All are true about Substantia nigra except:-
Substantia nigra is the pigmented sheet of nerve cells between the tegmentum and crus cerebri of mid brain It extends from the cranial border of Pons to sub thalamic region. It consists of dorsal pigmented and compact pa known as pars compacta (cell rich zone) and ventral less pigmented reticular pa known as pars reticularis (cell poor zone). Neurons of pars compacta are rich in melanin and those of pars reticularis are rich in iron. Afferents:- From the caudate nucleus and putamen as Strio-nigral fibers. These fibers convey Gama Amino Butyric Acid (GABA) to pars reticularis and exe inhibition in neuro transmission. Efferents:- They are Nigro-striate fibers from pars compacta to caudate nucleus and putamen. They are rich in dopamine which on reaching the neurons of striatum inhibits the excitation of later and prevent tremor and other involuntary acts.
Pars compacta is rich in melanin
Pallor of substantia nigra indicates Parkinsonism
Afferents are derived from caudate nucleus
Efferent fibers are rich in GABA
Neuroanatomy, Head and Neck