neuroanatomy 3 Flashcards
lobes of the cerebellum
anterior, posterior and flocculonodular
how is the cerebellum attatched to the brainstem
By three stalks (of white matter) called peduncles - middle cerebellar, surperior cerebellar and inferior cerebellar pudencles
middle of the cerebellum called?
vermis - middle pinched area ‘worm like’
what is the arbor vitae
white matter in the cerebellum - tree of life
some deep grey matter can be seen in it
how many deep nuclei are in the cerebellum
4
dentate nucleus is the deepest
three layers of teh cerebellar cortex
molecular layer (outer), purkinje layer(middle), granule cell layer (inner)
where does afferent info mainly project to
granule cell layer
where does the output info from cerebellum arise from
only output is via the axons of purkinje cells which synapse on neurons of deep cerebellar nuclei, so it conytributes to the coordination of all the motor tracts (coticospinal, vestibulospinal, rubrospinal)
where do efferent axons from the cerebellar synapse
cross the midline and synapse at the thalamus, the thalamus in turn sends them to the motor cortex
what do the cerebellar hemispheres do and what signs would a lesion cause?
influence the ipsilateral side of the bod, so lesions lead to ipsilateral signs (contrast to lesions of sensory/motor cortex)
unilateral hemispheric lesion - disturbance in coordination of limbs. can result in intention tremor and unstrady gait in the absence of weakness or sensory loss
bilateral dysfunction - slowed, slurred speech, bilateral incoordination of the arms and a staggering, wide based gait (cerebellar ataxia) (alcohol causes this)
what would a midline lesion in the cerebellum cause
disturbance if postural control. patient will fall when standing or sitting despite preserved limb coordination
what is the midline division of the cerebellum
spinocerebellum
what are the lateral divisions of the cerebellum called
pontocerebellum
what is the third division of the cerebellum called
vestibulocerebellum
list the functions of the basal ganglia
facilitate purpousful movement
inhibit unwanted movements
role in posture and muscle tone
where is the basal ganglia
base of cerebral hemispheres - grey matter structure
what makes up the basal ganglia
caudate nucleus, putamen, globus pallidus, subthalamic nucleus, substantia nigra
what makes up teh striatum
caudate nucleus and putamen
what makes up the corpus striatum
caudate nucleus, putamen and the globus pallidus
what makes up the lenticular nucleus
putamen and golbus pallidus
from what structure of the basal ganglia are cells lost in parkinsons
substantia nigra (degeneration of dopaminergic neurons of the substantia nigra)
main role of basal ganglia and indirct pathway
accentuate movements you want to occur - enhances outflow of thalamus. indirect pathway - dampens movements you dont want to occur
unilateral lesion in the basal ganglia - ipsilateral side affected or contralateral?
conyralateral side
what do lesions in the basal ganglia cause
changes in muscle tone, dyskinesia (abnormal involuntary movements including - tremor, chorea, myoclonus)
