ABSTRACT
It is clearly apparent that multiple neural systems-each with its own specific type of receptor and nerve fiber-mediate the detection of tactile stimuli of varying vibratory frequency. Furthermore, it appears that the minimal neural requirement for detecting the stimulus is unique for each neural system in ways that reflect other characteristics of the system, such as the capacity for spatial and temporal summation in the PC system and the presence of spontaneous activity in the SA II system. However, the fundamental question remains: do these neural systems constitute the inputs to separate information-processing channels, which serve as building blocks in the construction of complex tactile perceptions? To answer this question, it is necessary to demonstrate experimentally that: (1) at early stages each system independently extracts information to which it is optimally tuned, and in so doing is uninfluenced by changes in the neural activity in other systems resulting from factors such as adaptation, masking, and sensation-magnitude enhancement by prior stimulation; and (2) by combining their separate information, the channels interact at later stages to construct complex perceptual representations of tactile stimuli.
