WHITE MATTER TRACTS

list the ascending tracts

1. spinothalamic

   • ventral

   • lateral

2. spinocerebellar

   • anterior

   • posterior

3. dorsal column medial lemniscal

   • fasciculus gracilis

   • fasciculus cuneatus

ventral spinothalamic function

• crude touch and pressure

lateral spinothalamic function

• temperatures and pain

spinothalamic pathway

spinal cord (decussate in the spinal cord) —> thalamus —> primary somatosensory cortex

spinocerebellar function

• posterior and anterior both function in coordinated muscle contractions

spinocerebellar pathway

• posterior: spinal cord —> (do not decussate) —> cerebellum

• anterior: spinal cord —> (50/50 decussate) —> cerebellum

function of the dorsal column medial limniscal pathway

• both are for fine touch, precise movement, precise pressure

dorsal column medial limniscal pathway

• spinal cord —> medulla (both decussate here) —> thalamus —> somatosensory cortex

all ascending tracts originate from the _____ horn

• dorsal horn (sensory/afferent)

what are the 2 types of descending tracts?

1. corticospinal tracts/pyramidal tracts

2. extrapyramidal tracts

list the descending tracts

1. corticospinal tract

   • lateral

   • anterior/ventral

2. rubrospinal tract

3. tectospinal tract

4. vestibulospinal tract

5. reticulospinal tract

function of the corticospinal tracts / pyramidal tract?

• both are used for fine, skilled movement

lateral and anterior/ventral corticospinal tract pathway

• lateral

  • pyramidal neurons in primary motor cortex —> (decussate in medulla) —> spinal cord interneurons —> motor neurons (?)

• anterior/ventral

  • pyramidal neurons in primary motor cortex —> (decussate in spinal cord) —> motor neurons in ventral horn

rubrospinal tract function

• controls flexor muscles

rubrospinal tract pathway

• midbrain —> (decussates in pons) —> interneuron

tectospinal tract function

• control head movement in response to visual stimuli

tectospinal tract pathway

• midbrain —> decussate in pons

vestibulospinal tract function

• balance + postural muscle tone

vestibulospinal tract pathway

• midbrain —> DOES NOT DeCUSSATE

reticulospinal tract function

• balance + postural muscle tone

reticulospinal tract pathway

• pons or medulla —> decussate in mid brain