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Articles 4411 - 4440 of 5800

Full-Text Articles in Neuroscience and Neurobiology

Increased Resting-State Functional Connectivity Of Visual- And Cognitive-Control Brain Networks After Training In Children With Reading Difficulties, Tzipi Horowitz-Kraus, Mark Difrancesco, Benjamin Kay, Yingying Wang, Scott K. Holland Jul 2015

Increased Resting-State Functional Connectivity Of Visual- And Cognitive-Control Brain Networks After Training In Children With Reading Difficulties, Tzipi Horowitz-Kraus, Mark Difrancesco, Benjamin Kay, Yingying Wang, Scott K. Holland

Center for Brain, Biology, and Behavior: Faculty Publications

The Reading Acceleration Program, a computerized reading-training program, increases activation in neural circuits related to reading.We examined the effect of the training on the functional connectivity between independent components related to visual processing, executive functions, attention, memory, and language during rest after the training. Children 8–12 years old with reading difficulties and typical readers participated in the study. Behavioral testing and functional magnetic resonance imaging were performed before and after the training. Imaging data were analyzed using an independent component analysis approach. After training, both reading groups showed increased single-word contextual reading and reading comprehension scores. Greater positive correlations between …


The Mouse That Trolled: The Long And Tortuous History Of A Gene Mutation Patent That Became An Expensive Impediment To Alzheimer's Research, Tania M. Bubela, Saurabh Vishnubhakat, Robert Cook-Deegan Jul 2015

The Mouse That Trolled: The Long And Tortuous History Of A Gene Mutation Patent That Became An Expensive Impediment To Alzheimer's Research, Tania M. Bubela, Saurabh Vishnubhakat, Robert Cook-Deegan

Office of the Provost

This case study presents the tale of the academic discovery of a rare mutation for early-onset Alzheimer's disease that was patented by a sole inventor and licensed to a non-practicing entity (NPE), the Alzheimer's Institute of America (AIA). Our aims are (1) to relate this story about patents, research tools, and impediments to medical progress, and (2) to inform ongoing debates about how patents affect research, disposition of university inventions, and the distribution of benefits from publicly funded research. We present an account of the hunt for Alzheimer's genes, their patenting, assignment, and enforcement based on literature, litigation records and …


Erin: A Portal To Resources For Higher Education In Neuroscience, Richard F. Olivo, Joseph R. Burdo, Robert Calin-Jagemen, William Grisham, Monica L. Linden, Robert L. Rosenberg, Laura L. Symonds, Janice E. Thornton Jul 2015

Erin: A Portal To Resources For Higher Education In Neuroscience, Richard F. Olivo, Joseph R. Burdo, Robert Calin-Jagemen, William Grisham, Monica L. Linden, Robert L. Rosenberg, Laura L. Symonds, Janice E. Thornton

Neuroscience: Faculty Publications

ERIN, Educational Resources in Neuroscience, is the Society for Neuroscience's web portal to selected, high- quality materials for higher education. A Board of Editors approves resources after describing them and classifying them by topic, subtopic, media type, author, and appropriate educational level. Some resources are also accompanied by reviews and ratings from faculty who have used the resource. These features make a search of ERIN far more useful than a typical Google search.

ERIN's development was funded by the National Science Foundation with a three-year grant to SfN. Along the way, various unexpected problems arose and solutions were found, many …


Susceptibility Of Parkinson’S Disease Following Mild Blast Traumatic Brain Injury, Glen Howel Galicia Acosta Jul 2015

Susceptibility Of Parkinson’S Disease Following Mild Blast Traumatic Brain Injury, Glen Howel Galicia Acosta

Open Access Theses

Blast injury-induced neurotrauma (BINT) is steadily increasing in prevalence due to escalated terror activity and constitutes the signature injury associated with current military conflicts. BINT produces significant neurological deficiencies and there is a growing concern that the injury may produce long-term consequences that affect the resilience and the performance of soldiers. One of the potential consequences is an increased susceptibility to Parkinson's disease (PD). A vital goal aimed at curtailing the post-deployment long-term consequences of blast injury-induced neurotrauma is to further our knowledge of pathogenic mechanisms responsible for the escalation of post injury diseases. The purpose of this project is …


Spatiotemporal Fluctuations Of Olfactory Stimuli And Its Detection By An Optical Method, Mitu Chandra Acharjee Jul 2015

Spatiotemporal Fluctuations Of Olfactory Stimuli And Its Detection By An Optical Method, Mitu Chandra Acharjee

Graduate Theses and Dissertations

Olfactory processing in the mammalian brain is a highly dynamic process, yet most of the olfaction experiments have been studied primarily with static stimuli. Odors in the natural environment are transported by turbulent flow of air or water. Natural odorants have fluctuations in concentration and it changes rapidly with time. These rapid fluctuations may pose some challenges to identifying an odor; on the other hand, the variation itself may provide important clues about the odor source. The goal of this thesis project was to create a similar odorant environment like the rapid odor fluctuations encountered in nature – to meet …


Neonatal Isolation Stress Inhibits Pre-Weaning Weight Gain And Mild-Stressor Induced Locomotor Activity In Early Adolescent Male And Female Rats, Peter Villavecchia, Mindy Miserendino Jul 2015

Neonatal Isolation Stress Inhibits Pre-Weaning Weight Gain And Mild-Stressor Induced Locomotor Activity In Early Adolescent Male And Female Rats, Peter Villavecchia, Mindy Miserendino

Psychology Faculty Publications

The present study looked at the effects of neonatal isolation, an early life stress experience, in male and female early adolescent rats, an age which is underrepresented in the early stress literature. Four stress-sensitive indices were assessed: weight gain during the pre-weaning period, open field activity, and locomotor activity in response to two mild stressors: exposure to a novel environment, and a single IP saline injection. Rats in the neonatal isolation condition were removed from dam and littermates on postnatal days 2-9 in accord with the procedure used by Kehoe et al. (1995); behavioral testing occurred on PN25-PN30 during …


Subject Assessment Of In-Vehicle Auditory Warnings For Rail Grade Crossings, Steven Landry, Jayde Croschere, Myounghoon Jeon Jul 2015

Subject Assessment Of In-Vehicle Auditory Warnings For Rail Grade Crossings, Steven Landry, Jayde Croschere, Myounghoon Jeon

Michigan Tech Publications, Part 1

Human factors research has played an important role in reducing the incidents of vehicle-train collisions at rail grade crossings over the past 30 years. With the growing popularity of in-vehicle infotainment systems and GPS devices, new opportunities arise to cost-efficiently and effectively alert drivers of railroad crossings and to promote safer driving habits. To best utilize this in-vehicle technology, 32 auditory warnings (16 verbal, 7 train-related auditory icons, and 9 generic earcons) were generated and presented to 31 participants after a brief low-fidelity driving simulation. Participants rated each sound on eight dimensions deemed important in previous auditory warning literature. Preliminary …


Onset Time And Durability Of Huntingtin Suppression In Rhesus Putamen After Direct Infusion Of Antihuntingtin Sirna, Richard Grondin, Pei Ge, Qingmin Chen, Jessica E. Sutherland, Zhiming Zhang, Don M. Gash, David K. Stiles, Gregory R. Stewart, Dinah W. Y. Sah, William F. Kaemmerer Jun 2015

Onset Time And Durability Of Huntingtin Suppression In Rhesus Putamen After Direct Infusion Of Antihuntingtin Sirna, Richard Grondin, Pei Ge, Qingmin Chen, Jessica E. Sutherland, Zhiming Zhang, Don M. Gash, David K. Stiles, Gregory R. Stewart, Dinah W. Y. Sah, William F. Kaemmerer

Neuroscience Faculty Publications

One possible treatment for Huntington's disease involves direct infusion of a small, interfering RNA (siRNA) designed to reduce huntingtin expression into brain tissue from a chronically implanted programmable pump. Here, we studied the suppression of huntingtin mRNA achievable with short infusion times, and investigated how long suppression may persist after infusion ceases. Rhesus monkeys received 3 days of infusion of Magnevist into the putamen to confirm catheter patency and fluid distribution. After a 1-week washout period, monkeys received radiolabeled siRNA targeting huntingtin. After 1 or 3 days of siRNA delivery, monkeys were either terminated, or their pumps were shut off …


The Effects Of Sleep-Dependent Memory Consolidation On The Discriminability And Generalizability Of Learning, Bengt Grua, Dr. C Brock Kirwan Jun 2015

The Effects Of Sleep-Dependent Memory Consolidation On The Discriminability And Generalizability Of Learning, Bengt Grua, Dr. C Brock Kirwan

Journal of Undergraduate Research

The goal of this study was to determine how sleep affects memory recall in an academic setting with relation to memory discrimination and memory generalization. Memory generalization depends on the computational process of pattern completion, which is the brain’s ability to retrieve a memory representation based on a partial or modified stimulus (such as viewing a false statement as true if it has many true elements embedded in it). Memory discrimination depends on the computational process of pattern separation, which is the brain’s ability to store a memory as distinct and separate from other, similar memories. Current models of sleep …


The Effects Of Sleep-Dependent Memory Consolidation On The Discriminability And Generalizability Of Learning, Bengt Grua, Dr. C Brock Kirwan Jun 2015

The Effects Of Sleep-Dependent Memory Consolidation On The Discriminability And Generalizability Of Learning, Bengt Grua, Dr. C Brock Kirwan

Journal of Undergraduate Research

The goal of this study was to determine how sleep affects memory recall in an academic setting with relation to memory discrimination and memory generalization. Memory generalization depends on the computational process of pattern completion, which is the brain’s ability to retrieve a memory representation based on a partial or modified stimulus (such as viewing a false statement as true if it has many true elements embedded in it). Memory discrimination depends on the computational process of pattern separation, which is the brain’s ability to store a memory as distinct and separate from other, similar memories. Current models of sleep …


The Effect Of Exercise On Inhibitory Control To Images Of High And Low Calorie Food, Cory Pettit, Michael J. Larson Jun 2015

The Effect Of Exercise On Inhibitory Control To Images Of High And Low Calorie Food, Cory Pettit, Michael J. Larson

Journal of Undergraduate Research

The purpose of this study was to examine the effects of exercise on the neural correlates of response inhibition to high and low calorie foods. Specifically, we aimed to explore whether engaging in forty-five minutes of moderate intensity exercise affects brain activity that denotes inhibitory control while a person withholds practiced responses to pictures of high or low calorie food. We quantified inhibitory control by measuring the amplitude of the N2 event related potential (ERP; described below) using electroencephalogram (EEG) technology.


Induction Of Neuromelanin In Live Tissue, Corrine Morrison, Dr. Scott Steffensen Jun 2015

Induction Of Neuromelanin In Live Tissue, Corrine Morrison, Dr. Scott Steffensen

Journal of Undergraduate Research

An estimated seven to ten million people worldwide are living with Parkinson’s Disease (PD) and about 60,000 Americans are diagnosed with the disease each year (Parkinson’s Disease Foundation, 2013). The underlying cause of the movement disorders in PD is dopamine (DA) neuron degeneration in the substantia nigra pars compacta (SNc). A proposed mechanism behind DA cell death is additional oxidative stress that occurs in early stages of the disease state. NM is believed to be a protective agent against reactive oxygen species (ROS), but as NM depigmentation is a distinctive feature of PD, it is likely that there is a …


The Effect Of Exercise On Inhibitory Control To Images Of High And Low Calorie Food, Cory Pettit, Michael J. Larson, Phd Jun 2015

The Effect Of Exercise On Inhibitory Control To Images Of High And Low Calorie Food, Cory Pettit, Michael J. Larson, Phd

Journal of Undergraduate Research

The purpose of this study was to examine the effects of exercise on the neural correlates of response inhibition to high and low calorie foods. Specifically, we aimed to explore whether engaging in forty-five minutes of moderate intensity exercise affects brain activity that denotes inhibitory control while a person withholds practiced responses to pictures of high or low calorie food. We quantified inhibitory control by measuring the amplitude of the N2 event related potential (ERP; described below) using electroencephalogram (EEG) technology.


Cell Type Specificity Of Tissue Plasminogen Activator In The Mouse Barrel Cortex, Philip Chu, Eric Chen, Adesh Bajnath, Joshua C. Brumberg Jun 2015

Cell Type Specificity Of Tissue Plasminogen Activator In The Mouse Barrel Cortex, Philip Chu, Eric Chen, Adesh Bajnath, Joshua C. Brumberg

Publications and Research

It has been suggested that tissue-type plasminogen activator (tPA), a serine protease, plays a key role in regulating the extracellular matrix core proteins, thereby impacting the structural plasticity in the cerebral cortex. Much is known about its role in regulating plasticity in the visual cortex. However, its permissive role has not been demonstrated to generalize to other cerebral cortical areas. By utilizing a combination of immunofluorescent histochemistry and confocal microscopy, we demonstrate that endogenous tPA is indeed present in the somatosensory cortex, and its expression is experience-dependent. Chronic sensory deprivation induced by whisker trimming from birth for one month leads …


Neuron-Based Heredity And Human Evolution, Don M. Gash, Andrew S. Deane Jun 2015

Neuron-Based Heredity And Human Evolution, Don M. Gash, Andrew S. Deane

Neuroscience Faculty Publications

It is widely recognized that human evolution has been driven by two systems of heredity: one DNA-based and the other based on the transmission of behaviorally acquired information via nervous system functions. The genetic system is ancient, going back to the appearance of life on Earth. It is responsible for the evolutionary processes described by Darwin. By comparison, the nervous system is relatively newly minted and in its highest form, responsible for ideation and mind-to-mind transmission of information. Here the informational capabilities and functions of the two systems are compared. While employing quite different mechanisms for encoding, storing and transmission …


Behavioral And Cognitive Changes After Early Postnatal Lesions Of The Rat Mediodorsal Thalamus, Zakaria Ouhaz, Saadua B-M'Hamed, Anna S. Mitchell, Abdeslem Elidrissi, Mohamed Bennis Jun 2015

Behavioral And Cognitive Changes After Early Postnatal Lesions Of The Rat Mediodorsal Thalamus, Zakaria Ouhaz, Saadua B-M'Hamed, Anna S. Mitchell, Abdeslem Elidrissi, Mohamed Bennis

Publications and Research

Early insults to the thalamus result in functional and/or structural abnormalities in the cerebral cortex. However, differences in behavioral and cognitive changes after early insult are not well characterized. The present study assessed whether early postnatal damage to mediodorsal nucleus of the thalamus (MD), reciprocally interconnected with the prefrontal cortex, causes behavioral and cognitive alterations in young adult rats. Rat pups at postnatal day 4 received bilateral electrolytic lesion of MD, or aMD Sham lesion or were anesthetized controls; on recovery they were returned to their mothers until weaning. Seven weeks later, all rats were tested with the following behavioral …


The Effects Of Arginine Vasopressin On Maternal Behavior And Aggression In Peromyscus Californicus Mothers, Nathaniel Ng Jun 2015

The Effects Of Arginine Vasopressin On Maternal Behavior And Aggression In Peromyscus Californicus Mothers, Nathaniel Ng

Honors Projects

Research studies since the 1950s have shown that a chemical within the brain called arginine vasopressin (AVP) is associated with the modulation of many different social behaviors in mammals. Some of these behaviors are related to parenting, such as parental care initiation, aggression, social recognition, depression and anxiety. Understanding the physiology behind AVP regulation could allow for the creation of new therapies for treating human social disorders, such as using an AVP receptor antagonist to attenuate anxiety. This project examines how neural injections of AVP and an AVP receptor antagonist affect both maternal care and aggression in female Peromyscus californicus …


The Cognition-Enhancing Effects Of Psychostimulants Involve Direct Action In The Prefrontal Cortex, Robert C. Spencer, David M. Devilbiss, Craig Berridge Jun 2015

The Cognition-Enhancing Effects Of Psychostimulants Involve Direct Action In The Prefrontal Cortex, Robert C. Spencer, David M. Devilbiss, Craig Berridge

Rowan-Virtua School of Osteopathic Medicine Departmental Research

Psychostimulants are highly effective in the treatment of attention-deficit/hyperactivity disorder. The clinical efficacy of these drugs is strongly linked to their ability to improve cognition dependent on the prefrontal cortex (PFC) and extended frontostriatal circuit. The procognitive actions of psychostimulants are only associated with low doses. Surprisingly, despite nearly 80 years of clinical use, the neurobiology of the procognitive actions of psychostimulants has only recently been systematically investigated. Findings from this research unambiguously demonstrate that the cognition-enhancing effects of psychostimulants involve the preferential elevation of catecholamines in the PFC and the subsequent activation of norepinephrine α2 and dopamine D1 receptors. …


Evolutionary Convergence Of The Caffeine Biosynthetic Pathway In Chocolate Followed Duplication Of A Constrained Ancestral Enzyme, Andrew J. O'Donnell Jun 2015

Evolutionary Convergence Of The Caffeine Biosynthetic Pathway In Chocolate Followed Duplication Of A Constrained Ancestral Enzyme, Andrew J. O'Donnell

Masters Theses

Caffeine biosynthesis is widely distributed in flowering plants and requires three consecutive methylation steps of xanthine alkaloids. Genes that have previously been reported to participate in the multi-step pathway in Coffea sp. (coffee) and Camellia sinensis (tea) encode members of the SABATH family of methyltransferases. Two genes highly expressed in fruits of Theobroma cacao (cacao) are orthologous to the caffeine genes in tea and appear to have diversified following gene duplication. Biochemical characterization of the enzymes (XMTs) encoded by these genes strongly suggest an unprecedented major pathway to theobromine, a precursor to caffeine. These findings imply that caffeine biosynthesis evolved …


Category-Selective Attention Interacts With Partial Awareness Processes In A Continuous Manner: An Fmri Study, Shen Tu, Jerwen Jou, Qian Cui, Guang Zhao, Kangcheng Wang, Glenn Hitchman, Jiang Qiu, Qinglin Zhang Jun 2015

Category-Selective Attention Interacts With Partial Awareness Processes In A Continuous Manner: An Fmri Study, Shen Tu, Jerwen Jou, Qian Cui, Guang Zhao, Kangcheng Wang, Glenn Hitchman, Jiang Qiu, Qinglin Zhang

Psychological Science Faculty Publications

Recently, our team found that category-selective attention could modulate tool processing at the partial awareness level and unconscious face processing in the middle occipital gyrus (MOG). However, the modulation effects in MOG were in opposite directions across the masked tool and masked face conditions in that study: MOG activation decreased in the masked faces condition but increased in the masked tools condition under the consistent compared with the inconsistent cue-selective-attentional modulation. In the present study, in order to confirm that the opposite effects were due to the changed contours of the tools, using the same tool pictures and fMRI technique, …


Regulation Of Glial Cell Line-Derived Neurotrophic Factor (Gdnf) Production In Voluntary And Involuntary Muscle, John-Mary Vianney Jun 2015

Regulation Of Glial Cell Line-Derived Neurotrophic Factor (Gdnf) Production In Voluntary And Involuntary Muscle, John-Mary Vianney

Dissertations

Glia cell line-derived neurotrophic factor (GDNF) is a survival factor for subpopulations of neurons, including somatic and autonomic motor neurons. These neurons depend, in part, on GDNF that is synthesized and secreted by their target tissues. It has been shown that a number of tissues in the periphery express GDNF and these target tissues differ in their composition, function, and in the case of different muscle cell types, their contractile characteristics. Whether the processes regulating GDNF production in these different tissues is similar or different is poorly understood. The broad goal of this study is to examine factors that normally …


Disruption Of Columnar And Laminar Cognitive Processing In Primate Prefrontal Cortex Following Cocaine Exposure, Ioan Opris, Greg A. Gerhardt, Robert E. Hampson, Sam A. Deadwyler May 2015

Disruption Of Columnar And Laminar Cognitive Processing In Primate Prefrontal Cortex Following Cocaine Exposure, Ioan Opris, Greg A. Gerhardt, Robert E. Hampson, Sam A. Deadwyler

Neuroscience Faculty Publications

Prefrontal cortical activity in primate brain plays a critical role in cognitive processes involving working memory and the executive control of behavior. Groups of prefrontal cortical neurons within specified cortical layers along cortical minicolumns differentially generate inter- and intra-laminar firing to process relevant information for goal oriented behavior. However, it is not yet understood how cocaine modulates such differential firing in prefrontal cortical layers. Rhesus macaque nonhuman primates (NHPs) were trained in a visual delayed match-to-sample (DMS) task while the activity of prefrontal cortical neurons (areas 46, 8 and 6) was recorded simultaneously with a custom multielectrode array in cell …


Prenatal Predictors Of Infant Self-Regulation: The Contributions Of Placental Dna Methylation Of Nr3c1 And Neuroendocrine Activity, Elisabeth Conradt, Mary Fei, Linda Lagasse, Edward Tronick, Dylan Guerin, Daniel Gorman, Carmen J. Marsit, Barry M. Lester May 2015

Prenatal Predictors Of Infant Self-Regulation: The Contributions Of Placental Dna Methylation Of Nr3c1 And Neuroendocrine Activity, Elisabeth Conradt, Mary Fei, Linda Lagasse, Edward Tronick, Dylan Guerin, Daniel Gorman, Carmen J. Marsit, Barry M. Lester

Dartmouth Scholarship

We examined whether placental DNA methylation of the glucocorticoid receptor gene, NR3C1 was associated with self-regulation and neuroendocrine responses to a social stressor in infancy. Placenta samples were obtained at birth and mothers and their infants (n = 128) participated in the still-face paradigm when infants were 5 months old. Infant self-regulation following the still-face episode was coded and pre-stress cortisol and cortisol reactivity was assessed in response to the still-face paradigm. A factor analysis of NR3C1 CpG sites revealed two factors: one for CpG sites 1-4 and the other for sites 5-13. DNA methylation of the factor comprising NR3C1 …


Disease-Related Microglia Heterogeneity In The Hippocampus Of Alzheimer's Disease, Dementia With Lewy Bodies, And Hippocampal Sclerosis Of Aging, Adam D. Bachstetter, Linda J. Van Eldik, Frederick A. Schmitt, Janna H. Neltner, Eseosa T. Ighodaro, Scott J. Webster, Ela Patel, Erin L. Abner, Richard J. Kryscio, Peter T. Nelson May 2015

Disease-Related Microglia Heterogeneity In The Hippocampus Of Alzheimer's Disease, Dementia With Lewy Bodies, And Hippocampal Sclerosis Of Aging, Adam D. Bachstetter, Linda J. Van Eldik, Frederick A. Schmitt, Janna H. Neltner, Eseosa T. Ighodaro, Scott J. Webster, Ela Patel, Erin L. Abner, Richard J. Kryscio, Peter T. Nelson

Sanders-Brown Center on Aging Faculty Publications

Introduction: Neuropathological, genetic, and biochemical studies have provided support for the hypothesis that microglia participate in Alzheimer's disease (AD) pathogenesis. Despite the extensive characterization of AD microglia, there are still many unanswered questions, and little is known about microglial morphology in other common forms of age-related dementia: particularly, dementia with Lewy bodies (DLB) and hippocampal sclerosis of aging (HS-Aging). In addition, no prior studies have attempted to compare and contrast the microglia morphology in the hippocampus of various neurodegenerative conditions.

Results: Here we studied cases with pathologically-confirmed AD (n = 7), HS-Aging (n = 7), AD + HS-aging …


Autonomic And Brain Responses Associated With Empathy Deficits In Autism Spectrum Disorder, Xiaosi Gu, Tehila Eilam-Stock, Thomas Zhou, Evdokia Anagnostou, Alexander Kolevzon, Latha Soorya, Patrick R. Hof, Karl J. Friston, Jin Fan May 2015

Autonomic And Brain Responses Associated With Empathy Deficits In Autism Spectrum Disorder, Xiaosi Gu, Tehila Eilam-Stock, Thomas Zhou, Evdokia Anagnostou, Alexander Kolevzon, Latha Soorya, Patrick R. Hof, Karl J. Friston, Jin Fan

Publications and Research

Accumulating evidence suggests that autonomic signals and their cortical representations are closely linked to emotional processes, and that related abnormalities could lead to social deficits. Although socio-emotional impairments are a defining feature of autism spectrum disorder (ASD), empirical evidence directly supporting the link between autonomic, cortical, and socio-emotional abnormalities in ASD is still lacking. In this study, we examined autonomic arousal indexed by skin conductance responses (SCR), concurrent cortical responses measured by functional magnetic resonance imaging, and effective brain connectivity estimated by dynamic causal modeling in seventeen unmedicated high-functioning adults with ASD and seventeen matched controls while they performed an …


Characterizing Receptive Field Selectivity In Area V2, Corey M. Ziemba, Robbe Lt Goris, J Anthony Movshon, Eero P. Simoncelli May 2015

Characterizing Receptive Field Selectivity In Area V2, Corey M. Ziemba, Robbe Lt Goris, J Anthony Movshon, Eero P. Simoncelli

MODVIS Workshop

The computations performed by neurons in area V1 are reasonably well understood, but computation in subsequent areas such as V2 have been more difficult to characterize. When stimulated with visual stimuli traditionally used to investigate V1, such as sinusoidal gratings, V2 neurons exhibit similar selectivity (but with larger receptive fields, and weaker responses) relative to V1 neurons. However, we find that V2 responses to synthetic stimuli designed to produce naturalistic patterns of joint activity in a model V1 population are more vigorous than responses to control stimuli that lacked this naturalistic structure (Freeman, et. al. 2013). Armed with this signature …


‘Edge’ Integration Explains Contrast And Assimilation In A Gradient Lightness Illusion, Michael E. Rudd May 2015

‘Edge’ Integration Explains Contrast And Assimilation In A Gradient Lightness Illusion, Michael E. Rudd

MODVIS Workshop

In the ‘phantom’ illusion (Galmonte, Soranzo, Rudd, & Agostini, submitted), either an incremental or a decremental target, when surrounded by a luminance gradient, can to be made to appear as an increment or a decrement, depending on the gradient width. For wide gradients, incremental targets appear as increments and decremental targets appear as decrements. For narrow gradients, the reverse is true. Here, I model these phenomena with a two-stage neural lightness theory (Rudd, 2013, 2014) in which local steps in log luminance are first encoded by oriented spatial filters operating on a log-transformed version of the image; then the filter …


Time-Lapse Statistics Of Cone Signals From Natural Scenes, David H. Foster, Kinjiro Amano, Sérgio M C Nascimento May 2015

Time-Lapse Statistics Of Cone Signals From Natural Scenes, David H. Foster, Kinjiro Amano, Sérgio M C Nascimento

MODVIS Workshop

In the natural world, the spectrum and geometry of the illumination from the sun and sky vary over the day. These geometric changes make it especially difficult to extract from the reflected light invariant signals for surface color perception. The aim of this study was to test the utility of certain combinations of retinal cone excitations, in particular, spatial cone-excitation ratios, known to be approximately invariant under non-geometric changes in illumination. Hyperspectral radiance images were acquired at roughly hourly intervals in four outdoor scenes in the Minho region of Portugal. Spatial resolution of the camera was 1344×1024 pixels. Peak-transmission wavelength …


The Bounded Log-Odds Model Of Frequency And Probability Distortion, Hang Zhang, Laurence T. Maloney May 2015

The Bounded Log-Odds Model Of Frequency And Probability Distortion, Hang Zhang, Laurence T. Maloney

MODVIS Workshop

No abstract provided.


Putting Saliency In Its Place, John K. Tsotsos May 2015

Putting Saliency In Its Place, John K. Tsotsos

MODVIS Workshop

The role of attention and the place within the visual processing stream where the concept of saliency has been situated is critically examined by considering the experimental evidence and performing tests that link experiment to computation.