Prefrontal Cortex and Hippocampus Jointly Guide Flexible Working Memory
Mariana Lomeli Fernandez1,2, Randolph Helfrich2, Nicholas Myers1; 1School of Psychology, University of Nottingham, 2Hertie Institute for Clinical Brain Research, University Medical Center Tuebingen
A crucial role of working memory (WM) is the flexible manipulation of memories to guide behavior. Extensive research links WM to the prefrontal cortex (PFC), and more recently intracranial recordings in humans have also suggested a role for the hippocampus. Their roles in the flexible manipulation of WM are unclear. We explored this question by recording intracranial electroencephalography from the hippocampus and PFC of epileptic patients. Participants performed a match-to-sample task that required holding two visual stimuli in WM. On each trial, one of the stimuli was cued as the target. On consecutive trials, participants were cued to either the same (repeat trial) or the other stimulus (switch trial), requiring rapid reprioritization of the uncued memory. On switch vs. repeat trials, accuracy was lower for mismatch trials whose probe matched the cued stimulus in the previous trial. Match vs. mismatch conditions could be decoded from high-frequency (70-150 Hz) neural activity in both the PFC and the hippocampus. Our findings are consistent with hippocampal involvement in WM for adaptive memory-guided behavior. PFC dynamics during WM-guided decision-making may therefore hinge on accurate memory reinstatement in the hippocampus.
Topic Area: EXECUTIVE PROCESSES: Goal maintenance & switching
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April 13–16 | 2024