Role of the Posterior Parietal Cortex in the Processing of Sensory Information Modulating the Excitability of the Primary Motor Cortex in Humans

Although the primary motor cortex is considered has the common final pathway of motor commands, it is influenced by several structures as, for example, the premotor cortex and the posterior parietal cortex which are involved in motor planning and programming and which integrates movement-induced sensory impute (parieto-frontal circuits). Several studies have shown that there are some direct functional connections between the premotor cortex and the posterior parietal cortex and from these two regions to the primary motor cortex. The posterior parietal cortex can then be considered as a sensorimotor interface whose function in planification and motor control of upper limb is well demonstrated. The hypothesis is that the posterior parietal cortex could participate to the modulation of motor cortex excitability by proprioceptive sensory inputs namely long latency afferent inhibition and afferent induced facilitation.