The personalized auditory cortex of the mustached bat: adaptation for echolocation

Area of Science:

• Neuroscience
• Bioacoustics
• Animal Communication

Background:

• The mustached bat (Pteronotus parnellii) uses biosonar signals for echolocation.
• The constant-frequency component of the second harmonic (CF2) of these signals varies among individuals.
• Understanding individual variation in biosonar is crucial for deciphering auditory processing.

Purpose of the Study:

• To investigate the individual variation and sexual dimorphism in the CF2 resting frequency of mustached bat biosonar.
• To examine the relationship between individual CF2 resting frequency and the tonotopic representation in the auditory cortex's DSCF area.
• To explore the implications of this relationship for auditory processing and echolocation efficiency.

Main Methods:

• Measurements of CF2 resting frequencies in male and female mustached bats.
• Electrophysiological recordings in the DSCF area of the auditory cortex.
• Analysis of tonotopic maps in relation to individual CF2 resting frequencies.

Main Results:

• Significant individual variation in CF2 resting frequency (59.69–63.33 kHz) was observed.
• Male bats exhibited lower CF2 resting frequencies than females, indicating sexual dimorphism.
• A unique, personalized tonotopic representation was found in the DSCF area, matching each bat's CF2 resting frequency.
• This personalized auditory cortex overrepresents frequencies crucial for Doppler-shift compensation.

Conclusions:

• The mustached bat's biosonar orientation sound is sexually dimorphic.
• The auditory cortex is "personalized" to individual bats' biosonar frequencies, acting as a unique signature.
• This personalization enhances insect detection and reduces interference from other bats' echolocation signals.
• The tonotopic representation in the auditory cortex is also sexually dimorphic, reflecting the dimorphic biosonar.