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Ascending and descending neural tracts

Could someone PLEASE give a brief overview on what their understanding is of this? I have read up on it but was hoping someone could give a simpler explanation of the various tracts and consequences of lesions in each one !!!

Reply 1

Renal

http://upload.wikimedia.org/wikipedia/commons/f/fe/Medulla_spinalis_-_tracts_-_English.svg

Wiki each of those, read and note the first two sentences.

What you need to know is whether it's motor or sensory. Once you have that worry about what it carries.

Then, note where it decussates, that defines whether the effects of a lesion are ipsilateral (if the tract decussates in the brain and serves the side of the body that it's on) or contralateral (if the tract decussates in the spine and serves the opposite side of the body to the side it's on).

Reply 2

Saffie

Ascending TRACTS

-DCML – Dorsal column medial lemniscus (discriminative TOUCH), crosses high in medulla (A beta fibres)

• STT – Spinothalamic tract (PAIN and temp, itch and tickle), crosses on entry to spinal cord (A delta and C fibres)

• SCBT - Spinocerebellar tract (BALANCE) doesn’t cross over. (A alpha fibres)

Descending TRACTS

• Corticospinal/Pyramidal tract- precise movements. Lateral part (90%) crosses in medulla, medial part (10%) cross as exit spinal cord.

• Rubrospinal tract- gross movements

• Vestibulospinal & Reticulospinal tracts- posture & balance

I think thats a bit simplified cause its copied and pasted from my year 1 revision

Reply 3

SuccessSoon

Renal I can't access the link? Thank you for your explanation on decussation, that actually makes sense.

Saffie, thanks for your notes they're REALLY useful.

Reply 4

Renal

The picture is here; http://en.wikipedia.org/wiki/Image:Medulla_spinalis_-_tracts_-_English.svg

Or you can find it here.

Ignore the somatography - find out about the main tracts (in bold) first, then worry about the 'sub-tracts'.