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Articles 91 - 120 of 129

Full-Text Articles in Neuroscience and Neurobiology

Self-Regulatory Depletion Increases Emotional Reactivity In The Amygdala, Dylan D. Wagner, Todd F. Heatherton Aug 2013

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 …

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Smoothness Without Smoothing: Why Gaussian Naive Bayes Is Not Naive For Multi-Subject Searchlight Studies, Rajeev D.S Raizada, Yune-Sang Lee Jul 2013

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 …

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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 Jul 2013

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 …

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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 Jun 2013

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 …

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A World Unglued: Simultanagnosia As A Spatial Restriction Of Attention, Kirsten A. Dalrymple, Jason J.S. Barton, Alan Kingstone Apr 2013

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 …

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Implicitly Priming The Social Brain: Failure To Find Neural Effects, Katherine E. Powers, Todd F. Heatherton Feb 2013

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 …

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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 Dec 2012

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 …

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The Human Brain Intracerebral Microvascular System: Development And Structure, Miguel Marín-Padilla Sep 2012

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 …

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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 Sep 2012

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 …

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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 Jul 2012

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 …

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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 Jun 2012

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 …

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Imaging Prior Information In The Brain, Scott Gorlin, Ming Meng, Jitendra Sharma, Hiroki Sugihara May 2012

Imaging Prior Information In The Brain, Scott Gorlin, Ming Meng, Jitendra Sharma, Hiroki Sugihara

Dartmouth Scholarship

In making sense of the visual world, the brain's processing is driven by two factors: the physical information provided by the eyes (“bottom-up” data) and the expectancies driven by past experience (“top-down” influences). We use degraded stimuli to tease apart the effects of bottom-up and top-down processes because they are easier to recognize with prior knowledge of undegraded images. Using machine learning algorithms, we quantify the amount of information that brain regions contain about stimuli as the subject learns the coherent images. Our results show that several distinct regions, including high-level visual areas and the retinotopic cortex, contain more information …

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The Neurobiology Of Decision-Making And Responsibility: Reconciling Mechanism And Mindedness, Michael N. Shadlen, Adina L. Roskies Apr 2012

The Neurobiology Of Decision-Making And Responsibility: Reconciling Mechanism And Mindedness, Michael N. Shadlen, Adina L. Roskies

Dartmouth Scholarship

This essay reviews recent developments in neurobiology which are beginning to expose the mechanisms that underlie some elements of decision-making that bear on attributions of responsibility. These “elements” have been mainly studied in simple perceptual decision tasks, which are performed similarly by humans and non-human primates. Here we consider the role of neural noise, and suggest that thinking about the role of noise can shift the focus of discussions of randomness in decision-making away from its role in enabling alternate possibilities and toward a potential grounding role for responsibility.

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Electrical Advantages Of Dendritic Spines, Allan T. Gulledge, Nicholas T. Carnevale, Greg J. Stuart Apr 2012

Electrical Advantages Of Dendritic Spines, Allan T. Gulledge, Nicholas T. Carnevale, Greg J. Stuart

Dartmouth Scholarship

Many neurons receive excitatory glutamatergic input almost exclusively onto dendritic spines. In the absence of spines, the amplitudes and kinetics of excitatory postsynaptic potentials (EPSPs) at the site of synaptic input are highly variable and depend on dendritic location. We hypothesized that dendritic spines standardize the local geometry at the site of synaptic input, thereby reducing location-dependent variability of local EPSP properties. We tested this hypothesis using computational models of simplified and morphologically realistic spiny neurons that allow direct comparison of EPSPs generated on spine heads with EPSPs generated on dendritic shafts at the same dendritic locations. In all morphologies …

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Data Sharing In Neuroimaging Research, Jean-Baptiste Poline, Janis L. Breeze, Satrajit Ghosh, Krzysztof Gorgolewski, Yaroslav O. Halchenko Apr 2012

Data Sharing In Neuroimaging Research, Jean-Baptiste Poline, Janis L. Breeze, Satrajit Ghosh, Krzysztof Gorgolewski, Yaroslav O. Halchenko

Dartmouth Scholarship

Significant resources around the world have been invested in neuroimaging studies of brain function and disease. Easier access to this large body of work should have profound impact on research in cognitive neuroscience and psychiatry, leading to advances in the diagnosis and treatment of psychiatric and neurological disease. A trend toward increased sharing of neuroimaging data has emerged in recent years. Nevertheless, a number of barriers continue to impede momentum. Many researchers and institutions remain uncertain about how to share data or lack the tools and expertise to participate in data sharing. The use of electronic data capture (EDC) methods …

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Selective Serotonergic Excitation Of Callosal Projection Neurons, Daniel Avesar, Allan T. Gulledge Mar 2012

Selective Serotonergic Excitation Of Callosal Projection Neurons, Daniel Avesar, Allan T. Gulledge

Dartmouth Scholarship

Serotonin (5-HT) acting as a neurotransmitter in the cerebral cortex is critical for cognitive function, yet how 5-HT regulates information processing in cortical circuits is not well understood. We tested the serotonergic responsiveness of layer 5 pyramidal neurons (L5PNs) in the mouse medial prefrontal cortex (mPFC), and found three distinct response types: long-lasting 5-HT1A (1A) receptor-dependent inhibitory responses (84% of L5PNs), 5-HT2A (2A) receptor-dependent excitatory responses (9%), and biphasic responses in which 2A-dependent excitation followed brief inhibition (5%). Relative to 5-HT-inhibited neurons, those excited by 5-HT had physiological properties characteristic of callosal/commissural (COM) neurons that project to the …

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Vestibular And Attractor Network Basis Of The Head Direction Cell Signal In Subcortical Circuits, Benjamin J. Clark, Jeffrey S. Taube Mar 2012

Vestibular And Attractor Network Basis Of The Head Direction Cell Signal In Subcortical Circuits, Benjamin J. Clark, Jeffrey S. Taube

Dartmouth Scholarship

Accurate navigation depends on a network of neural systems that encode the moment-to-moment changes in an animal's directional orientation and location in space. Within this navigation system are head direction (HD) cells, which fire persistently when an animal's head is pointed in a particular direction (Sharp et al., 2001a; Taube, 2007). HD cells are widely thought to underlie an animal's sense of spatial orientation, and research over the last 25+ years has revealed that this robust spatial signal is widely distributed across subcortical and cortical limbic areas. The purpose of the present review is to summarize some of …

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Derivation Of A Novel Efficient Supervised Learning Algorithm From Cortical-Subcortical Loops, Ashok Chandrashekar, Richard Granger Jan 2012

Derivation Of A Novel Efficient Supervised Learning Algorithm From Cortical-Subcortical Loops, Ashok Chandrashekar, Richard Granger

Dartmouth Scholarship

Although brain circuits presumably carry out powerful perceptual algorithms, few instances of derived biological methods have been found to compete favorably against algorithms that have been engineered for specific applications. We forward a novel analysis of a subset of functions of cortical-subcortical loops, which constitute more than 80% of the human brain, thus likely underlying a broad range of cognitive functions. We describe a family of operations performed by the derived method, including a non-standard method for supervised classification, which may underlie some forms of cortically dependent associative learning. The novel supervised classifier is compared against widely used algorithms for …

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Domain Architecture Of A Calcium-Permeable Ampa Receptor In A Ligand-Free Conformation, Charles R. Midgett, Avinash Gill, Dean R. Madden Jan 2012

Domain Architecture Of A Calcium-Permeable Ampa Receptor In A Ligand-Free Conformation, Charles R. Midgett, Avinash Gill, Dean R. Madden

Dartmouth Scholarship

Ligand-gated ion channels couple the free energy of agonist binding to the gating of selective transmembrane ion pores, permitting cells to regulate ion flux in response to external chemical stimuli. However, the stereochemical mechanisms responsible for this coupling remain obscure. In the case of the ionotropic glutamate receptors (iGluRs), the modular nature of receptor subunits has facilitated structural analysis of the N-terminal domain (NTD), and of multiple conformations of the ligand-binding domain (LBD). Recently, the crystallographic structure of an antagonist-bound form of the receptor was determined. However, disulfide trapping of this conformation blocks channel opening, suggesting that channel activation involves …

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Aging Is Associated With Positive Responding To Neutral Information But Reduced Recovery From Negative Information, Carien M. Van Reekum, Stacey M. Schaefer, Regina C. Lapate, Catherine J. Norris, Lawrence L. Greischar, Richard J. Davidson Apr 2011

Aging Is Associated With Positive Responding To Neutral Information But Reduced Recovery From Negative Information, Carien M. Van Reekum, Stacey M. Schaefer, Regina C. Lapate, Catherine J. Norris, Lawrence L. Greischar, Richard J. Davidson

Dartmouth Scholarship

Studies on aging and emotion suggest an increase in reported positive affect, a processing bias of positive over negative information, as well as increasingly adaptive regulation in response to negative events with advancing age. These findings imply that older individuals evaluate information differently, resulting in lowered reactivity to, and/or faster recovery from, negative information, while maintaining more positive responding to positive information. We examined this hypothesis in an ongoing study on Midlife in the US (MIDUS II) where emotional reactivity and recovery were assessed in a large number of respondents (N = 159) from a wide age range (36–84 …

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Mind Perception: Real But Not Artificial Faces Sustain Neural Activity Beyond The N170/Vpp, Thalia Wheatley, Anna Weinberg, Christine Looser, Tim Moran, Greg Hajcak Mar 2011

Mind Perception: Real But Not Artificial Faces Sustain Neural Activity Beyond The N170/Vpp, Thalia Wheatley, Anna Weinberg, Christine Looser, Tim Moran, Greg Hajcak

Dartmouth Scholarship

Faces are visual objects that hold special significance as the icons of other minds. Previous researchers using event-related potentials (ERPs) have found that faces are uniquely associated with an increased N170/vertex positive potential (VPP) and a more sustained frontal positivity. Here, we examined the processing of faces as objects vs. faces as cues to minds by contrasting images of faces possessing minds (human faces), faces lacking minds (doll faces), and non-face objects (i.e., clocks). Although both doll and human faces were associated with an increased N170/VPP from 175–200 ms following stimulus onset, only human faces were associated with a sustained …

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Differential Activation Of Frontoparietal Attention Networks By Social And Symbolic Spatial Cues, Andrew D. Engell, Lauri Nummenmaa, Nikolaas N. Oosterhof, Richard N. Henson, James V. Haxby, Andrew J. Calder Mar 2010

Differential Activation Of Frontoparietal Attention Networks By Social And Symbolic Spatial Cues, Andrew D. Engell, Lauri Nummenmaa, Nikolaas N. Oosterhof, Richard N. Henson, James V. Haxby, Andrew J. Calder

Dartmouth Scholarship

Perception of both gaze-direction and symbolic directional cues (e.g. arrows) orient an observer’s attention toward the indicated location. It is unclear, however, whether these similar behavioral effects are examples of the same attentional phenomenon and, therefore, subserved by the same neural substrate. It has been proposed that gaze, given its evolutionary significance, constitutes a ‘special’ category of spatial cue. As such, it is predicted that the neural systems supporting spatial reorienting will be different for gaze than for non-biological symbols. We tested this prediction using functional magnetic resonance imaging to measure the brain’s response during target localization in which laterally …

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Behind The Mask: The Influence Of Mask-Type On Amygdala Response To Fearful Faces, M Justin Kim, Rebecca A. Loucks, Maital Neta, F. Caroline Davis, Jonathan A. Oler, Emily C. Mazzulla, Paul J. Whalen Feb 2010

Behind The Mask: The Influence Of Mask-Type On Amygdala Response To Fearful Faces, M Justin Kim, Rebecca A. Loucks, Maital Neta, F. Caroline Davis, Jonathan A. Oler, Emily C. Mazzulla, Paul J. Whalen

Dartmouth Scholarship

In this study, we compared the effects of using neutral face masks vs non-face pattern masks on amygdala activity to masked fearful faces. Twenty-seven subjects viewed 18 s blocks of either fearful or happy faces masked with either neutral faces or patterns, while their brain activity was measured using functional magnetic resonance imaging. Results replicated increased amygdala activation to face-masked fearful vs happy faces. In the pattern mask condition, the amygdala discriminated between masked fearful and happy faces, but this effect manifested as a decrease in activation to fearful faces compared to happy faces. This interactive effect between facial expression …

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Effects Of Socioeconomic Status On Brain Development, And How Cognitive Neuroscience May Contribute To Levelling The Playing Field, Rajeev Raizada, Mark M. Kishiyama Feb 2010

Effects Of Socioeconomic Status On Brain Development, And How Cognitive Neuroscience May Contribute To Levelling The Playing Field, Rajeev Raizada, Mark M. Kishiyama

Dartmouth Scholarship

The study of socioeconomic status (SES) and the brain finds itself in a circumstance unusual for Cognitive Neuroscience: large numbers of questions with both practical and scientific importance exist, but they are currently under-researched and ripe for investigation. This review aims to highlight these questions, to outline their potential significance, and to suggest routes by which they might be approached. Although remarkably few neural studies have been carried out so far, there exists a large literature of previous behavioural work. This behavioural research provides an invaluable guide for future neuroimaging work, but also poses an important challenge for it: how …

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The Principled Control Of False Positives In Neuroimaging, Craig M. Bennett, George L. Wolford, Michael B. Miller Dec 2009

The Principled Control Of False Positives In Neuroimaging, Craig M. Bennett, George L. Wolford, Michael B. Miller

Dartmouth Scholarship

An incredible amount of data is generated in the course of a functional neuroimaging experiment. The quantity of data gives us improved temporal and spatial resolution with which to evaluate our results. It also creates a staggering multiple testing problem. A number of methods have been created that address the multiple testing problem in neuroimaging in a principled fashion. These methods place limits on either the familywise error rate (FWER) or the false discovery rate (FDR) of the results. These principled approaches are well established in the literature and are known to properly limit the amount of false positives across …

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A Functional Role For The Ventrolateral Prefrontal Cortex In Non-Spatial Auditory Cognition, Y. E. Cohen, B. E. Russ, S. J. Davis, A. E. Baker, A. L. Ackelson, R. Niteck Nov 2009

A Functional Role For The Ventrolateral Prefrontal Cortex In Non-Spatial Auditory Cognition, Y. E. Cohen, B. E. Russ, S. J. Davis, A. E. Baker, A. L. Ackelson, R. Niteck

Dartmouth Scholarship

Spatial and non-spatial sensory information is hypothesized to be evaluated in parallel pathways. In this study, we tested the spatial and non-spatial sensitivity of auditory neurons in the ventrolateral prefrontal cortex (vPFC), a cortical area in the non-spatial pathway. Activity was tested while non-human primates reported changes in an auditory stimulus' spatial or non-spatial features. We found that vPFC neurons were reliably modulated during a non-spatial auditory task but were not modulated during a spatial auditory task. The degree of modulation during the non-spatial task correlated positively with the monkeys' behavioral performance. These results are consistent with the hypotheses that …

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Microsaccade Rate Varies With Subjective Visibility During Motion-Induced Blindness, Po-Jang Hsieh, Peter U. Tse Apr 2009

Microsaccade Rate Varies With Subjective Visibility During Motion-Induced Blindness, Po-Jang Hsieh, Peter U. Tse

Dartmouth Scholarship

Motion-induced blindness (MIB) occurs when a dot embedded in a motion field subjectively vanishes. Here we report the first psychophysical data concerning effects of microsaccade/eyeblink rate upon perceptual switches during MIB. We find that the rate of microsaccades/eyeblink rises before and after perceptual transitions from not seeing to seeing the dot, and decreases before perceptual transitions from seeing it to not seeing it. In addition, event-related fMRI data reveal that, when a dot subjectively reappears during MIB, the blood oxygen-level dependent (BOLD) signal increases in V1v and V2v and decreases in contralateral hMT+. These BOLD signal changes observed upon perceptual …

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The Sleeping Brain's Influence On Verbal Memory: Boosting Resistance To Interference, Jeffrey M. Ellenbogen, Justin C. Hulbert, Ying Jiang, Robert Stickgold Jan 2009

The Sleeping Brain's Influence On Verbal Memory: Boosting Resistance To Interference, Jeffrey M. Ellenbogen, Justin C. Hulbert, Ying Jiang, Robert Stickgold

Dartmouth Scholarship

Memories evolve. After learning something new, the brain initiates a complex set of post-learning processing that facilitates recall (i.e., consolidation). Evidence points to sleep as one of the determinants of that change. But whenever a behavioral study of episodic memory shows a benefit of sleep, critics assert that sleep only leads to a temporary shelter from the damaging effects of interference that would otherwise accrue during wakefulness. To evaluate the potentially active role of sleep for verbal memory, we compared memory recall after sleep, with and without interference before testing. We demonstrated that recall performance for verbal memory was greater …

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Medial Temporal Lobe Bold Activity At Rest Predicts Individual Differences In Memory Ability In Hhealthy Young Adults, Gagan S. Wig, Scott T. Grafton, Kathryn E. Demos, George L. Wolford, Steven E. Petersen, William M. Kelley Nov 2008

Medial Temporal Lobe Bold Activity At Rest Predicts Individual Differences In Memory Ability In Hhealthy Young Adults, Gagan S. Wig, Scott T. Grafton, Kathryn E. Demos, George L. Wolford, Steven E. Petersen, William M. Kelley

Dartmouth Scholarship

Human beings differ in their ability to form and retrieve lasting long-term memories. To explore the source of these individual differences, we used functional magnetic resonance imaging to measure blood-oxygen-level-dependent (BOLD) activity in healthy young adults (n = 50) during periods of resting fixation that were interleaved with periods of simple cognitive tasks. We report that medial temporal lobe BOLD activity during periods of rest predicts individual differences in memory ability. Specifically, individuals who exhibited greater magnitudes of task-induced deactivations in medial temporal lobe BOLD signal (as compared to periods of rest) demonstrated superior memory during offline testing. This relationship …

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Switching Language Switches Mind: Linguistic Effects On Developmental Neural Bases Of ‘Theory Of Mind’, Chiyoko Kobayashi, Gary H. Glover, Elise Temple Feb 2008

Switching Language Switches Mind: Linguistic Effects On Developmental Neural Bases Of ‘Theory Of Mind’, Chiyoko Kobayashi, Gary H. Glover, Elise Temple

Dartmouth Scholarship

Theory of mind (ToM)—our ability to predict behaviors of others in terms of their underlying intentions—has been examined through false-belief (FB) tasks. We studied 12 Japanese early bilingual children (8−12 years of age) and 16 late bilingual adults (18−40 years of age) with FB tasks in Japanese [first language (L1)] and English [second language (L2)], using fMRI. Children recruited more brain regions than adults for processing ToM tasks in both languages. Moreover, children showed an overlap in brain activity between the L1 and L2 ToM conditions in the medial prefrontal cortex (mPFC). Adults did not show such a convergent activity …

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