Question

how do convergence, receptive field size, acuity and cortical magnification relate?

Answer 1

The phenomenon of multiple sensory receptors that gives information to a smaller number of neural cells is referred to as convergence. The portion of sensory space which elicits the neural responses, when stimulated is referred to as the receptive filed. Visual acuity is nothing but a clarity of vision whereas the person will be able to recognize any small details with precision. Cortical magnification is the calculation whoich describes the number of neurons in the area of visual cortex which is responsible for processing a stimulus of a given size. If the same stimulus is seen in the periphery of the visual field (i.e. away from the center), it would be processed by a much smaller number of neurons.

The fundamental organization properties of the visual cortex are receptive field and cortical magnification factor. The receptive field size increases as the visual eccentricity increases. This relationship between the receptive field size and cortical magnification factor suggests the constancies in the corticalm architecture. The cortical representation of a receptive filed may be constant. A texhnique called fmri is used tom determine the relationship between the population receptive field and the cortical magnification factor. On an average of an individual data, the product of cortical magnification process and population receptive field, the population point image is constant.

The size of both Cortical magnification factor and receptive field vary systematically. This receptive filed is a property of individual nerons which describes the visual filed region, where the visual stimulation, elicits a response. In early visual cortex, neurons and their RFs are organized into visual field maps. Cortical Magnification factor is the cortical surface distance between the points that represents the visual field positions. Hence this explains the relationship between convergence, receptive field size, acuity and cortical magnification.