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Flashcards in Brain Tract Pathways Deck (33)
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1

Anterolateral System

o DRG  dorsal horn ipsilateral side  crosses spinal cord  spinothalamic tract  VPL intralaminar nuclei or periaqueductal gray in midbrain  internal capsule from thalamus  post-central gyrus.

2

Dorsal Column

DRG  cuneate or gracilis nuclei  medial lemniscus  crosses mid medulla  to VPL in thalamus  internal capsule  Post-central gyrus

3

Trigeminal Pain/Temp

o Trigeminal ganglion (by pons)  spinal trigeminal tract  spinal nucleus of V (ascending)  ventral trigeminothalamic tract  VPM  internal capsule  post central gyrus.

4

Trigeminal Touch

o Trigeminal ganglion  dorsal trigeminothalamic tract  ventral trigeminothalamic tract  ventral posteromedial nucleus  internal capsule  post central gyrus.
o OR Trigeminal ganglion  chief sensory of nucleus V

5

Visceral Sensation and Taste

VII, IX, and X ganglia  solitary tract to solitary nucleus  VPM  hypothalamus  post central gyrus and insula

6

Visual System

o Rods and Cones  ganglion cells  terminate in lateral geniculate  optic radiation (geniculocalcarine tract)  primary visual sensory cortex (aka striate cortex)
o Pituitary tumor produces a visual field defet called bitemporal hemianopia.
o Homonymous hemianopia  see image.

7

Vestibular System

o Semicircular canals and Otolith organs (saccule and utricles)  vestibular ganglia  vestibular nucleus and cerebellum  two descending tracts- medial and lateral vestibulospinal tract  ventral horn of spinal cord.
 Vestibular nuclei  form the medial longitudinal fasciculus  terminates in III, IV, and VI (EOM).
• Oculocephalic and doll’s eyes test MLF (VOR)

8

Auditory System

o Semicircular canals and Otolith organs (saccule and utricles)  vestibular ganglia  vestibular nucleus and cerebellum  two descending tracts- medial and lateral vestibulospinal tract  ventral horn of spinal cord.
 Vestibular nuclei  form the medial longitudinal fasciculus  terminates in III, IV, and VI (EOM).
• Oculocephalic and doll’s eyes test MLF (VOR)

9

Corticospinal tract

o Motor cortex  posterior limb of internal capsule  cerebral peduncle  pons  pyramid  decussation  lateral funiculus/ lateral corticospinal tract  ventral horn

10

Corticobulbar Tract

o Voluntary neurons in lateral motor cortex for neck and face  internal capsule genu  III, IV, and VI (for eye movements both sides), VII (wrinkling forehead (both) and smiling (contralateral)), XII (sticking out tongue)
 Central VII palsy refers to facial nucleus both sides

11

Vestibulospinal Tract

o Axons from utricle, saccule, and semicircular canals terminate in vestibular nuclei  vestibular nuclei or granule cells in cerebellum  purkinje cell axons from flocculus  fastigial nucleus  vestibular nuclei  lateral vestibulospinal tract  ventral horns, esp for extensors.
o Axons from the vestibular nuclei form the MLF  important for coordination of eye movements. (MLF damage = internuclear ophthalmoplegia.
 MLF becomes the medial vestibulospinal tract in the cervical spinal cord.

12

Basal Ganglia

o Principle source of striatal afferents is cerebral cortex
o Substantia nigra projects to the striatum.
o Striatum is caudate and putamen
o Striatal efferents terminate in the globus pallidus and subthalamus.
o Globus pallidus  VA, VL and CM (all in thalamus)
o Thalamocortical fiber terminate in the premotor and supplementary motor cortex.
o There are reciprocal connections in the pallidum and subthalamus.
o A lesion in the subthalamus results in hemiballismus
o Loss of striatal nucleus is huntingtons
o Loss of substantia nigra is parkinsons.

13

Lateral leminicus info

bilateral auditory information

14

Superior cerebellar peduncle input and output

dentate nucleus => VA/VL in thalamus
interposed => red nucleus

15

inferior colliculus info

bilateral auditory information

16

medial lateral fasciculus (MLF)

can cause internuclear opthalplegia - ipsilateral lesion where eye cannot medially turn in, while theother one turns lateral. Usually can still try to cross eye.

17

Pontine Nuclei (where do they end and what info?)

contralateral cerebellum; involved in motor coordination

18

Cerebral peduncle origin and termination

cortex => contralateral spinal cord, pontine nuclei, and motor nuclei in brainstem.

19

Trochlear Nucleus

CN IV innervates superior oblique. Lies posterior to MLF, in which superior cerebellar peduncle lies in front).

20

Oculomotor (lateral) and EW nuclei (medial)

Midbrain; can see fibers

21

Medial geniculate nucleus

upper midbrain; lateral to superior colliculus; axons originate in inferior colliculus; carries bilateral auditory information

22

Red nucleus

Axons that end here originate in contralateral cerebellum

23

Muffin top

upper medulla and pons present. vestibular nuclei and cochlear nucleus, also has 8th nerve.

24

Facial nucleus

wraps around abducens nucleus before exiting at pons

25

abducens nucleus

motor neurons that innervates lateral rectus; also has interneurons that project to contrallateral MLF to Nuc. III

26

Superior Olivary Nucleus

auditory, input from both cochlear nuclei. projects to inferior colliculus. medial to facial nucleus

27

Medial leminicus in pons

broken up by crossing auditory fibers in trapezoid body

28

Main sensory nucleus of V

lateral and by cat ears (superior cerebellar peduncle)

29

Spinal Trigeminal Nucleus

Medulla, lateral to cuneatus; pain and temp for ipsilateral face, also has spinal trigeminal tract

30

Inferior olive

in caudal medulla; project via the contralateral inferior cerebellar peduncle to cerebellar cortex where they end as climbing fibers