Conceptualizing mechanisms of human movement cancellation within a Pause-then-Cancel model of motor inhibition

Motor inhibition, the ability to cancel ongoing movements, is an ability that allows humans to exert control over their behavior to prevent bodily harm and pursue short-term goals despite changes in their environment. Despite the importance of this ability, psychologists and neuroscientists have struggled to determine what networks and activity in the brain support it. This is due in part to the design of tools used to study it and conflicts in the existing frameworks we have created to conceptualize this process.

In this thesis, I explain how a new way of thinking about the brain processes that underlie motor inhibition might lead to new breakthroughs in the field of human motor inhibition. This framework, called the Pause-then-Cancel (PTC) model was created by Schmidt and Berke based on findings from the rodent brain. The PTC model proposes that successfully stopping an action requires two phases: Pause and Cancel. During the Pause phase, movement is temporarily paused to allow for evaluation, while during the Cancel phase, movement is permanently cancelled. I discuss some of the work that motivated and that extends this a new human PTC model, including finding suppressed activity even in muscles that were not involved in a task following infrequent events, investigating electrical signals of inhibition in networks spanning surface and deep brain regions, and testing whether a particular deep brain region, the subthalamic nucleus, is responsible for some of the inhibitory signaling we see in those networks.