ABSTRACT
A key output is the motor system, which controls the contraction of skeletal muscles and thereby enables movement, such as reaching for and grasping an object, walking, talking, or maintaining the body’s posture. We study one important principle by which rhythmic activation of motor neurons and muscle contraction is achieved. The simplicity of the crustacean stomato-gastric ganglion (STG) system has enabled researchers to generate quantitative models based on the intrinsic properties of individual neurons and the connection strengths of the gap junction and inhibitory synapses. Analyses of movement angle encoding during reaching revealed that while some posterior parietal cortical neurons had lag times of 30-90 ms, consistent with their receiving sensory feedback, the majority of neurons had shorter or no lag times, supporting their participation in forward models. The properties of mirror neurons have been proposed to enable monkeys to understand intention and imitate the actions of others using the framework of the monkey's own action planning.
