Basal Ganglia Overview

<p>Motor Cortex (A)</p> Signup and view all the answers

<p>Decreased thalamic activity (D)</p> Signup and view all the answers

<p>It acts tonically and is excitatory to the cortex (A)</p> Signup and view all the answers

<p>Inhibit the thalamus (D)</p> Signup and view all the answers

<p>Huntington's Disease (B)</p> Signup and view all the answers

The Basal Ganglia (BG) is a group of interconnected brain nuclei located within the cerebrum and midbrain. It plays a crucial role in motor control, learning, and cognitive functions. It is composed of 5 distinct nuclei: Caudate, Putamen, Globus Pallidus, Subthalamic nuclei, and Substantia Nigra.

The Cortico-Basal Ganglia-Thalamocortical Loop is a circuit that involves a series of connections between the cerebral cortex, basal ganglia, thalamus, and back to the cortex. It forms a feedback loop that governs the fine-tuning of motor commands and movement planning.

Input Nuclei: Caudate and Putamen. These nuclei receive input from the cerebral cortex and project to the output nuclei.

Output Nuclei: SNr and GPi. These nuclei send signals to the thalamus, which in turn projects back to the cerebral cortex.

The thalamus plays an important role in relaying sensory information to the cerebral cortex. It has a tonic excitatory effect on the cortex, meaning it continuously excites the cortical neurons.

Output nuclei of the Basal Ganglia, SNr and GPi, have an inhibitory effect on the thalamus. This means they suppress the thalamic neurons activity.

Thalamus is the 'accelerator' and the basal ganglia is the 'brake' for controlling movements. The direct pathway promotes movement and the indirect pathway inhibits movement.

Impairments in the basal ganglia can lead to either hyperkinetic conditions (too much movement) or hypokinetic conditions (too little movement). Parkinson's Disease (PD) is an example of a hypokinetic condition and Huntington's Disease and Tourette's Syndrome are hyperkinetic conditions.