to defocusing and high attenuation because of transmission through the skull. Here, a novel virtual brain projection method is used to superimpose a magnetic resonance image of the brain in ex vivo human skulls to provide targets during trans-skull focused ultrasound single-element piezoelectric transducer pressure field mapping. Positions of the transducer, skull and hydrophone are tracked in real time using a stereoscopic navigation camera and 3-D Slicer software. Virtual targets of the left dorsolateral prefrontal cortex, left hippocampus and cerebellar vermis were chosen to illustrate the method's flexibility in evaluating focal-zone beam distortion and attenuation. The regions are of interest as non-invasive brain stimulation targets in the treatment of neuropsychiatric disorders via repeated ultrasound exposure. The technical approach can facilitate the assessment of transcranial ultrasound device operator positioning reliability, intracranial beam behavior and computational model validation., (Copyright © 2019 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.)
- Published
- 2019
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27. Cerebellar Theta Frequency Transcranial Pulsed Stimulation Increases Frontal Theta Oscillations in Patients with Schizophrenia.
- Author
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Singh A, Trapp NT, De Corte B, Cao S, Kingyon J, Boes AD, and Parker KL
- Subjects
- Adult, Female, Frontal Lobe physiopathology, Humans, Male, Middle Aged, Theta Rhythm physiology, Cerebellum physiopathology, Schizophrenia physiopathology, Schizophrenia therapy, Transcranial Direct Current Stimulation
- Abstract
Cognitive dysfunction is a pervasive and disabling aspect of schizophrenia without adequate treatments. A recognized correlate to cognitive dysfunction in schizophrenia is attenuated frontal theta oscillations. Neuromodulation to normalize these frontal rhythms represents a potential novel therapeutic strategy. Here, we evaluate whether noninvasive neuromodulation of the cerebellum in patients with schizophrenia can enhance frontal theta oscillations, with the future goal of targeting the cerebellum as a possible therapy for cognitive dysfunction in schizophrenia. We stimulated the midline cerebellum using transcranial pulsed current stimulation (tPCS), a noninvasive transcranial direct current that can be delivered in a frequency-specific manner. A single 20-min session of theta frequency stimulation was delivered in nine patients with schizophrenia (cathode on right shoulder). Delta frequency tPCS was also delivered as a control to evaluate for frequency-specific effects. EEG signals from midfrontal electrode Cz were analyzed before and after cerebellar tPCS while patients estimated the passage of 3- and 12-s intervals. Theta oscillations were significantly larger following theta frequency cerebellar tPCS in the midfrontal region, which was not seen with delta frequency stimulation. As previously reported, patients with schizophrenia showed a baseline reduction in accuracy estimating 3- and 12-s intervals relative to control subjects, which did not significantly improve following a single-session theta or delta frequency cerebellar tPCS. These preliminary results suggest that single-session theta frequency cerebellar tPCS may modulate task-related oscillatory activity in the frontal cortex in a frequency-specific manner. These preliminary findings warrant further investigation to evaluate whether multiple sessions delivered daily may have an impact on cognitive performance and have therapeutic implications for schizophrenia.
- Published
- 2019
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28. Understanding predation risk and individual variation in risk avoidance for threatened boreal caribou.
- Author
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Mumma MA, Gillingham MP, Johnson CJ, and Parker KL
- Abstract
Predation risk is a driver of species' distributions. Animals can increase risk avoidance in response to fluctuations in predation risk, but questions remain regarding individual variability and the capacity to respond to changes in spatial risk across human-altered landscapes. In northeast British Columbia, Canada, boreal caribou populations declined as roads and seismic lines have increased, which are theorized to increase gray wolf predation. Our goal was to model risk and to evaluate individual variability and the development of risk perception by examining individual risk avoidance in response to reproductive status and age. We used locations from collared caribou and wolves to identify landscape features associated with the risk of a potential wolf-caribou encounter and risk of being killed given an encounter. We built resource selection functions to estimate individual responses to risk. We used general linear regressions to evaluate individual risk and linear feature avoidance as a function of age and reproductive status (calf or no calf). Linear features increased the risk of encounter. Older caribou and caribou with calves demonstrated stronger avoidance of the risk of encounter and roads, but weaker avoidance in late summer to the risk of being killed relative to younger and calf-less individuals. Mechanisms explaining the inverse relationships between the risk of encounter and risk of being killed are uncertain, but it is conceivable that caribou learn to avoid the risk of encounter and roads. Responses by females with vulnerable calves to the risk of encounter and risk of being killed might be explained by a trade-off between these two risk types and a prioritization on the risk of encounter. Despite the capacity to alter their responses to risk, the global decline in Rangifer populations (caribou and wild reindeer) suggests these behaviors are insufficient to mitigate the impacts of anthropogenic disturbances.
- Published
- 2017
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29. Rodent Medial Frontal Control of Temporal Processing in the Dorsomedial Striatum.
- Author
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Emmons EB, De Corte BJ, Kim Y, Parker KL, Matell MS, and Narayanan NS
- Subjects
- Animals, Male, Neural Pathways physiology, Rats, Rats, Long-Evans, Action Potentials physiology, Cognition physiology, Corpus Striatum physiology, Nerve Net physiology, Prefrontal Cortex physiology, Time Perception physiology
- Abstract
Although frontostriatal circuits are critical for the temporal control of action, how time is encoded in frontostriatal circuits is unknown. We recorded from frontal and striatal neurons while rats engaged in interval timing, an elementary cognitive function that engages both areas. We report four main results. First, "ramping" activity, a monotonic change in neuronal firing rate across time, is observed throughout frontostriatal ensembles. Second, frontostriatal activity scales across multiple intervals. Third, striatal ramping neurons are correlated with activity of the medial frontal cortex. Finally, interval timing and striatal ramping activity are disrupted when the medial frontal cortex is inactivated. Our results support the view that striatal neurons integrate medial frontal activity and are consistent with drift-diffusion models of interval timing. This principle elucidates temporal processing in frontostriatal circuits and provides insight into how the medial frontal cortex exerts top-down control of cognitive processing in the striatum. SIGNIFICANCE STATEMENT The ability to guide actions in time is essential to mammalian behavior from rodents to humans. The prefrontal cortex and striatum are critically involved in temporal processing and share extensive neuronal connections, yet it remains unclear how these structures represent time. We studied these two brain areas in rodents performing interval-timing tasks and found that time-dependent "ramping" activity, a monotonic increase or decrease in neuronal activity, was a key temporal signal. Furthermore, we found that striatal ramping activity was correlated with and dependent upon medial frontal activity. These results provide insight into information-processing principles in frontostriatal circuits., (Copyright © 2017 the authors 0270-6474/17/378718-16$15.00/0.)
- Published
- 2017
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30. Delta-frequency stimulation of cerebellar projections can compensate for schizophrenia-related medial frontal dysfunction.
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Parker KL, Kim YC, Kelley RM, Nessler AJ, Chen KH, Muller-Ewald VA, Andreasen NC, and Narayanan NS
- Subjects
- Adult, Aged, Animals, Case-Control Studies, Cerebellum pathology, Cognition physiology, Disease Models, Animal, Electroencephalography methods, Female, Frontal Lobe pathology, Humans, Male, Middle Aged, Neural Pathways pathology, Neural Pathways physiopathology, Neurons pathology, Prefrontal Cortex pathology, Prefrontal Cortex physiopathology, Rats, Rats, Long-Evans, Schizophrenia pathology, Schizophrenia therapy, Thalamus physiopathology, Transcranial Direct Current Stimulation methods, Cerebellum physiopathology, Frontal Lobe physiopathology, Schizophrenia physiopathology
- Abstract
Schizophrenia involves abnormalities in the medial frontal cortex that lead to cognitive deficits. Here we investigate a novel strategy to normalize medial frontal brain activity by stimulating cerebellar projections. We used an interval timing task to study elementary cognitive processing that requires both frontal and cerebellar networks that are disrupted in patients with schizophrenia. We report three novel findings. First, patients with schizophrenia had dysfunctional delta rhythms between 1-4 Hz in the medial frontal cortex. We explored cerebellar-frontal interactions in animal models and found that both frontal and cerebellar neurons were modulated during interval timing and had delta-frequency interactions. Finally, delta-frequency optogenetic stimulation of thalamic synaptic terminals of lateral cerebellar projection neurons rescued timing performance as well as medial frontal activity in a rodent model of schizophrenia-related frontal dysfunction. These data provide insight into how the cerebellum influences medial frontal networks and the role of the cerebellum in cognitive processing.
- Published
- 2017
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31. Staged Repair of an Aortic Pseudoaneurysm Secondary to Delayed Methylmethacrylate Plate Migration.
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Parker KL, Thistlethwaite P, Suliman AS, Reid C, Tenenhaus M, El Khoury Z, and Golts EM
- Subjects
- Aneurysm, False diagnostic imaging, Aorta, Thoracic diagnostic imaging, Blood Vessel Prosthesis Implantation methods, Bone Neoplasms diagnostic imaging, Bone Neoplasms pathology, Bone Neoplasms surgery, Combined Modality Therapy, Follow-Up Studies, Foreign-Body Migration diagnostic imaging, Imaging, Three-Dimensional methods, Risk Assessment, Thoracic Wall pathology, Thoracic Wall surgery, Thoracotomy methods, Tomography, X-Ray Computed methods, Treatment Outcome, Vascular Surgical Procedures methods, Aneurysm, False surgery, Aorta, Thoracic surgery, Bone Plates adverse effects, Foreign-Body Migration surgery, Methylmethacrylate adverse effects, Thoracotomy adverse effects
- Abstract
Methylmethacrylate is a prosthetic material commonly used for the reconstruction of large chest wall defects. We present the first reported case of delayed methylmethacrylate plate migration, which resulted in an aortic pseudoaneurysm with aortopulmonary fistula. Treatment management, including staged repair combining endovascular and open approaches, is also discussed., (Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)
- Published
- 2017
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32. Corticostriatal Field Potentials Are Modulated at Delta and Theta Frequencies during Interval-Timing Task in Rodents.
- Author
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Emmons EB, Ruggiero RN, Kelley RM, Parker KL, and Narayanan NS
- Abstract
Organizing movements in time is a critical and highly conserved feature of mammalian behavior. Temporal control of action requires corticostriatal networks. We investigate these networks in rodents using a two-interval timing task while recording LFPs in medial frontal cortex (MFC) or dorsomedial striatum. Consistent with prior work, we found cue-triggered delta (1-4 Hz) and theta activity (4-8 Hz) primarily in rodent MFC. We observed delta activity across temporal intervals in MFC and dorsomedial striatum. Rewarded responses were associated with increased delta activity in MFC. Activity in theta bands in MFC and delta bands in the striatum was linked with the timing of responses. These data suggest both delta and theta activity in frontostriatal networks are modulated during interval timing and that activity in these bands may be involved in the temporal control of action.
- Published
- 2016
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33. Autoantibodies to Collagen XVII Are Present in Parkinson's Disease and Localize to Tyrosine-Hydroxylase Positive Neurons.
- Author
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Messingham KAN, Aust S, Helfenberger J, Parker KL, Schultz S, McKillip J, Narayanan NS, and Fairley JA
- Subjects
- Autoantibodies blood, Autoantigens immunology, Biomarkers blood, Case-Control Studies, Confidence Intervals, Female, Fluorescent Antibody Technique, Indirect, Humans, Male, Neurons metabolism, Neurons pathology, Non-Fibrillar Collagens immunology, Parkinson Disease blood, Parkinson Disease physiopathology, Pemphigoid, Bullous immunology, Pemphigoid, Bullous physiopathology, Reference Values, Tyrosine 3-Monooxygenase immunology, Collagen Type XVII, Autoantibodies immunology, Autoantigens metabolism, Non-Fibrillar Collagens metabolism, Parkinson Disease immunology, Tyrosine 3-Monooxygenase metabolism
- Published
- 2016
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34. Optogenetic approaches to evaluate striatal function in animal models of Parkinson disease.
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Parker KL, Kim Y, Alberico SL, Emmons EB, and Narayanan NS
- Subjects
- Animals, Humans, Nerve Net physiology, Optogenetics trends, Parkinson Disease diagnosis, Corpus Striatum physiology, Disease Models, Animal, Optogenetics methods, Parkinson Disease genetics, Parkinson Disease metabolism
- Abstract
Optogenetics refers to the ability to control cells that have been genetically modified to express light-sensitive ion channels. The introduction of optogenetic approaches has facilitated the dissection of neural circuits. Optogenetics allows for the precise stimulation and inhibition of specific sets of neurons and their projections with fine temporal specificity. These techniques are ideally suited to investigating neural circuitry underlying motor and cognitive dysfunction in animal models of human disease. Here, we focus on how optogenetics has been used over the last decade to probe striatal circuits that are involved in Parkinson disease, a neurodegenerative condition involving motor and cognitive abnormalities resulting from degeneration of midbrain dopaminergic neurons. The precise mechanisms underlying the striatal contribution to both cognitive and motor dysfunction in Parkinson disease are unknown. Although optogenetic approaches are somewhat removed from clinical use, insight from these studies can help identify novel therapeutic targets and may inspire new treatments for Parkinson disease. Elucidating how neuronal and behavioral functions are influenced and potentially rescued by optogenetic manipulation in animal models could prove to be translatable to humans. These insights can be used to guide future brain-stimulation approaches for motor and cognitive abnormalities in Parkinson disease and other neuropsychiatric diseases.
- Published
- 2016
35. Timing Tasks Synchronize Cerebellar and Frontal Ramping Activity and Theta Oscillations: Implications for Cerebellar Stimulation in Diseases of Impaired Cognition.
- Author
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Parker KL
- Abstract
Timing is a fundamental and highly conserved mammalian capability, yet the underlying neural mechanisms are widely debated. Ramping activity of single neurons that gradually increase or decrease activity to encode the passage of time has been speculated to predict a behaviorally relevant temporal event. Cue-evoked low-frequency activity has also been implicated in temporal processing. Ramping activity and low-frequency oscillations occur throughout the brain and could indicate a network-based approach to timing. Temporal processing requires cognitive mechanisms of working memory, attention, and reasoning, which are dysfunctional in neuropsychiatric disease. Therefore, timing tasks could be used to probe cognition in animals with disease phenotypes. The medial frontal cortex and cerebellum are involved in cognition. Cerebellar stimulation has been shown to influence medial frontal activity and improve cognition in schizophrenia. However, the mechanism underlying the efficacy of cerebellar stimulation is unknown. Here, we discuss how timing tasks can be used to probe cerebellar interactions with the frontal cortex and the therapeutic potential of cerebellar stimulation. The goal of this theory and hypothesis manuscript is threefold. First, we will summarize evidence indicating that in addition to motor learning, timing tasks involve cognitive processes that are present within both the cerebellum and medial frontal cortex. Second, we propose methodologies to investigate the connections between these areas in patients with Parkinson's disease, autism, and schizophrenia. Lastly, we hypothesize that cerebellar transcranial stimulation may rescue medial frontal ramping activity, theta oscillations, and timing abnormalities, thereby restoring executive function in diseases of impaired cognition. This hypothesis could inspire the use of timing tasks as biomarkers for neuronal and cognitive abnormalities in neuropsychiatric disease and promote the therapeutic potential of the cerebellum in diseases of impaired cognition.
- Published
- 2016
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36. Infusion of D1 Dopamine Receptor Agonist into Medial Frontal Cortex Disrupts Neural Correlates of Interval Timing.
- Author
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Parker KL, Ruggiero RN, and Narayanan NS
- Abstract
Medial frontal cortical (MFC) dopamine is essential for the organization of behavior in time. Our prior work indicates that blocking D1 dopamine receptors (D1DR) attenuates temporal processing and low-frequency oscillations by MFC neuronal networks. Here we investigate the effects of focal infusion of the D1DR agonist SKF82958 into MFC during interval timing. MFC D1DR agonist infusion impaired interval timing performance without changing overall firing rates of MFC neurons. MFC ramping patterns of neuronal activity that reflect temporal processing were attenuated following infusion of MFC D1DR agonist. MFC D1DR agonist infusion also altered MFC field potentials by enhancing delta activity between 1 and 4 Hz and attenuating alpha activity between 8 and 15 Hz. These data support the idea that the influence of D1-dopamine signals on frontal neuronal activity adheres to a U-shaped curve, and that cognition requires optimal levels of dopamine in frontal cortex.
- Published
- 2015
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37. Medial frontal ∼4-Hz activity in humans and rodents is attenuated in PD patients and in rodents with cortical dopamine depletion.
- Author
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Parker KL, Chen KH, Kingyon JR, Cavanagh JF, and Narayanan NS
- Subjects
- Animals, Antiparkinson Agents therapeutic use, Conditioning, Operant physiology, Electroencephalography, Female, Humans, Levodopa therapeutic use, Male, Middle Aged, Neurons physiology, Neuropsychological Tests, Oxidopamine, Parkinson Disease drug therapy, Rats, Long-Evans, Delta Rhythm physiology, Dopamine metabolism, Frontal Lobe physiopathology, Parkinson Disease physiopathology, Theta Rhythm physiology, Time Perception physiology
- Abstract
The temporal control of action is a highly conserved and critical mammalian behavior. Here, we investigate the neuronal basis of this process using an interval timing task. In rats and humans, instructional timing cues triggered spectral power across delta and theta bands (2-6 Hz) from the medial frontal cortex (MFC). Humans and rodents with dysfunctional dopamine have impaired interval timing, and we found that both humans with Parkinson's disease (PD) and rodents with local MFC dopamine depletion had attenuated delta and theta activity. In rodents, spectral activity in this range could functionally couple single MFC neurons involved in temporal processing. Without MFC dopamine, these neurons had less functional coupling with delta/theta activity and less temporal processing. Finally, in humans this 2- to 6-Hz activity was correlated with executive function in matched controls but not in PD patients. Collectively, these findings suggest that cue-evoked low-frequency rhythms could be a clinically important biomarker of PD that is translatable to rodent models, facilitating mechanistic inquiry and the development of neurophysiological biomarkers for human disease., (Copyright © 2015 the American Physiological Society.)
- Published
- 2015
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38. Concept Analysis: Health-Promoting Behaviors Related to Human Papilloma Virus (HPV) Infection.
- Author
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McCutcheon T, Schaar G, and Parker KL
- Subjects
- Concept Formation, Humans, Power, Psychological, Health Promotion methods, Nurses trends, Papillomaviridae
- Abstract
Problem: The concept of health-promoting behaviors incorporates ideas presented in the Ottawa Charter of Public Health and the nursing-based Health Promotion Model. Despite the fact that the concept of health-promoting behaviors has a nursing influence, literature suggests nursing has inadequately developed and used this concept within nursing practice. A further review of literature regarding health promotion behaviors and the human papilloma virus suggest a distinct gap in nursing literature., Method: This article presents a concept analysis of health-promoting behaviors related to the human papilloma virus in order to encourage the application of the concept into nursing practice, promote continued nursing research regarding this concept, and further expand the application of health-promoting behaviors to other situations and populations within the nursing discipline., Conclusion: Attributes of health-promoting behaviors are presented and include empowerment, participation, community, and a positive concept of health. Antecedents, consequences, and empirical referents are also presented, as are model, borderline, and contrary cases to help clarify the concept. Recommendations for human papilloma virus health-promoting behaviors within the nursing practice are also provided., (© 2014 Wiley Periodicals, Inc.)
- Published
- 2015
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39. D1-dependent 4 Hz oscillations and ramping activity in rodent medial frontal cortex during interval timing.
- Author
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Parker KL, Chen KH, Kingyon JR, Cavanagh JF, and Narayanan NS
- Subjects
- Animals, Brain Mapping methods, Conditioning, Operant physiology, Male, Neurons physiology, Rats, Rats, Long-Evans, Biological Clocks physiology, Frontal Lobe physiology, Reaction Time physiology, Receptors, Dopamine D1 physiology
- Abstract
Organizing behavior in time is a fundamental process that is highly conserved across species. Here we study the neural basis of timing processes. First, we found that rodents had a burst of stimulus-triggered 4 Hz oscillations in the medial frontal cortex (MFC) during interval timing tasks. Second, rodents with focally disrupted MFC D1 dopamine receptor (D1DR) signaling had impaired interval timing performance and weaker stimulus-triggered oscillations. Prior work has demonstrated that MFC neurons ramp during interval timing, suggesting that they underlie temporal integration. We found that MFC D1DR blockade strongly attenuated ramping activity of MFC neurons that correlated with behavior. These macro- and micro-level phenomena were linked, as we observed that MFC neurons with strong ramping activity tended to be coherent with stimulus-triggered 4 Hz oscillations, and this relationship was diminished with MFC D1DR blockade. These data provide evidence demonstrating how D1DR signaling controls the temporal organization of mammalian behavior., (Copyright © 2014 the authors 0270-6474/14/3416774-10$15.00/0.)
- Published
- 2014
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40. The therapeutic potential of the cerebellum in schizophrenia.
- Author
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Parker KL, Narayanan NS, and Andreasen NC
- Abstract
The cognitive role of the cerebellum is critically tied to its distributed connections throughout the brain. Accumulating evidence from anatomical, structural and functional imaging, and lesion studies advocate a cognitive network involving indirect connections between the cerebellum and non-motor areas in the prefrontal cortex. Cerebellar stimulation dynamically influences activity in several regions of the frontal cortex and effectively improves cognition in schizophrenia. In this manuscript, we summarize current literature on the cingulocerebellar circuit and we introduce a method to interrogate this circuit combining opotogenetics, neuropharmacology, and electrophysiology in awake-behaving animals while minimizing incidental stimulation of neighboring cerebellar nuclei. We propose the novel hypothesis that optogenetic cerebellar stimulation can restore aberrant frontal activity and rescue impaired cognition in schizophrenia. We focus on how a known cognitive region in the frontal cortex, the anterior cingulate, is influenced by the cerebellum. This circuit is of particular interest because it has been confirmed using tracing studies, neuroimaging reveals its role in cognitive tasks, it is conserved from rodents to humans, and diseases such as schizophrenia and autism appear in its aberrancy. Novel tract tracing results presented here provide support for how these two areas communicate. The primary pathway involves a disynaptic connection between the cerebellar dentate nuclei (DN) and the anterior cingulate cortex. Secondarily, the pathway from cerebellar fastigial nuclei (FN) to the ventral tegmental area, which supplies dopamine to the prefrontal cortex, may play a role as schizophrenia characteristically involves dopamine deficiencies. We hope that the hypothesis described here will inspire new therapeutic strategies targeting currently untreatable cognitive impairments in schizophrenia.
- Published
- 2014
- Full Text
- View/download PDF
41. Eyeblink conditioning in unmedicated schizophrenia patients: a positron emission tomography study.
- Author
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Parker KL, Andreasen NC, Liu D, Freeman JH, and O'Leary DS
- Subjects
- Adolescent, Adult, Cerebellum blood supply, Cerebellum physiopathology, Cerebrovascular Circulation, Cognition, Extinction, Psychological, Female, Frontal Lobe blood supply, Frontal Lobe physiopathology, Humans, Male, Middle Aged, Positron-Emission Tomography, Thalamus blood supply, Thalamus physiopathology, Young Adult, Blinking physiology, Conditioning, Classical physiology, Schizophrenia physiopathology
- Abstract
Previous studies suggest that patients with schizophrenia exhibit dysfunctions in a widely distributed circuit-the cortico-cerebellar-thalamic-cortical circuit, or CCTCC-and that this may explain the multiple cognitive deficits observed in the disorder. This study uses positron emission tomography (PET) with O(15) H₂O to measure regional cerebral blood flow (rCBF) in response to a classic test of cerebellar function, the associative learning that occurs during eyeblink conditioning, in a sample of 20 unmedicated schizophrenia patients and 20 closely matched healthy controls. The PET paradigm examined three phases of acquisition and extinction (early, middle and late). The patients displayed impaired behavioral performance during both acquisition and extinction. The imaging data indicate that, compared to the control subjects, the patients displayed decreases in rCBF in all three components of the CCTCC during both acquisition and extinction. Specifically, patients had less rCBF in the middle and medial frontal lobes, anterior cerebellar lobules I/V and VI, as well as the thalamus during acquisition and although similar areas were found in the frontal lobe, ipsilateral cerebellar lobule IX showed consistently less activity in patients during extinction. Thus this study provides additional support for the hypothesis that patients with schizophrenia have a cognitive dysmetria--an inability to smoothly coordinate many different types of mental activity--that affects even a very basic cognitive task that taps into associative learning., (© 2013 Elsevier Ireland Ltd. All rights reserved.)
- Published
- 2013
- Full Text
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42. The endoscopic approach to a fourth branchial pouch sinus presenting in an adult.
- Author
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Parker KL, Clary MS, and Courey MS
- Subjects
- Female, Humans, Otorhinolaryngologic Surgical Procedures methods, Young Adult, Branchial Region abnormalities, Branchial Region surgery, Endoscopy
- Abstract
Fourth branchial complex anomalies are rare and typically present in neonates or adolescents. Surgical management via open excision is the traditional approach to prevent recurrence. However, endoscopic sinus cauterization has recently been reported as a less invasive alternative. The current case report represents the first published account of a fourth branchial pouch presenting in an adult patient effectively managed through endoscopic excision. We compare this method to open excision and endoscopic ablative techniques., (Copyright © 2013 The American Laryngological, Rhinological and Otological Society, Inc.)
- Published
- 2013
- Full Text
- View/download PDF
43. Executive dysfunction in Parkinson's disease and timing deficits.
- Author
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Parker KL, Lamichhane D, Caetano MS, and Narayanan NS
- Abstract
Patients with Parkinson's disease (PD) have deficits in perceptual timing, or the perception and estimation of time. PD patients can also have cognitive symptoms, including deficits in executive functions such as working memory, planning, and visuospatial attention. Here, we discuss how PD-related cognitive symptoms contribute to timing deficits. Timing is influenced by signaling of the neurotransmitter dopamine in the striatum. Timing also involves the frontal cortex, which is dysfunctional in PD. Frontal cortex impairments in PD may influence memory subsystems as well as decision processes during timing tasks. These data suggest that timing may be a type of executive function. As such, timing can be used to study the neural circuitry of cognitive symptoms of PD as they can be studied in animal models. Performance of timing tasks also maybe a useful clinical biomarker of frontal as well as striatal dysfunction in PD.
- Published
- 2013
- Full Text
- View/download PDF
44. Bcl-2 overexpression ameliorates immune complex-mediated arthritis by altering FcγRIIb expression and monocyte homeostasis.
- Author
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Lawlor KE, van Nieuwenhuijze A, Parker KL, Drake SF, Campbell IK, Smith SD, Vince JE, Strasser A, and Wicks IP
- Subjects
- Animals, Antibodies blood, Antibodies immunology, Antigen-Antibody Complex biosynthesis, Apoptosis genetics, Apoptosis immunology, Arthritis, Experimental immunology, Arthritis, Experimental pathology, Arthritis, Rheumatoid chemically induced, Arthritis, Rheumatoid immunology, Arthritis, Rheumatoid pathology, B-Lymphocytes immunology, B-Lymphocytes metabolism, B-Lymphocytes pathology, Cell Differentiation immunology, Collagen Type II, Homeostasis, Humans, Interleukin-1, Mice, Monocytes metabolism, Monocytes pathology, Proto-Oncogene Proteins c-bcl-2 immunology, Receptors, IgG immunology, Serum Albumin, Bovine, Signal Transduction, T-Lymphocytes immunology, T-Lymphocytes metabolism, T-Lymphocytes pathology, Antigen-Antibody Complex immunology, Arthritis, Experimental genetics, Arthritis, Rheumatoid genetics, Gene Expression, Monocytes immunology, Proto-Oncogene Proteins c-bcl-2 genetics, Receptors, IgG genetics
- Abstract
RA is a chronic autoimmune disease characterized by accumulation of inflammatory cells within synovial joints. RA is associated with a failure of apoptosis of infiltrating leukocytes, thought to be a result of overexpression of prosurvival Bcl-2 proteins. Overexpression of Bcl-2 in hematopoietic cells can result in spontaneous autoimmunity. We therefore hypothesized that increased Bcl-2 in the hematopoietic compartment would reduce apoptosis and thereby, exacerbate inflammatory arthritis. Paradoxically, we found that overexpression of Bcl-2 in mice (vav-bcl-2) markedly reduced pathology in antibody-dependent models of RA (CIA and K/BxN serum transfer arthritis). No such protection was observed in a model of CD4(+) T cell-dependent, B cell-independent arthritis (mBSA/IL-1-induced arthritis). In CIA, vav-bcl-2 Tg mice had lower antibody production to CII, which might explain reduced disease. However, Bcl-2 overexpression also reduced passive K/BxN serum transfer arthritis. Overexpression of Bcl-2 caused a monocytosis, with preferential expansion of Ly6C(lo) monocytes and increased expression of the inhibitory receptor for IgG, FcγRIIb, on leukocytes. Skewing of the myeloid cell population, increases in FcγRIIb, and reduced arthritis were independent of the hypergammaglobulinemia found in vav-bcl-2 Tg mice. These data reveal selective effects of the Bcl-2-regulated apoptotic pathway on monocyte differentiation and the expression of FcRs critical for regulation of antibody/immune complex-mediated disease.
- Published
- 2013
- Full Text
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45. Hand-rearing wild caribou calves for studies of nutritional ecology.
- Author
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Parker KL and Barboza PS
- Subjects
- Aging, Alaska, Animals, Animal Feed analysis, Animal Husbandry methods, Animal Nutritional Physiological Phenomena, Animals, Newborn, Reindeer physiology
- Abstract
Caribou (Rangifer tarandus) are considered difficult to hand-rear in captivity because they are sensitive to the composition and volume of formulated milks. We used a strict feeding schedule and a commercial milk formula designed specifically for caribou to bottle-feed neonates captured from five wild caribou herds in Alaska. Under a feeding protocol adjusted for age and mass, the growth rates and body mass of 26 hand-reared caribou calves to weaning were similar to those of three maternally nursed caribou. This protocol allows caretakers to hand-rear caribou that are as representative as possible of maternally raised neonates., (© 2012 Wiley Periodicals, Inc.)
- Published
- 2013
- Full Text
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46. The road less traveled.
- Author
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Shaffer DP, Parker KL, Kantz BA, and Havens DS
- Subjects
- Hospitals, Rural, Humans, Nursing Administration Research, Nursing Evaluation Research, Nursing Methodology Research, Pennsylvania, Accreditation, Nursing Care standards, Nursing Staff, Hospital organization & administration
- Published
- 2013
- Full Text
- View/download PDF
47. Prefrontal D1 dopamine signaling is necessary for temporal expectation during reaction time performance.
- Author
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Parker KL, Alberico SL, Miller AD, and Narayanan NS
- Subjects
- Animals, Rats, Rats, Long-Evans, Anticipation, Psychological physiology, Dopamine metabolism, Reaction Time physiology, Receptors, Dopamine D1 metabolism, Signal Transduction physiology, Ventral Tegmental Area metabolism
- Abstract
Responses during a simple reaction time task are influenced by temporal expectation, or the ability to anticipate when a stimulus occurs in time. Here, we test the hypothesis that prefrontal D1 dopamine signaling is necessary for temporal expectation during simple reaction time task performance. We depleted dopamine projections to the medial prefrontal circuits by infusing 6-hydroxidopamine, a selective neurotoxin, into the ventral tegmental area (VTA) of rats, and studied their performance on a simple reaction time task with two delays. VTA dopamine depletion did not change movements or learning of the reaction time task. However, VTA dopamine-depleted animals did not develop delay-dependent speeding of reaction times, suggesting that mesocortical dopamine signaling is required for temporal expectation. Next, we manipulated dopamine signaling within the medial prefrontal cortex using local pharmacology. We found that SCH23390, a D1-type dopamine receptor antagonist, specifically attenuated delay-dependent speeding, while sulpiride, a D2-type receptor antagonist, did not. These data suggest that prefrontal D1 dopamine signaling is necessary for temporal expectation during performance of a simple reaction time task. Our findings provide insight into temporal processing of the prefrontal cortex, and how dopamine signaling influences prefrontal circuits that guide goal-directed behavior., (Copyright © 2013 IBRO. Published by Elsevier Ltd. All rights reserved.)
- Published
- 2013
- Full Text
- View/download PDF
48. Eyeblink conditioning in healthy adults: a positron emission tomography study.
- Author
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Parker KL, Andreasen NC, Liu D, Freeman JH, Ponto LL, and O'Leary DS
- Subjects
- Adult, Cerebellum physiology, Cerebrovascular Circulation physiology, Female, Frontal Lobe physiology, Gyrus Cinguli physiology, Humans, Male, Positron-Emission Tomography, Blinking physiology, Conditioning, Eyelid physiology
- Abstract
Eyeblink conditioning is a paradigm commonly used to investigate the neural mechanisms underlying motor learning. It involves the paired presentation of a tone-conditioning stimulus which precedes and co-terminates with an airpuff unconditioned stimulus. Following repeated paired presentations a conditioned eyeblink develops which precedes the airpuff. This type of learning has been intensively studied and the cerebellum is known to be essential in both humans and animals. The study presented here was designed to investigate the role of the cerebellum during eyeblink conditioning in humans using positron emission tomography (PET). The sample includes 20 subjects (10 male and 10 female) with an average age of 29.2 years. PET imaging was used to measure regional cerebral blood flow (rCBF) changes occurring during the first, second, and third blocks of conditioning. In addition, stimuli-specific rCBF to unpaired tones and airpuffs ("pseudoconditioning") was used as a baseline level that was subtracted from each block. Conditioning was performed using three, 15-trial blocks of classical eyeblink conditioning with the last five trials in each block imaged. As expected, subjects quickly acquired conditioned responses. A comparison between the conditioning tasks and the baseline task revealed that during learning there was activation of the cerebellum and recruitment of several higher cortical regions. Specifically, large peaks were noted in cerebellar lobules IV/V, the frontal lobes, and cingulate gyri.
- Published
- 2012
- Full Text
- View/download PDF
49. Application of multiple shrinkage methods to genomic predictions.
- Author
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Maltecca C, Parker KL, and Cassady JP
- Subjects
- Animals, Bayes Theorem, Cattle, Cluster Analysis, Female, Male, Quantitative Trait Loci, Computer Simulation, Genomics, Models, Genetic
- Abstract
New challenges have arisen with the development of large marker panels for livestock species. Models easily become overparameterized when all available markers are included. Solutions have led to the development of shrinkage or regularization techniques. The objective of this study was the application and comparison of Bayesian LASSO (B-L), thick-tailed (Student-t), and semiparametric multiple shrinkage methods. The B-L and Student-t methods were also each analyzed within a single shrinkage and a multiple shrinkage framework. Simulated and real data were used to evaluate each method's performance. Real data consisted of SNP genotypes of 4,069 Holstein sires. Traits included in analysis of real data were milk, fat, protein yield, and somatic cell score. The performance of each model was compared based on correlations between true and predicted genomic predicted transmitting abilities. Model performance was also compared with the performance of routinely used methods such as Bayes-A and GBLUP through cross-validation techniques. When using simulated data regardless of shrinkage framework, shrinkage models outperformed genomic BLUP (GBLUP). The average advantage of shrinkage models ranged from 1% to approximately 8% depending on the prior specification. When analyzing real data, shrinkage models slightly outperformed GBLUP for most traits. Shrinkage models were better able to model traits for which 1 or more SNP of large effect have been identified. Overall, results suggested a relatively small advantage in multiple shrinkage models. Multiple shrinkage methods could represent a useful alternative to current methods of prediction; however, their performance in a variety of scenarios needs to be investigated further.
- Published
- 2012
- Full Text
- View/download PDF
50. Steroidogenic factor 1 directs programs regulating diet-induced thermogenesis and leptin action in the ventral medial hypothalamic nucleus.
- Author
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Kim KW, Zhao L, Donato J Jr, Kohno D, Xu Y, Elias CF, Lee C, Parker KL, and Elmquist JK
- Subjects
- Animals, Homeostasis, Mice, Mice, Knockout, Steroidogenic Factor 1 genetics, Dietary Fats administration & dosage, Energy Intake, Leptin physiology, Steroidogenic Factor 1 physiology, Thermogenesis, Ventromedial Hypothalamic Nucleus physiology
- Abstract
The transcription factor steroidogenic factor 1 (SF-1) is exclusively expressed in the brain in the ventral medial hypothalamic nucleus (VMH) and is required for the development of this nucleus. However, the physiological importance of transcriptional programs regulated by SF-1 in the VMH is not well defined. To delineate the functional significance of SF-1 itself in the brain, we generated pre- and postnatal VMH-specific SF-1 KO mice. Both models of VMH-specific SF-1 KO were susceptible to high fat diet-induced obesity and displayed impaired thermogenesis after acute exposure to high fat diet. Furthermore, VMH-specific SF-1 KO mice showed significantly decreased LepR expression specifically in the VMH, leading to leptin resistance. Collectively, these results indicate that SF-1 directs transcriptional programs in the hypothalamus relevant to coordinated control of energy homeostasis, especially after excess caloric intake.
- Published
- 2011
- Full Text
- View/download PDF
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