TY - JOUR

T1 - The Adjustment of Echo Pulses Reflected from Objects Located at Different Distances to the Auditory Sensitivity of Dolphins

T2 - Model Studies

AU - Rimskaya-Korsakova, L. K.

AU - Rodionov, A. A.

AU - Ivanov, M. P.

N1 - Publisher Copyright: © 2021, Pleiades Publishing, Inc.

PY - 2021/3

Y1 - 2021/3

N2 - Dolphins emit a probing pulse and receive an echo pulse for echolocation during hunting, on the basis of which they detect and identify their prey in the search phase. In the capture phase, dolphins require a stable auditory response to the echo pulse. To explain the features of the perception of echo pulses in the search and capture phases, the pulse-induced response of an ensemble of high-frequency peripheral fibers was modeled. A pair of pulses with center frequencies of 70 kHz, different inter-pulse intervals and peak amplitudes was a model of a probing pulse and an echo pulse. The pulses entered the model at different processing steps, including the transformation of the receptor potential of inner hair cells into a sequence of action potentials of an ensemble of auditory nerve fibers. It was shown that in order to reproduce the temporal structure of the pulses in the ensemble response, the resulting receptor potential must correspond to the response thresholds of most of the ensemble fibers. At short intervals between pulses in a pair, the reproduction of the temporal structure of the second pulse (echo pulse) was facilitated by an increase in the response thresholds of the fibers of the ensemble due to the refractory properties caused by the action of the first pulse (probe pulse model). At large intervals between pulses in a pair, variations in the peak amplitudes of the first pulse (probing pulse models) could be responsible for the reproduction of the structure of the second pulse (echo pulse). It was shown that the modeling is a convenient means to identify different ways of the adjustment of echo pulses to the auditory sensitivity of dolphins in the phases of searching for and capturing prey.

AB - Dolphins emit a probing pulse and receive an echo pulse for echolocation during hunting, on the basis of which they detect and identify their prey in the search phase. In the capture phase, dolphins require a stable auditory response to the echo pulse. To explain the features of the perception of echo pulses in the search and capture phases, the pulse-induced response of an ensemble of high-frequency peripheral fibers was modeled. A pair of pulses with center frequencies of 70 kHz, different inter-pulse intervals and peak amplitudes was a model of a probing pulse and an echo pulse. The pulses entered the model at different processing steps, including the transformation of the receptor potential of inner hair cells into a sequence of action potentials of an ensemble of auditory nerve fibers. It was shown that in order to reproduce the temporal structure of the pulses in the ensemble response, the resulting receptor potential must correspond to the response thresholds of most of the ensemble fibers. At short intervals between pulses in a pair, the reproduction of the temporal structure of the second pulse (echo pulse) was facilitated by an increase in the response thresholds of the fibers of the ensemble due to the refractory properties caused by the action of the first pulse (probe pulse model). At large intervals between pulses in a pair, variations in the peak amplitudes of the first pulse (probing pulse models) could be responsible for the reproduction of the structure of the second pulse (echo pulse). It was shown that the modeling is a convenient means to identify different ways of the adjustment of echo pulses to the auditory sensitivity of dolphins in the phases of searching for and capturing prey.

KW - auditory nerve fibers

KW - Keywords: echolocation

KW - peripheral coding

KW - reproduction of the temporal structure of echo pulses

UR - http://www.scopus.com/inward/record.url?scp=85109133509&partnerID=8YFLogxK

U2 - 10.1134/S0006350921020172

DO - 10.1134/S0006350921020172

M3 - Article

AN - SCOPUS:85109133509

VL - 66

SP - 316

EP - 326

JO - Biophysics (Russian Federation)

JF - Biophysics (Russian Federation)

SN - 0006-3509

IS - 2

ER -