Myelins Functions Tracts Flashcards by Mary Slome

Gracile fasiculus

Fx: carries ipsilateral epicritic sense from lower half of the body
From: this is a primary nerve
To: medulla, gracile nucleus

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Dorsolateral fasiculus aka Lissauer’s tract

Fx: pain and temperature and nociceptive to dorsal horn
From: pain and temp sensory neurons
To: dorsal horn (substantia gelatinosa)

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Dorsal horn (substantia gelatinosa)

Fx: Integrates pain and temperature information
From: Lissauer’s tract
To: ALS via anterior white commissure, some terminate on interneurons to mediate spinal reflexes

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Ventral horn

Fx: contains cell bodies of motor neurons
From: Pyramidal and Extrapyramidal tracts
To: Muscles

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Lateral corticospinal tract

Fx: voluntary movement, discrete hand movements
From: part of the pyramidal tracts, cerebrum
To: gray matter at all spinal segents
Pathology: ipsilateral paralysis of distal muscles at that level

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Anterolateral system

Fx: carries protopathic contralateral information
From: sensory neurons in dorsal horn
To: brainstem reticular formation, thalamus, VPL, DM and intralaminar nuclei

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Anterior corticospinal tract

Fx: Voluntary movement of proximal muscles
From: Part of the pyramidal tracts, cerebrum
To: Intermediate gray area

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Cuneate fasciculus

Fx: Carries ipsilateral epicritic information from upper limbs
From: this is a primary nerve
To: cuneate nucleus in the medulla

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Hypthalamoreticulospinal tract (HRST)

Fx: carries preganglionic sympathetic axons destined for the intermediolateral cell column
From: hypothalamus and RF
To: intermediolateral cell column

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Ventral spinocerebellar tract

Fx: Carries proprioceptive information from the lower limbs
From: Mostly contralateral proprioceptive sensory neurons
To: Contralateral superior cerebellar peduncle
NOTE: THIS DECUSSATES (twice), but the DSCT does not

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Dorsal spinocerebellar tract

Fx: Carries proprioceptive information destined from the cerebellum from the lower half of the body
From: Proprioceptive neurons destined for the cerebellum
To: Cerebellum vis inferior cerebellar peduncle
***This tract DOES NOT decussate

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Rubrospinal tract

Fx: Distal motor control
From: Red nucleus
To: Projects ipsilaterally to portions of the gray matter

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Where do the HRST and the LST switch?

Upper cervical region

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Crus cerebri

Fx: Cortical control of movement, some descending gating of sensory signals
From: All cerebral areas
To: CN nuclei (corticobulbar tract), Pontine nuclei (corticopontine), gray matter of the spinal cord (corticospinal)

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Substantia nigra

Fx: pars compact - skeletal movement, dopamine synthesis
pars reticulata - skeletal and eye movements
From: globus pallidus and neostriatum
To: superior colliculus, midbrain RF

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Name a pathology of CN 3

External strabismus
Pupil Dilation (EW nucleus)

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Red nucleus:

Fx: Skeletal movement
From: Motor and premotor cortex, cerebellar nuclei
To: Rubrospinal tract

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Cerebellothalamic fibers

Fx: ?
From: Cerebellar nuclei
To: VL, VA and intralaminar nucleus in thalamus

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LGN

Fx: Vision, pattern, motion, color
From: optic tract
To: V1 of occipital lobe via optic radiations

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Pretectal area

Fx: Constricts pupil to light
From: Optic tract, both eyes
To: E-W nucleus

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MLF

Fx: Coordinates head and eye position
From: vestibular nuclei, CN 6
To: nuclei of CN 3, 4, 6, cervical spinal cord

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Internuclear ophthalmoplegia is a problem in the:

MLF, midbrain

When your eyes cannot move above the midline, it is a problem of the?

Posterior commissure, midbrain

Fx: pupillary light reflex and upward gaze

What is a crus cerebri pathology?

Loss of independent finger movement, slowed reaction times, perhaps slight weakness

MGN

Fx: Hearing From: Inferior colliculi To: Auditory cortex of the temporal lobe (via internal capsule)

An inability to discern patterns, or errors in localizing sound, can be a problem of the:

MGN

Superior colliculus

Fx: Sensory and motor functions Motor: Controls orienting movements of head and neck Sensory: Vision From: Optic tract, visual and parietal cortex To: Ascending to pulvinar nucleus, descending ocular premotor areas or RF

PAG

Fx: Pain sensation, rich in endorphin receptors From: ALS To: Nucleus Raphe Magnus

Pathology of the decussation of the superior cerebellar peduncle might include?

``` Intention tremor (midbrain) Cerebellar signs, ataxia ```

Subtle deficits in the localization of sound might be a problem of the:

Inferior colliculus

The nucleus of the trigeminal tract projects to:

VPM of the thalamus

a lesion to the facial colliculus would result in:

ipsilateral facial paralysis and ipsilateral unopposed eye medial deviation.

Where does the inferior olive project to:

The contralateral cerebellar cortex

What projects to the VPL of the thalamus?

Gracile nucleus, cuneate nucleus

Posterior commissure

Connects pretectal areas of the brainstem, and the oculomotor premotor areas of both sides of the brainstem Fx: upward gaze, pupillary light reflex

Nucleus Raphe Dorsalis

Found in midbrain | same course as the CT fibers, to the VA, VL and intralaminar nucleus of the thalamus

Decussation of the superior cerebellar peduncle

Found in midbrain Fx: carries signals from cerebellum to brainstem From: Cerebellum To: VL, VA of thalamus, red nucleus

Brachium of the inferior colliculus

Found in midbrain From: inferior colliculus To: MGN

Brachium of the superior colliculus

Found in midbrain From: optic tract, superior colliculus, visual cortex To: Superior colliculus, LGN, pulvinar nucleus General function is vision, but specifics not known

Lateral lemniscus

Found in midbrain and pons Fx: hearing From: Superior olive and cochlear nucleus To: Inferior colliculus

Superior olive

Found in pons Fx: hearing, locating the source of sound From: cochlear nucleus To: nucleus of lateral lemniscus, inferior colliculus

Inferior olive

Found in medulla Fx: relay sensory and motor information From: disparate motor and sensory areas of brainstem and cerebrum To: ***source of climbing fibers in cerebellar cortex

spinal tract of 5

Found in caudal pons and medulla From: axons of CN 5 To: spinal nucleus of 5 Fx: somatosensory for head and neck

spinal nucleus of 5

Found in caudal pons and medulla Fx: somatosensory for head and neck From: spinal tract of 5, axons of 5 To: RF, thalamus

A pathology of the spinal tract of 5 or spinal nucleus of 5 in the medulla would cause:

Loss of pain and temp sense in the face

A pathology of the spinal tract of 5 or spinal nucleus of 5 in the pons would cause:

Reduced epicritic (2 point) sense in the face

Raphe nucleus

Found in medulla Fx: sleep and descending control of pain From: diverse areas of the cerebrum and diencephalon To: serotonergic axons in cerebellum, spinal cord

A pathology of the Raphe Nucleus in cats might cause:

insomnia for REM sleep

Nucleus ambiguus

Found in medulla Fx: movement of larynx and pharynx From: RF, corticobulbar tract To: muscles of larynx and pharynx

A unilateral lesion in the nucleus ambiguus would cause:

hoarseness, choking, difficulty swallowing

A bilateral lesion in the nucleus ambiguus would cause:

aspiration of fluids into the lungs

Solitary nucleus and tract

Found in medulla Fx: taste, visceral afferents from 9 and 10 From: CN 7, 9, 10 To: solitary nucleus

Tectospinal tract

Found in medulla, then becomes part of the extrapyramidal tracts in the spinal cord Fx: Head movements during visual and auditory tracking From: deep layers of the superior colliculus To: anterior funiculus of spinal cord

A lesion of the tectospinal tract would cause what symptoms?

Nausea, dizziness, imbalance, nystagmus