Prolonged survival of axons terminating within lesions of cat visual cortex.

It is well known that brain lesions made by the injection of ibotenic acid destroy neuronal cell bodies but do not kill passing axons. We have found that axons terminating within such lesions in visual cortex also survive for at least 2 months, despite the absence of available synaptic sites. We made tracer injections in area 17, and observed dense patches of anterograde label within lesions in other visual cortical areas. Furthermore, because the retinotopic site of the tracer injection was known, we could conclude that the retinotopic site was encompassed within the lesion.