19 October 2021
09:30 - 11:00 AM
Virtually via Zoom
Ali Yousefi (Worcester)

Decoding hidden cognitive states from behavior and physiology using a Bayesian approach

Abstract: Cognitive processes, such as learning and cognitive flexibility, are both difficult to measure and to sample continuously using objective tools because cognitive processes arise from distributed, high-dimensional neural activity. For both research and clinical applications, that dimensionality must be reduced. To reduce dimensionality and measure underlying cognitive processes, we propose a modeling framework in which a cognitive process is defined as a low-dimensional dynamical latent variable — called a cognitive state, which links high-dimensional neural recordings and multidimensional behavioral readouts. This framework allows us to decompose the hard problem of modeling the relationship between neural and behavioral data into separable encoding-decoding approaches. We first use a state-space modeling framework, the behavioral decoder, to articulate the relationship between an objective behavioral readout (e.g., response times) and cognitive state. The second step, the neural encoder, involves using a generalized linear model (GLM) to identify the relationship between the cognitive state and neural signals, such as local field potential (LFP). We then use the neural encoder model and a Bayesian filter to estimate the cognitive state using neural data (LFP power) to generate the neural decoder. We provide goodness-of-fit analysis and model selection criteria in support of the encoding-decoding result. We apply this framework to estimate an underlying cognitive state from neural data in human participants (N=8) performing a cognitive conflict task. We successfully estimated the cognitive state within the 95% confidence intervals of that estimated using behavior readout for an average of 90% of task trials across participants. In contrast to previous encoder-decoder models, our proposed modeling framework incorporates LFP spectral power to encode and decode a cognitive state. The framework allowed us to capture the temporal evolution of the underlying cognitive processes, which could be key to the development of closed-loop experiments and treatments.

Brief Bio: Ali Yousefi is currently an Assistant Professor of Computer Science at Worcester Polytechnic Institute (WPI). He also has affiliations with Neuroscience and Bioinformatics & Computational Biology programs at WPI. He finished his Ph.D. at the University of Southern California (Ph.D. advisor: Theodore W. Berger). Before joining WPI, he was a postdoctoral trainee at Harvard Medical School and the Department of Mathematics and Statistics at Boston University (Postdoctoral mentors: Uri T. Eden, Emery N. Brown, Alik S. Widge, Darin D. Dougherty). His research focuses on developing methodological solutions to problems concerning neuroscience data analysis.

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Topic: KCN Event: Ali Yousefi

Time: Oct 19, 2021 09:30 Eastern Time (US and Canada)

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Meeting ID: 880 9561 0772

Passcode: 946320