This project is directed at understanding the mechanisms of postnatal development of neural processing of visual information from the retina through the thalamus and the structural development of retinal ganglion cells. The specific objectives are i) to evaluate the neurophysiological transfer function of visual signals from the retina to the dorsal lateral geniculate nucleus (LGNd) in kitten in vivo and, ii) to describe and model the rules that control retinal ganglion cell (RGC) shape, morphological class and spatial distribution in vitro. In the first series of experiments, electrophysiological recordings of manifestation of the dominant RGC drive to an LGNd neuron (the S- potential) will be extracellularly recorded concomitantly with the LGNd neurons' action potentials in response to visual stimulit which objectively evaluate the neuronal pairs' contrast sensitivity function. This experiment will directly evaluate the hypothesis of increased functional convergence in the neonatal X- cell pathway (and functioal degradation of spatial processing). In the second series of experiments, identified postnatal kitten RGCs are grown in cell culture for several weeks. Individual neurons and ensembles are monitored in real-time with digitization of time-lapsed images. Development of cellular morphology and establishment of neuronal territories are analyzed with the mathematical measure of fractal sets - the Hausdorff measure.
