Pathways and centres involved in movement Flashcards
What is the basal ganglia involved in and how does it do this? (3)
- initiation
- control
- cessation
of movement
- by providing a feedback mechanism to the cerebral cortex
Where do most outputs from the basal ganglia go through?
thalamus
What do most outputs from the basal ganglia do? (2)
- dampen
- excite
cerebral cortex
What do lesions of the basal ganglia lead to?
dyskinesia
What is dyskinesia?
abnormal and involuntary movements
Where does the basal ganglia develop from?
telencephalic grey matter
What makes up the telencephalic grey matter? (4)
- caudate nucleus
- lentiform nuclues
- amygdala
- claustrum
What is the lentiform nucleus made up of? (2)
- putamen
2. globus pallidus
What makes up the functional basal ganglia? (5)
- caudate nucleus
- putamen
- globus pallidus
- subthalamus
- substantia nigra
What is the globus pallidus split into and what parts of the substansia nigra is this related to?
- interna - pars reticulata
2. externa
What do the pars compact cells in the substantial nigra contain?
melanin
What else is the basal ganglia involved in other than initiation, cessation and control of movement? (2)
- cognitive processes
- perception
- learning
- memory
- abstract thought
- emotion
How does the basal ganglia modulate cortical output?
by using multiple, parallel looping circuits from cerebral cortex back to cerebral cortex
NOTE
learn the basal ganglia excitatory and inhibitory cycle
How does the basal ganglia influence movement?
- influence motor areas of cortex
- thalamus projects to motor cortex
- mainly premotor and supplementary motor areas
- motor cortex influences LMNs
- directly via the corticospinal pathway
- indirectly via connections to brainstem centres from which UMNs arise (reticulospinal pathway)
What does the direct pathway of the basal ganglia do?
facilitate behaviour and movements that are required and appropriate
What does the indirect pathway of the basal ganglia do?
inhibit unwanted behaviour and movements
Which pathway leads to excitation of the cortex from the thalamus and hence facilitates ongoing movement?
direct pathway
Which pathway leads to inhibition of the cortex from the thalamus hence inhibiting unwanted movement?
indirect pathway
What two things need to happen when flexing your fingers and what pathways do these involve?
- CONTRACT flexors - direct pathway
2. RELAX extensors - indirect pathway
What is the role of the pars compacta in the substantial nigra (x3) and what does it release?
ROLE
- initiate moevement
- modulatory role in movement
- opposing effects on the direct and direct pathways
RELEASES
- dopamine
What happens if the substantia nigra is diminished?
you are not able to initiate movement
What happens if the basal ganglia is damaged?
- disordered movements on the CONTRALATERAL side
- Hypokinesia (slow movement)
- poor initiation - Rigidity
- Tremor
What is the name of the disease of the basal ganglia where the nigrostriatal input is disrupted?
Parkinsons
