Motor inhibition and switching in variant stop signal tasks

Poster Session A - Saturday, April 13, 2024, 2:30 – 4:30 pm EDT, Sheraton Hall ABC

Rain Paul¹, Angela Gori¹, Chiang-shan R. Li², Sien Hu¹; ¹SUNY Oswego, ²Yale University

Motor switching involves interruption of a prepotent but inappropriate response and execution of the desired response. Previous research studying motor inhibition and switching used paradigms with high working memory demand, in which subjects learned to associate responses with different stopping/switching cues in a same session. To reduce working memory and goal maintenance, in the current experiment subjects completed the stop signal task (SST) and the stop signal response task (SSTr) in an fMRI scanner, with the order counter-balanced across subjects, on two separate days. In the SST, subjects were required to press a button quickly to a frequent “go” stimulus but withhold the response when the go was followed by a “stop” stimulus, which appeared in 1/3 of all trials. A non-responded stop trial was a stop success (SS) while a responded stop trial was a stop error (SE). In the SSTr, subjects were instructed to press their right index finger to the “go”, but to press their middle finger (without pressing their index finger) if the go was followed by the “stop” stimulus. SS indicated pressing with middle finger while SE indicated pressing with index finger on the stop signal. Hence, the SS>Go Success (GS) contrast in the SST examined inhibitory control while SS>GS in the SSTr examined motor switching between fingers. SS>GS showed greater activations in the supplementary motor area (SMA), left precentral gyrus, and right cerebellum in the SSTr than in SST. These results suggest the role of the SMA in updating motor plans to switch actions.

Topic Area: EXECUTIVE PROCESSES: Monitoring & inhibitory control