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Full-Text Articles in Psychology

Emotion Recognition With Audio, Video, Eeg, And Emg: A Dataset And Baseline Approaches, Jin Chen, Tony Ro, Zhigang Zhu Jan 2022

Emotion Recognition With Audio, Video, Eeg, And Emg: A Dataset And Baseline Approaches, Jin Chen, Tony Ro, Zhigang Zhu

Publications and Research

This paper describes a new posed multimodal emotional dataset and compares human emotion classification based on four different modalities - audio, video, electromyography (EMG), and electroencephalography (EEG). The results are reported with several baseline approaches using various feature extraction techniques and machine-learning algorithms. First, we collected a dataset from 11 human subjects expressing six basic emotions and one neutral emotion. We then extracted features from each modality using principal component analysis, autoencoder, convolution network, and mel-frequency cepstral coefficient (MFCC), some unique to individual modalities. A number of baseline models have been applied to compare the classification performance in emotion recognition, …


During Natural Viewing, Neural Processing Of Visual Targets Continues Throughout Saccades, Atanas D. Stankov, Jonathan Touryan, Stephen Gordon, Anthony J. Ries, Jason Ki, Lucas C. Parra Sep 2021

During Natural Viewing, Neural Processing Of Visual Targets Continues Throughout Saccades, Atanas D. Stankov, Jonathan Touryan, Stephen Gordon, Anthony J. Ries, Jason Ki, Lucas C. Parra

Publications and Research

Relatively little is known about visual processing during free-viewing visual search in realistic dynamic environments. Free-viewing is characterized by frequent saccades. During saccades, visual processing is thought to be suppressed, yet we know that the presaccadic visual content can modulate postsaccadic processing. To better understand these processes in a realistic setting, we study here saccades and neural responses elicited by the appearance of visual targets in a realistic virtual environment. While subjects were being driven through a 3D virtual town, they were asked to discriminate between targets that appear on the road. Using a system identification approach, we separated overlapping …


A Systematic Review And Meta-Analysis On The Efficacy Of Repeated Transcranial Direct Current Stimulation For Migraine, Guoshuai Cai, Zhu Xia, Leigh Charvet, Feifei Xiao, Abhishek Datta, X Michelle Androulakis Apr 2021

A Systematic Review And Meta-Analysis On The Efficacy Of Repeated Transcranial Direct Current Stimulation For Migraine, Guoshuai Cai, Zhu Xia, Leigh Charvet, Feifei Xiao, Abhishek Datta, X Michelle Androulakis

Publications and Research

Purpose: Transcranial direct current stimulation (tDCS) may have therapeutic potential in the management of migraine. However, studies to date have yielded conflicting results. We reviewed studies using repeated tDCS for longer than 4 weeks in migraine treatment, and performed meta-analysis on the efficacy of tDCS in migraine.

Methods: In this meta-analysis, we included the common outcome measurements reported across randomized controlled trials (RCTs). Subgroup analysis was performed at different post-treatment endpoints, and with different stimulation intensities and polarities.

Results: Five RCTs were included in the quantitative meta-analysis with a total of 104 migraine patients. We found a significant reduction of …


Visual Modulation Of Resting State Α Oscillations, Kelly Webster, Tony Ro Dec 2019

Visual Modulation Of Resting State Α Oscillations, Kelly Webster, Tony Ro

Publications and Research

Once thought to simply reflect passive cortical idling, recent studies have demonstrated that α oscillations play a causal role in cognition and perception. However, whether and how cognitive or sensory processes modulate various components of the α rhythm is poorly understood. Sensory input and resting states were manipulated in human subjects while electroencephalography (EEG) activity was recorded in three conditions: eyes-open fixating on a visual stimulus, eyes-open without visual input (darkness), and eyes-closed without visual input (darkness). We show that α power and peak frequency increase when visual input is reduced compared to the eyes open, fixating condition. These results …


Neural Correlates Of Decision Making Related To Information Security: Self-Control And Moral Potency, Robert West, Emily Budde, Qing Hu Sep 2019

Neural Correlates Of Decision Making Related To Information Security: Self-Control And Moral Potency, Robert West, Emily Budde, Qing Hu

Publications and Research

Security breaches of digital information represent a significant threat to the wellbeing of individuals, corporations, and governments in the digital era. Roughly 50% of breaches of information security result from the actions of individuals inside organizations (i.e., insider threat), and some evidence indicates that common deterrence programs may not lessen the insiders’ intention to violate information security. This had led researchers to investigate contextual and individual difference variables that influence the intention to violate information security policies. The current research builds upon previous studies and explores the relationship between individual differences in self-control and moral potency and the neural correlates …


Alpha Oscillations And Feedback Processing In Visual Cortex For Conscious Perception, Tony Ro Jul 2019

Alpha Oscillations And Feedback Processing In Visual Cortex For Conscious Perception, Tony Ro

Publications and Research

Variability in perception between individuals may be a consequence of different inherent neural processing speeds. To assess whether alpha oscillations systematically reflect a feedback pacing mechanism for cortical processing during visual perception, comparisons were made between alpha oscillations, visual suppression from TMS, visual evoked responses, and metacontrast masking. Peak alpha oscillation frequencies, measured through scalp EEG recordings, significantly correlated with the optimum latencies for visual suppression from TMS of early visual cortex. Individuals with shorter alpha periods (i.e., higher peak alpha frequencies) processed visual information faster than those with longer alpha periods (i.e., lower peak alpha frequencies). Moreover, peak alpha …


Neural Indices Of Vowel Discrimination In Monolingual And Bilingual Infants And Children, Yan H. Yu, Carol Tessel, Henry Han, Luca Campanelli, Nancy Vidal, Jennifer Gerometta, Karen Garrido-Nag, Hia Datta, Valerie L. Shafer Apr 2019

Neural Indices Of Vowel Discrimination In Monolingual And Bilingual Infants And Children, Yan H. Yu, Carol Tessel, Henry Han, Luca Campanelli, Nancy Vidal, Jennifer Gerometta, Karen Garrido-Nag, Hia Datta, Valerie L. Shafer

Publications and Research

Objectives: To examine maturation of neural discriminative responses to an English vowel contrast from infancy to 4 years of age and to determine how biological factors (age and sex) and an experiential factor (amount of Spanish versus English input) modulate neural discrimination of speech.

Design: Event-related potential (ERP) mismatch responses (MMRs) were used as indices of discrimination of the American English vowels [ε] versus [I] in infants and children between 3 months and 47 months of age. A total of 168 longitudinal and cross-sectional data sets were collected from 98 children (Bilingual Spanish–English: 47 male and 31 female …


Synchronicity: The Role Of Midbrain Dopamine In Whole-Brain Coordination, Jeff A. Beeler, Jakob Kiskye Dreyer Apr 2019

Synchronicity: The Role Of Midbrain Dopamine In Whole-Brain Coordination, Jeff A. Beeler, Jakob Kiskye Dreyer

Publications and Research

Midbrain dopamine seems to play an outsized role in motivated behavior and learning. Widely associated with mediating reward-related behavior, decision making, and learning, dopamine continues to generate controversies in the field. While many studies and theories focus on what dopamine cells encode, the question of how the midbrain derives the information it encodes is poorly understood and comparatively less addressed. Recent anatomical studies suggest greater diversity and complexity of afferent inputs than previously appreciated, requiring rethinking of prior models. Here, we elaborate a hypothesis that construes midbrain dopamine as implementing a Bayesian selector in which individual dopamine cells sample afferent …


The Serial Blocking Effect: A Testbed For The Neural Mechanisms Of Temporal-Difference Learning, Ashraf Mahmud, Petio Petrov, Guillem R. Esber, Mihaela D. Iordanova Apr 2019

The Serial Blocking Effect: A Testbed For The Neural Mechanisms Of Temporal-Difference Learning, Ashraf Mahmud, Petio Petrov, Guillem R. Esber, Mihaela D. Iordanova

Publications and Research

Temporal-difference (TD) learning models afford the neuroscientist a theory-driven roadmap in the quest for the neural mechanisms of reinforcement learning. The application of these models to understanding the role of phasic midbrain dopaminergic responses in reward prediction learning constitutes one of the greatest success stories in behavioural and cognitive neuroscience. Critically, the classic learning paradigms associated with TD are poorly suited to cast light on its neural implementation, thus hampering progress. Here, we present a serial blocking paradigm in rodents that overcomes these limitations and allows for the simultaneous investigation of two cardinal TD tenets; namely, that learning depends on …


Direct Current Stimulation Of Endothelial Monolayers Induces A Transient And Reversible Increase In Transport Due To The Electroosmotic Effect, Limary M. Cancel, Katherin Arias, Marom Bikson, John M. Tarbell Jun 2018

Direct Current Stimulation Of Endothelial Monolayers Induces A Transient And Reversible Increase In Transport Due To The Electroosmotic Effect, Limary M. Cancel, Katherin Arias, Marom Bikson, John M. Tarbell

Publications and Research

We investigated the effects of direct current stimulation (DCS) on fluid and solute transport across endothelial cell (EC) monolayers in vitro. Our motivation was transcranial direct current stimulation (tDCS) that has been investigated for treatment of neuropsychiatric disorders, to enhance neurorehabilitation, and to change cognition in healthy subjects. The mechanisms underlying this diversity of applications remain under investigation. To address the possible role of blood-brain barrier (BBB) changes during tDCS, we applied direct current to cultured EC monolayers in a specially designed chamber that generated spatially uniform direct current. DCS induced fluid and solute movement across EC layers that persisted …


Depressive Symptoms Are Associated With Cognitive Function In The Elderly With Type 2 Diabetes, Elizabeth Guerrero-Berroa, Ramit Ravona-Springer, James Schmeidler, Anthony Heymann, Laili Soleimani, Mary Sano, Derek Leroith, Rachel Preiss, Ruth Zukran, Jeremy M. Silverman, Michal Schnaider Beeri Jan 2018

Depressive Symptoms Are Associated With Cognitive Function In The Elderly With Type 2 Diabetes, Elizabeth Guerrero-Berroa, Ramit Ravona-Springer, James Schmeidler, Anthony Heymann, Laili Soleimani, Mary Sano, Derek Leroith, Rachel Preiss, Ruth Zukran, Jeremy M. Silverman, Michal Schnaider Beeri

Publications and Research

Background: Type 2 diabetes (T2D) is a metabolic condition associated with poor clinical and cognitive outcomes including vascular disease, depressive symptoms, cognitive impairment, and dementia. In the general elderly population, depression has been consistently identified as a risk factor for cognitive impairment/decline. However, the association between depression and cognitive function in T2D has been understudied.

Objective: We investigated the association between depression and cognitive function in a large sample of cognitively normal elderly with T2D.

Methods: In this cross-sectional study, we examined 738 participants, aged 65–88 years old, enrolled in the Israel Diabetes and Cognitive Decline study. For each …


Language Experience With A Native-Language Phoneme Sequence Modulates The Effects Of Attention On Cortical Sensory Processing, Valerie L. Shafer, Monica Wagner, Jungmee Lee, Francesca Mingino, Colleen O'Brien, Adam Constantine, Mitchell Steinschneider Nov 2017

Language Experience With A Native-Language Phoneme Sequence Modulates The Effects Of Attention On Cortical Sensory Processing, Valerie L. Shafer, Monica Wagner, Jungmee Lee, Francesca Mingino, Colleen O'Brien, Adam Constantine, Mitchell Steinschneider

Publications and Research

Auditory evoked potentials (AEP) reflect spectro-temporal feature changes within the spoken word and are sufficiently reliable to probe deficits in auditory processing. The current research assessed whether attentional modulation would alter the morphology of these AEPs and whether native-language experience with phoneme sequences would influence the effects of attention. Native-English and native-Polish adults listened to nonsense word pairs that contained the phoneme sequence onsets /st/, /sət/, /pət/ that occur in both the Polish and English languages and the phoneme sequence onset /pt/ that occurs in the Polish language, but not the English language. Participants listened to word pairs within two …


Combined Mnemonic Strategy Training And High-Definition Transcranial Direct Current Stimulation For Memory Deficits In Mild Cognitive Impairment, Benjamin M. Hampstead, Krishnankutty Sathian, Marom Bikson, Anthony Y. Stringer Sep 2017

Combined Mnemonic Strategy Training And High-Definition Transcranial Direct Current Stimulation For Memory Deficits In Mild Cognitive Impairment, Benjamin M. Hampstead, Krishnankutty Sathian, Marom Bikson, Anthony Y. Stringer

Publications and Research

Introduction: Memory deficits characterize Alzheimer’s dementia and the clinical precursor stage known as mild cognitive impairment. Nonpharmacologic interventions hold promise for enhancing functioning in these patients, potentially delaying functional impairment that denotes transition to dementia. Previous findings revealed that mnemonic strategy training (MST) enhances long-term retention of trained stimuli and is accompanied by increased blood oxygen level–dependent signal in the lateral frontal and parietal cortices as well as in the hippocampus. The present study was designed to enhance MST generalization, and the range of patients who benefit, via concurrent delivery of transcranial direct current stimulation (tDCS).

Methods: This protocol describes …


Error Rate On The Director’S Task Is Influenced By The Need To Take Another’S Perspective But Not The Type Of Perspective, Edward W. Legg, Laure Olivier, Steven Samuel, Robert Lurz, Nicola S. Clayton Jan 2017

Error Rate On The Director’S Task Is Influenced By The Need To Take Another’S Perspective But Not The Type Of Perspective, Edward W. Legg, Laure Olivier, Steven Samuel, Robert Lurz, Nicola S. Clayton

Publications and Research

Adults are prone to responding erroneously to another’s instructions based on what they themselves see and not what the other person sees. Previous studies have indicated that in instruction-following tasks participants make more errors when required to infer another’s perspective than when following a rule. These inference-induced errors may occur because the inference process itself is error-prone or because they are a side effect of the inference process. Crucially, if the inference process is error-prone, then higher error rates should be found when the perspective to be inferred is more complex. Here, we found that participants were no more error …


The Effects Of Changing Attention And Context In An Awake Offline Processing Period On Visual Long-Term Memory, Timothy M. Ellmore, Anna Feng, Kenneth Ng, Luthfunnahar Dewan, James C. Root Jan 2016

The Effects Of Changing Attention And Context In An Awake Offline Processing Period On Visual Long-Term Memory, Timothy M. Ellmore, Anna Feng, Kenneth Ng, Luthfunnahar Dewan, James C. Root

Publications and Research

There is accumulating evidence that sleep as well as awake offline processing is important for the transformation of new experiences into long-term memory (LTM). Yet much remains to be understood about how various cognitive factors influence the efficiency of awake offline processing. In the present study we investigated how changes in attention and context in the immediate period after exposure to new visual information influences LTM consolidation. After presentation of multiple naturalistic scenes within a working memory paradigm, recognition was assessed 30 min and 24 h later in three groups of subjects. One group of subjects engaged in a focused …


Orbitofrontal 18f-Dopa Uptake And Movement Preparation In Parkinson’S Disease, Lucio Marinelli, Arnoldo Piccardo, Laura Mori, Silvia Morbelli, Nicola Girtler, Antonio Castaldi, Agnese Picco, Carlo Trompetto, Maria Felice Ghilardi, Giovanni Abbruzzese, Flavio Nobili Jan 2015

Orbitofrontal 18f-Dopa Uptake And Movement Preparation In Parkinson’S Disease, Lucio Marinelli, Arnoldo Piccardo, Laura Mori, Silvia Morbelli, Nicola Girtler, Antonio Castaldi, Agnese Picco, Carlo Trompetto, Maria Felice Ghilardi, Giovanni Abbruzzese, Flavio Nobili

Publications and Research

In Parkinson’s disease (PD) degeneration of mesocortical dopaminergic projections may determine cognitive and behavioral symptoms. Choice reaction time task is related to attention, working memory, and goal-directed behavior. Such paradigm involves frontal cortical circuits receiving mesocortical dopamine which are affected early in PD. The aim of this study is to characterize the role of dopamine on the cognitive processes that precede movement in a reaction time paradigm in PD.We enrolled 16 newly diagnosed and untreated patientswith PDwithout cognitive impairment or depression and 10 control subjectswith essential tremor. They performed multiple-choice reaction time task with the right upper limb and brain …


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 Oct 2014

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 …


Behavioral And Neuroanatomical Abnormalities In Pleiotrophin Knockout Mice, Jason W. Krellman, Henry H. Ruiz, Veronica A. Marciano, Bracha Mondrow, Susan D. Croll Jul 2014

Behavioral And Neuroanatomical Abnormalities In Pleiotrophin Knockout Mice, Jason W. Krellman, Henry H. Ruiz, Veronica A. Marciano, Bracha Mondrow, Susan D. Croll

Publications and Research

Pleiotrophin (PTN) is an extracellular matrix-associated protein with neurotrophic and neuroprotective effects that is involved in a variety of neurodevelopmental processes. Data regarding the cognitive-behavioral and neuroanatomical phenotype of pleiotrophin knockout (KO) mice is limited. The purpose of this study was to more fully characterize this phenotype, with emphasis on the domains of learning and memory, cognitive-behavioral flexibility, exploratory behavior and anxiety, social behavior, and the neuronal and vascular microstructure of the lateral entorhinal cortex (EC). PTN KOs exhibited cognitive rigidity, heightened anxiety, behavioral reticence in novel contexts and novel social interactions suggestive of neophobia, and lamina-specific decreases in neuronal …


Direct Control Of Visual Perception With Phase-Specific Modulation Of Posterior Parietal Cortex, Andrew Jaegle, Tony Ro Feb 2014

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 …


A Kinder, Gentler Dopamine. . . Highlighting Dopamine's Role In Behavioral Flexibility, Jeff A. Beeler, Roshan Cools, Monica Luciana, Sean B. Ostlund, Giselle Petzinger Jan 2014

A Kinder, Gentler Dopamine. . . Highlighting Dopamine's Role In Behavioral Flexibility, Jeff A. Beeler, Roshan Cools, Monica Luciana, Sean B. Ostlund, Giselle Petzinger

Publications and Research

No abstract provided.


Unconscious Priming Requires Early Visual Cortex At Specific Temporal Phases Of Processing, Marjan Persuh, Tony Ro Sep 2013

Unconscious Priming Requires Early Visual Cortex At Specific Temporal Phases Of Processing, Marjan Persuh, Tony Ro

Publications and Research

Although examples of unconscious shape priming have been well documented, whether such priming requires early visual cortex (V1/V2) has not been established. In the current study, we used TMS of V1/V2 at varying temporal intervals to suppress the visibility of preceding shape primes while the interval between primes and targets was kept constant. Our results show that, although conscious perception requires V1/V2, unconscious priming can occur without V1/V2 at an intermediate temporal interval but not at early (5–25 msec) or later (65–125 msec) stages of processing. Because the later time window of unconscious priming suppression has been proposed to interfere …


Effortless Awareness: Using Real Time Neurofeedback To Investigate Correlates Of Posterior Cingulate Cortex Activity In Meditators' Self-Report, Kathleen A. Garrison, Juan F. Santoyo, Jake H. Davis, Thomas A. Thomhill Iv, Catherine E. Kerr, Judson A. Brewer Aug 2013

Effortless Awareness: Using Real Time Neurofeedback To Investigate Correlates Of Posterior Cingulate Cortex Activity In Meditators' Self-Report, Kathleen A. Garrison, Juan F. Santoyo, Jake H. Davis, Thomas A. Thomhill Iv, Catherine E. Kerr, Judson A. Brewer

Publications and Research

Neurophenomenological studies seek to utilize first-person self-report to elucidate cognitive processes related to physiological data. Grounded theory offers an approach to the qualitative analysis of self-report, whereby theoretical constructs are derived from empirical data. Here we used grounded theory methodology (GTM) to assess how the first-person experience of meditation relates to neural activity in a core region of the default mode network—the posterior cingulate cortex (PCC). We analyzed first-person data consisting of meditators' accounts of their subjective experience during runs of a real time fMRI neurofeedback study of meditation, and third-person data consisting of corresponding feedback graphs of PCC activity …


Unconscious Processing Of Unattended Features In Human Visual Cortex, Tatiana Aloi Emmanouil, Philip Burton, Tony Ro Mar 2013

Unconscious Processing Of Unattended Features In Human Visual Cortex, Tatiana Aloi Emmanouil, Philip Burton, Tony Ro

Publications and Research

Unconscious processing has been convincingly demonstrated for task-relevant feature dimensions. However, it is possible that the visual system is capable of more complex unconscious operations, extracting visual features even when they are unattended and task irrelevant. In the current study, we addressed this question by measuring unconscious priming using a task in which human participants attended to a target object's shape while ignoring its color. We measured both behavioral priming effects and priming-related fMRI activations from primes that were unconsciously presented using metacontrast masking. The results showed faster RTs and decreases in fMRI activation only when the primes were identical …


Iconic Memory Requires Attention, Marjan Persuh, Boris Genzer, Robert D. Melara May 2012

Iconic Memory Requires Attention, Marjan Persuh, Boris Genzer, Robert D. Melara

Publications and Research

Two experiments investigated whether attention plays a role in iconic memory, employing either a change detection paradigm (Experiment 1) or a partial-report paradigm (Experiment 2). In each experiment, attention was taxed during initial display presentation, focusing the manipulation on consolidation of information into iconic memory, prior to transfer into working memory. Observers were able to maintain high levels of performance (accuracy of change detection or categorization) even when concurrently performing an easy visual search task (low load). However, when the concurrent search was made difficult (high load), observers' performance dropped to almost chance levels, while search accuracy held at single-task …


Insightful Problem Solving In An Asian Elephant, Preston Foerder, Marie Galloway, Tony Barthel, Donald E. Moore Iii, Diana Reiss Aug 2011

Insightful Problem Solving In An Asian Elephant, Preston Foerder, Marie Galloway, Tony Barthel, Donald E. Moore Iii, Diana Reiss

Publications and Research

The ‘‘aha’’ moment or the sudden arrival of the solution to a problem is a common human experience. Spontaneous problem solving without evident trial and error behavior in humans and other animals has been referred to as insight. Surprisingly, elephants, thought to be highly intelligent, have failed to exhibit insightful problem solving in previous cognitive studies. We tested whether three Asian elephants (Elephas maximus) would use sticks or other objects to obtain food items placed out-of-reach and overhead. Without prior trial and error behavior, a 7-year-old male Asian elephant showed spontaneous problem solving by moving a large plastic cube, on …


“What” And “Where” In Auditory Sensory Processing: A High-Density Electrical Mapping Study Of Distinct Neural Processes Underlying Sound Object Recognition And Sound Localization, Victoria M. Leavitt, Sophie Molholm, Manuel Gomez-Ramirez, John J. Foxe Jun 2011

“What” And “Where” In Auditory Sensory Processing: A High-Density Electrical Mapping Study Of Distinct Neural Processes Underlying Sound Object Recognition And Sound Localization, Victoria M. Leavitt, Sophie Molholm, Manuel Gomez-Ramirez, John J. Foxe

Publications and Research

Functionally distinct dorsal and ventral auditory pathways for sound localization (WHERE) and sound object recognition (WHAT) have been described in non-human primates. A handful of studies have explored differential processing within these streams in humans, with highly inconsistent findings. Stimuli employed have included simple tones, noise bursts, and speech sounds, with simulated left–right spatial manipulations, and in some cases participants were not required to actively discriminate the stimuli. Our contention is that these paradigms were not well suited to dissociating processing within the two streams. Our aim here was to determine how early in processing we …


Alternation Rate In Perceptual Bistability Is Maximal At And Symmetric Around Equi-Dominance, Rubén Moreno-Bote, Asya Shpiro, John Rinzel, Nava Rubin Sep 2010

Alternation Rate In Perceptual Bistability Is Maximal At And Symmetric Around Equi-Dominance, Rubén Moreno-Bote, Asya Shpiro, John Rinzel, Nava Rubin

Publications and Research

When an ambiguous stimulus is viewed for a prolonged time, perception alternates between the different possible interpretations of the stimulus. The alternations seem haphazard, but closer inspection of their dynamics reveals systematic properties in many bistable phenomena. Parametric manipulations result in gradual changes in the fraction of time a given interpretation dominates perception, often over the entire possible range of zero to one. The mean dominance durations of the competing interpretations can also vary over wide ranges (from less than a second to dozens of seconds or more), but finding systematic relations in how they vary has proven difficult. Following …


To See Or Not To See: Prestimulus Α Phase Predicts Visual Awareness, Kyle E. Mathewson, Gabriele Gratton, Monica Fabiani, Diane M. Beck, Tony Ro Mar 2009

To See Or Not To See: Prestimulus Α Phase Predicts Visual Awareness, Kyle E. Mathewson, Gabriele Gratton, Monica Fabiani, Diane M. Beck, Tony Ro

Publications and Research

We often fail to see something that at other times is readily detectable. Because the visual stimulus itself is unchanged, this variability in conscious awareness is likely related to changes in the brain. Here we show that the phase of EEG α rhythm measured over posterior brain regions can reliably predict both subsequent visual detection and stimulus-elicited cortical activation levels in a metacontrast masking paradigm. When a visual target presentation coincides with the trough of an α wave, cortical activation is suppressed as early as 100 ms after stimulus onset, and observers are less likely to detect the target. Thus, …


Maintenance Of Visual Stability In The Human Posterior Parietal Cortex, Erik Chang, Tony Ro Feb 2007

Maintenance Of Visual Stability In The Human Posterior Parietal Cortex, Erik Chang, Tony Ro

Publications and Research

Visual stability refers to our stable visuospatial perceptions despite the unstable visual input caused by saccades. Functional neuroimaging results, studies on patients with posterior parietal cortex (PPC) lesions, and single-unit recordings in the lateral intraparietal sulcus of primates indirectly suggest that the PPC might be a potential locus of visual stability through its involvement with spatial remapping. Here we directly explored the role of the PPC in visual stability by applying transcranial magnetic stimulation (TMS) while participants performed a perisaccadic displacement detection task. We show that TMS over the PPC but not a frontal control site alters sensitivity to displacement …


Daily Rhythm Of Cerebral Blood Flow Velocity, Deirdre A. Conroy, Arthur J. Spielman, Rebecca Q. Scott Mar 2005

Daily Rhythm Of Cerebral Blood Flow Velocity, Deirdre A. Conroy, Arthur J. Spielman, Rebecca Q. Scott

Publications and Research

Background: CBFV (cerebral blood flow velocity) is lower in the morning than in the afternoon and evening. Two hypotheses have been proposed to explain the time of day changes in CBFV: 1) CBFV changes are due to sleep-associated processes or 2) time of day changes in CBFV are due to an endogenous circadian rhythm independent of sleep. The aim of this study was to examine CBFV over 30 hours of sustained wakefulness to determine whether CBFV exhibits fluctuations associated with time of day.

Methods: Eleven subjects underwent a modified constant routine protocol. CBFV from the middle cerebral artery was monitored …