University:
University of North Carolina Wilmington
Course:
PSY 105 | General Psychology
Academic year:

2023
Views:

158

Pages:

2
Author:

Jithin J I

CEREBELLUM AND BASAL GANGLIA IN MOTOR CONTROL I. Introduction  This lecture focuses on the crucial roles played by the cerebellum and basal ganglia in motor control and cognitive functions.  Understanding the anatomy and functions of these brain structures is essential for grasping their impact on neurocognition and movement. II. The Cerebellum A. Overview  The cerebellum comprises approximately 10% of the cerebral mass and 50-75% of the cerebral cortex's surface.  It contains roughly 50% of all neurons in the central nervous system.  Luigi Rolando was among the first to study the cerebellum's functions in the 19th century. B. Purkinje Cells  Purkinje cells (blue cells) play a pivotal role in cerebellar function.  They receive input from the sensory system about planned or ongoing movements.  Adjustment and coordination of movements are calculated based on sensory input. C. Beyond Motor Tasks  Traditionally, the cerebellum was associated solely with motor tasks.  Recent research by Schmahmann suggests its importance in modulating sensorimotor, cognitive, and limbic functions.  Damage to the cerebellum can result in cognitive impairments (cerebellar cognitive affective syndrome, CCAS), though not necessarily in all cases. III. Anatomy and Function of the Cerebellum  The cerebellum consists of the cerebellar cortex and deep cerebellar nuclei (DCN).  Key neuron types in the cerebellum include Purkinje cells, granule cells, Golgi cells, star cells, and basket cells.  Purkinje cells and DCN receive the same peripheral information.  Interneurons (black neurons) provide inhibitory feedback between Purkinje cells.  The cerebellum forms a feedforward inhibition network that adapts action programs to sensory conditions and associates sensory and motor functions. IV. Basal Ganglia  The basal ganglia are pivotal in planning and evaluating motor tasks.  They orchestrate slow, precisely coordinated movements by delivering adapted excitation patterns to the motor cortex.  Three projection paths are involved: direct (promotes movement), indirect (dampens movement), and hyperdirect (chooses actions).  Dopamine from the substantia nigra compacta (SNc) balances these pathways.  Basal ganglia evaluate movements in terms of correctness and preference, influencing the choice of actions and targets. In summary, the cerebellum and basal ganglia are integral to motor control and cognitive functions. Understanding their anatomy and functions enriches our comprehension of neurocognition and movement processes.