They carry information between brain and body (6)
I believe the answer is:
nerves
'they carry information between brain and body' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for nerves that I've seen before include "They connect the brain with other parts of the body" , "Bodily fibres carrying impulses of sensation" , "Bodily fibres that convey sensations" , "Fibres carrying impulses around the body" , "Feelings of angst" .)