Extrapyramidal Tracts

Question 1

Afferent connection to tectospinal tract (2)

Answer 1

1. IL lat geniculate body (visual) to sup colliculus

2. Lat lemniscus (auditory) to sup/inf colliculus

Question 2

Where does the tectospinal tract project to

Answer 2

axons project into lamina 5+6, 7+8 (cervical lvls)

Question 3

What is the patheay of the tectospinal tract

Answer 3

From sup colliculus will cross midline at decussion of tectospinal tract (cranial midbrain). Descend next to midline and in spinal cord occupies ant white column

Question 4

What is the function of the tectospinal tract

Answer 4

helps w automatic movements of head and neck based on unexpected visual/auditory stims

Question 5

What is the special collateral the tectospinal tract has

Answer 5

some collaterals leave at the lvl of the pons and go to facial nerve and cause automatic contraction (eg. close eyes when there is a loud sound

Question 6

Afferent and center of rubrospinal tract

Answer 6

• BL corticoreticular fibres
• CL cerebellum (dentorubral fibres)

center- Red nucleus (midbrain)

Question 7

Efferent connection of rubrospinal tract

Answer 7

CL laminae 7,8,9 (mostly cerv+UL)

Question 8

pathway of rubrospinal tract

Answer 8

Cross midline at ant tegmental decussian

descend thru lat portion of brainstem and keeps same pos when entering spinal cord

Question 9

Function of rubrospinal tract

Answer 9

Faculitates flexors of UL (+ neck)

Question 10

Afferent and efferent of medial reticulospinal tract

Answer 10

BL corticoreticular to pontine reticular nucleus for IL medial reticuospinal tract

IL lamina of 5/6,7,8,9 at every level

Question 11

Function of medial reticulospinal tract

Answer 11

Excitatory to extensor motor neurons an for axial mm
(inhibits flexors)
-essential for autonomic posture

Question 12

Afferent and efferent of lateral reticulospinal tract

Answer 12

BL corticoreticular firbes to medullary reticular nuc

BL lamina 5/6,7,8 of all lvls

Question 13

function of lateral reticulospinal tract

Answer 13

inhibitory to extensor motor neurons (+ axial mm)

excitatory to flexors

Question 14

afferent and efferent of medial vestibulospinal tract

Answer 14

IL cerebellum, IL vestibulococlear n to medial vestibular nuc

Efferent-medial vestibulospinal tract BL laminae 7,8,9 of cerv

Question 15

Function of medial vestibulospinal tract

Answer 15

Controls pos of head, neck, shoulders`

Question 16

afferent and efferent of lateral vestibulospinal tract

Answer 16

IL cerbellum and inner ear to lat vestibular nucleus

efferent- Il laminae 7,8,9 at all sc lvls

Question 17

function of lateral vestibulospinal tract

Answer 17

Excitatory to all extensor neurons for the neck, upper limb, trunk, lower limb

Question 18

Decorticate pos- how does it present

Answer 18

-elbows, wrists and fingers flexed, legs extended and rot in

Question 19

Decorticate pos- what is likely affected

Answer 19

lesion above red nucleus

-it becomes unopposed and rubrospinal tract becomes hyperactive

Question 20

decerebrate pos- presentation and what is likely affected

Answer 20

everything extended

• lesion below red nucles but above vestibular + pontine nuclei

vestibular nuclei become unsupressed and fires at higher rate and puts everything into ext

Question 21

Where is benedikt syndrome located and functions it affects

Answer 21

Midbrain tumor

1. Passage of CNIII- IL CNIII palsy
2. Red nucleus- CL involuntary mvmts of limbs
3. Medial + spinal lemnisucs- CL hemianesthesia