How the brain processes sounds
Sound is a common form of communication in many species, ranging from the very simple, like the fruit fly, to the very complex, like humans. To date, no research has characterised the nerves involved in processing sounds in the brain, for any animal. The EU-funded 'Auditory processing in insect brains' (AUDITORYFLY) project set out to identify the nerves involved in sound processing in fruit flies (Drosophila melanogaster). Fruit flies are commonly used as a model system to study brain physiology. Project members used advanced electrophysiological techniques to examine individual neurons' responses to auditory stimulation — in this case, the male fruit fly courtship call. Researchers identified 11 types of fruit fly brain neurons that responded to courtship sounds, nine of which had not previously been associated with sound processing. The neurons responded in different ways to the stimulation. Some transmitted strong electrical signals to other neurons, while others only showed small cellular changes. In addition, some produced sustained electrical signals, while in others there was a short burst of activity. Finally, the team constructed a model of the nerve circuits involved in processing the auditory signal. As AUDITORYFLY has mapped the nerves involved in this process for the first time, the project has paved the way for more complex studies.
Keywords
Brain, sounds, brain circuits, understanding sounds, communication, auditory processing, insect brains, sound processing, fruit flies, brain physiology, auditory stimulation, neurons