Different learning processes for response accuracy and precision in implicit perceptual-motor sequence learning

Poster Session C - Sunday, April 14, 2024, 5:00 – 7:00 pm EDT, Sheraton Hall ABC

Ziyan Y. Han¹, Paul Reber¹; ¹Northwestern University

We hypothesize that skilled expertise in sequential motor movements depends on both the basal ganglia for action order and the cerebellum for increasingly precisely timed responses. We used the Serial Interception Sequence Learning task to examine implicit perceptual-motor sequence learning, measuring both response accuracy and timing precision during learning. Participants were asked to make precisely timed responses to cues that followed a covert 12-item sequence with an embedded timing rhythm. Participants completed 4 blocks of practice with the trained sequence during which 20% of trials were interspersed non-repeating foil segments. After training, participants completed a test with 2 blocks of consistently repeating sequences equally balanced between the trained and two novel foil sequences. Sequence learning gradually developed during practice as seen by an increasing difference in accuracy between the trained sequence and occasional foil segments. Increased accuracy was observed for the trained sequence during test as well. However, the fine precision of correct responses exhibited a different pattern. During training, precision was lower for the foil segments almost immediately. But at test, precision declined at the beginning of each repeating sequence block regardless of whether it was practiced. Precision of the correct responses appears to be sensitive to whether the current sequence is a repetition of the prior sequence, implying a very rapid short-term learning effect quite different from the gradual increase in accuracy that occurs over hundreds of repetitions. The difference in learning timescale may reflect separate contributions of the basal ganglia and the cerebellum to sequential motor learning.

Topic Area: LONG-TERM MEMORY: Skill Learning