Biochemical plasticity in the superior colliculus of adult rats after chronic visual cortex ablation

We have measured the changes of several neurochemical parameters in the adult rat superior colliculus (SC) 1.5-4 months after unilateral visual cortex ablation. High-affinity uptake of D-[3H]Asp was increased by 22.5% and glutamate decarboxylase by 10% in the ipsilateral SC. This may be largely attributed to reactive synaptogenesis of intrinsic glutamatergic and GABAergic neurons, respectively. The noradrenaline content was increased by about 60 and 25% in the ipsi- and contralateral SCs, respectively. The latter probably reflects sprouting of noradrenergic fibres from the locus coeruleus.