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Neuroscience Brown Bag Series

Thursday, April 12, 2018,

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  • Location: Wilson Hall • 111 21St Ave S • Nashville, TN 37240
  • Room: 316

Amir Sajad, PhD

Department of Psychology 

Vanderbilt University

"Cortical microcircuitry of error and reward processing and executive control" Medial frontal cortex plays an important role in monitoring outcomes of actions and making adjustments to improve performance. However, near to nothing is known about the cortical microcircuitry that enables this cognitive function. In this talk I will present our recent findings that provide insights into the microcircuit mechanisms for error, reward gain, and loss processing in an area in medial frontal cortex known as the Supplementary Eye Field (SEF). We simultaneously recorded EEG over the medial frontal cortex and sampled neural spiking across all layers of SEF while monkeys performed the saccade countermanding (stop signal) task. In this task the monkey was instructed to make an eye movement to a visual stimulus (NO STOP trial: eye movement = correct response), but to inhibit the eye movement if a stop-signal was presented during movement preparation (STOP trial: eye movement = error response). We found distinct patterns of organization, across cortical laminae, of spike rate facilitation and suppression signaling error production, feedback predicting reward gain or loss, and delivery of fluid reward. Interestingly, variation of error- and reinforcement-related spike rates in the upper but not lower cortical layers predicted the magnitude of adaptive response time adjustments. Furthermore, variation in error-related spike rate in the upper but not lower layers predicted the magnitude of the EEG marker, known as the error-related negativity (ERN), that indexes performance monitoring. These findings reveal novel features of cortical microcircuitry supporting performance monitoring and demonstrate a cortical source of the ERN.