Excitability of the corneal reflex in man

The corneal reflex evoked by electrical stimulation of the corneal mucosa and the blink reflex evoked by electrical stimulation of the supraorbital nerve were recorded in 8 normal subjects. Habituation to repetitive stimulation and the recovery cycle to double shock were studied. The corneal reflex habituated significantly to repetitive stimulations at a rate of 0.2-1 Hz but was more resistant than the late component of the blink reflex (R2). There was a clear dissociation between the recovery of the corneal reflex and that of R2; the corneal reflex was again less affected by the proceeding impulse. These results suggest that the corneal reflex is relayed through fewer intramedullary synapses than R2.