Auditory cortex of newborn bats is prewired for echolocation

Area of Science:

• Neuroscience
• Auditory Neuroscience
• Sensory Processing

Background:

• Echolocating bats navigate and hunt using object distance calculations based on echo delay.
• Neurons in the dorsal auditory cortex respond to specific call-echo combinations, aiding target range calculation.
• The developmental origin (innate vs. experience-dependent) of these neuronal circuits remains unclear.

Purpose of the Study:

• To investigate whether the neuronal computation of object distance in bats is innate or learned.
• To determine if functional circuits for distance calculation exist in the dorsal auditory cortex before the onset of echolocation and flight.

Main Methods:

• Electrophysiological recordings in the dorsal auditory cortex of bats during the first postnatal week.
• Presentation of simulated auditory stimuli mimicking emitted calls and delayed echoes.
• Analysis of neuronal responses to varying temporal separations between simulated pulse and echo.

Main Results:

• Functional circuits capable of calculating distance from temporal separation were identified in the dorsal auditory cortex.
• These circuits were present before the bats began echolocating or flying.
• The study demonstrates an innate computational mechanism for sonar ranging.

Conclusions:

• The dorsal auditory cortex possesses innate mechanisms for calculating object distance from echo delay.
• This innate ability likely enhances the survival of juvenile bats during their initial flights and echolocation behaviors.
• Experience-dependent plasticity may further refine this crucial sensory computation later in development.