Neurolab 8/9 Flashcards
Where does the anterior limb of the internal capsule connect?
Frontal cortex
What does damage to the SMA cause?
Unable to learn new sequences of movements
Involves alien hand syndrome and inappropriate motor usage of objects
What limb does the corticospinal tract pass through?
Posterior limb of the internal capsule
What does the pyramidal tract mean?
Corticospinal and corticobulbar tract
Where does the corticospinal tract cross?
At the decussation of the pyramids
What is the somatotopic orientation of the corticospinal tract in the spinal cord?
Sacral - lateral
Lumber
Thoracic
Cervical - medial
What is the somatotopic organization of the corticospinal tract?
CTLS
Anterior to posterior (all in the posterior limb of the internal capsule)
Midbrain:
CTLS anterior to posterior
What is in the area of the genu?
Corticobulbar tract
What nucleus does the corticobulbar tract supply?
Occularmotor
What does the corticobulbar tract go?
Trigeminal motor nucleus
Facial nerve (bilateral to upper face, contralateral to lower face)
Hypoglossus in the medulla (bilateral)
Where does the cortico-olivary tract start and end?
Cortex to the inferior olivary nucleus (red nucleus in the way?)
All ipsilateral
Where does the rubro-olivary nucleus start and end?
Red nucleus to the inferior olivary nucleus
Carries corticorubral fibers and others from the cerebellum
Where does the cortico pontine tract go?
Cortex –> pons
Ipsilateral
What is the cortico-cerebellar pathway?
Corticopontine tract goes from the cortex to the pontine nucleus
–> the pontocerebellar fibers start and go contralateral to the cerebellum through the middle cerebellar peduncle
Where does the vestibulospinal detract go?
Medial VST –> MLF –> abducens, trochlear, occularmotor + head and neck muscles (via alpha and motor): coordinates head and eye movements
Lateral VST –> primarily extensors of extremities (flex thigh, extend upper extremetis)
What is the reticulospinal tract?
Starts in the RF everything the cranial nuclei
Two nuclei –> pontine and medullary
What does the pontine nucleus of the reticulospinal tract do?
Antigravity extensor muscles
What does the medullary nucleus of the reticulospinal tract do?
responsible for inhibiting excitatory axial extensor muscles of movement
What does the rubrospinal tract do?
Contributes to flexion of lower limb
What is decorticate and decerebrate?
Decorticate (supratentorial) - above the red nucleus (upper limb flexed, lower limb extended)
Decerebrate (posterior fossa) - loss of red nucleus and brainstem involvement (all limbs flexed)
What is the olivocerebellar pathway?
Contralateral unlike the others
From the inferior olivary nucleus –> inferior cerebellum peduncle –> climbing fibers –> molecular layer
What is the only cerebellum tract that does not go through the inferior cerebellar peduncle?
Pontocerebellar peduncle
What do all the tracts besides the olivocerebellar tract do?
Terminate in the granular cell layer as mossy fibers
What tract gives rise to climbing fibers?
The olivocerebellar tract
Where do pontocerebellar tract fibers go?
Come from pontine nuclei (ipsilateral)
Cross midline through the Middle cerebellar peduncle
Mossy fibers in the granule layer and innervate the deep cerebellar nuclei
What is everything in the molecular layer of the cerebellum?
Excitatory except the purkinje cells
What are the deep cerebellar nuclei inhibited by?
The purkinje cells
Where do mossy fibers synapse?
Granule cells and deep cerebellar nuclei
Where do the dorsal spinocerebellar and cuneocerebellar tracts start and end?
Clarke’s nucleus in the spinal cord –> tracts –> inferior CP –> mossy fibers –> granular layer and deep cerebellar nuclei
ALL ipsilateral
What are the dentato-rubro-thalamic and where do they go?
Come from Dentate or interposed nucleus –> red nucleus of thalamus (VL nucleus) –> cross?
Where does the dentato-rubro-thalamic fibers decussate?
Below the trochlear nucleus and go to the contra lateral rednucleus
Where do efferents of the Dentate nucleus go?
Superior CP –> VL
Where does the interposed (emboliform and globose) go?
Superior CP –> red nucleus
Where does the fastigial nucleus go?
Inferior CP –> VN
What is the basal ganglion direct pathway?
Excitatory
What is the STN lesion like?
Hemiplosimis?
Wild movements of the muscles on the contralateral side
Where is the substantia Nigra?
Midbrain c then r
Where is dopamine synthesized?
The nerve terminals of the striatum
What are the neurons in the direct pathway?
GABA and substance P
Excitatory by D1
What are the neurons in the indirect pathway?
GABA and enkephalin
Inhibitory by D2
(Less inhibition, more stimulation of the thalamus)
What is the function of the direct and indirect pathway?
Direct - excitatory
Indirect - inhibitory
