Meeting Abstract
Animal flight stability can be attributed to the rapid control mediated by mechanosensory feedback. In insects, this control involves reflexive changes in airframe configuration for redirection of lift forces. There is ample proof that visual stimuli drive this active control of the abdomen including morphological evidence that sensory hair plates are distributed in critical regions around abdominal joints. However, the neural encoding of this crucial sensory system remains poorly understood. To explore encoding properties of abdominal mechanosensors in the hawkmoth Manduca sexta, we delivered white noise mechanical stimuli to the abdomen-thorax joint and recorded extracellular neural responses from the ventral nerve cord. We used spike-sorting analyses to identify the single neural units and further extracted the stimulus features that most likely generate action potentials. We identified the spike triggered average (STA) which represents the average motion stimulus that generates spikes. We found that the abdomen-thorax joint indeed contains units which respond rapidly (5 – 10 ms) and preferentially to a certain feature in the stimulus. We were also able to determine the specificity to the STA by calculating the probability of spike generation given the STA and found that units fire not only with high temporal precision, but also high fidelity to a stimulus feature. Taken together these results show that there is neural evidence for mechanosensory information from the abdomen to modulate insect flight dynamics. These results demonstrate the presence of ubiquitous encoding properties across many taxa and mechanosensory structures, including halteres, wings, antennae as well as the abdomen
