Function of internal clock neurons in fruit flies

Evidence suggests that two groups of lateral neurons in Drosophila respond differently to light, leading to distinct morning and evening activity rhythms.

• Drosophila exhibits bimodal activity rhythms with morning and evening bouts.
• Two groups of lateral neurons are proposed to act as oscillators for these activity rhythms.
• These neuronal groups can be desynchronized by constant light exposure.
• A long-period activity component originates from the evening peak.
• A short-period activity component is not solely derived from the morning peak but is more prominent from the evening peak.
• This finding challenges the original model of mutually coupled oscillators governing circadian rhythms.

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