Myelins Functions Tracts Flashcards
Gracile fasiculus
Fx: carries ipsilateral epicritic sense from lower half of the body
From: this is a primary nerve
To: medulla, gracile nucleus
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)
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
Ventral horn
Fx: contains cell bodies of motor neurons
From: Pyramidal and Extrapyramidal tracts
To: Muscles
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
Anterolateral system
Fx: carries protopathic contralateral information
From: sensory neurons in dorsal horn
To: brainstem reticular formation, thalamus, VPL, DM and intralaminar nuclei
Anterior corticospinal tract
Fx: Voluntary movement of proximal muscles
From: Part of the pyramidal tracts, cerebrum
To: Intermediate gray area
Cuneate fasciculus
Fx: Carries ipsilateral epicritic information from upper limbs
From: this is a primary nerve
To: cuneate nucleus in the medulla
Hypthalamoreticulospinal tract (HRST)
Fx: carries preganglionic sympathetic axons destined for the intermediolateral cell column
From: hypothalamus and RF
To: intermediolateral cell column
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
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
Rubrospinal tract
Fx: Distal motor control
From: Red nucleus
To: Projects ipsilaterally to portions of the gray matter
Where do the HRST and the LST switch?
Upper cervical region
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)
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
Name a pathology of CN 3
External strabismus Pupil Dilation (EW nucleus)
Red nucleus:
Fx: Skeletal movement
From: Motor and premotor cortex, cerebellar nuclei
To: Rubrospinal tract
Cerebellothalamic fibers
Fx: ?
From: Cerebellar nuclei
To: VL, VA and intralaminar nucleus in thalamus
LGN
Fx: Vision, pattern, motion, color
From: optic tract
To: V1 of occipital lobe via optic radiations
Pretectal area
Fx: Constricts pupil to light
From: Optic tract, both eyes
To: E-W nucleus
MLF
Fx: Coordinates head and eye position
From: vestibular nuclei, CN 6
To: nuclei of CN 3, 4, 6, cervical spinal cord
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
