Thoracic limb and Pelvic limb Neuro Pathways

Block 3

How many conscious pathways does the thoracic limb have?

one

How many subconscious pathways does the thoracic limb have?

two

What is the conscious proprioception pathway of the thoracic limb called?

fasciculus cuneatus

What is the first neuron of the fasciculus cuneatus pathway?

dorsal root ganglion- axons ascend ipsilaterally

What is the second neuron in the fasciculus cuneatus pathway?

medial cuneate nucleus- axons cross midline as deep arcuate fibers

What do the axons of the medial cuneate nucleus form?

contralateral medial lemniscus and ascend through brainstem

What is the third neuron in the fasciculus cuneatus pathway?

ventral caudal lateral nucleus- axons form internal capsule

Where does the axons from the VCL terminate?

parietal lobe

What are the names of the subconscious proprioception tracts in the thoracic limb?

cuneocerebellar tract

rostral spinocerebellar tract

What is the first neuron of the cuneocerebellar tract?

DRG- axons ascend ipsilaterally in most lateral part of fasciculus cuneatus

What is the second neuron of the cuneocerebellar tract?

lateral cuneate nucleus- axons enter caudal cerebellar peduncle

What is the second neuron of the rostral spinocerebellar tract?

dorsal gray column- axons enter caudal and rostral cerebellar peduncle

What is a conscious deficit known as?

knuckling

What is an unconscious deficit known as?

sensory ataxia

What does conscious proprioception detect?

changes in limb position at rest

What does subconscious proprioception detect?

changes in limb position while moving

What do GP Proprioceptors respond to?

movement, pressure, and stretch

What is the conscious proprioception pathway for the pelvic limb?

fasciculus gracilis

What is the second neuron in the fasciculus gracilis pathway?

nucleus gracilis

What is the third neuron on the fasciclus gracilis pathway?

VCL- parietal lobe

What are the two subconscious pathways in the pelvic limb?

dorsal spinocerebellar tract

ventral spinocerebellar tract

What is the second neuron of the dorsal spinocerebellar tract?

dorsal gray column in Clarke’s nucleus- axons ascend ipsilateral and enter caudal cerebellar peduncle

What is the second nucleus of the ventral spinocerebellar tract?

dorsal gray column- cross ventral white commissure and ascend contralaterally and enter cerebellar peduncle

What nerves are part of the spinothalmic tract?

spinal nerves

What nerves are part of the quinothalamic tract?

cranial nerves

What are local pain stimuli pathways called?

reflex

What are pathways that can travel to higher centers in cranial and spinal systems?

relay

What is a monosynaptic pathway?

spinal reflex arc with direct synapse of sensory fiber with motor neuron

What does a polysynaptic pathway contain?

interneurons

What is the first neuron in the spinothalamic tract?

DRG- axons ascend or descend forming dorsolateral fasciculus

What is the second neuron in the spinothalamic tract?

dorsal gray horn of spinal cord- axons cross and ascend contrallaterally in ventrolateral funiculus

What is the third neuron of the spinothalamic tract?

VCL

What is the difference for nociception in animals?

bilateral and diffuse with many synaspses

What are the quintothalamic tracts?

cranial reflex arc

quintothalamic tract for relay in higher centers

What is the first neuron in the cranial reflex arc?

trigeminal ganglion- form spinal tract of trigeminal nerve

What is the second neuron of the cranial reflex arc?

location depends on modality-

pontine sensory nucleus

spinal nucleus of trigeminal nerve

What type of sensation does the pontine sensory nucleus sense?

mechanical type of sensation

What type of sensation does the spinal nucleus of the trigeminal nerve sense?

thermal type of sensation

What is the third neuron of the cranial reflex arc?

any motor neuron

What is the first neuron of the quintothalamic tract?

trigeminal ganglion

What is the second neuron of the quintothalamic tract?

depends on modality of sensation- axons will cross to opposite side ascend contralaterally as the trigeminal lemniscus

What is the third neuron of the quintothalamic tract?

ventral caudal medial nucleus 

What is the embryologic origin of the cerebellum?

rhombi lip (metencephalon)

What is the midline strip called?

vermis and hemispheres

What is the term for ridges in the cerebellum?

folia

What is the term for grooves in the cerebellum?

sulci

What is the gray matter on the surface called?

corticol

What is the gray matter under the surface called?

subcorticol

What is deeper white matter called?

arbor vitae

What lobes are on the dorsal surface?

rostral lobe

caudal lobe

What lobe is on the ventral surface?

flocculondular

What does the primary fissure separate?

caudal lobes

What does the caudolateral fissure separate?

caudal and flocculonodular lobes

Where are the fastigial nuclei located?

midline

Where are the interpositus nuclei located?

between other two nuclei

Where are the dentate nuclei located?

most lateral

What is the first part to develop of the vestibulocerebellum?

archicerebellum

What is the function of the vestibular system?

equilibrium and conjugate eye movement

What is the flocculonodular lobe involved in?

vestibulocerebellum

What is the first to develop of the spinalocerebellum?

paleocerebellum

What is the rostral lobe involved in?

spinalocerebellum

What is the function of the spinalocerebellum?

muscle tone, posture, and sterotyped movement

What is the first part of the pontocerebellum?

neocerebellum

What is the caudal lobe involved in?

pontocerebellum

What is the function of the pontocerebellum?

voluntary planned movement and highly skilled movement

What does the granular layer do?

receive and send information through cerebral cortex

What does the purkunje layer contain?

cell bodies

What does the molecular layer contain?

synapse & cell processes

What system does climbing fibers receive information from?

extrapyramidal motor system

What systems does mossy fibers receive information from?

pyramidal motor system

general proprioception

balance and equilibrium

Where do climbing fibers go?

from olivary complex to molecular layer to purkinje dendrites

Where do mossy fibers go?

widespread origin, brianstem and cord to granule cells

Where do parallel fibers go?

from granule cells to purkinje cells

What is the middle cerebellar peduncle involved in?

pyramidal motor system

What is the rostral cerebellar peduncle involved in?

efferent pathways

Both the fasciculus gracilis and fasciculus cuneatus are located in which funiculus of the spinal cord?

dorsal

Deep cerebellar nuclei send axons to the:

UMN nuclei in the brainstem

Which term refers to the superficial layer of the cerebellar cortex?

molecular