Basal Ganglia

Question 1

What are the basal nuclei composed of?

Answer 1

• corpus striatum
• subthalamic nuclei
• substantia nigra

Question 2

what is the corpus striatum composed of?

Answer 2

• lentiform nucleus

- caudate nucleus (grey matter)

Question 3

what is the lentiform nucleus composed of?

Answer 3

• putamen

- globes pallidus (internal and external divisions)

Question 4

the putamen and caudate nucleus form the ____

Answer 4

striatum

Question 5

Where is the internal capsule located?

Answer 5

in the space between the lentiform nucleus and the thalamus

Question 6

where is the posterior limb of the internal capsule located?

Answer 6

between the lentiform nucleus and the thalamus

Question 7

where is the anterior limb of the internal capsule located?

Answer 7

between the lentiform nucleus and the caudate nuclei

Question 8

What regions do the basal ganglia communicate with?

Answer 8

receives input from the substantial nigra and motor cortex, and sends signals back to these regions

Question 9

cortical-basal ganglia-thalamus loop

Answer 9

as there is no direct access to the motor cortex from the basal ganglia, the communication to the cerebral cortex is through the thalamus, creating a loop

Question 10

What are the functions of the basal ganglia?

Answer 10

• motor control
• regulation of attention and cognition
• inhibition of unnecessary movements (acts like a break)
• influence the function of spinal cord motor neurons (indirectly)

Question 11

What is the basal ganglia break mechanism?

Answer 11

the basal ganglia acts as a break so only ordered movement occurs, preventing unnecessary movements.
inhibitory neurons in the basal ganglia are constantly firing, inhibiting the motor cortex. to create movement, inhibitory neurons are activated so to inhibit the basal ganglia inhibitory neurons. this activation happens by the cortex. once the basal ganglia inhibitory neurons are inhibited, thalamic neurons are excite the motor cortex and generate movement.

Question 12

Parkinson’s disease

Answer 12

occurs due to dopamine neuron degeneration in the substantia nigra.
this results in motor deficits as such rigidity, tremor, difficulty initiating movement, postural instability, and more.
treatment involves the replacement of dopamine, stem cell therapy and deep brain stimulation