About Our Research
■ Auditory System of Fruit Flies
- Genes, Neural Circuits, and Behaviors -
Hearing is an important sensory modality for most animals to detect sound as they mate, look for food, or fend off prey. We believe that the fruit fly, Drosophila melanogaster, is an ideal model organism for dissecting mechanisms underlying sound perception and evaluation in the brain, because of its small brain and a large variety of molecular and genetic tools available to visualize and manipulate neurons in a behaving animal. During courtship, fruit-fly males produce an acoustic signal, so-called the “love song”, which has a species-specific temporal pattern. This means that flies can discriminate sound patterns in the brain. We are trying to understand the neural mechanism how flies discriminate these acoustic signals, by establishing the comprehensive anatomical and functional map of the auditory neural circuit in the brain. So far, we have identified the primary auditory neurons and their downstream neural circuits in the brain. We have started to image the activity of these neurons and also to manipulate their activity to find a causal relationship between neurons and behaviors. We believe that our studies together are an essential path to understand the logic how the brain translates a given acoustic signal into meaningful information in a species-specific manner.
■ Neuroanatomy-Based Systems Neurobiology
In the fruit fly, anatomic identification of a novel neural circuit provides a direct avenue for its functional analysis, e.g., activity imaging by expressing calcium indicator proteins, loss-of-function analysis by expressing neural toxins, and gain-of-function analysis using optogenetics or temperature-activated cation channels. Given such genetic and experimental accessibility, the antennal ear of fruit flies and its downstream neural circuits clearly constitute attractive model systems to study the fundamental aspects of sensory processing and the multimodal integration related to these mechanical signals sensed by the ear. To discover general principles underlying how the species-specific sounds are represented and evaluated within the fly brain, we are exploring the structural and functional organization of the higher-order auditory neural circuits.