The lateral geniculate nucleus (LGN) provides the primary route by which retinal inputs ascend to visual Icortex to become our visual perceptions. Because the receptive field properties of LGN neurons are so similar to the retinal counterpart, the LGN was viewed as a relay of retinal information. However, it is a complicated relay appearing to serve a number of functions, and its significance in the context of understanding vision is obscure. This project is concerned with elucidating these functions by measuring retinogeniculate transmission in the awake, behaving monkey. Our logic is that if we can quantitatively characterize both the retinal input providing the major drive to the LGN neuron as well as the LGN neuron itself, we can gain insight into LGN function in vision. Of particular interest are the efficacy and temporal dynamics of retinogeniculate transmission in an animal inspecting its environment. We will characterize the basic receptive field characteristics of retina and LGN neurons, and then record from the neuron as the monkey views brief videos. Since we can reconstruct the pattern of stimulation to the retina, as well as the distribution of spikes in the retina and LGN, we can measure the coding efficiency of each, and the degree to which saccades influence coding efficiency. Such records will also enable us to measure the relative """"""""sparseness"""""""" of retina and LGN activity. The results of this project will provide novel information for understanding the functional significance of the LGN in vision, and it will be appropriately done in an awake, behaving, perceiving primate. ? ?
