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Poster B in Poster Session B: Tuesday, August 4, 2:00 – 3:45 pm, Kimmel Center, Shorin & Rosenthal Rooms

Changes in local field potential in non-human primate prefrontal cortex during a transitive inference task

Fabian Munoz Silva¹, Greg Jensen², Rael Sammeroff¹, Herbert S. Terrace¹, Vincent P. Ferrera¹; ¹Columbia University, ²Reed College

Presenter: Fabian Munoz Silva

Transitive inference (TI) consists of deducing that if A > B and B > C, then A > C. This process relies on mental schemas organizing hierarchical relationships, yet its neural computations remain poorly understood. We recorded local field potentials (LFPs) from the lateral prefrontal cortex of two rhesus macaques (M. mulatta) performing a TI task in which they learned the rank order of seven novel stimuli by exposure to the 6 adjacent pairs for ~150 training trials. To demonstrate TI after training, they were tested with all 21 pairs for ~200 trials. They achieved asymptotic accuracy of 80–90% and exhibited the Symbolic Distance Effect, an indication of relational reasoning. LFP analyses revealed dominant beta-band (20–25 Hz) oscillations. Training-to-Testing comparison showed frequency-specific modulations across alpha, beta, and gamma bands. During Testing, beta and gamma power increased during the decision period, while low gamma (30–50 Hz) selectively predicted symbolic distance. These findings implicate PFC beta synchrony in hierarchical rule retrieval and gamma-band activity in representing abstract relations.

Topic Area: Decision-Making, Cognitive Control & Event Cognition