It is commonly assumed that the two-segmented input-output functions of the whole-nerve action potential are a result of the activity of two sets of primary fibers: A low- and a high-sensitivity group. While anatomical studies show the existence of two populations of fibers, there are no clear-cut electrophysiological signs of two distinct populations responding with different thresholds. in light of this physiological result, it is desirable to construct a scheme for the growth of the whole-nerve action potential that involves only one group of fibers. This can be done in a qualitative fashion by considering the.pattern of single-unit tuning curves and assessing the contribution of populations of units to the compound response. Thus the slowly growing low-level segment of the input-output function is identified with the sharp tip region of the tuning curves of the responding units, while the high-level, rapidly growing, segment is associated with the recruitment of higher-frequency units that respond on the tail segment of their tuning curves. Thus the low and high parts of the input-output functions are interpreted in terms of the excitation of narrow and wide segments of the cochlear receptor. Masking experiments that support the scheme are described.
ASJC Scopus subject areas
- Arts and Humanities (miscellaneous)
- Acoustics and Ultrasonics