Indirect pathway of movement

Indirect Pathway of Movement

The Indirect Pathway of Movement is a complex neural circuit within the basal ganglia that plays a crucial role in the regulation of voluntary movement. This pathway, also known as the extrapyramidal system, is one of the two major routes for transmitting motor signals from the cerebral cortex to the spinal cord, the other being the direct pathway of movement.

Anatomy

The indirect pathway begins in the striatum, a part of the basal ganglia that receives input from the cerebral cortex. From the striatum, signals are sent to the globus pallidus externus (GPe) and the subthalamic nucleus (STN). The GPe inhibits the STN, which in turn excites the globus pallidus internus (GPi) and the substantia nigra pars reticulata (SNr). These two structures then inhibit the thalamus, which sends signals back to the cerebral cortex.

Schematic representation of the indirect pathway of movement in the basal ganglia.

Function

The indirect pathway of movement is primarily involved in inhibiting unwanted movements. It works in opposition to the direct pathway, which facilitates desired movements. The balance between these two pathways is crucial for normal movement. Disruptions in this balance can lead to movement disorders such as Parkinson's disease and Huntington's disease.

Clinical significance

Understanding the indirect pathway of movement has important implications for the treatment of movement disorders. For example, deep brain stimulation of the subthalamic nucleus, a treatment for Parkinson's disease, is thought to work by modulating the activity of the indirect pathway.

See also

• Direct pathway of movement
• Basal ganglia
• Movement disorders