Blink reflex under external emotional-stimuli in bipolar I and II disorders

Responses to External Emotions or their Transitions at Central to Peripheral Nervous System Levels: A Methodological Contribution to Mental Health

Background:

Responses to external emotional-stimuli or their transitions might help to elucidate the scientific background and assist the clinical management of psychiatric problems, but pure emotional-materials and their utilization at different levels of neurophysiological processing are few.

Objective:

We aimed to describe the responses at central and peripheral levels in healthy volunteers and psychiatric patients when facing external emotions and their transitions.

Methods:

Using pictures and sounds with pure emotions of Disgust, Erotica, Fear, Happiness, Neutral, and Sadness or their transitions as stimuli, we have developed a series of non-invasive techniques, i.e., the event-related potentials, functional magnetic resonance imaging, excitatory and inhibitory brainstem reflexes, and polygraph, to assess different levels of neurophysiological responses in different populations.

Results:

Sample outcomes on various conditions were specific and distinguishable at cortical to peripheral levels in bipolar I and II disorder patients compared to healthy volunteers.

Conclusions:

Methodologically, designs with these pure emotions and their transitions are applicable, and results per se are specifically interpretable in patients with emotion-related problems.

Peripherally Physiological Responses to External Emotions and Their Transitions in Bipolar I Disorder With and Without Hypersexuality

Hypersexuality is associated with psychiatric disorders such as mania; however, it remains unclear whether bipolar I disorder with (BW) or without (BO) hypersexuality demonstrates different responses to external emotional stimuli and their transitions that were composed of pictures and sounds of same domain. In 21 BW patients, 20 BO patients, and 41 healthy volunteers, we administered polygraph tests (electrocardiogram, electromyogram, electrooculogram, and galvanic skin response) to measure transitions from a primer emotion (i.e., external disgust, erotica, fear, happiness, neutral, and sadness) to a noncongruent emotion (out of the remaining five) and to the primer emotion again (repeat-primer). We also evaluated participants' concurrent states of mania, hypomania, and depression. With neutral as the noncongruent emotion, the heart rate difference in BW was greater than in controls when responses to the primer erotica were subtracted from responses to the repeat-primer erotica, or when to the primer sadness were subtracted from the repeat-primer sadness. The difference of the masseter electromyographic activity in BW was lower than in BO and controls when responses to the noncongruent happiness were subtracted from responses to the repeat-primer neutral, and was lower than in BO when to the noncongruent neutral were subtracted from the repeat-primer erotica. The eyeball movement difference was greater in BW than in BO and controls when responses to the noncongruent sadness were subtracted from responses to the repeat-primer neutral. The heart rate difference when responses to the primer happiness were subtracted from responses to the noncongruent neutral was negatively correlated with mania in BO. BW and BO patients behaved differently to external emotions and their transitions, particularly regarding erotica and sadness, which might characterize unique pathophysiological processes of the two bipolar I disorder subtypes.

Visual event-related potentials in external emotional conditions in bipolar disorders I and II

OBJECTIVES

Mutual influences of cognitive and emotional functions occur in bipolar disorder, but specific alterations in relation to external emotional stimuli in bipolar I (BD I) and II (BD II) subtypes remain unknown. This study aimed to explore the effects of external emotional stimuli on cerebral attentional function in BD I and BD II.

METHODS

We tested visual oddball event-related potentials (ERPs) during various external emotional stimuli (Disgust, Fear, Erotica, Happiness, Neutral and Sadness) in 31 patients with BD I, 19 BD II and 47 healthy volunteers. Participants' concurrent affective states were also evaluated.

RESULTS

The ERP N2 latencies during Fear and Happiness were prolonged, P3 amplitudes during Disgust and Erotica were decreased in BD I; P3 amplitudes during Disgust, Erotica, Happiness and Neutral conditions were decreased in BD II. Increased frontal and parietal and decreased temporal and occipital activations were found in BD I, while increased occipital and parietal and decreased frontal and limbic activations in BD II in relation to different external emotions. ERP components were not correlated with concurrent affective states in patients.

CONCLUSIONS

Automatic attention during Happiness and Fear, and voluntary attention during Disgust and Erotica conditions were impaired in BD I; and voluntary attention during Disgust, Happiness, Erotica and Neutral conditions was impaired in BD II. Our study illustrates different patterns of visual attentional deficits associated with different external emotional stimuli in BD I and BD II.

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

Bipolar disorder has two main types, bipolar I (BD I) and II (BD II), which present different affective states and personality characteristics, they might present different modes of emotional regulation. We hypothesized that the electrocardiogram and electrooculogram to external emotions are different in BD I and BD II. We asked 69 BD I and 54 BD II patients, and 139 healthy volunteers to undergo these tests in response to disgust, erotica, fear, happiness, neutral, and sadness, and their transitions. Their affective states were also measured. The heart rate in BD I was significantly higher under background fear after target neutral. The eyeball movement was quicker in BD I under target happiness after background disgust; in BD I under target sadness after background disgust; and in BD I under background disgust after target neutral. Some electrocardiographic and electrooculographic changes were correlated with affective states in patients. BD I and BD II had different physiological responses to external emotions and their transitions, indicating different pathophysiologies and suggesting different emotional-therapies for BD I and BD II.

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

Objective: Bipolar disorder (BD) is a common psychiatric disease. Although structural and functional abnormalities of the cerebellum in BD patients have been reported by recent neuroimaging studies, the cerebellar-cerebral functional connectivity (FC) has not yet been examined. The present study aims to investigate the FC between the cerebellum and cerebrum, particularly the central executive network (CEN) and the default-mode network (DMN) in bipolar II disorder (BD II). Methods: Ninety-four patients with unmedicated BD II depression and 100 healthy controls (HCs) underwent the resting-state functional magnetic resonance imaging. Seed-based connectivity analyses were performed using cerebellar seeds previously identified as being involved in the CEN (bilateral Crus Ia) and DMN (bilateral Crus Ib). Results: Compared with HCs, BD II depression patients appeared decreased FC in the right Crus Ia-left dorsal lateral prefrontal cortex (dlPFC) and -left anterior cingulate cortex (ACC), the right Crus Ib-left medial prefrontal cortex (mPFC), -left middle temporal gyrus (MTG), and -left inferior temporal gyrus (ITG). No altered FC between the left Crus Ia or Crus Ib and the cerebral regions was found. Conclusions: Patients with BD II depression showed disrupted FC between the cerebellum and the CEN (mainly in the left dlPFC and ACC) and DMN (mainly in the left mPFC and temporal lobe), suggesting the significant role of the cerebellum-CEN and -DMN connectivity in the pathogenesis of BD.