Action Enhances Acoustic Cues for 3-D Target Localization by Echolocating Bats

Abstract

Under natural conditions, animals encounter a barrage of sensory information from which they must select and interpret biologically relevant signals. Active sensing can facilitate this process by engaging motor systems in the sampling of sensory information. The echolocating bat serves as an excellent model to investigate the coupling between action and sensing because it adaptively controls both the acoustic signals used to probe the environment and movements to receive echoes at the auditory periphery. We report here that the echolocating bat controls the features of its sonar vocalizations in tandem with the positioning of the outer ears to maximize acoustic cues for target detection and localization. The bat’s adaptive control of sonar vocalizations and ear positioning occurs on a millisecond timescale to capture spatial information from arriving echoes, as well as on a longer timescale to track target movement. Our results demonstrate that purposeful control over sonar sound production and reception can serve to improve acoustic cues for localization tasks. This finding also highlights the general importance of movement to sensory processing across animal species. Finally, our discoveries point to important parallels between spatial perception by echolocation and vision.

Modified synaptic dynamics predict neural activity patterns in an auditory field within the frontal cortex

“…This could explain why responses from frontal neurons are less reliable than those of cortical neurons when tested with simple stimuli such as the pure tones used in this study. The reliability of neuronal responses could increase during active behaviour (i.e., echolocation), which involves a set of variables such as attention, and the build‐up of expectations based on previous sensory history (Feng & Ratnam, ; Wohlgemuth, Kothari, & Moss, ). The roles of these variables are much diminished in experiments conducted in anaesthetized, passively listening animals (this study).…”

Cortical neurons of bats respond best to echoes from nearest targets when listening to natural biosonar multi-echo streams

“…Different behavioral adjustments can change the sensory world that bats are facing or perceiving. During call emission, the animals can variably adjust their sonar beam49 and the echo perception can be influenced through motor behaviors of the head or the pinnae4950. A recent study on insect-eating bats demonstrated that, while hunting, the bats shift their sonar beam and flight path towards the second prey before capturing the immediate prey which increases the capture rate51.…”

Precision of auditory responses deteriorates on the way to frontal cortical areas

“…The reliability of neuronal responses could increase during active behavior (i.e. echolocation), which involves a set of variables such as attention, and the build-up of expectations based on previous sensory history (Feng & Ratnam, 2000; Wohlgemuth et al , 2016). The roles of these variables is much diminished in experiments conducted in anesthetized, passively listening animals (this study).…”