Interactive effects of deafferentation and target removal on cell death in the parabigeminal nucleus of developing rats.

This study was designed to test the effects of simultaneous deafferentation and target removal on cell death in the parabigeminal nucleus. Bilateral lesions of the superior colliculus were made in newborn rats and neuron death was evaluated in the dorsal (PBd), middle (PBm) and ventral (PBv) divisions of the nucleus. When the results of the bilateral lesions were compared with the effects of unilateral lesions reported in a previous study simultaneous deafferentation and target removal were found to produce an increase in the rate of cell death greater than, and with a time course differing from that, predicted by the sum of the separate effects of removal of afferents or targets. These data suggest that the trophic effects of afferents and targets interact during the period of naturally occurring cell death.