Prediction of optimal auditory signals using auditory evoked magnetic responses

• We looked for an auditory signal that was easy to identify using brain responses.
• The songs of the Cuckoo produced the largest brain response.
• The songs of the Oriental Scops Owl correlated best with the brain response.
• The Cuckoo and Oriental Scops Owl songs are candidates for optimal auditory signals.

Birdsong is often used as an auditory signal for visually-challenged people in public spaces in Japan. However, more than 40% of visually-challenged people reported that such auditory signals were difficult to identify. We used auditory evoked magnetic field (AEF) responses in the human auditory cortex to uncover an auditory signal that was easy to identify. As an auditory signal, we focused on birdsong, which is currently used to inform passengers about the location of stairs in train stations in Japan. We presented birdsongs to participants in silent, noisy, reverberated, and interaural time-delay conditions. We analyzed the most prominent AEF response, N1m, and the correlation between the birdsong envelopes and the AEF. We found that the N1m amplitudes were maximal when the participants listened to the song of the Cuckoo and the above-mentioned correlation was maximal when the participants listened to the song of the Oriental Scops Owl. Thus, we believe the songs of the Cuckoo and Oriental Scops Owl to be candidates for optimal auditory signals.