Altered circadian rhythmicity is an early sign of murine dietary thiamine deficiency.

To determine if circadian clock function is affected by thiamine deficiency, the rhythm of locomotor (wheel-running) activity was measured in a murine model of dietary thiamine deficiency. About 1 month before the expected onset of overt neurological illness, locomotor rhythmicity in deficient animals exhibited a shortened free-running period without a change in amplitude. This effect was fully reversible by thiamine administration. Disordered circadian timekeeping may contribute to altered physiological responses in Wernicke's encephalopathy.