TASK 3 - CEREBELLUM Flashcards
1
Q
cerebellum
A
- located in hindbrain
- metencephalon (cerebellum + pons)
- played critical role in development of cortical/ cognitive functions
- allows info input into and out of cerebellum
- -> input via brainstem into cerebellum
- -> output via pons out of cerebellum –> into cortex
2
Q
structural divisions
A
- laminated cerebellar cortex on surface
- cerebellar deep nuclei deep in white matter
3
Q
structural divisions
- lobes
A
- anterior lobe: somatosensory info
- posterior lobe: output to cortex
- flocculonodular lobe: oldest cerebellar structure
4
Q
structural divisions
- vermis + hemispheres
A
- vermis: runs along midline of cerebellum, separates 2 hemispheres
5
Q
functional divisions
1. cerebrocerebellum
A
= lateral hemispheres
- receives input from the CEREBRUM
- planning, initiation of movement + sensory feedback of motor movements
- coordination of voluntary movements
- cognitive, emotional control
6
Q
functional divisions
2. spinocerebellum
A
= vermis
- input from SPINAL cord
- visual + auditory signals (relayed in brainstem nuclei)
- regulates body + limb movements and muscle tone
- compares info from where body stand and where it should be –> if discrepancy: corrects error signal
7
Q
functional divisions
3. vestibulocerebellum
A
= floculonodular/flocular lobe
- input from VESTIBULAR complex
- regulates balance, posture, eye movements
8
Q
pathways
A
- via cerebellar peduncles
2. via deep cerebellar nuclei
9
Q
pathways
1. cerebellar peduncles
A
= white matter connections
- connections between the cerebellum and other parts of the nervous system
- contain fine branching nerve fibres
10
Q
- cerebellar peduncles
a) superior
A
= largest output structure/ almost entirely efferent pathway
- origin: deep cerebellar nuclei neurones –> to upper motor neurones in deep layers of superior colliculus –> delay in dorsal thalamus –> primary motor, premotor areas of cortex
- limbic movements
11
Q
- cerebellar peduncles
b) middle
A
= biggest peduncle; afferent pathway to cerebellum; descending
- origin: pontine nuclei (neurones in the base of the contralateral pons) –> receives input from many sources (almost all cortical areas and superior colliculus) –> axons (transverse pontine fibres) cross midline and enter cerebellum via middle cerebellar peduncle
- regulates info from proprioception (orient body in space) + regulates other sensory functioning
12
Q
- cerebellar peduncles
c) inferior
A
= smallest but most complex peduncle
- contains afferent + efferent pathways
1) afferent ascending = axons from vestibular nuclei, spinal cord and brainstem tegmentum (inferior olive)
2) efferent = axons project to vestibular nuclei and reticular formation - proprioceptive info (how different body parts relate to one another
13
Q
pathways
2. deep cerebellar nuclei
A
= in each cerebellar hemisphere there are 4 major deep nuclei
- each receiving input from different parts of cerebellum
a) fastigal nuclei
b) interposed nuclei (x2)
c) dentate nuclei
14
Q
input
A
- major destination of input: cerebrocerebellum
1. top-down/descending: cerebral cortex via pons
2. bottom-up/ascending: from vestibular inputs, inferior olive, spinal cord
15
Q
input
1. descending
A
= cerebral cortex via pons
- axons synapse on ipsilateral neurones in pontine nuclei
- pontine nuclei give rise to transverse projections that cross midline (form middle cerebellar peduncle) –> relays cortical signals to contralateral cerebellar hemisphere
- signals derived from one cerebral hemisphere are processed by the neural circuits in the opposite cerebellar hemisphere
- majority arises from primary and pre-motor cortices (frontal), primary and secondary somatic sensory cortices (anterior parietal) and higher order visual regions (posterior parietal)
