01725nas a2200181   4500008004100000022001400041245010400055210006900159260001600228300001600244490000800260520114100268100002201409700002001431700002101451700002001472856005101492       2018                        eng d  a0001-496600aResponses of the auditory system of odontocetes to level changes of long lasting acoustical stimuli0 aResponses of the auditory system of odontocetes to level changes  cJan-09-2018  a1741 - 17410 v1443 a<p>The effects of level changes of long lasting sound stimuli (tone pip trains) on evoked potentials (the rate following response, RFR) were investigated in a beluga whale (Delphinapterus leucas). The stimuli were of 64 kHz carrier frequency at levels from 80 to 140 dB re 1 &mu;Pa. During stimulation, the stimulus level either was kept constant (the steady-state stimulation) or was changed up/down by 20 or 40 dB every 1000 ms. After transition from a lower to upper stimulus level (increase), the response amplitude increased quickly and then decayed slowly. After transition from an upper to lower stimulus level (decrease), the response amplitude fell quickly and later recovered slowly. In the both cases, during the 1000 ms stimulus, the response amplitude almost reached that of the steady-state stimulus of the same level. The auditory system of the beluga (and, hypothetically, other odontocetes) may be characterized as quickly flexible and capable of quick adjustment of its responses to the current auditory scene. [This study was supported the Russian Science Foundation (Project No. 17-74-20107) awarded to E.V.S.]</p>
1 aSysueva, Evgeniya1 aNechaev, Dmitry1 aSupin, Alexander1 aPopov, Vladimir  uhttp://asa.scitation.org/doi/10.1121/1.5067719