Question

1. Retinal ganglion cells located at the center of vision, in the fovea, have the smallest receptive fields and those located in the visual periphery have the largest receptive fields. The large receptive field size of neurons in the visual periphery explains the poor spatial resolution of our vision outside the point of fixation. Why is this true?

2. Principles in Sensory Systems”:

Transduction

Sensory Encoding

Neural Pathways

Receptive Fields

Topographic Maps

Pick one of the systems (taste, smell or auditory) and discuss how these five principles apply to that sensory modality.

Answer 1

Ans 1) The large receptive field size of neurons in the visual periphery is the reasons for the poor spatial resolution of our vision outside the point of fixation. It is because when there is large receptive neuron field size at low background intensities the contrast sensitivity function shows little bandpass behavior and hence there is little effect of the inhibitory surround. As the intensity of the background increases, there is a change in shape of the contrast sensitivity stimuli. When there is low mean level the neurons simply sums the quanta incident within the receptive field. With high mea level, the quanta is more abundant and this makes the spatial receptive field of the neuron more sensitive to the stimuli