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Articles 31 - 60 of 88
Full-Text Articles in Neuroscience and Neurobiology
Functional And Developmental Identification Of A Molecular Subtype Of Brain Serotonergic Neuron Specialized To Regulate Breathing Dynamics, Rachael D. Brust, Andrea E. Corcoran, George B. Richerson, Eugene Nattie, Susan M. Dymecki
Functional And Developmental Identification Of A Molecular Subtype Of Brain Serotonergic Neuron Specialized To Regulate Breathing Dynamics, Rachael D. Brust, Andrea E. Corcoran, George B. Richerson, Eugene Nattie, Susan M. Dymecki
Dartmouth Scholarship
Serotonergic neurons modulate behavioral and physiological responses from aggression and anxiety to breathing and thermoregulation. Disorders involving serotonin (5HT) dysregulation are commensurately heterogeneous and numerous. We hypothesized that this breadth in functionality derives in part from a developmentally determined substructure of distinct subtypes of 5HT neurons each specialized to modulate specific behaviors. By manipulating developmentally defined subgroups one by one chemogenetically, we find that the Egr2-Pet1 subgroup is specialized to drive increased ventilation in response to carbon dioxide elevation and acidosis. Furthermore, this subtype exhibits intrinsic chemosensitivity and modality-specific projections-increasing firing during hypercapnic acidosis and selectively projecting to respiratory chemosensory …
Dissociation Between Face Perception And Face Memory In Adults, But Not Children, With Developmental Prosopagnosia, Kirsten A. Dalrymple, Lúcia Garrido, Brad Duchaine
Dissociation Between Face Perception And Face Memory In Adults, But Not Children, With Developmental Prosopagnosia, Kirsten A. Dalrymple, Lúcia Garrido, Brad Duchaine
Dartmouth Scholarship
Cognitive models propose that face recognition is accomplished through a series of discrete stages, including perceptual representation of facial structure, and encoding and retrieval of facial information. This implies that impaired face recognition can result from failures of face perception, face memory, or both. Studies of acquired prosopagnosia, autism spectrum disorders, and the development of normal face recognition support the idea that face perception and face memory are distinct processes, yet this distinction has received little attention in developmental prosopagnosia (DP). To address this issue, we tested the face perception and face memory of children and adults with DP. By …
Activity-Dependent Serotonergic Excitation Of Callosal Projection Neurons In The Mouse Prefrontal Cortex, Emily K. Stephens, Daniel Avesar, Allan T. Gulledge
Activity-Dependent Serotonergic Excitation Of Callosal Projection Neurons In The Mouse Prefrontal Cortex, Emily K. Stephens, Daniel Avesar, Allan T. Gulledge
Dartmouth Scholarship
Layer 5 pyramidal neurons (L5PNs) in the mouse prefrontal cortex respond to serotonin (5-HT) according to their long-distance axonal projections; 5-HT1A (1A) receptors mediate inhibitory responses in corticopontine (CPn) L5PNs, while 5-HT2A (2A) receptors can enhance action potential (AP) output in callosal/commissural (COM) L5PNs, either directly (in “COM-excited” neurons), or following brief 1A-mediated inhibition (in “COM-biphasic” neurons). Here we compare the impact of 5-HT on the excitability of CPn and COM L5PNs experiencing variable excitatory drive produced by current injection (DC current or simulated synaptic current) or with exogenous glutamate. 5-HT delivered at resting membrane potentials, or paired …
What Can Individual Differences Reveal About Face Processing?, Galit Yovel, Jeremy B. Wilmer, Brad Duchaine
What Can Individual Differences Reveal About Face Processing?, Galit Yovel, Jeremy B. Wilmer, Brad Duchaine
Dartmouth Scholarship
Faces are probably the most widely studied visual stimulus. Most research on face processing has used a group-mean approach that averages behavioral or neural responses to faces across individuals and treats variance between individuals as noise. However, individual differences in face processing can provide valuable information that complements and extends findings from group-mean studies. Here we demonstrate that studies employing an individual differences approach—examining associations and dissociations across individuals—can answer fundamental questions about the way face processing operates. In particular these studies allow us to associate and dissociate the mechanisms involved in face processing, tie behavioral face processing mechanisms to …
Unconscious Neural Processing Differs With Method Used To Render Stimuli Invisible, Sergey V. Fogelson, Peter J. Kohler, Kevin J. Miller, Richard Granger, Peter U. Tse
Unconscious Neural Processing Differs With Method Used To Render Stimuli Invisible, Sergey V. Fogelson, Peter J. Kohler, Kevin J. Miller, Richard Granger, Peter U. Tse
Dartmouth Scholarship
Visual stimuli can be kept from awareness using various methods. The extent of processing that a given stimulus receives in the absence of awareness is typically used to make claims about the role of consciousness more generally. The neural processing elicited by a stimulus, however, may also depend on the method used to keep it from awareness, and not only on whether the stimulus reaches awareness. Here we report that the method used to render an image invisible has a dramatic effect on how category information about the unseen stimulus is encoded across the human brain. We collected fMRI data …
Online Tracking Of The Contents Of Conscious Perception Using Real-Time Fmri, Christoph Reichert, Robert Fendrich, Johannes Bernarding, Claus Tempelmann, Hermann Hinrichs, Jochem W. Rieger
Online Tracking Of The Contents Of Conscious Perception Using Real-Time Fmri, Christoph Reichert, Robert Fendrich, Johannes Bernarding, Claus Tempelmann, Hermann Hinrichs, Jochem W. Rieger
Dartmouth Scholarship
Perception is an active process that interprets and structures the stimulus input based on assumptions about its possible causes. We use real-time functional magnetic resonance imaging (rtfMRI) to investigate a particularly powerful demonstration of dynamic object integration in which the same physical stimulus intermittently elicits categorically different conscious object percepts. In this study, we simulated an outline object that is moving behind a narrow slit. With such displays, the physically identical stimulus can elicit categorically different percepts that either correspond closely to the physical stimulus (vertically moving line segments) or represent a hypothesis about the underlying cause of the physical …
Fatty Acids Increase Neuronal Hypertrophy Of Pten Knockdown Neurons, Catherine J. Fricano, Tyrone Despenza, Paul W. Frazel, Meijie Li, A. James O'Malley, Gary Westbrook, Bryan Luikart
Fatty Acids Increase Neuronal Hypertrophy Of Pten Knockdown Neurons, Catherine J. Fricano, Tyrone Despenza, Paul W. Frazel, Meijie Li, A. James O'Malley, Gary Westbrook, Bryan Luikart
Dartmouth Scholarship
Phosphatase and tensin homolog (Pten) catalyzes the reverse reaction of PI3K by dephosphorylating PIP3 to PIP2. This negatively regulates downstream Akt/mTOR/S6 signaling resulting in decreased cellular growth and proliferation. Co-injection of a lentivirus knocking Pten down with a control lentivirus allows us to compare the effects of Pten knockdown between individual neurons within the same animal. We find that knockdown of Pten results in neuronal hypertrophy by 21 days post-injection. This neuronal hypertrophy is correlated with increased p-S6 and p-mTOR in individual neurons. We used this system to test whether an environmental factor that has been implicated in cellular hypertrophy …
Movement-Based Embodied Contemplative Practices: Definitions And Paradigms, Laura Schmalzl, Mardi A. Crane-Godreau, Peter Payne
Movement-Based Embodied Contemplative Practices: Definitions And Paradigms, Laura Schmalzl, Mardi A. Crane-Godreau, Peter Payne
Dartmouth Scholarship
Over the past decades, cognitive neuroscience has witnessed a shift from predominantly disembodied and computational views of the mind, to more embodied and situated views of the mind. These postulate that mental functions cannot be fully understood without reference to the physical body and the environment in which they are experienced. Within the field of contemplative science, the directing of attention to bodily sensations has so far mainly been studied in the context of seated meditation and mindfulness practices. However, the cultivation of interoceptive, proprioceptive and kinesthetic awareness is also said to lie at the core of many movement-based contemplative …
Normal Acquisition Of Expertise With Greebles In Two Cases Of Acquired Prosopagnosia, Constantin Rezlescu, Jason J. S. Barton, David Pitcher, Bradley Duchaine
Normal Acquisition Of Expertise With Greebles In Two Cases Of Acquired Prosopagnosia, Constantin Rezlescu, Jason J. S. Barton, David Pitcher, Bradley Duchaine
Dartmouth Scholarship
Face recognition is generally thought to rely on different neurocognitive mechanisms than most types of objects, but the specificity of these mechanisms is debated. One account suggests the mechanisms are specific to upright faces, whereas the expertise view proposes the mechanisms operate on objects of high within-class similarity with which an observer has become proficient at rapid individuation. Much of the evidence cited in support of the expertise view comes from laboratory-based training experiments involving computer-generated objects called greebles that are designed to place face-like demands on recognition mechanisms. A fundamental prediction of the expertise hypothesis is that recognition deficits …
The N400 As An Index Of Racial Stereotype Accessibility, Eric Hehman, Hannah I. Volpert, Robert F. Simons
The N400 As An Index Of Racial Stereotype Accessibility, Eric Hehman, Hannah I. Volpert, Robert F. Simons
Dartmouth Scholarship
The current research examined the viability of the N400, an event-related potential (ERP) related to the detection of semantic incongruity, as an index of both stereotype accessibility and interracial prejudice. Participants’ EEG was recorded while they completed a sequential priming task, in which negative or positive, stereotypically black (African American) or white (Caucasian American) traits followed the presentation of either a black or white face acting as a prime. ERP examination focused on the N400, but additionally examined N100 and P200 reactivity. Replicating and extending previous N400 stereotype research, results indicated that the N400 can indeed function as an index …
Exploring Emotions Using Invasive Methods: Review Of 60 Years Of Human Intracranial Electrophysiology, Sean A. Guillory, Krzysztof A. Bujarski
Exploring Emotions Using Invasive Methods: Review Of 60 Years Of Human Intracranial Electrophysiology, Sean A. Guillory, Krzysztof A. Bujarski
Dartmouth Scholarship
Over the past 60 years, human intracranial electrophysiology (HIE) has been used to characterize seizures in patients with epilepsy. Secondary to the clinical objectives, electrodes implanted intracranially have been used to investigate mechanisms of human cognition. In addition to studies of memory and language, HIE methods have been used to investigate emotions. The aim of this review is to outline the contribution of HIE (electrocorticography, single-unit recording and electrical brain stimulation) to our understanding of the neural representations of emotions. We identified 64 papers dating back to the mid-1950s which used HIE techniques to study emotional states. Evidence from HIE …
Investigating Habits: Strategies,Technologies And Models, Kyle S. Smith, Ann M. Graybiel
Investigating Habits: Strategies,Technologies And Models, Kyle S. Smith, Ann M. Graybiel
Dartmouth Scholarship
Understanding habits at a biological level requires a combination of behavioral observations and measures of ongoing neural activity. Theoretical frameworks as well as definitions of habitual behaviors emerging from classic behavioral research have been enriched by new approaches taking account of the identification of brain regions and circuits related to habitual behavior. Together, this combination of experimental and theoretical work has provided key insights into how brain circuits underlying action-learning and action-selection are organized, and how a balance between behavioral flexibility and fixity is achieved. New methods to monitor and manipulate neural activity in real time are allowing us to …
The Mammalian Neocortex New Pyramidal Neuron: A New Conception, Miguel Marín-Padilla
The Mammalian Neocortex New Pyramidal Neuron: A New Conception, Miguel Marín-Padilla
Dartmouth Scholarship
The new cerebral cortex (neocortex) and the new type of pyramidal neuron are mammalian innovations that have evolved for operating their increasing motor capabilities while essentially using analogous anatomical and neural makeups. The human neocortex starts to develop in 6-week-old embryos with the establishment of a primordial cortical organization, which resembles the primitive cortices of amphibian and reptiles. From the 8th to the 15th week of age, new pyramidal neurons, of ependymal origin, are progressively incorporated within this primordial cortex forming a cellular plate that divides its components into those above it (neocortex first layer) and those below it (neocortex …
Enrichment And Training Improve Cognition In Rats With Cortical Malformations, Kyle R. Jenks, Marcella M. Lucas, Ben A. Duffy, Ashlee A. Robbins, Barjor Gimi, Jeremy M. Barry, Rod C. Scott
Enrichment And Training Improve Cognition In Rats With Cortical Malformations, Kyle R. Jenks, Marcella M. Lucas, Ben A. Duffy, Ashlee A. Robbins, Barjor Gimi, Jeremy M. Barry, Rod C. Scott
Dartmouth Scholarship
Children with malformations of cortical development (MCD) frequently have associated cognitive impairments which reduce quality of life. We hypothesized that cognitive deficits associated with MCD can be improved with environmental manipulation or additional training. The E17 methylazoxymethanol acetate (MAM) exposure model bears many anatomical hallmarks seen in human MCDs as well as similar behavioral and cognitive deficits. We divided control and MAM exposed Sprague-Dawley rats into enriched and non-enriched groups and tested performance in the Morris water maze. Another group similarly divided underwent sociability testing and also underwent Magnetic Resonance Imaging (MRI) scans pre and post enrichment. A third group …
On The Evolution Of The Serotonin Transporter Linked Polymorphic Region (5-Httlpr) In Primates, Seth D. Dobson, Lauren J.N Brent
On The Evolution Of The Serotonin Transporter Linked Polymorphic Region (5-Httlpr) In Primates, Seth D. Dobson, Lauren J.N Brent
Dartmouth Scholarship
Some allelic variants of the serotonin transporter linked polymorphic region (5-HTTLPR) result in lower levels of expression of the serotonin transporter gene (SLC6A4). These low-expressing (LE) alleles are associated with mental-health disorders in a minority of humans that carry them. Humans are not the only primates that exhibit this polymorphism; other species, including some monkeys, also have LE and high-expressing (HE) variants of 5-HTTLPR. We propose a behavioral genetic framework to explain the adaptive evolution of this polymorphism in primates, including humans. We hypothesize that both LE and HE alleles are maintained by balancing selection in species characterized …
Short Duration Waveforms Recorded Extracellularly From Freely Moving Rats Are Representative Of Axonal Activity, Ashlee A. Robbins, Steven E. Fox, Gregory L. Holmes, Rod C. Scott, Jeremy M. Barry
Short Duration Waveforms Recorded Extracellularly From Freely Moving Rats Are Representative Of Axonal Activity, Ashlee A. Robbins, Steven E. Fox, Gregory L. Holmes, Rod C. Scott, Jeremy M. Barry
Dartmouth Scholarship
While extracellular somatic action potentials from freely moving rats have been well characterized, axonal activity has not. We report direct extracellular tetrode recordings of putative axons whose principal feature is a short duration waveform (SDW) with an average peak-trough length less than 179 μs. While SDW recordings using tetrodes have previously been treated as questionable or classified as cells, we hypothesize that they are representative of axonal activity. These waveforms have significantly shorter duration than somatic action potentials, are triphasic and are therefore similar to classic descriptions of microelectrode recordings in white matter and of in vitro action potential propagation …
Socially Excluded Individuals Fail To Recruit Medial Prefrontal Cortex For Negative Social Scenes, Katherine E. Powers, Dylan D. Wagner, Catherine J. Norris, Todd F. Heatherton
Socially Excluded Individuals Fail To Recruit Medial Prefrontal Cortex For Negative Social Scenes, Katherine E. Powers, Dylan D. Wagner, Catherine J. Norris, Todd F. Heatherton
Dartmouth Scholarship
Converging behavioral evidence suggests that people respond to experiences of social exclusion with both defensive and affiliative strategies, allowing them to avoid further distress while also encouraging re-establishment of positive social connections. However, there are unresolved questions regarding the cognitive mechanisms underlying people's responses to social exclusion. Here, we sought to gain insight into these behavioral tendencies by using functional magnetic resonance imaging (fMRI) to examine the impact of social exclusion on neural responses to visual scenes that varied on dimensions of sociality and emotional valence. Compared to socially included participants, socially excluded participants failed to recruit dorsomedial prefrontal cortex …
Network Structure And Dynamics Of The Mental Workspace, Alexander Schlegel, Peter J. Kohler, Sergei V. Fogelson, Prescott Alexander
Network Structure And Dynamics Of The Mental Workspace, Alexander Schlegel, Peter J. Kohler, Sergei V. Fogelson, Prescott Alexander
Dartmouth Scholarship
The conscious manipulation of mental representations is central to many creative and uniquely human abilities. How does the human brain mediate such flexible mental operations? Here, multivariate pattern analysis of functional MRI data reveals a widespread neural network that performs specific mental manipulations on the contents of visual imagery. Evolving patterns of neural activity within this mental workspace track the sequence of informational transformations carried out by these manipulations. The network switches between distinct connectivity profiles as representations are maintained or manipulated.
Understanding Less Than Nothing: Children's Neural Response To Negative Numbers Shifts Across Age And Accuracy, Margaret M. Gullick, George Wolford
Understanding Less Than Nothing: Children's Neural Response To Negative Numbers Shifts Across Age And Accuracy, Margaret M. Gullick, George Wolford
Dartmouth Scholarship
We examined the brain activity underlying the development of our understanding of negative numbers, which are amounts lacking direct physical counterparts. Children performed a paired comparison task with positive and negative numbers during an fMRI session. As previously shown in adults, both pre-instruction fifth-graders and post-instruction seventh-graders demonstrated typical behavioral and neural distance effects to negative numbers, where response times and parietal and frontal activity increased as comparison distance decreased. We then determined the factors impacting the distance effect in each age group. Behaviorally, the fifth-grader distance effect for negatives was significantly predicted only by positive comparison accuracy, indicating that …
Self-Regulatory Depletion Increases Emotional Reactivity In The Amygdala, Dylan D. Wagner, Todd F. Heatherton
Self-Regulatory Depletion Increases Emotional Reactivity In The Amygdala, Dylan D. Wagner, Todd F. Heatherton
Dartmouth Scholarship
The ability to self-regulate can become impaired when people are required to engage in successive acts of effortful self-control, even when self-control occurs in different domains. Here, we used functional neuroimaging to test whether engaging in effortful inhibition in the cognitive domain would lead to putative dysfunction in the emotional domain. Forty-eight participants viewed images of emotional scenes during functional magnetic resonance imaging in two sessions that were separated by a challenging attention control task that required effortful inhibition (depletion group) or not (control group). Compared to the control group, depleted participants showed increased activity in the left amygdala to …
Smoothness Without Smoothing: Why Gaussian Naive Bayes Is Not Naive For Multi-Subject Searchlight Studies, Rajeev D.S Raizada, Yune-Sang Lee
Smoothness Without Smoothing: Why Gaussian Naive Bayes Is Not Naive For Multi-Subject Searchlight Studies, Rajeev D.S Raizada, Yune-Sang Lee
Dartmouth Scholarship
Spatial smoothness is helpful when averaging fMRI signals across multiple subjects, as it allows different subjects' corresponding brain areas to be pooled together even if they are slightly misaligned. However, smoothing is usually not applied when performing multivoxel pattern-based analyses (MVPA), as it runs the risk of blurring away the information that fine-grained spatial patterns contain. It would therefore be desirable, if possible, to carry out pattern-based analyses which take unsmoothed data as their input but which produce smooth images as output. We show here that the Gaussian Naive Bayes (GNB) classifier does precisely this, when it is used in …
What Can The Organization Of The Brain’S Default Mode Network Tell Us About Self-Knowledge?, Joseph. M. Moran, William M. Kelley, Todd F. Heatherton
What Can The Organization Of The Brain’S Default Mode Network Tell Us About Self-Knowledge?, Joseph. M. Moran, William M. Kelley, Todd F. Heatherton
Dartmouth Scholarship
Understanding ourselves has been a fundamental topic for psychologists and philosophers alike. In this paper we review the evidence linking specific brain structures to self-reflection. The brain regions most associated with self-reflection are the posterior cingulate and medial prefrontal (mPFC) cortices, together known as the cortical midline structures (CMSs). We review evidence arguing that self-reflection is special in memory, while noting that these brain regions are often engaged when we think about others in our social worlds. Based on the CMSs’ patterns of connectivity and activity, we speculate about three possible interpretations of their role in supporting self-reflection that are …
Prioritized Detection Of Personally Familiar Faces, Maria Ida Gobbini, Jason D. Gors, Yaroslav O. Halchenko, Courtney Rogers, J Swaroop Guntupalli, Howard C. Hughes, Carlo Cipolli
Prioritized Detection Of Personally Familiar Faces, Maria Ida Gobbini, Jason D. Gors, Yaroslav O. Halchenko, Courtney Rogers, J Swaroop Guntupalli, Howard C. Hughes, Carlo Cipolli
Dartmouth Scholarship
We investigated whether personally familiar faces are preferentially processed in conditions of reduced attentional resources and in the absence of conscious awareness. In the first experiment, we used Rapid Serial Visual Presentation (RSVP) to test the susceptibility of familiar faces and faces of strangers to the attentional blink. In the second experiment, we used continuous flash interocular suppression to render stimuli invisible and measured face detection time for personally familiar faces as compared to faces of strangers. In both experiments we found an advantage for detection of personally familiar faces as compared to faces of strangers. Our data suggest that …
A World Unglued: Simultanagnosia As A Spatial Restriction Of Attention, Kirsten A. Dalrymple, Jason J.S. Barton, Alan Kingstone
A World Unglued: Simultanagnosia As A Spatial Restriction Of Attention, Kirsten A. Dalrymple, Jason J.S. Barton, Alan Kingstone
Dartmouth Scholarship
Simultanagnosia is a disorder of visual attention that leaves a patient’s world unglued: scenes and objects are perceived in a piecemeal manner. It is generally agreed that simultanagnosia is related to an impairment of attention, but it is unclear whether this impairment is object- or space-based in nature. We first consider the findings that support a concept of simultanagnosia as deficit of object-based attention. We then examine the evidence suggesting that simultanagnosia results from damage to a space-based attentional system, and in particular a model of simultanagnosia as a narrowed spatial window of attention. We ask whether seemingly object-based deficits …
Implicitly Priming The Social Brain: Failure To Find Neural Effects, Katherine E. Powers, Todd F. Heatherton
Implicitly Priming The Social Brain: Failure To Find Neural Effects, Katherine E. Powers, Todd F. Heatherton
Dartmouth Scholarship
Humans have a fundamental need for social relationships. Rejection from social groups is especially detrimental, rendering the ability to detect threats to social relationships and respond in adaptive ways critical. Indeed, previous research has shown that experiencing social rejection alters the processing of subsequent social cues in a variety of socially affiliative and avoidant ways. Because social perception and cognition occurs spontaneously and automatically, detecting threats to social relationships may occur without conscious awareness or control. Here, we investigated the automaticity of social threat detection by examining how implicit primes affect neural responses to social stimuli. However, despite using a …
Adenosine Deaminase Enhances The Immunogenicity Of Human Dendritic Cells From Healthy And Hiv-Infected Individuals, Víctor Casanova, Isaac Isaac Naval-Macabuhay, Marta Massanella, Marta Rodríguez-García
Adenosine Deaminase Enhances The Immunogenicity Of Human Dendritic Cells From Healthy And Hiv-Infected Individuals, Víctor Casanova, Isaac Isaac Naval-Macabuhay, Marta Massanella, Marta Rodríguez-García
Dartmouth Scholarship
ADA is an enzyme implicated in purine metabolism, and is critical to ensure normal immune function. Its congenital deficit leads to severe combined immunodeficiency (SCID). ADA binding to adenosine receptors on dendritic cell surface enables T-cell costimulation through CD26 crosslinking, which enhances T-cell activation and proliferation. Despite a large body of work on the actions of the ecto-enzyme ADA on T-cell activation, questions arise on whether ADA can also modulate dendritic cell maturation. To this end we investigated the effects of ADA on human monocyte derived dendritic cell biology. Our results show that both the enzymatic and non-enzymatic activities of …
The Human Brain Intracerebral Microvascular System: Development And Structure, Miguel Marín-Padilla
The Human Brain Intracerebral Microvascular System: Development And Structure, Miguel Marín-Padilla
Dartmouth Scholarship
The capillary from the meningeal inner pial lamella play a crucial role in the development and structural organization of the cerebral cortex extrinsic and intrinsic microvascular compartments. Only pial capillaries are capable of perforating through the cortex external glial limiting membrane (EGLM) to enter into the nervous tissue, although incapable of perforating the membrane to exit the brain. Circulatory dynamics and functional demands determine which capillaries become arterial and which capillaries become venous. The perforation of the cortex EGLM by pial capillaries is a complex process characterized by three fundamental stages: (1) pial capillary contact with the EGLM with fusion …
Time-Dependent Statistical And Correlation Properties Of Neural Signals During Handwriting, Valery I. Rupasov, Mikhail A. Lebedev, Joseph S. Erlichman, Stephen L. Lee, James C. Leiter, Michael Linderman
Time-Dependent Statistical And Correlation Properties Of Neural Signals During Handwriting, Valery I. Rupasov, Mikhail A. Lebedev, Joseph S. Erlichman, Stephen L. Lee, James C. Leiter, Michael Linderman
Dartmouth Scholarship
To elucidate the cortical control of handwriting, we examined time-dependent statistical and correlational properties of simultaneously recorded 64-channel electroencephalograms (EEGs) and electromyograms (EMGs) of intrinsic hand muscles. We introduced a statistical method, which offered advantages compared to conventional coherence methods. In contrast to coherence methods, which operate in the frequency domain, our method enabled us to study the functional association between different neural regions in the time domain. In our experiments, subjects performed about 400 stereotypical trials during which they wrote a single character. These trials provided time-dependent EMG and EEG data capturing different handwriting epochs. The set of trials …
Multivoxel Patterns In Face-Sensitive Temporal Regions Reveal An Encoding Schema Based On Detecting Life In A Face, Christine E. Looser, Jyothi S. Guntupalli, Thalia Wheatley
Multivoxel Patterns In Face-Sensitive Temporal Regions Reveal An Encoding Schema Based On Detecting Life In A Face, Christine E. Looser, Jyothi S. Guntupalli, Thalia Wheatley
Dartmouth Scholarship
More than a decade of research has demonstrated that faces evoke prioritized processing in a ‘core face network’ of three brain regions. However, whether these regions prioritize the detection of global facial form (shared by humans and mannequins) or the detection of life in a face has remained unclear. Here, we dissociate form-based and animacy-based encoding of faces by using animate and inanimate faces with human form (humans, mannequins) and dog form (real dogs, toy dogs). We used multivariate pattern analysis of BOLD responses to uncover the representational similarity space for each area in the core face network. Here, we …
Amygdala Responses To Averted Vs Direct Gaze Fear Vary As A Function Of Presentation Speed, Reginald B. Adams, Robert G. Franklin Jr, Kestutis Kveraga, Nalini Ambady, Robert E. Kleck, Paul J. Whalen, Nouchine Hadjikhani, Anthony J. Nelson
Amygdala Responses To Averted Vs Direct Gaze Fear Vary As A Function Of Presentation Speed, Reginald B. Adams, Robert G. Franklin Jr, Kestutis Kveraga, Nalini Ambady, Robert E. Kleck, Paul J. Whalen, Nouchine Hadjikhani, Anthony J. Nelson
Dartmouth Scholarship
We examined whether amygdala responses to rapidly presented fear expressions are preferentially tuned to averted vs direct gaze fear and conversely whether responses to more sustained presentations are preferentially tuned to direct vs averted gaze fear. We conducted three functional magnetic resonance imaging (fMRI) studies to test these predictions including: Study 1: a block design employing sustained presentations (1 s) of averted vs direct gaze fear expressions taken from the Pictures of Facial Affect; Study 2: a block design employing rapid presentations (300 ms) of these same stimuli and Study 3: a direct replication of these studies in the context …