Cerebellum (Stephens) Flashcards
1
Q
- part of the brain that coordinates all somatic motor activity, but does not initiate this activity
- involved w/ unconscious proprioceptive and tactile info to affect gradual alterations of muscle tension necessary for proper maintenance of equilibrium and posture
- assures the smooth and orderly sequence of muscular contraction characteristic of voluntary skilled movements
A
cerebellum
2
Q
- central core of white matter in cerebellum
- composed of dense bundles of afferent and efferent fibers interconnecting cerebellar peduncles, cerebellar nuclei, and cerebellar cortex
- four pairs of cerebellar nuclei located here: fastigial nucleus, globose nucleus, emboliform nucleus, and dentate nucleus
A
corpus medullaris
3
Q
- most medial nucleus within the CM
- has vestibular connections and functions
A
fatigial nucleus
4
Q
- nucleus of the CM that is divided into medial and lateral parts
- medial part: cerebellovestibular efferents from this area to fastigial nuclei project to vestibular system
- lateral part: efferents from this area w/ fibers from emboliform and dentate nuclei
A
globose nucleus
5
Q
- small, worm-shaped nucleus of the CM
- sends efferents through superior cerebellar peduncle along w/ fibers from dentate nucleus
A
emboliform nucleus
6
Q
- large, convoluted cup-shaped nucleus of the CM
- gives rise to vast majority of efferents from neocerebellum
- these efferents along w/ those from globose and emboliform, project to red nucleus, ventral lateral nucleus of thalamus, brainstem tegmentum, and RF
- most of the efferents in the superior cerebellar peduncle originate in this nucleus
- mostly reponsible for planning and execution of fine movement
A
dentate nucleus
7
Q
What are the different afferent fiber courses of the inferior cerebellar peduncle?
A
cerebellar afferent fibers, use the mnemonic: DDT Always Ruins Olives
- Dorsal spinocerebellar tract (DSCT)
- Direct arcuate fibers (or cuneocerebellar tract)
- Trigeminocerebellar tract
- Arcuocerebellar fibers
- Reticulocerebellar fibers
- Olivocerebellar fibers
8
Q
- afferent fibers tract of the inferior cerebellar peduncle
- conveys unconscious, precise, proprioceptive info from lower 1/2 of the body and lower extremities to cerebellum
- originates in the nucleus dorsalis (C8-L1), courses through ipsilateral inferior cerebellar peduncle, and terms in the anterior vermis of cerebellum
A
dorsal spinocerebellar tract (DSCT)
9
Q
- afferent fibers tract of the inferior cerebellar peduncle
- conveys unconscious, precise proprioceptive info from upper 1/2 of the body and upper extremities to the cerebellum
- fibers originate in the accessory cuneate nucleus and term in the vermis
A
direct arcuate fibers (or cuneocerebellar tract)
10
Q
- fiber tract that originates in main sensory trigeminal nucleus and project to anterior vermis via inferior and superior cerebellar peduncles
- one of the two unconscious sensory tracts from face
- conveys general unconscious, precise tactile, and proprioceptive info from head to cerebellum
A
trigeminocerebellar tract
11
Q
- afferent fibers tract of the inferior cerebellar peduncle
- form important cerebro-cerebellar motor feedback loop
- originate in arcuate nuclei of upper medulla and are displaced pontine nuclei
- arcuate nuclei receive fibers from ipsilateral cerebral cortex and project to contralateral cerebellar hemisphere via external arcuate fibers
A
arcuocerebellar fibers
12
Q
- afferent fibers tract of the inferior cerebellar peduncle
- convey general sensory modalities to the cerebellum
- originate in the lateral reticular nuclei and project bilat to cerebellar hemispheres
A
reticulocerebellar fibers
13
Q
- afferent fibers tract of the inferior cerebellar peduncle
- originate in inferior olivary nucleus (ION) and term as climbing fibers in contralateral cerebellar hemisphere
- ION: important processing and relay center for sensory info from SC and motor info from RF and pyramidal system; receives direct input from central tegmental fasciculus and spino-olivary tract
A
olivocerebellar fibers
14
Q
- consists of ascending and descending fibers from medial group (motor) of reticular nuclei
- located in center of tegmental RF
- originates in red nucleus, central (periaqueductal) gray matter and midbrain tegmentum
- critical link between extrapyramidal system and cerebellum
A
central tegmental fasciculus (CTF)
15
Q
- comprised of pontocerebellar fibers, which form an important feedback loop between motor cortex and cerebellum
- originates in pontine nuclei
- in cross-section, this structure forms islands of neurons separated by coarse fascicles of descending corticospinal corticopontine fibers and transversely oriented pontocerebellar fibers
- corticopontine fibers term in ipsilateral pontine nuclei which project to cortex of contralateral cerebellar hemispheres
A
middle cerebellar peduncle
16
Q
What are the fiber tracts present through the superior cerebellar peduncle?
A
- ventral spinocerebellar tract (VSCT)
- trigeminocerebellar tract
- tectocerebellar fibers