Revisiting the association between hypnotisability and blink rate.

Blink rate (BR), which is considered an index of the dopaminergic tone, has been studied in 41 subjects with high (highs), medium (mediums) and low (lows) hypnotisability scores in resting conditions. It has been found higher in highs; relaxation (indicated by skin conductance), anxiety and the proneness to absorption in tasks (assessed by questionnaires) were not responsible for the observed difference. In contrast, the BR difference did not survive controlling for mind wandering (MW questionnaire) whose variability could account for contrasting earlier reports, although no significant hypnotisability-related difference has been observed in MW scores. Findings do not allow to exclude that mechanisms other than dopaminergic ones may be involved in the observed difference in BR. In particular, we suggest that one of the mechanisms possibly sustaining the highs' higher BR may be a reduced cerebellar inhibition. In fact, cerebellar impairment is associated with higher BR and several studies of sensorimotor integration indicate different cerebellar controls in the highs' and lows' behavior.