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Articles 571 - 600 of 715

Full-Text Articles in Neurosciences

Observing Object Lifting Errors Modulates Cortico-Spinal Excitability And Improves Object Lifting Performance., Gavin Buckingham, Jeremy D Wong, Minnie Tang, Paul L Gribble, Melvyn A Goodale Jan 2014

Observing Object Lifting Errors Modulates Cortico-Spinal Excitability And Improves Object Lifting Performance., Gavin Buckingham, Jeremy D Wong, Minnie Tang, Paul L Gribble, Melvyn A Goodale

Brain and Mind Institute Researchers' Publications

Observing the actions of others has been shown to modulate cortico-spinal excitability and affect behaviour. However, the sensorimotor consequences of observing errors are not well understood. Here, participants watched actors lift identically weighted large and small cubes which typically elicit expectation-based fingertip force errors. One group of participants observed the standard overestimation and underestimation-style errors that characterise early lifts with these cubes (Error video--EV). Another group watched the same actors performing the well-adapted error-free lifts that characterise later, well-practiced lifts with these cubes (No error video--NEV). We then examined actual object lifting performance in the subjects who watched the EV …


Sign Language Ability In Young Deaf Signers Predicts Comprehension Of Written Sentences In English., Kathy N Andrew, Jennifer Hoshooley, Marc F Joanisse Jan 2014

Sign Language Ability In Young Deaf Signers Predicts Comprehension Of Written Sentences In English., Kathy N Andrew, Jennifer Hoshooley, Marc F Joanisse

Brain and Mind Institute Researchers' Publications

We investigated the robust correlation between American Sign Language (ASL) and English reading ability in 51 young deaf signers ages 7;3 to 19;0. Signers were divided into 'skilled' and 'less-skilled' signer groups based on their performance on three measures of ASL. We next assessed reading comprehension of four English sentence structures (actives, passives, pronouns, reflexive pronouns) using a sentence-to-picture-matching task. Of interest was the extent to which ASL proficiency provided a foundation for lexical and syntactic processes of English. Skilled signers outperformed less-skilled signers overall. Error analyses further indicated greater single-word recognition difficulties in less-skilled signers marked by a higher …


Links Between White Matter Microstructure And Cortisol Reactivity To Stress In Early Childhood: Evidence For Moderation By Parenting., Haroon I Sheikh, Marc F Joanisse, Sarah M Mackrell, Katie R Kryski, Heather J Smith, Shiva M Singh, Elizabeth P Hayden Jan 2014

Links Between White Matter Microstructure And Cortisol Reactivity To Stress In Early Childhood: Evidence For Moderation By Parenting., Haroon I Sheikh, Marc F Joanisse, Sarah M Mackrell, Katie R Kryski, Heather J Smith, Shiva M Singh, Elizabeth P Hayden

Brain and Mind Institute Researchers' Publications

Activity of the hypothalamic-pituitary-adrenal axis (measured via cortisol reactivity) may be a biological marker of risk for depression and anxiety, possibly even early in development. However, the structural neural correlates of early cortisol reactivity are not well known, although these would potentially inform broader models of mechanisms of risk, especially if the early environment further shapes these relationships. Therefore, we examined links between white matter architecture and young girls' cortisol reactivity and whether early caregiving moderated these links. We recruited 45 6-year-old girls based on whether they had previously shown high or low cortisol reactivity to a stress task at …


Sensitivity Of Human Auditory Cortex To Rapid Frequency Modulation Revealed By Multivariate Representational Similarity Analysis., Marc F Joanisse, Diedre D Desouza Jan 2014

Sensitivity Of Human Auditory Cortex To Rapid Frequency Modulation Revealed By Multivariate Representational Similarity Analysis., Marc F Joanisse, Diedre D Desouza

Brain and Mind Institute Researchers' Publications

Functional Magnetic Resonance Imaging (fMRI) was used to investigate the extent, magnitude, and pattern of brain activity in response to rapid frequency-modulated sounds. We examined this by manipulating the direction (rise vs. fall) and the rate (fast vs. slow) of the apparent pitch of iterated rippled noise (IRN) bursts. Acoustic parameters were selected to capture features used in phoneme contrasts, however the stimuli themselves were not perceived as speech per se. Participants were scanned as they passively listened to sounds in an event-related paradigm. Univariate analyses revealed a greater level and extent of activation in bilateral auditory cortex in response …


Dopaminergic Medication Impairs Feedback-Based Stimulus-Response Learning But Not Response Selection In Parkinson's Disease., Andrew Vo, Nole M Hiebert, Ken N Seergobin, Stephanie Solcz, Allison Partridge, Penny A Macdonald Jan 2014

Dopaminergic Medication Impairs Feedback-Based Stimulus-Response Learning But Not Response Selection In Parkinson's Disease., Andrew Vo, Nole M Hiebert, Ken N Seergobin, Stephanie Solcz, Allison Partridge, Penny A Macdonald

Brain and Mind Institute Researchers' Publications

Cognitive dysfunction is a feature of Parkinson's Disease (PD). Some cognitive functions are impaired by dopaminergic medications prescribed to address the movement symptoms that typify PD. Learning appears to be the cognitive function most frequently worsened by dopaminergic therapy. However, this result could reflect either impairments in learning (i.e., acquisition of associations among stimuli, responses, and outcomes) or deficits in performance based on learning (e.g., selecting responses). We sought to clarify the specific effects of dopaminergic medication on (a) stimulus-response association learning from outcome feedback and (b) response selection based on learning, in PD. We tested 28 PD patients on …


Rule-Based Category Learning In Children: The Role Of Age And Executive Functioning., Rahel Rabi, John Paul Minda Jan 2014

Rule-Based Category Learning In Children: The Role Of Age And Executive Functioning., Rahel Rabi, John Paul Minda

Brain and Mind Institute Researchers' Publications

Rule-based category learning was examined in 4-11 year-olds and adults. Participants were asked to learn a set of novel perceptual categories in a classification learning task. Categorization performance improved with age, with younger children showing the strongest rule-based deficit relative to older children and adults. Model-based analyses provided insight regarding the type of strategy being used to solve the categorization task, demonstrating that the use of the task appropriate strategy increased with age. When children and adults who identified the correct categorization rule were compared, the performance deficit was no longer evident. Executive functions were also measured. While both working …


Accumulation Of Subcortical Iron As A Modifier Of Volumetric And Cognitive Decline In Healthy Aging: Two Longitudinal Studies, Ana Marie Daugherty Jan 2014

Accumulation Of Subcortical Iron As A Modifier Of Volumetric And Cognitive Decline In Healthy Aging: Two Longitudinal Studies, Ana Marie Daugherty

Wayne State University Dissertations

Accumulation of non-heme iron in the brain has been theorized as a cellular mechanism underlying global neural and cognitive decline in normal aging and neurodegenerative disease. Relatively few studies of brain iron in normal aging exist and extant studies are almost exclusively cross-sectional. Here, I estimated iron content via T2* and measured volumes in several brain regions in two independent samples of healthy adults. The first sample (N = 89) was measured twice with a two-year delay; and the second sample (N = 32) was assessed four times over a span of 7 years. Latent models estimated change in iron …


Longitudinal Change In Regional Cortices And Fluid Intelligence, Peng Yuan Jan 2014

Longitudinal Change In Regional Cortices And Fluid Intelligence, Peng Yuan

Wayne State University Dissertations

Fluid intelligence (Gf) and crystalized intelligence (Gc) are two factors of the general intelligence. They have distinct age-related trajectories of change. Jung and Haier proposed Parieto-Frontal Integration Theory (P-FIT, 2007) to account for the inter-person variance in reasoning intelligence. Some brain regions such as prefrontal, parietal, temporal and anterior cingulate cortices were included in the P-FIT model and were hypothesized to be involved in fluid reasoning task. Therefore, in the current study, we examined latent growth curves (LGC) of longitudinal change in Gf, Gc, prefrontal cortex, parietal cortex, anterior cingulate, temporal cortex and primary visual cortex. Forty-six healthy middle-aged and …


The Effect Of Gaba A Antagonism On Locomotor Activity And Dopamine Release In The Mouse Caudate Putamen Following Acute Toluene Inhalation: An In-Vivo Microdialysis Study, Sean Callan Jan 2014

The Effect Of Gaba A Antagonism On Locomotor Activity And Dopamine Release In The Mouse Caudate Putamen Following Acute Toluene Inhalation: An In-Vivo Microdialysis Study, Sean Callan

Wayne State University Theses

Toluene is ubiquitous solvent commonly inhaled recreationally. Despite its frequency of misuse, there is little understanding of how toluene acts within the brain. To examine this, this master's thesis examined the impact of acutely inhaled toluene on dopamine (DA) release in the mouse CPu in vivo using microdialysis techniques. Toluene inhalation produced dose-dependent increases in DA levels as well as changes in locomotor activity. These effects were potentiated by pre-treatment with the GABAA antagonist bicuculline via reverse microdialysis delivery. These results suggest that the DA dynamics of toluene abuse are related to toluene's previously explored effects on the GABA system. …


Inattention And Hyperactivity Among Preschool Age Children Born Prematurely, Andrew Heitzer Jan 2014

Inattention And Hyperactivity Among Preschool Age Children Born Prematurely, Andrew Heitzer

Wayne State University Theses

A large body of literature shows that compared to children born at term, preterm- children are at increased risk for difficulties with inattention and hyperactivity. Less consistency exists, however, in the limited body of research exploring the contribution of early biological risk to behavioral disinhibition within the population of children born prematurely. Therefore, our goal was to examine perinatal variables that may influence activity level and hyperactivity among preterm preschoolers. Ninety-eight preterm (23.4 - 33.9 weeks gestation) preschoolers (3-4 years) participated in the study. Direct measures of inattention and hyperactivity as well as parental ratings were used to evaluate behavior. …


The Quetiapine Active Metabolite N-Desalkylquetiapine And The Neurotensin Nts1 Receptor Agonist Pd149163 Exhibit Antidepressant-Like Effects On Operant Responding In Male Rats, Todd M. Hillhouse, Zachary Shankland, Katelin S. Matazel, Ashley Keiser, Adam J. Prus Jan 2014

The Quetiapine Active Metabolite N-Desalkylquetiapine And The Neurotensin Nts1 Receptor Agonist Pd149163 Exhibit Antidepressant-Like Effects On Operant Responding In Male Rats, Todd M. Hillhouse, Zachary Shankland, Katelin S. Matazel, Ashley Keiser, Adam J. Prus

Journal Articles

Major depressive disorder (MDD) is the most common mood disorder in the United States and European Union; however, the limitations of clinically available antidepressant drugs have led researchers to pursue novel pharmacological treatments. Clinical studies have reported that monotherapy with the atypical antipsychotic drug quetiapine produces a rapid reduction in depressive symptoms that are apparent following one week of quetiapine treatment, and it is possible that the active metabolite N-Desalkylquetiapine, which structurally resembles an antidepressant drug, produces antidepressant effects. Neuropharmacological evaluations of the neurotensin NTS1 receptor agonist PD149163 are suggestive of antidepressant efficacy, but the effects of a NTS …


The Effects Of Nesting Environment On Neonatal Hypoxic-Ischemic Injury, Laura Grace Rollins Dec 2013

The Effects Of Nesting Environment On Neonatal Hypoxic-Ischemic Injury, Laura Grace Rollins

Graduate Masters Theses

Term neonates with hypoxic-ischemic (HI) injury are at risk for devastating neurological sequelae. The objective of this study is to determine if altering the early environment for maternal care-taking impacts the immediate and long-term sequelae of HI offspring. The Rice-Vannucci model was used to induce HI in postnatal day (PND) 7 Long-Evans pups. Litters were assigned to a closed nest (CN) or normal standard housing (SH) condition. Neurobehavioral development, cognitive ability, and stress response were assessed to establish any benefits of the CN condition. Finally, postmortem brain tissue was analyzed for morphometric markers of injury.


Beyond Perceptual Expertise: Revisiting The Neural Substrates Of Expert Object Recognition, Assaf Harel, Dwight J. Kravitz, Chris I. Baker Dec 2013

Beyond Perceptual Expertise: Revisiting The Neural Substrates Of Expert Object Recognition, Assaf Harel, Dwight J. Kravitz, Chris I. Baker

Psychology Faculty Publications

Real-world expertise provides a valuable opportunity to understand how experience shapes human behavior and neural function. In the visual domain, the study of expert object recognition, such as in car enthusiasts or bird watchers, has produced a large, growing, and often-controversial literature. Here, we synthesize this literature, focusing primarily on results from functional brain imaging, and propose an interactive framework that incorporates the impact of high-level factors, such as attention and conceptual knowledge, in supporting expertise. This framework contrasts with the perceptual view of object expertise that has concentrated largely on stimulus-driven processing in visual cortex. One prominent version of …


The Relation Between Finger Gnosis And Mathematical Ability: Why Redeployment Of Neural Circuits Best Explains The Finding, Marcie Penner-Wilger, Michael L. Anderson Dec 2013

The Relation Between Finger Gnosis And Mathematical Ability: Why Redeployment Of Neural Circuits Best Explains The Finding, Marcie Penner-Wilger, Michael L. Anderson

Brain and Mind Institute Researchers' Publications

This paper elaborates a novel hypothesis regarding the observed predictive relation between finger gnosis and mathematical ability. In brief, we suggest that these two cognitive phenomena have overlapping neural substrates, as the result of the re-use ("redeployment") of part of the finger gnosis circuit for the purpose of representing numbers. We offer some background on the relation and current explanations for it; an outline of our alternate hypothesis; some evidence supporting redeployment over current views; and a plan for further research.


Functional And Structural Changes Throughout The Auditory System Following Congenital And Early-Onset Deafness: Implications For Hearing Restoration, Blake E. Butler, Stephen G. Lombar Nov 2013

Functional And Structural Changes Throughout The Auditory System Following Congenital And Early-Onset Deafness: Implications For Hearing Restoration, Blake E. Butler, Stephen G. Lombar

Brain and Mind Institute Researchers' Publications

The absence of auditory input, particularly during development, causes widespread changes in the structure and function of the auditory system, extending from peripheral structures into auditory cortex. In humans, the consequences of these changes are far-reaching and often include detriments to language acquisition, and associated psychosocial issues.Much of what is currently known about the nature of deafness-related changes to auditory structures comes from studies of congenitally deaf or early-deafened animal models. Fortunately, the mammalian auditory system shows a high degree of preservation among species, allowing for generalization from these models to the human auditory system. This review begins with a …


Bdnf In The Dentate Gyrus Is Required For Consolidation Of "Pattern-Separated" Memories., Pedro Bekinschtein, Brianne A Kent, Charlotte A Oomen, Gregory D Clemenson, Fred H Gage, Lisa M Saksida, Timothy J Bussey Nov 2013

Bdnf In The Dentate Gyrus Is Required For Consolidation Of "Pattern-Separated" Memories., Pedro Bekinschtein, Brianne A Kent, Charlotte A Oomen, Gregory D Clemenson, Fred H Gage, Lisa M Saksida, Timothy J Bussey

Brain and Mind Institute Researchers' Publications

Successful memory involves not only remembering information over time, but also keeping memories distinct and less confusable. The computational process for making representations for similar input patterns more distinct from each other has been referred to as "pattern separation." In this work, we developed a set of behavioral conditions that allowed us to manipulate the load for pattern separation at different stages of memory. Thus, we provide experimental evidence that a brain-derived neurotrophic factor (BDNF)-dependent pattern separation process occurs during the encoding/storage/consolidation, but not the retrieval stage of memory processing. We also found that a spontaneous increase in BDNF in …


The Touchscreen Operant Platform For Testing Learning And Memory In Rats And Mice., Alexa E Horner, Christopher J Heath, Martha Hvoslef-Eide, Brianne A Kent, Chi Hun Kim, Simon R O Nilsson, Johan Alsiö, Charlotte A Oomen, Andrew Holmes, Lisa M Saksida, Timothy J Bussey Oct 2013

The Touchscreen Operant Platform For Testing Learning And Memory In Rats And Mice., Alexa E Horner, Christopher J Heath, Martha Hvoslef-Eide, Brianne A Kent, Chi Hun Kim, Simon R O Nilsson, Johan Alsiö, Charlotte A Oomen, Andrew Holmes, Lisa M Saksida, Timothy J Bussey

Brain and Mind Institute Researchers' Publications

An increasingly popular method of assessing cognitive functions in rodents is the automated touchscreen platform, on which a number of different cognitive tests can be run in a manner very similar to touchscreen methods currently used to test human subjects. This methodology is low stress (using appetitive rather than aversive reinforcement), has high translational potential and lends itself to a high degree of standardization and throughput. Applications include the study of cognition in rodent models of psychiatric and neurodegenerative diseases (e.g., Alzheimer's disease, schizophrenia, Huntington's disease, frontotemporal dementia), as well as the characterization of the role of select brain regions, …


The Touchscreen Operant Platform For Testing Working Memory And Pattern Separation In Rats And Mice., Charlotte A Oomen, Martha Hvoslef-Eide, Christopher J Heath, Adam C Mar, Alexa E Horner, Timothy J Bussey, Lisa M Saksida Oct 2013

The Touchscreen Operant Platform For Testing Working Memory And Pattern Separation In Rats And Mice., Charlotte A Oomen, Martha Hvoslef-Eide, Christopher J Heath, Adam C Mar, Alexa E Horner, Timothy J Bussey, Lisa M Saksida

Brain and Mind Institute Researchers' Publications

The automated touchscreen operant chamber for rats and mice allows for the assessment of multiple cognitive domains within the same testing environment. This protocol presents the location discrimination (LD) task and the trial-unique delayed nonmatching-to-location (TUNL) task, which both assess memory for location. During these tasks, animals are trained to a predefined criterion during ∼20-40 daily sessions. In LD sessions, touching the same location on the screen is rewarded on consecutive trials, followed by a reversal of location-reward contingencies. TUNL, a working memory task, requires animals to 'nonmatch' to a sample location after a delay. In both the LD and …


The Touchscreen Operant Platform For Assessing Executive Function In Rats And Mice., Adam C Mar, Alexa E Horner, Simon R O Nilsson, Johan Alsiö, Brianne A Kent, Chi Hun Kim, Andrew Holmes, Lisa M Saksida, Timothy J Bussey Oct 2013

The Touchscreen Operant Platform For Assessing Executive Function In Rats And Mice., Adam C Mar, Alexa E Horner, Simon R O Nilsson, Johan Alsiö, Brianne A Kent, Chi Hun Kim, Andrew Holmes, Lisa M Saksida, Timothy J Bussey

Brain and Mind Institute Researchers' Publications

This protocol details a subset of assays developed within the touchscreen platform to measure various aspects of executive function in rodents. Three main procedures are included: extinction, measuring the rate and extent of curtailing a response that was previously, but is no longer, associated with reward; reversal learning, measuring the rate and extent of switching a response toward a visual stimulus that was previously not, but has become, associated with reward (and away from a visual stimulus that was previously, but is no longer, rewarded); and the 5-choice serial reaction time (5-CSRT) task, gauging the ability to selectively detect and …


A Multivariate Method To Determine The Dimensionality Of Neural Representation From Population Activity., Jörn Diedrichsen, Tobias Wiestler, Naveed Ejaz Aug 2013

A Multivariate Method To Determine The Dimensionality Of Neural Representation From Population Activity., Jörn Diedrichsen, Tobias Wiestler, Naveed Ejaz

Brain and Mind Institute Researchers' Publications

How do populations of neurons represent a variable of interest? The notion of feature spaces is a useful concept to approach this question: According to this model, the activation patterns across a neuronal population are composed of different pattern components. The strength of each of these components varies with one latent feature, which together are the dimensions along which the population represents the variable. Here we propose a new method to determine the number of feature dimensions that best describes the activation patterns. The method is based on Gaussian linear classifiers that use only the first d most important pattern …


Alternations Of Nmda And Gabab Receptor Function In Development: A Potential Animal Model Of Schizophrenia, Monica Bolton Aug 2013

Alternations Of Nmda And Gabab Receptor Function In Development: A Potential Animal Model Of Schizophrenia, Monica Bolton

UNLV Theses, Dissertations, Professional Papers, and Capstones

Schizophrenia is a debilitating mental disorder that affects up to 3% of the world population. The behavioral symptoms are categorized into positive and negative symptoms, which appear during late adolescence/early adulthood. Unfortunately, the underlying cellular and molecular mechanisms of the disease are poorly understood. Several hypotheses exist to explain mechanisms contributing to these behavioral alterations. One model proposes that a reduced function of the NMDA glutamate receptor on specific GABAergic interneurons may be responsible for deficits in schizophrenia. Post-mortem investigations provide evidence of reductions in both glutamate and GABA-related proteins in patients with schizophrenia. Further, GABAergic interneurons that are activated …


Skill Learning Strengthens Cortical Representations Of Motor Sequences., Tobias Wiestler, Jörn Diedrichsen Jul 2013

Skill Learning Strengthens Cortical Representations Of Motor Sequences., Tobias Wiestler, Jörn Diedrichsen

Brain and Mind Institute Researchers' Publications

Motor-skill learning can be accompanied by both increases and decreases in brain activity. Increases may indicate neural recruitment, while decreases may imply that a region became unimportant or developed a more efficient representation of the skill. These overlapping mechanisms make interpreting learning-related changes of spatially averaged activity difficult. Here we show that motor-skill acquisition is associated with the emergence of highly distinguishable activity patterns for trained movement sequences, in the absence of average activity increases. During functional magnetic resonance imaging, participants produced either four trained or four untrained finger sequences. Using multivariate pattern analysis, both untrained and trained sequences could …


Erps Reveal The Temporal Dynamics Of Auditory Word Recognition In Specific Language Impairment., Jeffrey G Malins, Amy S Desroches, Erin K Robertson, Randy Lynn Newman, Lisa M D Archibald, Marc F Joanisse Jul 2013

Erps Reveal The Temporal Dynamics Of Auditory Word Recognition In Specific Language Impairment., Jeffrey G Malins, Amy S Desroches, Erin K Robertson, Randy Lynn Newman, Lisa M D Archibald, Marc F Joanisse

Brain and Mind Institute Researchers' Publications

We used event-related potentials (ERPs) to compare auditory word recognition in children with specific language impairment (SLI group; N=14) to a group of typically developing children (TD group; N=14). Subjects were presented with pictures of items and heard auditory words that either matched or mismatched the pictures. Mismatches overlapped expected words in word-onset (cohort mismatches; see: DOLL, hear: dog), rhyme (CONE -bone), or were unrelated (SHELL -mug). In match trials, the SLI group showed a different pattern of N100 responses to auditory stimuli compared to the TD group, indicative of early auditory processing differences in SLI. However, the phonological mapping …


Dynamic And Opposing Adjustment Of Movement Cancellation And Generation In An Oculomotor Countermanding Task., Brian D Corneil, Joshua C Cheng, Samanthi C Goonetilleke Jun 2013

Dynamic And Opposing Adjustment Of Movement Cancellation And Generation In An Oculomotor Countermanding Task., Brian D Corneil, Joshua C Cheng, Samanthi C Goonetilleke

Brain and Mind Institute Researchers' Publications

Adaptive adjustments of strategies help optimize behavior in a dynamic and uncertain world. Previous studies in the countermanding (or stop-signal) paradigm have detailed how reaction times (RTs) change with trial sequence, demonstrating adaptive control of movement generation. Comparatively little is known about the adaptive control of movement cancellation in the countermanding task, mainly because movement cancellation implies the absence of an outcome and estimates of movement cancellation require hundreds of trials. Here, we exploit a within-trial proxy of movement cancellation based on recordings of neck muscle activity while human subjects attempted to cancel large eye-head gaze shifts. On a subset …


Intracranial Injection Of Gammagard, A Human Ivig, Modulates The Inflammatory Response Of The Brain And Lowers AΒ In App/Ps1 Mice Along A Different Time Course Than Anti-AΒ Antibodies, Tiffany L. Sudduth, Abigail Greenstein, Donna M. Wilcock Jun 2013

Intracranial Injection Of Gammagard, A Human Ivig, Modulates The Inflammatory Response Of The Brain And Lowers AΒ In App/Ps1 Mice Along A Different Time Course Than Anti-AΒ Antibodies, Tiffany L. Sudduth, Abigail Greenstein, Donna M. Wilcock

Sanders-Brown Center on Aging Faculty Publications

Gammagard IVIg is a therapeutic approach to treat Alzheimer's disease currently in phase 3 clinical trials. Despite the reported efficacy of the approach the mechanism of action is poorly understood. We have previously shown that intracranial injection of anti-Aβ antibodies into the frontal cortex and hippocampus reveals important information regarding the time course of events once the agent is in the brain. In the current study we compared IVIg, mouse-pooled IgG, and the anti-Aβ antibody 6E10 injected intracranially into the frontal cortex and hippocampus of 7-month-old APP/PS1 mice. We established a time course of events ranging from 1 …


Two Distinct Ipsilateral Cortical Representations For Individuated Finger Movements., Jörn Diedrichsen, Tobias Wiestler, John W Krakauer Jun 2013

Two Distinct Ipsilateral Cortical Representations For Individuated Finger Movements., Jörn Diedrichsen, Tobias Wiestler, John W Krakauer

Brain and Mind Institute Researchers' Publications

Movements of the upper limb are controlled mostly through the contralateral hemisphere. Although overall activity changes in the ipsilateral motor cortex have been reported, their functional significance remains unclear. Using human functional imaging, we analyzed neural finger representations by studying differences in fine-grained activation patterns for single isometric finger presses. We demonstrate that cortical motor areas encode ipsilateral movements in 2 fundamentally different ways. During unimanual ipsilateral finger presses, primary sensory and motor cortices show, underneath global suppression, finger-specific activity patterns that are nearly identical to those elicited by contralateral mirror-symmetric action. This component vanishes when both motor cortices are …


Prefrontal Neurons Of Opposite Spatial Preference Display Distinct Target Selection Dynamics., Therese Lennert, Julio C Martinez-Trujillo May 2013

Prefrontal Neurons Of Opposite Spatial Preference Display Distinct Target Selection Dynamics., Therese Lennert, Julio C Martinez-Trujillo

Brain and Mind Institute Researchers' Publications

Neurons in the primate dorsolateral prefrontal cortex (dlPFC) of one hemisphere are selective for the location of attended targets in both visual hemifields. Whether dlPFC neurons with selectivity for opposite hemifields directly compete with each other for target selection or instead play distinct roles during the allocation of attention remains unclear. We explored this issue by recording neuronal responses in the right dlPFC of two macaques while they allocated attention to a target in one hemifield and ignored a distracter on the opposite side. Forty-nine percent of the recorded neurons were target location selective. Neurons selective for contralateral targets (58%) …


Decoding The Neural Mechanisms Of Human Tool Use., Jason P Gallivan, D Adam Mclean, Kenneth F Valyear, Jody C Culham May 2013

Decoding The Neural Mechanisms Of Human Tool Use., Jason P Gallivan, D Adam Mclean, Kenneth F Valyear, Jody C Culham

Brain and Mind Institute Researchers' Publications

Sophisticated tool use is a defining characteristic of the primate species but how is it supported by the brain, particularly the human brain? Here we show, using functional MRI and pattern classification methods, that tool use is subserved by multiple distributed action-centred neural representations that are both shared with and distinct from those of the hand. In areas of frontoparietal cortex we found a common representation for planned hand- and tool-related actions. In contrast, in parietal and occipitotemporal regions implicated in hand actions and body perception we found that coding remained selectively linked to upcoming actions of the hand whereas …


The Human Brain Processes Syntax In The Absence Of Conscious Awareness., Laura Batterink, Helen J Neville May 2013

The Human Brain Processes Syntax In The Absence Of Conscious Awareness., Laura Batterink, Helen J Neville

Brain and Mind Institute Researchers' Publications

Syntax is the core computational component of language. A longstanding idea about syntactic processing is that it is generally not available to conscious access, operating autonomously and automatically. However, there is little direct neurocognitive evidence on this issue. By measuring event-related potentials while human observers performed a novel cross-modal distraction task, we demonstrated that syntactic violations that were not consciously detected nonetheless produced a characteristic early neural response pattern, and also significantly delayed reaction times to a concurrent task. This early neural response was distinct from later neural activity that was observed only to syntactic violations that were consciously detected. …


Activation And Suppression Of The Innate Immune System: Effects On Alcohol Intake, Marjorie Levinstein May 2013

Activation And Suppression Of The Innate Immune System: Effects On Alcohol Intake, Marjorie Levinstein

Seton Hall University Dissertations and Theses (ETDs)

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