A suprachiasmatic-independent circadian clock(s) in the habenula is affected by Per gene mutations and housing light conditions in mice

Circadian expression of clock genes was observed in the lateral habenula of wild-type mice under constant darkness conditions.

• The lateral habenula shows circadian features, but its clock properties are not fully understood.
• In double Per1-Per2 clock-mutant mice, circadian gene expression in the habenula is disrupted.
• Self-sustained oscillatory activity was detected in the rostral and caudal parts of the habenula of SCN-ablated mice.
• Under constant darkness or in SCN-lesioned mice, the rostral and caudal habenula regions exhibited out-of-phase oscillations.
• The integrity of circadian genes is necessary for the autonomous clock in the habenula to function properly.

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