(Company of Biologists, 2018-11-26)
Cardinal, Emily A.; Radford, Craig A.; Mensinger, Allen F.
Male oyster toadfish (Opsanus tau) acoustically attract females to
nesting sites using a boatwhistle call. The rapid speed of sound
underwater combined with the close proximity of the otolithic organs
makes inner ear interaural time differences an unlikely mechanism to
localize sound. To determine the role that the mechanosensory lateral
line may play in sound localization, microwire electrodes were
bilaterally implanted into the anterior lateral line nerve to record
neural responses to vibrational stimuli. Highest spike rates and
strongest phase-locking occurred at distances close to the fish and
decreased as the stimulus was moved further from the fish. Bilateral
anterior lateral line neuromasts displayed differential directional
sensitivity to incoming vibrational stimuli, which suggests the
potential for the lateral line to be used for sound localization in the
near field. The present study also demonstrates that the spatially
separated neuromasts of the toadfish may provide sufficient time
delays between sensory organs for determining sound localization
cues. Multimodal sensory input processing through both the inner ear
(far field) and lateral line (near field) may allow for effective sound
localization in fish.