Neuroscience and Neurobiology Commons^™

From Image Gradients To A Perceptual Metric Space, Alan Johnston

MODVIS Workshop

How do we achieve a sense of spatial dimension from a sense of location? There are three predominant ideas about how we achieve this; spatial isomorphism, in which what we see reflects differences in distance or size in the brain; that spatial extent depends upon motor sensations or intentions related to eye movements; and that distance is computed from the degree of correlation in neural activity between adjacent locations, with distance inversely proportional to the correlation. There are problems with each of these approaches, for example, neural correlation may depend more on image structure than adjacency - consider the case …

V1 Saliency Hypothesis And Central-Peripheral Dichotomy (Cpd), Li Zhaoping Prof. Dr.

MODVIS Workshop

No abstract provided.

A Dynamical Model Of Binding In Visual Cortex During Incremental Grouping And Search, Daniel Schmid, Daniel A. Braun, Heiko Neumann

MODVIS Workshop

Binding of visual information is crucial for several perceptual tasks. To incrementally group an object, elements in a space-feature neighborhood need to be bound together starting from an attended location (Roelfsema, TICS, 2005). To perform visual search, candidate locations and cued features must be evaluated conjunctively to retrieve a target (Treisman&Gormican, Psychol Rev, 1988). Despite different requirements on binding, both tasks are solved by the same neural substrate. In a model of perceptual decision-making, we give a mechanistic explanation for how this can be achieved. The architecture consists of a visual cortex module and a higher-order thalamic module. While the …

Efficient Coding Of Local 2d Shape, James Elder, Timothy D. Oleskiw, Ingo Fruend, Gerick M. Lee, Andrew Sutter, Anitha Pasupathy, Eero Simoncelli, J Anthony Movshon, Lynne Kiorpes, Najib Majaj

MODVIS Workshop

Efficient coding provides a concise account of key early visual properties, but can it explain higher-level visual function such as shape perception? If curvature is a key primitive of local shape representation, efficient shape coding predicts that sensitivity of visual neurons should be determined by naturally-occurring curvature statistics, which follow a scale-invariant power-law distribution. To assess visual sensitivity to these power-law statistics, we developed a novel family of synthetic maximum-entropy shape stimuli that progressively match the local curvature statistics of natural shapes, but lack global structure. We find that humans can reliably identify natural shapes based on 4^th and …

Impact Of Adolescent Social Isolation On Adult, Binge-Like Ethanol Consumption And Plasma Corticosterone In High-Alcohol-Preferring Mice, Eva Cullins

The Journal of Purdue Undergraduate Research

Adolescent stress exposure increases the likelihood of alcohol misuse and alcohol use disorder (AUD) in adulthood; however, it is not clear how genetic and environmental factors interact to increase risk. This study examined how adolescent social isolation affects adult binge-like ethanol drinking and levels of the stress hormone corticosterone in male and female mice with a genetic predisposition toward high alcohol preference (HAP). Twenty-eight HAP mice were separated into group-housed (GH) and socially isolated (SI) conditions (n = 13, 13). Binge drinking was assessed using a drinking in the dark (DID) procedure. Blood samples were taken before DID and after …

Validity Of Neural Distance Measures In Representational Similarity Analysis, Fabian A. Soto, Emily R. Martin, Hyeonjeong Lee, Nafiz Ahmed, Juan Estepa, Kianoosh Hosseini, Olivia A. Stibolt, Valentina Roldan, Alycia Winters, Mohammadreza Bayat

MODVIS Workshop

No abstract provided.

Visual Expertise In An Anatomically-Inspired Model Of The Visual System, Garrison W. Cottrell, Martha Gahl, Shubham Kulkarni

MODVIS Workshop

We report on preliminary results of an anatomically-inspired deep learning model of the visual system and its role in explaining the face inversion effect. Contrary to the generally accepted wisdom, our hypothesis is that the face inversion effect can be accounted for by the representation in V1 combined with the reliance on the configuration of features due to face expertise. We take two features of the primate visual system into account: 1) The foveated retina; and 2) The log-polar mapping from retina to V1. We simulate acquisition of faces, etc., by gradually increasing the number of identities the network learns. …

Characterization Of Local And Global Statistics In Three Kinds Of Medical Images, And An Example Of Their Role In A Clinical Judgment, Jonathan Victor, Amanda Simon, Craig K. Abbey

MODVIS Workshop

No abstract provided.

A Two-Layer Model Explains Higher-Order Feature Selectivity Of V2 Neurons, Timothy D. Oleskiw, Justin D. Lieber, J. Anthony Movshon, Eero P. Simoncelli

MODVIS Workshop

Neurons in cortical area V2 respond selectively to higher-order visual features, such as the quasi-periodic structure of natural texture. However, a functional account of how V2 neurons build selectivity for complex natural image features from their inputs – V1 neurons locally tuned for orientation and spatial frequency – remains elusive.

We made single-unit recordings in area V2 in two fixating rhesus macaques. We presented stimuli composed of multiple superimposed grating patches that localize contrast energy in space, orientation, and scale. V2 activity is modeled via a two-layer linear-nonlinear network, optimized to use a sparse combination of V1-like outputs to account …

A Bayesian Account Of Depth From Shadow, James Elder, Patrick Cavanagh, Roberto Casati

MODVIS Workshop

When an object casts a shadow on a background surface, the offset of the shadow can be a compelling cue to the relative depth between the object and the background (e.g., Kersten et al 1996, Fig. 1). Cavanagh et al (2021) found that, at least for small shadow offsets, perceived depth scales almost linearly with shadow offset. Here we ask whether this finding can be understood quantitatively in terms of Bayesian decision theory.

Estimating relative depth from shadow offset is complicated by the fact that the shadow offset is co-determined by the slant of the light source relative to the …

Fixational Eye Movements, Perceptual Filling-In, And Perceptual Fading Of Grayscale Images, Michael E. Rudd

MODVIS Workshop

No abstract provided.

Constraining Computational Models Of Brightness Perception: What’S The Right Psychophysical Data?, Guillermo Aguilar, Joris Vincent, Marianne Maertens

MODVIS Workshop

No abstract provided.

Identifying And Localizing Multiple Objects Using Artificial Ventral And Dorsal Visual Cortical Pathways, Zhixian Han, Anne Sereno

MODVIS Workshop

We concluded in our previous study that model cortical visual pathways actively retained information differently according to the different goals of the training tasks. One limitation of our study was that there was only one object in each input image whereas in reality there may be multiple objects in a scene. In our current study, we try to find a brain-like algorithm that can recognize and localize multiple objects.

Model Of Visual Contrast Gain Control And Pattern And Noise Masking, Joshua A. Solomon

MODVIS Workshop

The first stage of the model can be subdivided into a global contrast sensitivity function (a 2-D log-parabolic filter of spatial frequency), followed by an array of sensors having Gabor-pattern receptive fields. The second stage is contrast gain control. At this stage, sensor outputs are subjected to an expansive transformation. Then the outputs are pooled and used to inhibit (or “normalize”) each other. Inhibition is strongest between sensors with similar preferences for orientation, spatial frequency and spatial location. In the final stage of the model, the nomalized sensor outputs for each image are subjected to Minkowski pooling. Two-alternative, forced-choice detection …

Influence Of Core Temperature On Psychomotor Performance During Cold Weather Military Training, Douglas Jones, Rebecca Weller, Stephen Eggan, Nicholas Roberts, Weimin Zheng, Jay Heaney, Timothy Dunn

Journal of Human Performance in Extreme Environments

Purpose: Cold environments may deteriorate psychomotor performance due to slowing of neuronal signals, distractions caused by pain and discomfort, and a loss of manual dexterity. The extent to which core temperature (T_c) influences psychomotor performance in the cold has not been established. Therefore, psychomotor performance and T_c were assessed during a cold weather military training exercise to evaluate this relationship.

Methods: Thirty-six military personnel (age: 26 ± 4 yr, ht: 175 ± 8 cm, wt: 79.1 ± 11.1 kg) participating in cold weather training volunteered for this study. Participants completed a 10-min immersion in cold (1°C) water, …

Methylmercury Cytotoxicity On Developing Neuronal Lineages And Differences In Susceptibility Based On Media Type, Madeline Henley

The Journal of Purdue Undergraduate Research

No abstract provided.

Characterization Of Neuronal Differentiation And Activity In Human-Induced Pluripotent Neural Stem Cells, Allison Biddinger

The Journal of Purdue Undergraduate Research

No abstract provided.

The Effects Of Adolescent Chronic Mild Stress: In Female Wistar-Kyoto Rats, Anna Hallowell

The Journal of Purdue Undergraduate Research

Despite years of research to understand under-lying mechanisms and develop more effective treatment approaches for mood disorders, numerous challenges exist. Many chronic stress models are used to study mood disorders, how-ever the majority have been established with adult males. This is problematic considering that affective disorders are more common in women, and generally develop during late adolescence. Studies have indicated fundamental behavioral, physiological, and neural differences between males and females in response to the same external stressors, furthering a need to develop sex-specific paradigms to accurately model the etiology of mood disorders in females. The Wistar-Kyoto (WKY) rat strain is …

Development Of An Imaging Analysis Algorithm For Fluorescence-Based High Content Screening In Parkinson’S Disease, Ryan Arlinghaus

The Journal of Purdue Undergraduate Research

No abstract provided.

A Pharmacological Model Of Trpa1-Mediated Nociception In Zebrafish For Therapeutic Discovery, Emre Coskun

The Journal of Purdue Undergraduate Research

No abstract provided.

Is The Selective Tuning Model Of Visual Attention Still Relevant?, John K. Tsotsos

MODVIS Workshop

No abstract provided.

Functional Organization Of Cortical Maps For Ocular Dominance And Light-Dark Polarity In Primary Visual Cortex, Sohrab Najafian, Jian Zhong Jin, Jose-Manuel Alonso

MODVIS Workshop

No abstract provided.

Computations Of Top-Down Attention By Modulating V1 Dynamics, David Berga, Xavier Otazu

MODVIS Workshop

The human visual system processes information defining what is visually conspicuous (saliency) to our perception, guiding eye movements towards certain objects depending on scene context and its feature characteristics. However, attention has been known to be biased by top-down influences (relevance), which define voluntary eye movements driven by goal-directed behavior and memory. We propose a unified model of the visual cortex able to predict, among other effects, top-down visual attention and saccadic eye movements. First, we simulate activations of early mechanisms of the visual system (RGC/LGN), by processing distinct image chromatic opponencies with Gabor-like filters. Second, we use a cortical …

Differentiating Changes In Population Encoding Models With Psychophysics And Neuroimaging, Jason Hays, Fabian Soto Phd

MODVIS Workshop

It is now common among visual scientists to make inferences about neural population coding of stimuli from indirect measures such as those provided by neuroimaging and psychophysics. The success of such studies depends strongly on simulation work using standard population encoding models extended with decoders (in psychophysics) and measurement models (in neuroimaging). However, not all studies are accompanied by simulation work, and those that are tend to vary widely in their assumptions about encoding, decoding, and measurement. To solve these issues, we designed a Python package (PEMGUIN) to assist computational modelling by providing simple ways to manage encoders' tuning functions, …

Virtual Eye: A Spatial-Temporal Bottom-Up Eye Sensitivity Model, Todd Goodall

MODVIS Workshop

Video quality and compression models use the

spatial contrast sensitivity function (CSF), which is solved

based on a linear system approximation. This function measures

the eye’s sensitivity to sinusoid gratings, ignoring the subtle

connectivity and inhomogeniety of cell density across the

visual field. Non-linear aspects of the eye, such as the change

in frequency sensitivity with changing illumination, are not

captured by this simple approximation. We propose Virtual

Eye, a bottom-up approach that models the spatio-temporal

dynamics of the eye across the visual field. Each functional

retinal cell layer in the eye is modeled using non-uniform spatial

cell responses, which …

Variance Partitioning Reveals Consistent Representation Of Object Boundary Contours In Lo Across Different Datasets, Mark D. Lescroart, Utkarsh Singhal

MODVIS Workshop

No abstract provided.

The Challenge For Vision Of Fluctuating Real-World Illumination, David H. Foster

MODVIS Workshop

No abstract provided.

Targeting Pro-Inflammatory Function Of Microglia Using Small Molecules To Combat Neurodegeneration, Gabrielle C. Williams, Priya Prakash, Gaurav Chopra

The Summer Undergraduate Research Fellowship (SURF) Symposium

Microglia are the brain’s resident immune cells that are responsible for maintaining homeostasis in healthy conditions. During injury or infection, resting microglia get activated and produce pro-inflammatory cytokines such as IL-1b, IL-1a, IL-6, etc. along with reactive oxygen species like nitric oxide (NO) to combat neuroinflammatory diseases such as Alzheimer’s disease (AD). Inflammation is characterized by the activation of resident-immune cells in the brain called microglia that respond to the eat-me signals released by the toxic amyloid beta peptides as well as the dying neurons in the microenvironment. Recent studies have shown that activated microglia induce neuronal death by secreting …

Neural Coding Of An Auditory Pitch Illusion, Maria Alejandra Barrera, Mark Sayles, Ravinderjit Singh

The Summer Undergraduate Research Fellowship (SURF) Symposium

Pitch is an important perceptual dimension in audition, supporting auditory object segregation, melody recognition and lexical distinction. Huggins’ pitch, for example, is a phenomenon evoked by two sources of broadband noise presented binaurally with an inter-aural phase shift over a narrow frequency band. Huggins’ pitch and other dichotic pitches have been studied extensively using perceptual experiments. Several models have been proposed to explain and predict the perception of pitch; however, no studies have tried to record in vivo neuron responses to Huggins’ pitch (HP) nor have tried to explain how the HP is coded by neurons. The existence of pitches …

‘Preferred’ Stimulus Of A Whole Model Visual System, Olivier Penacchio, Julie M. Harris

MODVIS Workshop

No abstract provided.