motor anatomy Flashcards
from what areas of the brain does the corticospinal tract arise?
areas 4, 6, 312
as they leave the cortex, corticospinal fibers are
the corona radiata
through what do corticospinal fibers trival in the diencephalon?
the internal capsule
in the midbrain, cortico spinal fibers become
the cerebral peduncles
what is the the pyramidal decussation?
where 90% of corticospinal fibers split, at the junction of the spinal cortd brainstem.
After the pyramidal decussation, the crossed corticospinal tract goes to the —– and the uncrossed fibers go to the —-
dorsolateral white matter, anterior corticospinal tract.
what other pathway subserves motor control through its connections in the brainstem?
corticobulbar tract
in the internal capsule, what is the somatotopic organanization?
Fibers controling upper body are found anteriorly, axons that influence the lower body are found post
How does the map of the internal capsule change in the cerebral peduncle?
upper body is represented medially and lower body is represented laterally
what areas of the cortex project to the red nucleus?
motor, premotor,
where do axons leaving the red nucleus, destined for the spinals cord go?
the cross in the ventral tegmental decussation and travel in the dorsolateral funiculus
what is a disynaptic connection from the motor cortex to the spinal motorneurons?
the rubrospinal tract
where does the tectospinal tract arise from?
the intermediate and deep layers of the superior colliculus
Where does the superior colliculus project?
to the cervical spinal cord only
What kind of information do reticulospinal efferents carry?
vestibular info
What descending noradrenergic projection controls background excitability in MN?
Projections from the locus coeruleus
What descending projection from the brainstem is serotonergic?
caudal raphe nuclei.
what is the effect of descending connections from the raphe?
inhibitory; prevent hyper activity
This fiber tract has a role in maintenance of balance, has bilateral projections in the cord, runs throughout the SC, and effects A and G EXT and FLEX
LVST
This tract is for coordinated eye and head movements, projects contralaterally through only neck levels in the cord, and only influences neck muscles
tectospinal
Where does MVST project and what does it do?
Bilateral, cervical, Alpha neck MN, maintains head stability
where does reticulospinal project?
bilaterally to a and g flex and ext at all sc levels
coeruleospinal pathway is—,raphe-spinal is —–
ipsi, bilateral
latin name for anterior lobe of the cerebellum
paleocerebellum
the nodulus and flocculus, also called—- are separated from the rest of the cerebellum by the—-
vestibulocerebellum; posterolateral fissure
what structure of the cerebellum forms the roof of the 4th ventricle?
nodulus
Input to the cerebellum chiefly goes to —-, which send info to—– in the —- layer.
granule cells, PC, Molecular layer
information going out of the cerebellum travels in which peduncle?
superior
info going into the cerebellum goes by way of what?
middle (brachium pontis) inf (corp restiform)
the restiform body of the inferior peduncle carries what fibers?
Olive, dorsal spinocerebellar tract and medullary reticular formation
the juxtarestiform body of the inferior peduncle carries what?
vestibular info, also efferents
In what peduncle do pontine fibers to the cb travel in?
middle cerebellar peduncle
where do axons in the superior cerebellar peduncle go?
contralateral red nucleus or thalamus
the magnocellular division of the red nucleus receives what?
interpositus, mostly
the parvocellular red receives what?
dentate
what two tracts are near the superior cerebellar peduncl?
the uncinate fasiculus and spinocerebellar tract
the lentiform nucleus is made out of what structures?
putamen and gp
the neostriatum is what?
caudate and putamen
what separates the neostriatum?
the internal capsule
what structure forms the lateral wall of the lateral ventricle?
the caudate
what is the ventral striatum?
is rostr and vent to the ant comm, consists of the NAmb, Striatum and parts of the olfactory tubercle
what fiber structure separates the gp and the putamen?
external meduliary lamina
what separates the thalamus from th lenticular nucleus?
internal capsule
what is special about the substantia nigra pars compacta?
hs large cells that produce dA
what NT does the pars reticulata produce?
GABA
In the BG, what region is mostly motor?
Most of the Putamen
what kind of area occupies most of the caudate
Association
where is the limbic portion of the bg?
Ventral,
Major inputs to the striatum are from
the corex and the IL thalamic nuclei
efferents from the striatum include
MSN expressing substance-P and GABA project to the gp internal segment (direct) and MSN expressing enkephalin and gaba to gp ext.
Describe the indirect path
From the GP ext segment, to the sTN, to the GP internal segment
where does the gp internal segment project to?
VA, VL thalamus via lenticular fasciculus and the ansa lenticularis (the thalamic fasciculus)
where does the substantia nigra pars compacta project?
the striatum and ventral striatum (DA)
what are the motor nuclei of the eye muscles?
abducens, trochlear, and occulomotor
the pathway the carries the vestibuloocular reflex goes from the semicirc, vestibular and then to the motor nuclei by two pathways:
mediallongitudinal fasiculus, or by way of the nucleus prepositus hypoglossi. also, to the flocculus.
where does the command for saccadic eye movements originate?
FEF, sEF, intraparietal area of CCX.
Signals for saccades are ultimately carried to the — and the —- to get to the remotor burst neurons.
Superior colliculus, caudate, and to vermis via the nrtp.
for saccad, horizonal movements are — and veritical movements
pontine;midbrain reticular formations (premotor burst neurons)
describe the pathfor smooth pursuit detection
Mt and Mst send signal to dl ponine, to flocculus and posterior veermis. then to mn via vestibular and prepositus hypoglossi. Also, fastigial to mn
