Excitatory Brainstem Reflexes Under External Emotional-stimuli In Bioolar ? And ? Disorders

Background:Bipolar disorder types ?(BP ?)and ?(BP ?)might present different cortico-brainstem circuit dysfunctions under external emotions,which might be reflected by the excitatory brainstem reflexes.Methods:We therefore invited 32 BP ? and 23 BP ? patients,and 46 healthy volunteers to answer the Mood Disorder Questionnaire,the Hypomania Checklist-32,and the Plutchik-van Praag Depression inventory,and to undergo the excitatory brainstem reflex(blink reflex)test under external emotions(emotional pictures plus sounds)of Happiness,Erotica,Fear,Disgust,and Sadness.Results:Compared to healthy controls,BP ? showed prolonged R2/R2' latencies under most emotions,and their PVP scores were negatively correlated with the areas under curve(AUCs)of R2 and R2' under Erotica;and BP ? showed reduced R2/R2' AUCs under all emotions.Moreover,R2' AUCs under Happiness,Fear,and Disgust were significantly reduced in BP II than those in BP ?.Conclusions:Our results have shown that,irrespective of patients' on-going affective states,the R2/R2' components were delayed in BP ? but suppressed in BP ? under most external emotions.Our study provides some hints to distinguish the two types of bipolar disorder,referring to the cortico-brainstem circuit dysfunctions under external emotions.