Relationship between preferred orientation and receptive field position of neurons in cat striate cortex

Abstract

It has been known for two decades that neurons in mammalian visual cortex respond selectively to stimuli falling on the retina at a particular angular orientation (Hubel and Wiesel, '62). Recent evidence suggests that most cat retinal ganglion cells (Levick and Thibos, '82) and relay cells (Vidyasagar and Urbas, '82) in the cat's dorsal lateral geniculate nucleus are also orientation selective. In the retina there is a systematic relationship between receptive field position (polar angle) and preferred orientation. Outside of the area centralis, most retinal ganglion cells have oriented dendritic fields (Leventhal and Schall, '83) and respond best to stimuli oriented radially, i.e., oriented parallel to the line connecting their receptive fields to the area centralis (Levick and Thibos, '82). This relationship is strongest close to the horizontal meridian (the visual streak) of the retina (Leventhal and Schall, '83). To determine if a relationship between preferred orientation and polar angle exists in visual cortex, the preferred orientations and receptive field positions of 768 striate cortical neurons were studied. As in the retina, a systematic relationship exists between preferred orientation and visual field position in area 17. In parts of striate cortex 15–80° from the area centralis projection there is a strong tendency for cells to respond best to lines oriented radially. In regions 4–15° from the area centralis projection this relationship appears weaker. In regions subserving the central 4° of visual angle no such relationship exists. Throughout area 17 the relationship between preferred orientation and polar angle is strongest in regions subserving the horizontal meridian. It is suggested that the systematic relationship between preferred orientation and polar angle which begins in the retina provides an intrinsic framework for the organized arrangement of orientation “columns” in visual cortex (Hubel and Wiesel, '63). This relationship may also be responsible for the “oblique effect” as well as the visual system's preferential response to radially oriented gratings (Rovamo et al.,'82).