Monday 1 - Severson - neuro lab 8 Flashcards
Where are betz cells in the brain
Agranular layer of the MOTOR cortex - later 5 of that
horizontal control center of gaze
paramedian pontine reticular formation, right lateral to abducens nucleus
vertical control center of gaze
rostral midbrain (rostral MLF)
Corticospinal tract from brain to muscle
pyramidal cells in cortex, more medial than the corticobulbar in the homunculus
posterior limb of internal capsule
cerebral peduncles in the midbrain, more lateral than the corticobulbar
basilar pons (it’s right in the middle of the pons)
pyramids of medulla
CROSS OVER at the pyramidal deccusation
in the spinal cord, they are in the lateral corticospinal tract
somatotopic organization of the posterior limb of the internal capsule
what fibers run here?
nearest genu (anterior)
it goes: cervical, thoracic, lumbar, sacral
corticospinal
what does the pyramidal tract consist of
corticospinal and corticobulbar tracts
somatotopic organization of the corticospinal tract in the spine
sacral - lateral
lumbar - more medial
thoracic fibers - even more medial
cervical fibers - most medial, if they haven’t already gone into the lateral horn.
corticobulbar tract from brain to muscle
pyramidal cells in cortex, more lateral in the humunculus than the corticospinal
genu of the internal capsule
cerebral peduncles in midbrain, more medial than the corticospinal, some branch off into the occulomotor nucleus here
“big, dark eyes” in the pons, some branch off bilaterally to form trigeminal nucleii here
Ponto-medulary region, some branch off bilaterally into the facial nuclei
Medulla where it branches off in to the hypoglossal and nucleus ambiguus
Cortico-olivary tract from brain to where it ends
motor cortex
ipsilateral to inferior olivary nucleus
“its very simple”
Rubro-olivary tract
red nucleus
inferior olivary nucleus
“also very simple”
Cortico pontine
z
inferior olivary nucleus gives rise to what
climbing fibers
Cortico-cerebellar pathway
cortex
goes to IPSILATERAL pontine nucleus as corticopontine cract
synapse in pons
crosses contralaterally
is now the pontocerebellar tract
goes to middle cerebellar peduncle and into the cerebellum as mossy fibers in the granular cell layer (innervates the deep cerebellar nuclei)
What connects the occulomotor, trochlear, and abducens nuclei?
medial longitudinal fasciculus
vestibulocollic reflex
when you go down you extent your head
vestibulospinal reflex
coordinates head and neck with body, keeping head in upright position
reticular formation
in brain stem, pons and medulary both
packing material between all of the nuclei like the facial nucleus and nucleus ambiguus.
involved in arousal and consciousness
black box for respiratory function, cardiovascular function
olivocerebellar fibers pathway
olive in the medulla
cross over
go to inferior cerebellar peduncle
terminate in molecular layer of cerebellum as climbing fibers
what do the climbing fibers in the cerebellum innervate
deep cerebellar nuclei
and
purkinje cells
(this seems counter-intuitive because the purkinje cells inhibit the deep cerebellar nuclei but the climbing fibers stimulate both)
what is the general purpose of the inferior olive (think really general)
it modifies information and sends it to the cerebellum via the inferior cerebellar peduncle
what innervates the deep cerebellar nuclei?
Trick question:
everything going into the cerebellum innervates the deep cerebellar nuclei
what forms the paralell fibers in the cerebellum?
the granule cells
everything in the molecular layer of the cerebellum is
excitatory
purkinje cells are the only things that are inhibitory
when there is a lesion in the cerebellum, it presents on the _______ side
ipsilateral
What tract(s) give info to the cerebellum (unconscious proprioception) regarding what is going on in the limbs
which peduncle do they go through
and what do they synapse on
dorsal spinocerebellar (lower limb) and cuneocerebellar (upper extremity)
inferior cerebellar peduncle
like ALL mossy fibers, they synapse on deep cerebellar nuclei and granule cells
what two types of fibers go into the cerebellum
where do they come from
what do they synapse onto
Climbing fibers -
from inferior olivary nucleus
synapse onto the deep cerebellar nuclei and the purkinje cells
mossy fibers -
everything else
synapse on granule cells and deep cerebellar nuclei
The fastigial nucleus is associated with what system
vestigial nuclei
What comes from the cerebellum up to the cortex through the superior cerebellar peduncle?
Dentato-rubro-thalamic fibers
efferent fibers from the dentate, emboliform, and globose nuclei (but not fastigial)
Dentato-rubro-thalamic tract
goes from where to where?
ipsilateral to where?
contralateral to where?
crosses over where?
goes from cerebellum to cerebrum via the superior cerebellar peduncle
ipsilateral to body
contralateral to cerebrum (red nucleus and thalmus)
crosses over at the decussation of the superior cerebellar peduncle,
excitatory basal ganglia pathway (direct pathway)
motor cortex
striatum (caudate and putamen)
globus pallidus interna
thalmus
back to the cortex
indirect basal ganglia pathway vs direct
indirect - inhibition of motor function via STN activating GPi
direct - excitation of motor function via striatum inhibiting GPi
Lesion in the sub thalamic nucleus produces what
hemiballismus - wild swinging of the extremity on the contralateral side
where is dopamine synthesized in the basal ganglia
the nerve terminals of the substantia nigra compacta, which terminate on the striatum
