Nerve growth factor treatment prevents dendritic atrophy and promotes recovery of function after cortical injury

This study examined the behavioural and anatomical effects of intraventricular injections of nerve growth factor in rats with unilateral damage that included Zilles' areas Fr1, FL, HL, Par1 and the anterior portion of Oc2. Nerve growth factor-treated lesion rats showed attenuation of behavioural symptoms in measures of forelimb function (Whishaw reaching task) and hindlimb function (beam traversing task) as well as a measure of spatial navigation (Morris water task). Analysis of dendritic arborization using a modified Golgi–Cox procedure also showed a complete reversal of lesion-induced atrophy of dendritic fields in pyramidal neurons in motor (Zilles' Fr2) and cingulate (Zilles' Cg1) cortex. In addition, there was a reversal of a lesion-induced reduction in spine density. These results demonstrate that nerve growth factor treatment can facilitate functional recovery from cortical injury. This recovery may be mediated by a reorganization of intrinsic cortical circuitry that is reflected in changes in dendritic arborization and spine density of pyramidal neurons.