Basal nuclei structure Flashcards
Proprioception
The body’s ability to sense movement, action, and location. It’s present in every muscle movement you have.
What are the two loops involved in the motor system ?
Two major processing “loops”:
Basal nuclei
Cerebellum
What are the different parts of the motor cortex ?
Premotor cortex (PMA; lateral to SMA):
Planning and selection of movement
Supplementary motor area (SMA):
Co-ordination of complex movement (often bilateral)
Where is the motor cortex located ?
Part of frontal lobe rostral to central sulcus
Somatotopic map of the PMC
“Homunculus” of body represented in M1
Similar maps in SMA and somatosensory
Note larger areas of cortex dedicated to areas of complex motor requirements
Damage to areas of motor cortex may affect specific areas of the periphery (contralateral)
+ Hands are so big because they are so intricate which is why we need a lot of cortex given to it; this is equally the same with the mouth. In contrast, the arms and legs need less are they are a lot simpilar to move.
Explain the difference between an upper motor neuron and lower motor nueron disease.
What is the role of the Basal Nuclei
- Voluntary motor control.
Also elements in the …
- Executive function
Motivation
Reward
Decision making
Working memory?
What are the main nuclei of the basal ganglia ?
What is the overall structure of the corpus striatum ?
What is striatum?
Ventral striatum
Ventral striatum: at ventral end of caudate head
Strong connections with prefrontal cortex
Nucleus accumbens
Major nucleus in reward pathway
Innervated by dopaminergic neurones from ventral tegmental area (VTA)
Associations with amygdala, hippocampus
(Olfactory tubercle) – partly in temporal lobe, sensory, attention, reward
Globus Pallidus
External (lateral) and internal (medial) segments
Separated by narrow white matter tract, medial medullary lamina
Functionally distinct:
External has wider connections to rest of basal nuclei
Internal is an output station to the thalamus; similar cells and connections to substantia nigra pars reticulata
Mostly populated by inhibitory GABAergic neurones
Substantia Nigra
Located in midbrain dorsal to cerebral peduncles. Two components:
Substantia nigra pars compacta:
Main source of dopaminergic neurones in the basal nuclei, innervating the striatum
Substantia nigra pars reticulata:
Mainly GABAergic neurones; output station to thalamus
