Nonselective Changes in Receptive Field Organization Induced by Laser Irradiation.

Abstract : Receptive field organization of cells in the turtle optic tectum are complexly organized without evidence of traditional center surround relationships. Chromatic bleaching has been conventionally used as one means of depicting the absorption spectra of underlying photopigments and their retinal interactions. Exposure of these cells to laser radiation, however, did not produce obvious spectrally selective losses. Laser light differs from incoherent light in two fundamental ways: its narrower bandwidth and its speckle pattern. Our experiments suggest that in tectal cells intense exposure to coherent light does not readily separate the underlying cone mechanisms but instead reveals some of the complexities of temporal, spatial, and chromatic interactions that can occur at higher levels of the visual pathways. Such mechanisms may be relevant to the kinds of effects observed in behavioral measures of spatial vision with non-human primates. Keywords: Laser; Irridation; Retinal interactions; Turtle optic tectum; Optical cone mechanisms; Spatial vision.