Abstract
The lateral geniculate nucleus (LGN) of the thalamus conveys visual information to the primary visual cortex. Because activity of LGN neurons is elicited by retinal inputs , amount of LGN activity is expected to represent strength of visual inputs. Thus, visual deprivation is assumed to decrease the LGN activity and induce experience-driven cortical plasticity in young animals. However, it is not clear whether neural activity of the LGN faithfully represents the input strength in awake condition. Therefore, we recorded neural activity in the LGN of behaving rats and examined the influence of visual environments on the LGN activity. Mean firing rate of some LGN neurons was significantly higher in normal light condition than in the dark, while the other neurons exibited similar or rather lower firing rate in the light condition. Thus, the rate of LGN firing does not necessarily reflect the amount of visual inputs. Auto- correlation analysis revealed oscillatory activities in a group of neurons, although we found no significant correlation between the oscillatory activities and the firing rate or light/dark conditions. We further explored the effect of visual deprivation on the firing characteristics of the LGN neurons. [J Physiol Sci. 2008;58 Suppl:S150]
