Inhibitory brainstem reflexes under external emotional-stimuli in bipolar I and II disorders

Abstract

BackgroundBipolar disorder types I (BD I) and II (BD II) might present different dysfunctions of the cortex and brainstem, as reflected by the second exteroceptive suppression period of temporalis muscle activity (ES2) under different stimuli of external emotions.MethodsThis study included 30 BD I and 20 BD II patients, and 40 healthy volunteers. All participants were invited to answer the Mood Disorder Questionnaire, the Hypomania Checklist-32, and the Plutchik-van Praag Depression inventory, as well as to undergo the ES2 test under external emotional-stimuli (emotional pictures plus sounds) of Disgust, Erotica, Fear, Happiness, and Sadness.ResultsThe scale scores were elevated in both patient groups, but were not correlated with ES2 parameters. Compared to healthy controls, BD I showed prolonged ES2 latency under Erotica, and their perceived happiness and sadness intensities were negatively correlated with the respective ES2 durations, while BD II showed prolonged ES2 latencies under Disgust and Happiness, and shortened ES2 durations under Disgust, Happiness and Sadness. Moreover, ES2 duration under Sadness was significantly shorter in BD II than that in BD I.ConclusionsThe cortico-brainstem inhibitory dysfunctions in BD I and BD II was different, and this difference was independent of the patient’s ongoing emotions. Our study thus provides some hints to distinguish the two types of bipolar disorders.

Electrocardiographic and Electrooculographic Responses to External Emotions and Their Transitions in Bipolar I and II Disorders

“…Moreover, we found higher PVP in BD II than those in BD I and controls, higher MDQ in BD I than those in BD II and controls, and higher HCL-32 in both BD I and BD II than that in controls, which were consistent with previous reports [ 47 , 48 , 49 ]. The higher score of HCL-32 in BD I than that in BD II was consistent with what we have found previously [ 31 , 32 , 49 ], which might be due to the coexistence of mania and hypomania in bipolar disorder [ 50 ] and to the sufficiency of one mania episode to diagnose BD I [ 2 ].…”

“…Characterization of peripheral physiological responses when an individual is emerged in an external emotion or during the transition from one external emotion to another would identify more differences between BD I and BD II. When referring to the inhibitory brainstem reflex, the duration of the second exteroceptive suppression of temporalis muscle activity was more shortened under sadness in BD II than that in BD I, and the latency of the second exteroceptive suppression under erotica was more prolonged in BD I, while more prolonged under happiness and sadness in BD II [ 31 ]. When referring to the excitatory brainstem reflex, blink reflex R2 components were more delayed under disgust, erotica, fear, and happiness in BD I, and were more decreased under disgust, erotica, fear, happiness, and sadness in BD II [ 32 ].…”

Disrupted Cerebellar Connectivity With the Central Executive Network and the Default-Mode Network in Unmedicated Bipolar II Disorder

“…Though patients with BD II have less severe intensity, several studies suggest that patients with BD II may have a more chronic course, higher frequency of depressive episodes and comorbidity, more suicidal behavior, and rapid cycling than patients with BD I (25–29). There are reports about the genetic (28, 30, 31), metabolic (32), and electrophysiological (25, 33, 34) differences between BD II and BD I. And neuroimaging studies have shown the differences in structure (29, 35–39), and task-based function (40–42) between BD II and BD I.…”