Schedule of Events | Symposia

Perceptual discrimination of temporal patterns in humans and monkeys

Poster Session B - Sunday, March 30, 2025, 8:00 – 10:00 am EDT, Back Bay Ballroom/Republic Ballroom

Marisol Espinoza Monroy¹ (marisol.em02@gmail.com), Karla Mercado¹, Victor de Lafuente¹; ¹Institute of Neurobiology, National Autonomous University of Mexico

The motor system executes and controls complex movement sequences that require tight temporal constraints, such as those observed in dance, speech, and music production. However, less is known about its role in behavioral contexts that do not require immediate movement execution. We propose that internal brain simulations that arise from learning the temporal structure of sensory events might be a mechanism by which the motor system influences the perception of rhythms and other temporal patterns. To explore this, we asked humans (n=15) and trained monkeys (n=2) to discriminate sequences of brief sensory pulses interleaved with either constant or variable inter-pulse intervals. Importantly, subjects were free to determine the stimulus observation time. The behavioral results are consistent with the proposal that humans and monkeys discriminate regular from irregular temporal patterns by accumulating sensory prediction errors over time. Humans seem to follow an accumulation-to-bound strategy in which the sum of prediction errors triggers the choice and response time. Monkeys, however, seem to incorporate a deadline over the total elapsed time to determine their choice. Thus, our behavioral results suggest that humans and monkeys discriminate temporal patterns by implementing different speed-accuracy tradeoff strategies. Finally, while monkeys performed our discrimination task, we recorded neural activity in the supplementary motor area (SMA). We show that the firing rate of this node in the motor system captures temporal features of the trial and the stimulus that can help subjects solve this perceptual discrimination task.

Topic Area: THINKING: Decision making