Our sense of smell attracts us to substances we need, such as food, and repels us from rotting or poisonous matter that is hazardous. How molecules entering your nose can affect behaviour is a puzzle that’s slowly being pieced together. In experiments on fruit flies (also known as vinegar flies), scientists found that smell information is processed in part of the brain called the lateral horn, which has three main areas of activity. One area (here false coloured green) deals with attractive odours, another (yellow) repulsive odours and the third (magenta) is thought to be responsible for odour identification. By disrupting nerve impulses in these areas, the flies were tricked into changing behaviour, even avoiding a favourite food, balsamic vinegar. The function of the lateral horn is similar to the amygdala in the human brain – so the study of flies is not to be sniffed at!
Written by Mick Warwicker
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