The central thalamus tracks attentional fluctuations in humans

<title>Abstract</title> <p>Moment-to-moment fluctuations in sustained attention impair goal-directed behaviour. Although distributed cortical networks support attentional control, the contribution of subcortical electrophysiology remains poorly understood. As a key regulator of arousal and consciousness, the central thalamus is ideally positioned to support sustained attention, but direct evidence in humans remains scarce. Here we leveraged rare intracranial recordings from the centromedian (CM) nucleus of the thalamus in children with epilepsy, a population predisposed to attention deficits. During an attentional set-shifting task, we identified a robust CM event-related potential (ERP) following trial onset, arising temporally between two canonical scalp ERPs (N1 and P2) measured concurrently. Across all task conditions, larger thalamic ERP amplitudes predicted faster trial-by-trial reaction times, whereas ERP amplitudes progressively declined with time-on-task, paralleling behavioural slowing. Together, these findings demonstrate that central thalamic responses predict moment-to-moment behavioural performance, providing direct human evidence that the central thalamus contributes to the neural processes underlying fluctuations in sustained attention.</p>