Control of movement Flashcards
What is the basal ganglia?
A group of nuclei deep inside the brain
What do the basal ganglia do?
It takes massive input from multiple cortical and brain stem regions and output to selected parts of these same areas
What are the 3 different circuits involved in the basal ganglia?
- Motor circuit
- Associative Circuit
- Limbic circuit
How are basal ganglia segregated?
Basal ganglia segregated anatomically between different loops
What is the main output of the basal ganglia and what does this mean?
The main output of the basal ganglia is inhibitory, so more activity is less movement
What are the 2 pathways that exist through the basal ganglia and what has different effects on it?
- One which decreases output activity
- One which increases output activity
Dopamine has different effects on these 2 pathways
What does the rate model state?
The rate model states that changes in firing rate determine the degree of thalamic inhibition and therefore the amount of movement possible
What is parkinsons disease clinically dominated by?
Clinically dominated by lack of movement
What happens in Parkinson disease and what does this do?
In parkinsons, the substantia nigra degenerates and therefore don’t get dopamine
This turns off the movement and non-movement pathway
What is hemiballismus?
It is a flinging movement of one side of the body
What is hemiballismus typically caused by?
-Typically caused by subthalamic nucleus stroke
What is a key node in in the stop movement pathway?
STH nucleus is a key node in the stop movement pathway
What happens in a normal functioning STN
Multiple channels with independent temporal coded
What happens in parkinsons disease STN
Channels synchronized so less information processing and transfer
What is the evidence that beta activity is antikinetic
- Beta suppression which levodopa correlates with therapeutic outcome
- Beta suppression by deep brain stimulation
- Direct stimulation of STN at beta band frequencies worsens parkinsons
