Dear Colleagues:
The paper below has just been published in JEB:
Songhai Li, Paul E. Nachtigall and Marlee Breese. 2011. Dolphin hearing during
echolocation: evoked potential responses in an Atlantic
bottlenose dolphin (Tursiops truncatus). The Journal of Experimental Biology
214, 2027-2035. doi:10.1242/jeb.053397
SUMMARY
Auditory evoked potential (AEP) responses were recorded during echolocation in
an Atlantic bottlenose dolphin (Tursiops
truncatus) trained to accept suction-cup EEG electrodes and detect targets by
echolocation. AEP recording was triggered by the
echolocation clicks of the animal. Three targets with target strengths of –34,
–28 and –22dB were used at a target distance of 2 to
6.5m for each target. The results demonstrated that the AEP appeared to both
outgoing echolocation clicks and echoes during
echolocation, with AEP complexes consisting of alternative positive and
negative waves. The echo-related AEP amplitudes were
obviously lower than the outgoing click-related AEP amplitudes for all the
targets at the investigated target distances. However,
for targets with target strengths of –22 and –28dB, the peak-to-peak
amplitudes of the echo-related AEPs were dependent on the
target distances. The echo-related AEP response amplitudes increased at further
target distances, demonstrating an
overcompensation of echo attenuation with target distance in the
echo-perception system of the dolphin biosonar. Measurement
and analysis of outgoing click intensities showed that the click levels
increased with target distance (R) by a factor of
approximately 10 to 17.5logR depending on target strength. The results
demonstrated that a dual-component biosonar control
system formed by intensity compensation behavior in both the transmission and
receiving phases of a biosonar cycle exists
synchronously in the dolphin biosonar system.
If anybody is interested in getting a pdf copy, please email Dr. Songhai Li at
[email protected]
Aloha
Songhai
2011-05-25
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Songhai LI, Ph.D
http://www2.hawaii.edu/~songhai/
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