How do we “stop”? Elucidating the source of behavioral interruption in the brain: Focus on the role of the subthalamic nucleus
The subthalamic nucleus (STN) is a small excitatory nucleus with a significant role in response inhibition. STN activity has been previously shown to be correlated with behavioral stopping or switching, but no studies have yet shown a causal role. This dissertation provides the first evidence that STN activation interrupts behavior, and blocking the STN blunts the interruptive effect of surprise. Thus, the STN is both necessary and sufficient for such forms of behavioral response suppression. Further, STN activation also is sufficient to interrupt cognition, decreasing performance on a working memory task. Finally, viral tracing evidence demonstrates a topological organization of cortical “hyperdirect pathway” inputs onto STN, with motor cortex projecting dominantly to lateral STN and limbic and associative-related cortical regions projecting dominantly to medial STN.