Impaired low-frequency temporal prediction links to psychomotor dysfunction in depression.

Major depressive disorder (MDD) exhibits psychomotor retardation which concerns abnormal slowness of both thoughts and movements. While traditionally viewed as a motor deficit, the underlying cognitive mechanisms remain unclear. Here, we investigated whether psychomotor disturbance in MDD reflects a disruption of temporal prediction, a cognitive capacity whereby the motor system provides predictive timing signals to sensory regions. We tested MDD subjects' (N = 38) ability to synchronize finger taps to rhythmic tone sequences across multiple temporal frequencies, compared with healthy controls (N = 65). Critically, we found frequency-specific desynchronization: timing between finger taps and tones was altered in MDD mainly at low frequencies below 1 Hz-the range corresponding to the motor system's natural delta rhythm-while basic motor functions (tapping speed, stability, interval) remained intact. This low-frequency auditory-motor desynchronization correlated with depression severity and specifically with psychomotor anhedonia and vegetative symptoms. Our findings reveal that psychomotor retardation in MDD involves impaired temporal prediction at slow timescales, suggesting dysfunction in motor-to-sensory predictive signaling rather than motor execution per se. This supports a cognitive and therefore psychomotor, rather than purely motor, mechanism underlying psychomotor symptoms in depression, with implications for the role of motor-based temporal prediction networks in mood disorders.