T2 L6: Anatomy and function of basal ganglia Flashcards
Which structures make up the basal ganglia?
The caudate nucleus, thalamus, putamen, globus pallidus, and the red nucleus
What is the globus pallidus split into?
Into pars externa and pars interna
Which structures is the Pallidum made up of?
The internal and external Globus pallidus
Which structures is the Lentiform nucleus made up of?
The putamen and globus pallidus
Which structures is the corpus striatum made up of?
Caudate nucleus, putamen, and pallidum
What divides the structures within the corpus striatum and what is it made up of?
It’s divided by the internal capsule made up of ascending and descending tracts (white matter)
Which structures is the neostriatum made up of?
The caudate nucleus and putamen
What is the nucleus Accumbens for?
It mediates reward behaviour and addiction
What are the 4 basal ganglia loops?
Motor, oculomotor, prefrontal, and limbic
What the direct pathway for?
To promote movement
Which structures are involved in the direct pathway?
The cortex, striatum, internal globus pallidus, and the thalamus
What is the indirect pathway for?
To withhold movement
Which structures are involved in the indirect pathway?
The cortex, striatum, external globus pallidus, subthalamic nucleus, internal globus pallidus, and the thalamus
What is the hyperdirect pathway for?
As an emergency stop
Which structures are involved in the hyperdirect pathway?
The cortex, subthalamic nucleus, internal globus pallidus, and the thalamus (it bypasses the striatum and the external globus pallidus
What effect does the cortex have on the striatum?
Excitatory
What effect does the striatum have?
Inhibitory
What effect does the thalamus have in the cortex?
Excitatory
What effect does inhibiting the thalamus have?
Prevents movement
What effect does reducing the inhibition of the thalamus have?
Facilitates movement
What substance does the substancia nigra release?
Dopamine
What effect does dopamine have on direct (D1) medium spiny neurones?
Increases their excitation
What effect does dopamine have on indirect (D2) medium spiny neurones?
Decreases their excitation
What is the function of interneurons?
They tune transmission
Which molecule opposes the effects of dopamine when it comes to striatum neurones ?
Acetylcholine
How are the different pathways of the striatum balanced?
Through the activity of 2 medium spiny neurones which are influenced by dopamine and acetylcholine
