Spine density on neostriatal neurones changes with 6-hydroxydopamine lesions and with age.

Golgi-impregnated medium-size spiny neurones were studied in the rat neostriatum at various times after a unilateral 6-hydroxydopamine lesion of the medial forebrain bundle. At both short (12-26 days) and long (7-12 months) survival times, the density of spines was significantly lower (13%) on neostriatal neurones ipsilateral to the 6-hydroxydopamine injection. At longer times the density of spines was lower on neurones both ipsilateral and contralateral to the lesion when compared to neurones taken from short-term animals (23%).