32 results on '"Kaping D"'
Search Results
2. Orientation Congruency Effects for Familiar Objects: Coordinate Transformations in Object Recognition
- Author
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Graf, M., Kaping, D., and Bülthoff, H. H.
- Published
- 2005
3. Attentional selection can be predicted by reinforcement learning of task-relevant stimulus features weighted by value-independent stickiness
- Author
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Universitat Politècnica de València. Instituto de Investigación para la Gestión Integral de Zonas Costeras - Institut d'Investigació per a la Gestió Integral de Zones Costaneres, Canadian Institutes of Health Research, Ontario Ministry of Economic Development and Innovation, Natural Sciences and Engineering Research Council of Canada, Balcarras, M., Ardid-Ramírez, Joan Salvador, Kaping, D., Everling, S., Womelsdorf, T., Universitat Politècnica de València. Instituto de Investigación para la Gestión Integral de Zonas Costeras - Institut d'Investigació per a la Gestió Integral de Zones Costaneres, Canadian Institutes of Health Research, Ontario Ministry of Economic Development and Innovation, Natural Sciences and Engineering Research Council of Canada, Balcarras, M., Ardid-Ramírez, Joan Salvador, Kaping, D., Everling, S., and Womelsdorf, T.
- Abstract
[EN] Attention includes processes that evaluate stimuli relevance, select the most relevant stimulus against less relevant stimuli, and bias choice behavior toward the selected information. It is not clear how these processes interact. Here, we captured these processes in a reinforcement learning framework applied to a feature-based attention task that required macaques to learn and update the value of stimulus features while ignoring nonrelevant sensory features, locations, and action plans. We found that value-based reinforcement learning mechanisms could account for feature-based attentional selection and choice behavior but required a value-independent stickiness selection process to explain selection errors while at asymptotic behavior. By comparing different reinforcement learning schemes, we found that trial-by-trial selections were best predicted by a model that only represents expected values for the task-relevant feature dimension, with nonrelevant stimulus features and action plans having only a marginal influence on covert selections. These findings show that attentional control subprocesses can be described by (1) the reinforcement learning of feature values within a restricted feature space that excludes irrelevant feature dimensions, (2) a stochastic selection process on feature-specific value representations, and (3) value-independent stickiness toward previous feature selections akin to perseveration in the motor domain. We speculate that these three mechanisms are implemented by distinct but interacting brain circuits and that the proposed formal account of feature-based stimulus selection will be important to understand how attentional subprocesses are implemented in primate brain networks.
- Published
- 2016
4. Anterior cingulate cortex cells identify process-specific errors of attentional control prior to transient prefrontal-cingulate inhibition
- Author
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Universitat Politècnica de València. Instituto de Investigación para la Gestión Integral de Zonas Costeras - Institut d'Investigació per a la Gestió Integral de Zones Costaneres, Canadian Institutes of Health Research, Ontario Ministry of Economic Development and Innovation, Natural Sciences and Engineering Research Council of Canada, Deutsche Akademie der Naturforscher Leopoldina - Nationale Akademie der Wissenschaften, Shen, C., Ardid-Ramírez, Joan Salvador, Kaping, D., Westendorff, S., Everling, S., Womelsdorf, T., Universitat Politècnica de València. Instituto de Investigación para la Gestión Integral de Zonas Costeras - Institut d'Investigació per a la Gestió Integral de Zones Costaneres, Canadian Institutes of Health Research, Ontario Ministry of Economic Development and Innovation, Natural Sciences and Engineering Research Council of Canada, Deutsche Akademie der Naturforscher Leopoldina - Nationale Akademie der Wissenschaften, Shen, C., Ardid-Ramírez, Joan Salvador, Kaping, D., Westendorff, S., Everling, S., and Womelsdorf, T.
- Abstract
[EN] Errors indicate the need to adjust attention for improved future performance. Detecting errors is thus a fundamental step to adjust and control attention. These functions have been associated with the dorsal anterior cingulate cortex (dACC), predicting that dACC cells should track the specific processing states giving rise to errors in order to identify which processing aspects need readjustment. Here, we tested this prediction by recording cells in the dACC and lateral prefrontal cortex (latPFC) of macaques performing an attention task that dissociated 3 processing stages. We found that, across prefrontal subareas, the dACC contained the largest cell populations encoding errors indicating (1) failures of inhibitory control of the attentional focus, (2) failures to prevent bottom-up distraction, and (3) lapses when implementing a choice. Error-locked firing in the dACC showed the earliest latencies across the PFC, emerged earlier than reward omission signals, and involved a significant proportion of putative inhibitory interneurons. Moreover, early onset error-locked response enhancement in the dACC was followed by transient prefrontal-cingulate inhibition, possibly reflecting active disengagement from task processing. These results suggest a functional specialization of the dACC to track and identify the actual processes that give rise to erroneous task outcomes, emphasizing its role to control attentional performance.
- Published
- 2015
5. Mapping of functionally characterized cell classes onto canonical circuit operations in primate prefrontal cortex
- Author
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Universitat Politècnica de València. Instituto de Investigación para la Gestión Integral de Zonas Costeras - Institut d'Investigació per a la Gestió Integral de Zones Costaneres, Canadian Institutes of Health Research, Ontario Ministry of Economic Development and Innovation, Natural Sciences and Engineering Research Council of Canada, Ardid-Ramírez, Joan Salvador, Vinck, M., Kaping, D., Marquez, S., Everling, S., Womelsdorf, T., Universitat Politècnica de València. Instituto de Investigación para la Gestión Integral de Zonas Costeras - Institut d'Investigació per a la Gestió Integral de Zones Costaneres, Canadian Institutes of Health Research, Ontario Ministry of Economic Development and Innovation, Natural Sciences and Engineering Research Council of Canada, Ardid-Ramírez, Joan Salvador, Vinck, M., Kaping, D., Marquez, S., Everling, S., and Womelsdorf, T.
- Abstract
[EN] Microcircuits are composed of multiple cell classes that likely serve unique circuit operations. But how cell classes map onto circuit functions is largely unknown, particularly for primate prefrontal cortex during actual goal-directed behavior. One difficulty in this quest is to reliably distinguish cell classes in extracellular recordings of action potentials. Here we surmount this issue and report that spike shape and neural firing variability provide reliable markers to segregate seven functional classes of prefrontal cells in macaques engaged in an attention task. We delineate an unbiased clustering protocol that identifies four broad spiking (BS) putative pyramidal cell classes and three narrow spiking (NS) putative inhibitory cell classes dissociated by how sparse, bursty, or regular they fire. We speculate that these functional classes map onto canonical circuit functions. First, two BS classes show sparse, bursty firing, and phase synchronize their spiking to 3-7 Hz (theta) and 12-20 Hz (beta) frequency bands of the local field potential (LFP). These properties make cells flexibly responsive to network activation at varying frequencies. Second, one NS and two BS cell classes show regular firing and higher rate with only marginal synchronization preference. These properties are akin to setting tonically the excitation and inhibition balance. Finally, two NS classes fired irregularly and synchronized to either theta or beta LFP fluctuations, tuning them potentially to frequency-specific subnetworks. These results suggest that a limited set of functional cell classes emerges in macaque prefrontal cortex (PFC) during attentional engagement to not only represent information, but to subserve basic circuit operations.
- Published
- 2015
6. Sharp Wave Ripples during Visual Exploration in the Primate Hippocampus
- Author
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Leonard, T. K., primary, Mikkila, J. M., additional, Eskandar, E. N., additional, Gerrard, J. L., additional, Kaping, D., additional, Patel, S. R., additional, Womelsdorf, T., additional, and Hoffman, K. L., additional
- Published
- 2015
- Full Text
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7. Mapping of Functionally Characterized Cell Classes onto Canonical Circuit Operations in Primate Prefrontal Cortex
- Author
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Ardid, S., primary, Vinck, M., additional, Kaping, D., additional, Marquez, S., additional, Everling, S., additional, and Womelsdorf, T., additional
- Published
- 2015
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8. Face distortion aftereffect activates motion and face sensitive areas: an fMRI study
- Author
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Kaping, D., primary, Morawetz, C., additional, Baudewig, J., additional, Treue, S., additional, Webster, M. A., additional, and Dechent, P., additional
- Published
- 2010
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9. Effect of adaptation suggests role of low-level processes in rapid scene categorization
- Author
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Kaping, D., primary, Tzvetanov, T., additional, and Treue, S., additional
- Published
- 2010
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10. Adapting to a new visual environment: A field study of face perception
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Kaping, D., primary, Mizokami, Y., additional, and Webster, M. A, additional
- Published
- 2010
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11. Selective tuning of face perception
- Author
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Ng, M., primary, Kaping, D., additional, Webster, M. A., additional, Anstis, S., additional, and Fine, I., additional
- Published
- 2010
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12. Adaptation and categorical judgments of faces
- Author
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Kaping, D., primary, Bilson, A. C., additional, and Webster, M. A., additional
- Published
- 2010
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13. Stimulus configurations supporting the perception of faces
- Author
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Bilson, A. C., primary, Kaping, D., additional, and Webster, M. A., additional
- Published
- 2010
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14. Adaptation and individual differences in categorical judgments of faces
- Author
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Yasuda, M., primary, Bedard, K., additional, Mizokami, Y., additional, Kaping, D., additional, and Webster, M. A., additional
- Published
- 2005
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15. Adaptation and the perception of facial symmetry
- Author
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Paras, C. L., primary, Kaping, D., additional, and Webster, M. A., additional
- Published
- 2004
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16. Adaptation to natural facial categories
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Kaping, D., primary, Duhamel, P., additional, and Webster, M. A., additional
- Published
- 2002
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17. Phase of neural oscillations as a reference frame for attention-based routing in visual cortex.
- Author
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Aboutorabi E, Baloni Ray S, Kaping D, Shahbazi F, Treue S, and Esghaei M
- Subjects
- Animals, Brain, Cerebral Cortex, Action Potentials physiology, Neurons physiology, Visual Cortex physiology
- Abstract
Selective attention allows the brain to efficiently process the image projected onto the retina, selectively focusing neural processing resources on behaviorally relevant visual information. While previous studies have documented the crucial role of the action potential rate of single neurons in relaying such information, little is known about how the activity of single neurons relative to their neighboring network contributes to the efficient representation of attended stimuli and transmission of this information to downstream areas. Here, we show in the dorsal visual pathway of monkeys (medial superior temporal area) that neurons fire spikes preferentially at a specific phase of the ongoing population beta (∼20 Hz) oscillations of the surrounding local network. This preferred spiking phase shifts towards a later phase when monkeys selectively attend towards (rather than away from) the receptive field of the neuron. This shift of the locking phase is positively correlated with the speed at which animals report a visual change. Furthermore, our computational modeling suggests that neural networks can manipulate the preferred phase of coupling by imposing differential synaptic delays on postsynaptic potentials. This distinction between the locking phase of neurons activated by the spatially attended stimulus vs. that of neurons activated by the unattended stimulus, may enable the neural system to discriminate relevant from irrelevant sensory inputs and consequently filter out distracting stimuli information by aligning the spikes which convey relevant/irrelevant information to distinct phases linked to periods of better/worse perceptual sensitivity for higher cortices. This strategy may be used to reserve the narrow windows of highest perceptual efficacy to the processing of the most behaviorally relevant information, ensuring highly efficient responses to attended sensory events., 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 © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)
- Published
- 2024
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18. mTOR inhibitor improves autistic-like behaviors related to Tsc2 haploinsufficiency but not following developmental status epilepticus.
- Author
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Petrasek T, Vojtechova I, Klovrza O, Tuckova K, Vejmola C, Rak J, Sulakova A, Kaping D, Bernhardt N, de Vries PJ, Otahal J, and Waltereit R
- Subjects
- Animals, Haploinsufficiency, Male, Rats, TOR Serine-Threonine Kinases genetics, Autistic Disorder, Status Epilepticus, Tuberous Sclerosis Complex 2 Protein genetics
- Abstract
Background: Tuberous sclerosis complex (TSC), a multi-system genetic disorder often associated with autism spectrum disorder (ASD), is caused by mutations of TSC1 or TSC2, which lead to constitutive overactivation of mammalian target of rapamycin (mTOR). In several Tsc1+/- and Tsc2+/- animal models, cognitive and social behavior deficits were reversed by mTOR inhibitors. However, phase II studies have not shown amelioration of ASD and cognitive deficits in individuals with TSC during mTOR inhibitor therapy. We asked here if developmental epilepsy, common in the majority of individuals with TSC but absent in most animal models, could explain the discrepancy., Methods: At postnatal day P12, developmental status epilepticus (DSE) was induced in male Tsc2+/- (Eker) and wild-type rats, establishing four experimental groups including controls. In adult animals (n = 36), the behavior was assessed in the paradigms of social interaction test, elevated plus-maze, light-dark test, Y-maze, and novel object recognition. The testing was carried out before medication (T1), during a 2-week treatment with the mTOR inhibitor everolimus (T2) and after an 8-week washing-out (T3). Electroencephalographic (EEG) activity was recorded in a separate set of animals (n = 18)., Results: Both Tsc2+/- mutation and DSE caused social behavior deficits and epileptiform EEG abnormalities (T1). Everolimus led to a persistent improvement of the social deficit induced by Tsc2+/-, while deficits related to DSE did not respond to everolimus (T2, T3)., Conclusions: These findings may contribute to an explanation why ASD symptoms in individuals with TSC, where comorbid early-onset epilepsy is common, were not reliably ameliorated by mTOR inhibitors in clinical studies.
- Published
- 2021
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19. Tuberous Sclerosis (tsc2+/-) Model Eker Rats Reveals Extensive Neuronal Loss with Microglial Invasion and Vascular Remodeling Related to Brain Neoplasia.
- Author
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Kútna V, Uttl L, Waltereit R, Krištofiková Z, Kaping D, Petrásek T, Hoschl C, and Ovsepian SV
- Subjects
- Animals, Astrocytes pathology, Axons pathology, Brain blood supply, Brain pathology, Brain Neoplasms blood supply, Brain Neoplasms etiology, Female, Male, Rats, Long-Evans, Tuberous Sclerosis complications, Tuberous Sclerosis Complex 2 Protein genetics, Brain Neoplasms pathology, Microglia pathology, Neurons pathology, Tuberous Sclerosis pathology, Vascular Remodeling
- Abstract
Tuberous sclerosis complex (TSC) is a genetic disorder characterized by frequent noncancerous neoplasia in the brain, which can induce a range of severe neuropsychiatric symptoms in humans, resulting from out of control tissue growth. The causative spontaneous loss-of-function mutations have been also identified in rats. Herein, we studied histopathological and molecular changes in brain lesions of the Eker rat model carrying germline mutation of the tsc2 gene, predisposed to multiple neoplasias. Predominant subcortical tumors were analyzed, along with a rare form occurring within the pyriform lobe. The uniform composition of lesions supports the histochemical parity of malformations, with immunofluorescence data supporting their neuro-glial origin. Massive depletion of mature neurons and axonal loss were evident within lesions, with occasional necrotic foci implying advanced stage of pathology. Enrichment of mesenchymal-derived cell markers with hallmarks of neurogenesis and active microglia imply enhanced cell proliferation, with local immune response. The depletion of capillaries within the core was complemented by the formation of dense mesh of nascent vessels at the interface of neoplasia with healthy tissue, implying large-scale vascular remodeling. Taken as a whole, these findings present several novel features of brain tumors in Eker rat model, rendering it suitable for studies of the pathobiology and progression of primary brain tumors, with therapeutic interventions.
- Published
- 2020
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20. A Systematic Review on Donepezil-based Derivatives as Potential Cholinesterase Inhibitors for Alzheimer's Disease.
- Author
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Korabecny J, Spilovska K, Mezeiova E, Benek O, Juza R, Kaping D, and Soukup O
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- Acetylcholinesterase metabolism, Alzheimer Disease metabolism, Animals, Butyrylcholinesterase metabolism, Cholinesterase Inhibitors chemistry, Donepezil chemistry, Humans, Molecular Structure, Neuroprotective Agents chemistry, Alzheimer Disease drug therapy, Cholinesterase Inhibitors pharmacology, Cholinesterase Inhibitors therapeutic use, Donepezil pharmacology, Donepezil therapeutic use, Neuroprotective Agents pharmacology, Neuroprotective Agents therapeutic use
- Abstract
Alzheimer's Disease (AD) is a multifactorial progressive neurodegenerative disorder characterized by memory loss, disorientation, and gradual deterioration of intellectual capacity. Its etiology has not been elucidated yet. To date, only one therapeutic approach has been approved for the treatment of AD. The pharmacotherapy of AD has relied on noncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist - memantine, and acetylcholinesterase (AChE) inhibitors (AChEIs) - tacrine, donepezil, rivastigmine and galantamine. Donepezil was able to ameliorate the symptoms related to AD mainly via AChE, but also through reduction of β-amyloid burden. This review presents the overview of donepezilrelated compounds as potential anti-AD drugs developed on the basis of cholinergic hypothesis to act as solely AChE and butyrylcholinesterase (BChE) inhibitors., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)
- Published
- 2019
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21. Levels of 17β-hydroxysteroid dehydrogenase type 10 in CSF are not a valuable biomarker for multiple sclerosis.
- Author
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Kristofikova Z, Ricny J, Kaping D, Klaschka J, Kotoucova J, and Bartos A
- Subjects
- Adult, Amyloid beta-Peptides cerebrospinal fluid, Biomarkers cerebrospinal fluid, Female, Humans, Male, Peptide Fragments cerebrospinal fluid, 3-Hydroxyacyl CoA Dehydrogenases cerebrospinal fluid, Multiple Sclerosis cerebrospinal fluid
- Abstract
Aim: We aimed to characterize the role of mitochondrial 17β-hydroxysteroid dehydrogenase type 10 (17β-HSD10) overexpression in multiple sclerosis (MS) and to evaluate its use as a biomarker. Materials & methods: We estimated levels of 17β-HSD10, amyloid β 1-42, cyclophilin D, 17β-HSD10-cyclophilin D complexes or 17β-HSD10-parkin complexes in cerebrospinal fluid (CSF) samples., Results: The increase in 17β-HSD10 levels or in 17β-HSD10-parkin complexes and links to leukocytes were found only in relapsing-remitting MS. The sensitivity of the biomarker was 64%, the specificity equaled 60-63% compared with controls., Conclusion: Increased CSF levels of 17β-HSD10 in later stages of MS could be interpreted via its upregulation in demyelinated neuronal axons. CSF levels of 17β-HSD10 are not the valuable biomarker for the early diagnosis or for the progression of MS.
- Published
- 2018
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22. Trans-generational neurochemical modulation of methamphetamine in the adult brain of the Wistar rat.
- Author
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Fujáková-Lipski M, Kaping D, Šírová J, Horáček J, Páleníček T, Zach P, Klaschka J, Kačer P, Syslová K, Vrajová M, Bubenikova-Valešová V, Beste C, and Šlamberová R
- Subjects
- Animals, Dopamine metabolism, Female, Glutamic Acid metabolism, Methamphetamine administration & dosage, Methamphetamine pharmacokinetics, Pregnancy, Rats, Wistar, Serotonin metabolism, gamma-Aminobutyric Acid, Brain drug effects, Brain metabolism, Methamphetamine toxicity, Prenatal Exposure Delayed Effects
- Abstract
Chronic methamphetamine (METH) abuse has been shown to elicit strong neurotoxic effects. Yet, with an increasing number of children born to METH abusing mothers maturing into adulthood, one important question is how far do the neurotoxic effects of METH alter various neurotransmitter systems in the adult METH-exposed offspring. The purpose of this study was to investigate long-term trans-generational neurochemical changes, following prenatal METH exposure, in the adult Wistar rat brain. METH or saline (SAL-control animals) was administered to pregnant dams throughout the entire gestation period (G0-G22). At postnatal day 90, dopamine, serotonin, glutamate and GABA were measured in the adult brain before (baseline) and after a METH re-administration using in vivo microdialysis and liquid chromatography/mass spectrometry. The results show that METH-exposure increased basal levels of monoamines and glutamate, but decreased GABA levels in all measured brain regions. Acute challenge with METH injection in the METH-exposed group induced a lower increase in the monoamine system relative to the increase in the GABAergic and glutamatergic system. The data show that prenatal METH exposure has strong effects on the monoaminergic, GABAergic and glutamatergic system even when exposure to METH was limited to the prenatal phase. Toxicological effects of METH have therefore longer lasting effects as currently considered and seem to affect the excitatory-inhibitory balance in the brain having strong implications for cognitive and behavioral functioning.
- Published
- 2017
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23. Development of 2-Methoxyhuprine as Novel Lead for Alzheimer's Disease Therapy.
- Author
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Mezeiova E, Korabecny J, Sepsova V, Hrabinova M, Jost P, Muckova L, Kucera T, Dolezal R, Misik J, Spilovska K, Pham NL, Pokrievkova L, Roh J, Jun D, Soukup O, Kaping D, and Kuca K
- Subjects
- Acetylcholinesterase, Alzheimer Disease drug therapy, Aminoquinolines chemical synthesis, Binding Sites, Blood-Brain Barrier metabolism, Butyrylcholinesterase, Catalytic Domain, Cell Line, Tumor, Cell Survival drug effects, Cholinesterase Inhibitors chemistry, Cholinesterase Inhibitors pharmacology, Drug Design, Enzyme Activation drug effects, Heterocyclic Compounds, 4 or More Rings chemistry, Heterocyclic Compounds, 4 or More Rings pharmacology, Humans, Hydrolysis, Inhibitory Concentration 50, Models, Molecular, Molecular Conformation, Molecular Structure, Permeability, Protein Binding, Structure-Activity Relationship, Tacrine analogs & derivatives, Tacrine chemistry, Tacrine pharmacology, Aminoquinolines chemistry, Aminoquinolines pharmacology, Drug Discovery
- Abstract
Tacrine (THA), the first clinically effective acetylcholinesterase (AChE) inhibitor and the first approved drug for the treatment of Alzheimer's disease (AD), was withdrawn from the market due to its side effects, particularly its hepatotoxicity. Nowadays, THA serves as a valuable scaffold for the design of novel agents potentially applicable for AD treatment. One such compound, namely 7-methoxytacrine (7-MEOTA), exhibits an intriguing profile, having suppressed hepatotoxicity and concomitantly retaining AChE inhibition properties. Another interesting class of AChE inhibitors represents Huprines, designed by merging two fragments of the known AChE inhibitors-THA and (-)-huperzine A. Several members of this compound family are more potent human AChE inhibitors than the parent compounds. The most promising are so-called huprines X and Y. Here, we report the design, synthesis, biological evaluation, and in silico studies of 2-methoxyhuprine that amalgamates structural features of 7-MEOTA and huprine Y in one molecule., Competing Interests: The authors declare no conflict of interest.
- Published
- 2017
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24. Novel Tacrine-Scutellarin Hybrids as Multipotent Anti-Alzheimer's Agents: Design, Synthesis and Biological Evaluation.
- Author
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Spilovska K, Korabecny J, Sepsova V, Jun D, Hrabinova M, Jost P, Muckova L, Soukup O, Janockova J, Kucera T, Dolezal R, Mezeiova E, Kaping D, and Kuca K
- Subjects
- Acetylcholinesterase metabolism, Alzheimer Disease enzymology, Blood-Brain Barrier metabolism, Butyrylcholinesterase metabolism, Cholinesterase Inhibitors chemical synthesis, Drug Design, Enzyme Activation drug effects, Humans, Molecular Docking Simulation, Structure-Activity Relationship, Tacrine chemistry, Apigenin chemistry, Cholinesterase Inhibitors chemistry, Cholinesterase Inhibitors pharmacology, Glucuronates chemistry, Tacrine analogs & derivatives
- Abstract
A novel series of 6-chlorotacrine-scutellarin hybrids was designed, synthesized and the biological activity as potential anti-Alzheimer's agents was assessed. Their inhibitory activity towards human acetylcholinesterase ( h AChE) and human butyrylcholinesterase ( h BChE), antioxidant activity, ability to cross the blood-brain barrier (BBB) and hepatotoxic profile were evaluated in vitro. Among these compounds, hybrid K1383 , bearing two methylene tether between two basic scaffolds, was found to be very potent h AChE inhibitor (IC
50 = 1.63 nM). Unfortunately, none of the hybrids displayed any antioxidant activity (EC50 ≥ 500 μM). Preliminary data also suggests a comparable hepatotoxic profile with 6-Cl-THA (established on a HepG2 cell line). Kinetic studies performed on h AChE with the most active compound in the study, K1383 , pointed out to a mixed, non-competitive enzyme inhibition. These findings were further corroborated by docking studies., Competing Interests: The authors declare no conflict of interest.- Published
- 2017
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25. Spatial Attention Reduces Burstiness in Macaque Visual Cortical Area MST.
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Xue C, Kaping D, Ray SB, Krishna BS, and Treue S
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- Animals, Macaca mulatta, Male, Attention physiology, Biological Clocks physiology, Brain Waves physiology, Nerve Net physiology, Space Perception physiology, Visual Cortex physiology, Visual Fields physiology
- Abstract
Visual attention modulates the firing rate of neurons in many primate cortical areas. In V4, a cortical area in the ventral visual pathway, spatial attention has also been shown to reduce the tendency of neurons to fire closely separated spikes (burstiness). A recent model proposes that a single mechanism accounts for both the firing rate enhancement and the burstiness reduction in V4, but this has not been empirically tested. It is also unclear if the burstiness reduction by spatial attention is found in other visual areas and for other attentional types. We therefore recorded from single neurons in the medial superior temporal area (MST), a key motion-processing area along the dorsal visual pathway, of two rhesus monkeys while they performed a task engaging both spatial and feature-based attention. We show that in MST, spatial attention is associated with a clear reduction in burstiness that is independent of the concurrent enhancement of firing rate. In contrast, feature-based attention enhances firing rate but is not associated with a significant reduction in burstiness. These results establish burstiness reduction as a widespread effect of spatial attention. They also suggest that in contrast to the recently proposed model, the effects of spatial attention on burstiness and firing rate emerge from different mechanisms., (© The Author 2016. Published by Oxford University Press.)
- Published
- 2017
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26. Prefrontal and anterior cingulate cortex neurons encode attentional targets even when they do not apparently bias behavior.
- Author
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Westendorff S, Kaping D, Everling S, and Womelsdorf T
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- Action Potentials physiology, Analysis of Variance, Animals, Bias, Choice Behavior physiology, Cues, Macaca mulatta, Male, Neurons classification, Photic Stimulation, Reaction Time physiology, Time Factors, Attention physiology, Gyrus Cinguli cytology, Neurons physiology, Prefrontal Cortex cytology, Space Perception physiology
- Abstract
Neurons in anterior cingulate and prefrontal cortex (ACC/PFC) carry information about behaviorally relevant target stimuli. This information is believed to affect behavior by exerting a top-down attentional bias on stimulus selection. However, attention information may not necessarily be a biasing signal but could be a corollary signal that is not directly related to ongoing behavioral success, or it could reflect the monitoring of targets similar to an eligibility trace useful for later attentional adjustment. To test this suggestion we quantified how attention information relates to behavioral success in neurons recorded in multiple subfields in macaque ACC/PFC during a cued attention task. We found that attention cues activated three separable neuronal groups that encoded spatial attention information but were differently linked to behavioral success. A first group encoded attention targets on correct and error trials. This group spread across ACC/PFC and represented targets transiently after cue onset, irrespective of behavior. A second group encoded attention targets on correct trials only, closely predicting behavior. These neurons were not only prevalent in lateral prefrontal but also in anterior cingulate cortex. A third group encoded target locations only on error trials. This group was evident in ACC and PFC and was activated in error trials "as if" attention was shifted to the target location but without evidence for such behavior. These results show that only a portion of neuronaly available information about attention targets biases behavior. We speculate that additionally a unique neural subnetwork encodes counterfactual attention information., (Copyright © 2016 the American Physiological Society.)
- Published
- 2016
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27. Attentional Selection Can Be Predicted by Reinforcement Learning of Task-relevant Stimulus Features Weighted by Value-independent Stickiness.
- Author
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Balcarras M, Ardid S, Kaping D, Everling S, and Womelsdorf T
- Subjects
- Algorithms, Animals, Choice Behavior, Executive Function, Eye Movement Measurements, Eye Movements, Logistic Models, Macaca, Male, Neuropsychological Tests, Photic Stimulation, Psychological Tests, Reversal Learning, Stochastic Processes, Visual Perception, Attention, Models, Psychological, Reinforcement, Psychology
- Abstract
Attention includes processes that evaluate stimuli relevance, select the most relevant stimulus against less relevant stimuli, and bias choice behavior toward the selected information. It is not clear how these processes interact. Here, we captured these processes in a reinforcement learning framework applied to a feature-based attention task that required macaques to learn and update the value of stimulus features while ignoring nonrelevant sensory features, locations, and action plans. We found that value-based reinforcement learning mechanisms could account for feature-based attentional selection and choice behavior but required a value-independent stickiness selection process to explain selection errors while at asymptotic behavior. By comparing different reinforcement learning schemes, we found that trial-by-trial selections were best predicted by a model that only represents expected values for the task-relevant feature dimension, with nonrelevant stimulus features and action plans having only a marginal influence on covert selections. These findings show that attentional control subprocesses can be described by (1) the reinforcement learning of feature values within a restricted feature space that excludes irrelevant feature dimensions, (2) a stochastic selection process on feature-specific value representations, and (3) value-independent stickiness toward previous feature selections akin to perseveration in the motor domain. We speculate that these three mechanisms are implemented by distinct but interacting brain circuits and that the proposed formal account of feature-based stimulus selection will be important to understand how attentional subprocesses are implemented in primate brain networks.
- Published
- 2016
- Full Text
- View/download PDF
28. Inferior-frontal cortex phase synchronizes with the temporal-parietal junction prior to successful change detection.
- Author
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Micheli C, Kaping D, Westendorff S, Valiante TA, and Womelsdorf T
- Subjects
- Alpha Rhythm, Beta Rhythm, Electrocorticography, Epilepsy physiopathology, Evoked Potentials, Visual, Female, Humans, Male, Neural Pathways physiology, Attention physiology, Cortical Synchronization physiology, Frontal Lobe physiology, Parietal Lobe physiology, Signal Detection, Psychological physiology, Temporal Lobe physiology, Visual Perception physiology
- Abstract
The inferior frontal gyrus (IFG) and the temporo-parietal junction (TPJ) are believed to be core structures of human brain networks that activate when sensory top-down expectancies guide goal directed behavior and attentive perception. But it is unclear how activity in IFG and TPJ coordinates during attention demanding tasks and whether functional interactions between both structures are related to successful attentional performance. Here, we tested these questions in electrocorticographic (ECoG) recordings in human subjects using a visual detection task that required sustained attentional expectancy in order to detect non-salient, near-threshold visual events. We found that during sustained attention the successful visual detection was predicted by increased phase synchronization of band-limited 15-30 Hz beta band activity that was absent prior to misses. Increased beta-band phase alignment during attentional engagement early during the task was restricted to inferior and lateral prefrontal cortex, but with sustained attention it extended to long-range IFG-TPJ phase synchronization and included superior prefrontal areas. In addition to beta, a widely distributed network of brain areas comprising the occipital cortex showed enhanced and reduced alpha band phase synchronization before correct detections. These findings identify long-range phase synchrony in the 15-30 Hz beta band as the mesoscale brain signal that predicts the successful deployment of attentional expectancy of sensory events. We speculate that localized beta coherent states in prefrontal cortex index 'top-down' sensory expectancy whose coupling with TPJ subregions facilitates the gating of relevant visual information., (Copyright © 2015 Elsevier Inc. All rights reserved.)
- Published
- 2015
- Full Text
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29. Anterior Cingulate Cortex Cells Identify Process-Specific Errors of Attentional Control Prior to Transient Prefrontal-Cingulate Inhibition.
- Author
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Shen C, Ardid S, Kaping D, Westendorff S, Everling S, and Womelsdorf T
- Subjects
- Action Potentials, Animals, Macaca, Male, Microelectrodes, Neuropsychological Tests, Photic Stimulation, Saccades physiology, Visual Perception physiology, Attention physiology, Gyrus Cinguli physiology, Inhibition, Psychological, Neurons physiology, Prefrontal Cortex physiology
- Abstract
Errors indicate the need to adjust attention for improved future performance. Detecting errors is thus a fundamental step to adjust and control attention. These functions have been associated with the dorsal anterior cingulate cortex (dACC), predicting that dACC cells should track the specific processing states giving rise to errors in order to identify which processing aspects need readjustment. Here, we tested this prediction by recording cells in the dACC and lateral prefrontal cortex (latPFC) of macaques performing an attention task that dissociated 3 processing stages. We found that, across prefrontal subareas, the dACC contained the largest cell populations encoding errors indicating (1) failures of inhibitory control of the attentional focus, (2) failures to prevent bottom-up distraction, and (3) lapses when implementing a choice. Error-locked firing in the dACC showed the earliest latencies across the PFC, emerged earlier than reward omission signals, and involved a significant proportion of putative inhibitory interneurons. Moreover, early onset error-locked response enhancement in the dACC was followed by transient prefrontal-cingulate inhibition, possibly reflecting active disengagement from task processing. These results suggest a functional specialization of the dACC to track and identify the actual processes that give rise to erroneous task outcomes, emphasizing its role to control attentional performance., (© The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)
- Published
- 2015
- Full Text
- View/download PDF
30. Beta coherence within human ventromedial prefrontal cortex precedes affective value choices.
- Author
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Lipsman N, Kaping D, Westendorff S, Sankar T, Lozano AM, and Womelsdorf T
- Subjects
- Adult, Facial Expression, Female, Humans, Male, Middle Aged, Young Adult, Affect physiology, Beta Rhythm physiology, Choice Behavior physiology, Prefrontal Cortex physiology
- Abstract
Ventromedial prefrontal cortex (vmPFC) forms a core region of larger brain circuits that assign value to sensory inputs and interfaces motivational and cognitive dominated brain processes. This network function of the vmPFC could be realized by synchronizing local activity at time scales that are shared by connected brain areas, but it is unknown whether vmPFC circuitry engages in functionally specific synchronization. Here, we recorded in human subcallosal vmPFC while subjects engaged in an emotion tracking task that required the assignment of positive or negative affective value to ambiguous (happy-sad) facial expressions. We found that vmPFC engages in low beta-band (15-20 Hz) coherent activation just before subjects subjectively judged ambiguous facial expressions as conveying negative valence ('sad') information, but not before positive valence ('happy') judgments. The predictive beta coherence emerged particularly for conflicting rather than pure emotional facial cues and dissipated slowly after the choice was made. These results suggest that 15-20 Hz coherent activity within vmPFC marks a functional signature of a valuation process that informs categorical affective choices. We hypothesize that coherent beta band activation signifies functional interactions to anatomical vmPFC projection targets, raising the possibility that dysfunctional biases in affective valuation and an enhanced decision conflict in clinical depression could be indexed by alterations of beta coherent network activation., (Copyright © 2013 Elsevier Inc. All rights reserved.)
- Published
- 2014
- Full Text
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31. Specific contributions of ventromedial, anterior cingulate, and lateral prefrontal cortex for attentional selection and stimulus valuation.
- Author
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Kaping D, Vinck M, Hutchison RM, Everling S, and Womelsdorf T
- Subjects
- Analysis of Variance, Animals, Gyrus Cinguli cytology, Macaca psychology, Male, Models, Statistical, Photic Stimulation, Prefrontal Cortex cytology, Reward, Time Factors, Attention physiology, Discrimination, Psychological physiology, Gyrus Cinguli physiology, Macaca physiology, Prefrontal Cortex physiology
- Abstract
Attentional control ensures that neuronal processes prioritize the most relevant stimulus in a given environment. Controlling which stimulus is attended thus originates from neurons encoding the relevance of stimuli, i.e. their expected value, in hand with neurons encoding contextual information about stimulus locations, features, and rules that guide the conditional allocation of attention. Here, we examined how these distinct processes are encoded and integrated in macaque prefrontal cortex (PFC) by mapping their functional topographies at the time of attentional stimulus selection. We find confined clusters of neurons in ventromedial PFC (vmPFC) that predominantly convey stimulus valuation information during attention shifts. These valuation signals were topographically largely separated from neurons predicting the stimulus location to which attention covertly shifted, and which were evident across the complete medial-to-lateral extent of the PFC, encompassing anterior cingulate cortex (ACC), and lateral PFC (LPFC). LPFC responses showed particularly early-onset selectivity and primarily facilitated attention shifts to contralateral targets. Spatial selectivity within ACC was delayed and heterogeneous, with similar proportions of facilitated and suppressed responses during contralateral attention shifts. The integration of spatial and valuation signals about attentional target stimuli was observed in a confined cluster of neurons at the intersection of vmPFC, ACC, and LPFC. These results suggest that valuation processes reflecting stimulus-specific outcome predictions are recruited during covert attentional control. Value predictions and the spatial identification of attentional targets were conveyed by largely separate neuronal populations, but were integrated locally at the intersection of three major prefrontal areas, which may constitute a functional hub within the larger attentional control network., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2011
- Full Text
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32. Adaptation to natural facial categories.
- Author
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Webster MA, Kaping D, Mizokami Y, and Duhamel P
- Subjects
- Adaptation, Physiological, Emotions, Ethnicity, Facial Expression, Female, Humans, Male, Photic Stimulation, Sex Characteristics, Face, Visual Perception physiology
- Abstract
Face perception is fundamentally important for judging the characteristics of individuals, such as identification of their gender, age, ethnicity or expression. We asked how the perception of these characteristics is influenced by the set of faces that observers are exposed to. Previous studies have shown that the appearance of a face can be biased strongly after viewing an altered image of the face, and have suggested that these after-effects reflect response changes in the neural mechanisms underlying object or face perception. Here we show that these adaptation effects are pronounced for natural variations in faces and for natural categorical judgements about faces. This suggests that adaptation may routinely influence face perception in normal viewing, and could have an important role in calibrating properties of face perception according to the subset of faces populating an individual's environment.
- Published
- 2004
- Full Text
- View/download PDF
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