Descending coordination of coactivated muscles in long-latency responses

Establish how descending motor pathways coordinate coactivated agonist and antagonist muscles to produce task-dependent long-latency responses that accommodate features of the task, body, and environment, and identify the mechanisms underlying these adjustments.

Background

Long-latency responses (LLRmechanical) involve transcortical feedback pathways and are known to reflect task goals and biomechanical context. Prior studies often used reciprocal activation via background loads, focusing on stretched agonists while antagonists were inhibited.

Under coactivation, descending control must coordinate both agonist and antagonist activation, but how this coordination produces functional long-latency responses remains explicitly unclear.