title: Receptive field characteristics of neurones in striate cortex of newborn lambs and adult sheep.
abstract: The properties of cells of the striate visual cortex (V1) have been studied in the normal adult sheep and in new-born lambs without visual experience, the majority of cells in the lamb are orientation specific, but 20% are non-oriented compared to only 3% cells in the adult. In the lamb there was little or no facilitation of binocularly-driven cells by simultaneous stimulation of both receptive fields. Cells which responded only to binocular stimulation of particular disparities ('obligate binocular' cells) were rarely encountered. In the adult, 15% of the sample were obligate binocular cells and a further 28% showed binocular facilitation. Simple and complex receptive fields were found in similar proportions in both new-born lambs and adult sheep. End-stopped cells comprised 17% of the sample in adults but only 2% in the lambs. Direction sensitive cells were found more frequently in the sheep (21% of cells) than in the lamb (4% of cells). It is concluded that facilitatory processes in binocular cells and inhibitory mechanisms generally, seem much less developed in the lamb.
mesh_terms: D000818:Animals; D000831:Animals, Newborn / Q000502:physiology*; D007839:Functional Laterality; D009474:Neurons / Q000502:physiology*; D009799:Ocular Physiological Phenomena; D010775:Photic Stimulation; D012756:Sheep / Q000502:physiology*; D014793:Visual Cortex / Q000166:cytology / Q000502:physiology*; D014794:Visual Fields