From the Research
The basal ganglia are a complex subcortical structure that is principally involved in the selection and implementation of purposeful actions in response to external and internal cues, playing a crucial role in motor control, learning, and executive functions. These structures include the striatum (caudate nucleus and putamen), globus pallidus (internal and external segments), subthalamic nucleus, and substantia nigra (pars compacta and pars reticulata) 1. The basal ganglia function through two main pathways:
- the direct pathway, which facilitates movement,
- and the indirect pathway, which inhibits movement. Dopamine from the substantia nigra pars compacta modulates these pathways, with dopamine exciting the direct pathway via D1 receptors and inhibiting the indirect pathway via D2 receptors, as described in earlier studies 2, 3, 4. This balance is critical for smooth, coordinated movements. Dysfunction in the basal ganglia leads to movement disorders like Parkinson's disease (characterized by dopamine deficiency, resulting in tremor, rigidity, and bradykinesia) and Huntington's disease (involving striatal degeneration, causing chorea and cognitive decline) 1. Treatment for basal ganglia disorders often targets neurotransmitter systems, such as levodopa for Parkinson's disease to replenish dopamine, or deep brain stimulation targeting specific nuclei to modulate abnormal circuit activity, with recent advances in understanding the role of the basal ganglia providing new insights into their organization and functional importance 1. Understanding the basal ganglia's complex circuitry helps explain both normal motor control and the pathophysiology of movement disorders, with the most recent study providing a comprehensive overview of basal ganglia organization and functional importance 1.