Search

BACKGROUND: The 'default network' consists of a number of brain regions that exhibit correlated low-frequency activity at rest and that have been suggested to be involved in the processing of self-relevant stimuli. Activity in many of these areas has also been shown to be altered in individuals with posttraumatic stress disorder (PTSD). We hypothesized that the posterior cingulate cortex (PCC)/precuneus, part of the default network, would exhibit altered connectivity at rest with other areas of the default network and regions associated with PTSD. METHODS: Seventeen medicated and unmedicated female patients with chronic posttraumatic stress disorder (PTSD) related to early-life trauma and 15 healthy female controls underwent a 5.5-minute functional magnetic resonance imaging scan with their eyes closed. We assessed areas of the brain whose activity positively and negatively correlated with that of the PCC/precuneus in both groups. RESULTS: At rest, spontaneous low-frequency activity in the PCC/precuneus was more strongly correlated with activity in other areas of the default network in healthy controls than in patients with PTSD. Direct comparison of the 2 groups showed that PCC/ precuneus connectivity was also greater in healthy controls than in patients with PTSD in a number of areas previously associated with PTSD, including the right amygdala and the hippocampus/parahippocampal gyrus. LIMITATIONS: Because our PTSD sample comprised only women with chronic early-life trauma exposure, our results may not be generalizeable to male patients, to a population with single trauma exposure or to those who were adults when the trauma occurred. In addition, our sample included patients taking medication and it is not yet clear how altered connectivity is affected by medication. CONCLUSION: Spontaneous activity in the default network during rest, as measured using PCC correlations, is altered in patients with PTSD. The potential effects of psychotropic medications on default network connectivity in the present sample remain unknown. In this patient population, the observed alterations may be associated with the disturbances in self-referential processing often observed in patients with chronic PTSD related to early-life trauma. [ABSTRACT FROM AUTHOR]

There is a general expectation that urban populations will be fragmented and the movement of individuals will be restricted leading to low effective population sizes, low genetic diversity, higher inbreeding, and higher differentiation than populations living in more continuous habitat. In this study, we compare the genetic diversity and differentiation of Texas horned lizards that are found in four small towns (Kenedy, Karnes City, Rockdale, and Smithville) in Texas and at Tinker Air Force Base, Oklahoma to populations that occur in 16 natural areas and to an introduced population in South Carolina. We also present more detailed spatial genetic data and home range data for several of the towns. Texas horned lizards ( Phrynosoma cornutum ) living in small towns have lower genetic diversity, higher differentiation, and smaller effective population sizes than populations located in more natural areas. There was evidence for human-mediated movement of lizards into town; however, it has not been enough to counteract the effects of drift. Home range size is smaller in town than in more natural areas. Genetic patterns suggest dispersal occurs over short distances and is inhibited across areas with a high percent of impervious surface and major roads. These data suggest that effective planning to maintain suitable habitat and corridors to facilitate movement is critical to maintaining small terrestrial species like the Texas horned lizard and must be integrated into the early stages of urban development., Competing Interests: The authors declare no conflicts of interest., (© 2024 The Author(s). Ecology and Evolution published by John Wiley & Sons Ltd.)

Context: Total pancreatectomy (TP) with islet cell autotransplantation (IAT) can reduce or prevent diabetes by preserving beta cell function and is normally performed with on-site isolation laboratory facilities., Objective: We examined factors associated with islet yield and metabolic outcomes in patients with chronic pancreatitis undergoing TP-IAT. We report our experience of TP-IAT with an off-site islet isolation laboratory., Patients and Methods: Data (August 2008 to February 2014) were obtained from a TP-IAT database which included information from medical records, clinic visits, questionnaires, and follow-up telephone calls. Each patient was assessed with pre- and postoperative 5-hour mixed-meal tolerance tests for metabolic measurements and with serial glycosylated hemoglobin (HbA1c) determinations., Results: Thirty-six patients with a mean age of 38 years (range, 16-72 y) underwent TP-IAT for different etiologies. At a median follow-up time of 28 months (range, 3-66 mo), 12 patients were insulin independent and 24 patients were on at least one insulin injection a day. Postoperatively, C-peptide levels ≥0.3 ng/mL were present in 23/33 (70%) of the patients, with a median fasting C-peptide value of 0.8 ng/mL (range, <0.2-1.5 ng/mL). Those who were insulin independent were more likely to be female (P = .012), have normal morphology on pre-operative pancreatic imaging (P = .011), and have significantly higher median islet yield (6845 islet equivalent numbers [IEQ]/kg, n = 12 vs 3333 IEQ/kg, n = 24; P < .001)., Conclusions: IAT after TP performed in our facility with an off-site islet isolation laboratory shows islet yield and rates of insulin independence that are comparable to other large centers with on-site laboratories.

Emotion theory emphasizes the distinction between social vs non-social emotional-processing (E-P) although few functional neuroimaging studies have examined whether the neural systems that mediate social vs non-social E-P are similar or distinct. The present fMRI study of script-driven imagery in 20 women demonstrates that social E-P, independent of valence, more strongly recruits brain regions involved in social- and self-referential processing, specifically the dorsomedial prefrontal cortex, posterior cingulate/precuneus, bilateral temporal poles, bilateral temporoparietal junction and right amygdala. Functional response within brain regions involved in E-P was also significantly more pronounced during negatively relative to positively valenced E-P. Finally, the effect for social E-P was increased for positive relative to negative stimuli in many of these same regions. Future research directions for social and affective neuroscience are discussed.

Although multiple regions of the cerebral cortex have been implicated in swallowing, the functional contributions of each brain area remain unclear. The present study sought to clarify the roles of these cortical foci in swallowing by comparing brain activation associated with voluntary saliva swallowing and voluntary tongue elevation. Fourteen healthy right-handed subjects were examined with single-event-related functional magnetic resonance imaging (fMRI) while laryngeal movements associated with swallowing and tongue movement were simultaneously recorded. Both swallowing and tongue elevation activated 1) the left lateral pericentral and anterior parietal cortex, and 2) the anterior cingulate cortex (ACC) and adjacent supplementary motor area (SMA), suggesting that these brain regions mediate processes shared by swallowing and tongue movement. Tongue elevation activated a larger total volume of cortex than swallowing, with significantly greater activation within the ACC, SMA, right precentral and postcentral gyri, premotor cortex, right putamen, and thalamus. Although a contrast analysis failed to identify activation foci specific to swallowing, superimposed activation maps suggested that the most lateral extent of the left pericentral and anterior parietal cortex, rostral ACC, precuneus, and right parietal operculum/insula were preferentially activated by swallowing. This finding suggests that these brain areas may mediate processes specific to swallowing. Approximately 60% of the subjects showed a strong functional lateralization of the postcentral gyrus toward the left hemisphere for swallowing, whereas 40% showed a similar activation bias for the tongue elevation task. This finding supports the view that the oral sensorimotor cortices within the left and right hemispheres are functionally nonequivalent.

It is important for primary care physicians to take fecal incontinence seriously and not dismiss it as a normal part of aging. Elderly patients may be reluctant to admit fecal incontinence, so clinicians need to ask about it. Two of the most common causes are fecal impaction (especially in nursing home patients) and rectosphincter dysfunction in people with diabetes.