Cerebellum Flashcards
Damage to cerebellum causes/does not cause:
general
- NO paralysis
- DOES change rate, range, direction, accuracy of motor movements
3 anatomical lobes of cerebellum
- anterior
- posterior
- floculonodular lobe (smallest)
3 anatomical/functional zones of cerebellum
- vermis (single midline connecting region)
- paravermis (zones on either side of vermis)
- lateral hemisphere (zones outside of paravermis, makes bulk of cerebellum)
3 layers of cerebellar cortex and what is deep to it
names/location only
- molecular (superficial)
- purkinje (middle)
- granular (deep)
White matter core
Cerebellar folia
-folds of cerebellum (caused by highly convoluted surface)
Molecular layer of cerebellar cortex
contains local circuit neurons and abundant axons and dendrites.
lots of communication
Purkinje layer of cerebellar cortex
single layer of large neurons (Purkinje cells/PC)
only layer with axons terminating outside cerebellar cortex (in white matter)
Granular layer of cerebellar cortex
composed mainly of small granule cells, with other cell types
Name 4 deep cerebellar nuclei (DCN)
- Fastigial nucleus
- globose nucleus
- emboliform nucleus
- dentate nucleus
Fastigial nucleus
A deep cerebellar nucleus (DCN)
- most medial
- receives projections from vermis
Globose nucleus
A deep cerebellar nucleus (DCN)
- lateral to fastigial nucleus
- receives projections from paravermis
Emboliform nucleus
A deep cerebellar nucleus (DCN)
- lateral to globose nucleus
- receives projections from paravermis
Dentate nucleus
A deep cerebellar nucleus (DCN)
- most lateral
- receives projections from lateral hemisphere
Fractured somatotropy
- in cerebellar cortex, body parts represented discontinuously
- trunk is represented in vermis
- extremities represented more laterally in paravermis
Locations that cerebellum connects to brain stem (3)
Note: all pairs
- inferior cerebellar peduncle
- middle cerebellar peduncle
- superior cerebellar peduncle
inferior cerebellar peduncle
mainly afferents to cerebellum from spinal cord and medulla
middle cerebellar peduncle
- mainly afferents to cerebellum from pontine nuclei (info from virtually all cortical areas to lateral hemisphere)
- largest
superior cerebellar peduncle
-mainly EFFERENTS from cerebellum
Vestibulocerebellar system
functions/pathways
Via inferior cerebellar peduncle
-for maintaining balance/posture/etc; coordination of eye/head movements
- primary and secondary (from vestibular nucleus) vestibular afferents to FN node
- secondary (from vestibular nucleus) vestibular afferents to vermis
- Purkinje from FN node to vestibular nucleus
- Purkinje from vermis to fastigial nucleus (relay to vestibular nucleus)
-corrections while task is performed
Posterior spinocerebellar tract
function
carries proprioceptive info from trunk and LE (T1 and below)
-corrections while task is performed
Cuneocerebellar tract
function
carries proprioceptive info from neck and UE (above T1)
-corrections while task is performed
anterior spinocerebellar tract
function
carries proprioceptive info and cutaneous info from receptors with large receptive fields from LE
-corrections while task is performed
trigeminocerebellar tract
function
- carries proprioceptive info from oral cavity
- corrections while task is performed
Posterior spinocerebellar tract
pathway
- proprioceptive afferents from L2 and down travel in dorsal column (fasiculus gracilis)
- at L2-T12 level synapse in Clarke’s column
- travel to vermis/paravermis via inferior cerebellar peduncle
Cuneocerebellar tract
pathway
- proprioceptive afferents from C1-C8 travel up through dorsal column (fasciculus cuneatus)
- synapse at lateral/external/accessory cuneate nucleus in caudal medulla
- travel to vermis/paravermis via inferior cerebellar peduncle
anterior spinocerebellar tract
pathway
- proprioceptive afferents from trunk and LE synapse on spinal border cells
- decussate via anterior white commissure
- travel to vermis/paravermis via superior cerebellar peduncle
- decussates again to cerebellar cortex
trigeminocerebellar tract
pathway
- proprioceptive info carried along CN V through mesencephalic nucleus (but doesn’t synapse here)
- primary afferent synapse in spinal trigeminal nucleus
- secondary axons project to cerebellum via inferior cerebellar peduncle
- cerebellum then projects to trigeminal motor nucleus
Dysmetria
overshooting a target
Cerebrocerebellar system
functions
- corrections for next time task is formed
- planning, initiaion, timing and control of motor movements
Cerebrocerebellar system
pathway
- input from somatosensory/auditory/visual cortices
- pontine nuclei
- middle cerebellar peduncle to dentate nucleus or lateral hemisphere (then purkinje to dentate nucleus)
- superior cerebellar peduncle to red nucleus or VA/VL (then to motor cortex)
- corticospinal or rubrospinal to skeletal muscle output
- from red nucleus also to inferior olive to inferior cerebellar peduncle (climbing fibers) to dentate nucleus or lateral hemisphere for corrections
