Somatosensory System
In the somatosensory system, receptive fields are regions of the skin or of internal organs. Some types of mechanoreceptors have large receptive fields, while others have smaller ones.
Large receptive fields allow the cell to detect changes over a wider area, but lead to a less precise perception. Thus, the fingers, which require the ability to detect fine detail, have many, densely packed (up to 500 per cubic cm) mechanoreceptors with small receptive fields (around 10 square mm), while the back and legs, for example, have fewer receptors with large receptive fields. Receptors with large receptive fields usually have a "hot spot", an area within the receptive field (usually in the center, directly over the receptor) where stimulation produces the most intense response.
Tactile-sense-related cortical neurons have receptive fields on the skin that can be modified by experience or by injury to sensory nerves resulting in changes in the field's size and position. In general these neurons have relatively large receptive fields (much larger than those of dorsal root ganglion cells). However, the neurons are able to discriminate fine detail due to patterns of excitation and inhibition relative to the field which leads to spatial resolution.
Read more about this topic: Receptive Field
Famous quotes containing the word system:
“Short of a wholesale reform of college athletics—a complete breakdown of the whole system that is now focused on money and power—the women’s programs are just as doomed as the men’s are to move further and further away from the academic mission of their colleges.... We have to decide if that’s the kind of success for women’s sports that we want.”
—Christine H. B. Grant, U.S. university athletic director. As quoted in the Chronicle of Higher Education, p. A42 (May 12, 1993)