All are true about Decerebrate posture except:-
Extension of both upper and lower extremity
Flexion of upper extremity and extension of lower extremity
Exaggerated gamma motor neuron discharge
Reticulo spinal tract is also involved
Decerebrate rigidity: When brain stem of animal is sectioned below midlevel of mesencephalon but pontine & medullary reticular systems as well as vestibular system are intact, this is decerebrate animal This results in rigidity of antigravity muscles a muscles of neck & trunk & extensors (i.e all extensors go into spasm) This decerebrate rigidity is due to blockage of normally strong input to medullary reticular nuclei from cerebral coex, Red nuclei & the basal ganglion. Lacking this input, medullary reticular inhibitor system becomes nonfunctional, full overactivity of pontine excitatory system occurs & rigidity develops. (Due to exaggerated gamma motor neuron discharge) Decoicate rigidity: Thick layer of coex is removed & all other structures are preserved. This results in decoicate rigidity a flexors of upper limb & extensors of lower limb goes into spasm (flexion).
NEET 2019