Neurophysiological and morphological techniques were used to describe changes in the optic tract and superior colliculus (SC) in response to monocular enucleation. Long-Evans, male, (250g) rats were implanted with chronic bipolar stimulating electrodes located in the optic chiasm and a recording electrode located below the stratum griseum superficiale (SGS) and referenced to a skull screw electrode. In rats with satisfactory electrode placements (n=17), peaks corresponding to rapidly conducting presynaptic activity (Pre), rapidly conducting postsynaptic activity (Nl), and slowly conducting postsynaptic activity (P3), were identified according to peak latency, polarity, stimulation threshold, and resistance to 100 Hz stimulation. These peaks diminished differentially over a seven day (D1-7) post-enucleation period. Those peaks reflecting rapidly conducting axons (i.e., Pre, N1) decayed by D2, whereas those reflecting slowly conducting axons (i.e., P3) persisted until D4 and completely decayed by D7.