Cognitive Neuroscience Commons^™

Focal Cortical Thickness Correlates Of Exceptional Memory Training In Vedic Priests, Giridhar P. Kalamangalam, Timothy M. Ellmore

Publications and Research

The capacity for semantic memory—the ability to acquire and store knowledge of the world—is highly developed in the human brain. In particular, semantic memory assimilated through an auditory route may be a uniquely human capacity. One method of obtaining neurobiological insight into memory mechanisms is through the study of experts. In this work, we study a group of Hindu Vedic priests, whose religious training requires the memorization of vast tracts of scriptural texts through an oral tradition, recalled spontaneously during a lifetime of subsequent spiritual practice. We demonstrate focal increases of cortical thickness in regions of the left prefrontal lobe …

Dynamics Of Alpha Control: Preparatory Suppression Of Posterior Alpha Oscillations By Frontal Modulators Revealed With Combined Eeg And Event-Related Optical Signal, Kyle E. Mathewson, Diane M. Beck, Tony Ro, Edward L. Maclin, Kathy A. Low, Monica Fabiani, Gabriele Gratton

Publications and Research

We investigated the dynamics of brain processes facilitating conscious experience of external stimuli. Previously, we proposed that alpha (8–12 Hz) oscillations, which fluctuate with both sustained and directed attention, represent a pulsed inhibition of ongoing sensory brain activity. Here we tested the prediction that inhibitory alpha oscillations in visual cortex are modulated by top–down signals from frontoparietal attention networks. We measured modulations in phase-coherent alpha oscillations from superficial frontal, parietal, and occipital cortices using the event-related optical signal (EROS), a measure of neuronal activity affording high spatiotemporal resolution, along with concurrently recorded EEG, while participants performed a visual target detection …

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 …

Sticking Your Neck Out And Burying The Hatchet: What Idioms Reveal About Embodied Simulation, Natalie A. Kacinik

Publications and Research

Idioms are used in conventional language twice as frequently as metaphors, but most research, particularly recent work on embodiment has focused on the latter. However, idioms have the potential to significantly deepen our understanding of embodiment because their meanings cannot be derived from their component words. To determine whether sensorimotor states could activate idiomatic meaning, participants were instructed to engage in postures/actions reflecting various idioms (e.g.,sticking your neck out) relative to non-idiomatic control postures/actions while reading and responding to statements designed to assess idiomatic meaning. The results showed that statements were generally more strongly endorsed after idiom embodiment than control …

Hemispheric Asymmetry In New Neurons In Adulthood Is Associated With Vocal Learning And Auditory Memory, Shuk C. Tsoi, Utsav V. Aiya, Kobi D. Wasner, Mimi L. Phan, Carolyn L. Pytte, David S. Vicario

Publications and Research

Many brain regions exhibit lateral differences in structure and function, and also incorporate new neurons in adulthood, thought to function in learning and in the formation of new memories. However, the contribution of new neurons to hemispheric differences in processing is unknown. The present study combines cellular, behavioral, and physiological methods to address whether 1) new neuron incorporation differs between the brain hemispheres, and 2) the degree to which hemispheric lateralization of new neurons correlates with behavioral and physiological measures of learning and memory. The songbird provides a model system for assessing the contribution of new neurons to hemispheric specialization …

Integrating Cognitive Science With Innovative Teaching In Stem Disciplines, Mark A. Mcdaniel, Regina F. Frey, Susan M. Fitzpatrick, Henry L. Roediger Iii

Books and Monographs

This volume collects the ideas and insights discussed at a novel conference, the Integrating Cognitive Science with Innovative Teaching in STEM Disciplines Conference, which was held September 27-28, 2012 at Washington University in St. Louis. With funding from the James S. McDonnell Foundation, the conference was hosted by Washington University’s Center for Integrative Research on Cognition, Learning, and Education (CIRCLE), a center established in 2011. Available for download as a PDF. Titles of individual chapters can be found at http://openscholarship.wustl.edu/circle_book/.

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 …

The New Normal: Goodness Judgments Of Non-Invariant Speech, Julia R. Drouin

Honors Scholar Theses

Previous research has found that perceptual learning, or normalizing the idiosyncratic phonemes of speech, causes a shift in speech sound category boundaries. The present study examined if perceptual learning was limited to the boundary or if also caused a shift in internal category structure. Seventeen individuals participated in three behavioral tasks to explicate this question. In the Lexical Decision task, participants were trained in either /s/-biasing or /ʃ/- biasing context. In the Goodness Judgment task, participants rated a continuum of sounds on perceived /s/ goodness using a designated scale. Finally, in the Phoneme Identification task, participants listened to the same …

Effects Of Resting State On Perceptual Learning, Sarah Eagleman Ph.D.

Dissertations and Theses (Open Access)

Psychophysical experiments in humans have demonstrated that improvements in perceptual learning tasks occur following daytime rests. The neural correlates of how rest influences subsequent sensory processing during these tasks remain unclear. One possible neural mechanism that may underlie this behavioral improvement is reactivation. Previously evoked network activity reoccurs – reactivates - in the absence of further stimulation. Reactivation was initially discovered in the hippocampus but has now been found in several brain areas including cortex. This phenomenon has been implicated as a general mechanism by which neural networks learn and store sensory information. However, whether reactivation occurs in areas relevant …

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

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 Developmental Trajectory Of Contour Integration In Autism Spectrum Disorders, Ted S. Altschuler

Dissertations, Theses, and Capstone Projects

Sensory input is inherently ambiguous and complex, so perception is believed to be achieved by combining incoming sensory information with prior knowledge. One model envisions the grouping of sensory features (the local dimensions of stimuli) to be the outcome of a predictive process relying on prior experience (the global dimension of stimuli) to disambiguate possible configurations those elements could take. Contour integration, the linking of aligned but separate visual elements, is one example of perceptual grouping. Kanizsa-type illusory contour (IC) stimuli have been widely used to explore contour integration processing. Consisting of two conditions which differ only in the alignment …

Direct Control Of Visual Perception With Phase-Specific Modulation Of Posterior Parietal Cortex, Andrew Jaegle, Tony Ro

Publications and Research

We examined the causal relationship between the phase of alpha oscillations (9–12 Hz) and conscious visual perception using rhythmic TMS (rTMS) while simultaneously recording EEG activity. rTMS of posterior parietal cortex at an alpha frequency (10 Hz), but not occipital or sham rTMS, both entrained the phase of subsequent alpha oscillatory activity and produced a phase-dependent change on subsequent visual perception, with lower discrimination accuracy for targets presented at one phase of the alpha oscillatory waveform than for targets presented at the opposite phase. By extrinsically manipulating the phase of alpha before stimulus presentation, we provide direct evidence that the …

Short-Term Activity-Dependent Changes In Schaffer Collateral Axon Function, Benjamin Michael Owen

Theses, Dissertations and Capstones

Schaffer collaterals are the unmyelinated axons of pyramidal neurons in the CA3 area of the hippocampus, a brain structure essential for memory formation. Schaffer collateral axons conduct electrical signals in the form of action potentials from CA3 pyramidal cells to synaptic terminals in area CA1. The fidelity with which these axons conduct action potentials determines the nature of the information which can be transmitted between areas CA3 and CA1. Conduction fidelity may be affected by both normal and abnormal patterns of firing, fluctuations in ion concentration, and some drugs and toxins. In this dissertation, I examined the function of Schaffer …

Perceived Depth In Non-Transitive Stereo Displays, Bart Farell, Cherlyn J. Ng

Biomedical and Chemical Engineering - All Scholarship

The separation between the eyes shapes the distribution of binocular disparities and gives a special role to horizontal disparities. However, for one-dimensional stimuli, disparity direction, like motion direction, is linked to stimulus orientation. This makes the perceived depth of one-dimensional stimuli orientation dependent and generally non-veridical. It also allows perceived depth to violate transitivity. Three stimuli, A, B, and C, can be arranged such that A > B (stimulus A is seen as farther than stimulus B when they are presented together) and B > C, yet A 6 C. This study examines how the visual system handles the depth of A, …

The Neural Substrates Of Natural Reading: A Comparison Of Normal And Nonword Text Using Eyetracking And Fmri, W. Choi, Rutvik Desai, J. M. Henderson

Faculty Publications

Most previous studies investigating the neural correlates of reading have presented text using serial visual presentation (SVP), which may not fully reflect the underlying processes of natural reading. In the present study, eye movements and BOLD data were collected while subjects either read normal paragraphs naturally or moved their eyes through “paragraphs” of pseudo-text (pronounceable pseudowords or consonant letter strings) in two pseudo-reading conditions. Eye movement data established that subjects were reading and scanning the stimuli normally. A conjunction fMRI analysis across natural- and pseudo-reading showed that a common eye-movement network including frontal eye fields (FEF), supplementary eye fields (SEF), …

Examining The Intersection Of The Cognitive Advantages And Disadvantages Of The Bilingual Brain, Irina Rabkina

Scripps Senior Theses

Two conflicting findings characterize cognitive processing accompanying bilingualism. The “bilingual advantage” refers to improved cognitive performance for bilingual compared to monolingual participants. Most bilingual advantages fall under the umbrella of cognitive control mechanisms, most frequently demonstrated using the Stroop task and the Simon task (e.g., Bialystok, 2008; Coderre, Van Heuven, & Conklin, 2013). The “bilingual disadvantage,” on the other hand, refers to bilinguals’ diminished performance on tasks that require word retrieval or switching between languages. This study examined the intersection of the bilingual advantage and the bilingual disadvantage to investigate whether they stem from a single cognitive control process. The …

Variance Predicts Salience In Central Sensory Processing, Ann M. Hermundstad, John J. Briguglio, Mary M. Conte, Jonathan D. Victor, Vijay Balasubramanian, Gašper Tkačik

Publications and Research

Information processing in the sensory periphery is shaped by natural stimulus statistics. In the periphery, a transmission bottleneck constrains performance; thus efficient coding implies that natural signal components with a predictably wider range should be compressed. In a different regime—when sampling limitations constrain performance—efficient coding implies that more resources should be allocated to informative features that are more variable. We propose that this regime is relevant for sensory cortex when it extracts complex features from limited numbers of sensory samples. To test this prediction, we use central visual processing as a model: we show that visual sensitivity for local multi-point …

The Effects Of Anxiety On Sensory Gating, Jonathon Meier

Honors Projects

Sensory gating is a proposed important physiological process of inhibiting neuronal responses of repetitious stimuli in the central nervous system to allocate more cognitive resources to additional salient information. Sensory gating is currently being studied to better understand psychiatric illnesses, especially those characterized by emotional changes and the inability to concentrate such as schizophrenia, ADHD, anxiety disorder, and Parkinson’s. Anxiety is a strong feeling of nervousness that occurs in all individuals at varying degrees and is associated with detrimental health effects as well as hindering concentration. Numerous brain regions are associated with anxiety levels such as the anterior limbic system, …

Time, Perspectives, Verbs, And Imagining Events, Jeffrey P. Hong

Theses and Dissertations (Comprehensive)

During the processing of verbs, readers form internal representations of the events described by those verbs. Two key elements in the construction of event representations are temporal information, given by the verbs that describe the represented events, and the visual perspective from which the events are represented. The current study is composed of two experiments aimed at examining the roles these two factors play in event representation. Specifically, the study aimed to determine how temporal information and visual perspective are represented during event imagination.

Experiment 1 investigated the role of temporal information associated with verbs, given by grammatical aspect (GA) …