CATLAB

category laboratory

Navigation Menu

Amir joins the lab

Posted on Dec 1, 2022

Amirsaman Sajad joined the collaboration with Gordon Logan and Jeffrey Schall as a Research Assistant Professor in December 2022. Amir did his PhD in Toronto and did postdoctoral work in primate neurophysiology at Vanderbilt. His recent work has focused on dissecting the neural circuitry serving performance monitoring and adaptive behavior, and on linking this to non-invasive electrophysiological biomarkers. He joined the collaboration to extend his computational expertise and integrate decision-making modeling with models of performance monitoring and cognitive control. His scientific mission is to discover the building blocks of cognition and their biomarkers and translate this knowledge to real-world applications.

Read More


New Psychological Review article: Salience by Competitive and Recurrent Interactions

Posted on Feb 22, 2022

Our major new theoretical paper has been accepted for publication in Psychological Review: Cox, G.E., Palmeri, T.J., Logan, G.D., Smith, P.L., Schall, J.D. (in press). Salience by competitive and recurrent interactions: Bridging neural spiking and computation in visual attention. Psychological Review. PsyArXiv: https://psyarxiv.com/rkh8g/

Decisions about where to move the eyes depend on neurons in Frontal Eye Field (FEF). Movement neurons in FEF accumulate salience evidence derived from FEF visual neurons to select the location of a saccade target among distractors. How visual neurons achieve this salience representation is unknown. We present a neuro-computational model of target selection called Salience by Competitive and Recurrent Interactions (SCRI), based on the Competitive Interaction model of attentional selection and decision making (Smith & Sewell, 2013). SCRI selects targets by synthesizing localization and identification information to yield a dynamically evolving representation of salience across the visual field. SCRI accounts for neural spiking of individual FEF visual neurons, explaining idiosyncratic differences in neural dynamics with specific parameters. Many visual neurons resolve the competition between search items through feedforward inhibition between signals representing different search items, some also require lateral inhibition, and many act as recurrent gates to modulate the incoming flow of information about stimulus identity. SCRI was tested further by using simulated spiking representations of visual salience as input to the Gated Accumulator Model of FEF movement neurons (Purcell et al., 2010; Purcell, Schall, Logan, & Palmeri, 2012). Predicted saccade response times fit those observed for search arrays of different set size and different target-distractor similarity, and accumulator trajectories replicated movement neuron discharge rates. These findings offer new insights into visual decision making through converging neuro-computational constraints and provide a novel computational account of the diversity of FEF visual neurons.

Read More


New Papers

Posted on Feb 16, 2022

Cox, G.E., Palmeri, T.J., Logan, G.D., Smith, P.L., & Schall, J.D. (in press). Spiking, salience, and saccades: Using cognitive models to bridge the gap between “how” and “why”. In B. Forstmann & B.M. Turner (Eds.), An Introduction to Model-Based Cognitive Neuroscience (2nd Ed.), Springer Neuroscience.

Chow, J.K., Palmeri, T.J., Mack, M.L. (in press). Revealing a competitive dynamic in rapid categorization with object substitution masking. Attention, Perception, & Performance.

Carrigan, A.J., Charlton, A., Wiggins, M.W., Georgiou, A., Palmeri, T.J., & Curby, K.M. (in press). Cue utilisation reduces the impact of response bias in histopathology. Applied Ergonomics.

Chow, J.K., Palmeri, T.J., Gauthier, I. (in press). Haptic object recognition based on shape relates to visual object recognition ability. Psychological Research.

Chow, J.K., Palmeri, T.J., Gauthier, I. (in press). Visual object recognition ability is not related to experience with visual arts. Journal of Vision.

Carrigan, A.J., Charlton, A., Foucar, E., Wiggins, M., Georgiou, A., Palmeri, T.J., & Curby, K. (in press). The role of cue based strategies in skilled diagnosis amongst pathologists. Human Factors.

Read More


Welcome Giwon!

Posted on Jan 20, 2022

Giwon Bahg joined the lab, working as part of the collaboration with Palmeri, Logan, and Schall on their NEI-funded grant. Giwon received his Ph.D. from The Ohio State University in 2021 under the supervision of Dr. Brandon Turner, where he studied how category learning interacts with attention, information search, and other higher-order cognitive processes. His particular interest lies in understanding how such processes evolve over time in a closed-loop, interactive environment. His research also involves joint modeling of multimodal data using computational cognitive modeling, Bayesian methods, and machine learning approaches. His current research project involves linking our computational models of visual selection, attention, and decision making (SCRI+GAM) with behavioral, EEG, and neural spiking data.

Read More


Welcome Jin!

Posted on Sep 22, 2021

We welcomed Jinhyeok Jeong to the lab this Fall 2021. Jin received his bachelor’s degree in Psychology and master’s degree in Cognitive Science at Yonsei University. Under the supervision of Professor Sang Chul Chong, he studied ensemble perception, especially the variability perception of multiple visual items. As a graduate student at Vanderbilt, he is interested in the computational mechanisms of ensemble perception and how it relates to object categorization. Jinhyeok also has great interests in cognitive models of perception, memory, and decision-making processes, and how deep neural networks can be combined with these models. His current first year research project involves developing and testing computational models of ensemble processing and looking at relations with models of categorization, memory, and decision making.

Read More