Hyperdirect pathway

THE DIRECT, INDIRECT AND HYPERDIRECT PATHWAYS OF BASAL GANGLIA INFORMATION PROCESSING... 

The STh receives also direct excitatory input from the cerebral cortex, especially from the frontal cortical areas the primary motor cortex, with a minor contribution of prefrontal and premotor areas (see for review Nambu et al., 2002). Cortical afferents from the primary motor cortex in rodents and cats are composed of collaterals of the pyramidal tract or of corticostriatal fibers (reviewed by Hamani et al., 2004). The hyperdirect pathway is a cortico-STN-pallidal pathway, which conveys excitatory input from the motor-related cortical areas to the GP bypassing the striatum, and therefore with shorter conduction time. According to the model of the hyperdirect pathway, the activity of the cortico-STh-pallidal route could result in a wide inhibitory effect on motor programs, with adjustments of signals through the direct cortico-striato-pallidal pathway (Nambu et al., 2002). 

Nambu A, Tokuno H, Takada M (2002) Functional significance of the cortico-subthalamo-pallidal hyperdirect pathway. Neurosci Res 43 111-117. 

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