Effectiveness of TTX in Promoting Anatomical Recovery from MD in Kittens

Abstract

Monocular deprivation (MD) during the critical period of visual development precipitates neuronal alterations in the dorsal lateral geniculate nucleus (dLGN) of kittens that include significant reduction in axon terminals and dendritic fields reflected by decreased neuron soma size within deprived layers. This thesis examined the effectiveness of binocular retinal inactivation to promote balanced anatomical recovery within eye-specific layers of the dLGN. After 7-days of MD, animals were intravitreally injected with tetrodotoxin (TTX) to abolish retinal activity. Neuron soma sizes were measured across increasing durations of binocular inactivation that extended to 10-days. The reduction in deprived neuron size produced by 7-days of MD was erased following 10-days of binocular inactivation. Although overall size of neurons was slightly reduced following retinal inactivation, balanced neuron size between eye-specific layers was restored to normal. Finally, neurons were considerably larger than those from animals subjected to the same period of monocular inactivation, indicating true recovery.