8.3 Basal ganglia loops in non-motor functions

Basal ganglia loops in non-motor functions

• self-regulatory loops that the basal ganglia form with them cortex seem

• includes: decision-making, habit information, & emotional regulation

non-motor functions

• Prefrontal Loop

• Limbic Loop

Prefrontal Loop

• Planning, short-term memory, & attention regulation.

Limbic Loop

• Emotional & motivated behavior regulation, mood state transitions.

Clinical Significance

• Cognitive & emotional function deterioration in Parkinson’s & Huntington’s diseases is linked to non-motor loop disruption.

• Obsessive-compulsive disorder, depression, & anxiety potentially involve limbic loop dysfunctions.

• Tourette syndrome

Tourette syndrome

• Undesired utterances due to excessive activity in cognitive regulatory loops.

CEREBELLUM

• movement

• coordination

• balance

CEREBELLUM fact about the structure

• Second largest structure in the brain

• High neural density: half of brain neurons

• Divided into two hemispheres joined by the vermis

• Grey matter outside / white matter inside (tree of life)

Center for motor modulation

• correcting errors

• Feedback circuit that allows the correction of movements

CEREBELLUM & detects errors in

• execution of the movement that is in progress & sends orders to the motor cortex to adjust them

cerebellum participates in

• motor learning through error-based adaptation

Functions of cerebellum

• Motor learning → Play an instrument, ride a bike

• Execution of accurate movements (carry a spoonful into your mouth)

• Correction of a movement’s trajectory

• Posture maintenance & balance

Cerebellar lesions cause

• ATAXIA

• DYSARTHRIA

• UNSTEADY WALK

• ALTERED VISUAL CONTROL

Ataxia

• Disorder characterized by the reduced ability to coordinate voluntary movements

DYSARTHRIA

• Slurred/slow speech

UNSTEADY WALK

• Affects the control of the legs (e.g. drunken gait).

ALTERED VISUAL CONTROL

• Lack of control in the eye fixation on objects.

Other pathologies affecting the cerebellum

• Acute alcohol intoxication, involving cerebellar GABA receptors

• Multiple sclerosis, tumors