Learning the relationship between biosonar pulse trains and peripheral dynamics in hipposiderid bats

Abstract

The biosonar system of hipposiderid bats is characterized by a peripheral dynamics consisting of variable noseleaf and pinna motions as well as temporal variability in the emitted pulse trains. It may be hypothesized that a well-integrated biosonar emission system should coordinate noseleaf and pinna motions with the biosonar pulse trains if this leads to synergistic effects. To investigate whether a relationship between these two sources of variability in the emission system of hipposiderid bats exists, a data set with high-speed stereo video recordings of noseleaf and pinna motions that were synchronized with ultrasonic recordings of the biosonar pulses has been analyzed. Different similarity metrics that were developed for analyzing neural spike sequences have been tested for comparing the individual biosonar pulse trains. Based on these metrics, pulse trains were clustered and the results were compared to the different categories of noseleaf and pinna motions that were found in the video recordings. The results obtained so far for 80 recorded sequences show that noseleaf/pinna motions and pulse trains can be organized into joint clusters, i.e., certain categories of peripheral motions cluster with specific types of biosonar pulse trains. These links could indicate a synergistic relationship between noseleaf/pinna motions and pulse timings.The biosonar system of hipposiderid bats is characterized by a peripheral dynamics consisting of variable noseleaf and pinna motions as well as temporal variability in the emitted pulse trains. It may be hypothesized that a well-integrated biosonar emission system should coordinate noseleaf and pinna motions with the biosonar pulse trains if this leads to synergistic effects. To investigate whether a relationship between these two sources of variability in the emission system of hipposiderid bats exists, a data set with high-speed stereo video recordings of noseleaf and pinna motions that were synchronized with ultrasonic recordings of the biosonar pulses has been analyzed. Different similarity metrics that were developed for analyzing neural spike sequences have been tested for comparing the individual biosonar pulse trains. Based on these metrics, pulse trains were clustered and the results were compared to the different categories of noseleaf and pinna motions that were found in the video recordings. T...