Wolfram Regen

Increased EEG sigma and beta power during NREM sleep in primary insomnia.

The hyperarousal model of primary insomnia suggests that a deficit of attenuating arousal during sleep might cause the experience of non-restorative sleep. In the current study, we examined EEG spectral power values for standard frequency bands as indices of cortical arousal and sleep protecting mechanisms during sleep in 25 patients with primary insomnia and 29 good sleeper controls. Patients with primary insomnia demonstrated significantly elevated spectral power values in the EEG beta and sigma frequency band during NREM stage 2 sleep. No differences were observed in other frequency bands or during REM sleep. Based on prior studies suggesting that EEG beta activity represents a marker of cortical arousal and EEG sleep spindle (sigma) activity is an index of sleep protective mechanisms, our findings may provide further evidence for the concept that a simultaneous activation of wake-promoting and sleep-protecting neural activity patterns contributes to the experience of non-restorative sleep in primary insomnia.

Comorbid Sleep Disorders in Neuropsychiatric Disorders Across the Life Cycle

The association between psychopathology and poor sleep has long been recognized. The current review focuses on the association between the most prevalent sleep disorders (insomnia, sleep-related breathing disorders and restless legs syndrome) and four major psychiatric disorders: alcohol dependence, schizophrenia, depression and anxiety disorders. Decreased total sleep time and increased sleep onset latency as measured by polysomnography as well an increase of the prevalence of insomnia has been reported in all of these psychiatric disorders. Furthermore, sleep disturbance is a risk factor for their development. Cognitive-behavioral therapy for insomnia has been shown to have a positive impact on both sleep and symptoms of depression and anxiety. Whether adequate treatment of sleep disorders can prevent the incidence of psychiatric disorders, remains to be investigated.

Insomnia Does Not Appear to be Associated With Substantial Structural Brain Changes

STUDY OBJECTIVES Sleep has been demonstrated to significantly modulate brain plasticity and the manifestation of mental disorders. However, previous studies on the effect of disrupted sleep on brain structure have reported inconsistent results. The goal of the current study was to investigate brain morphometry in a well-characterized large sample of patients with primary insomnia (PI) in comparison with good sleeper controls. DESIGN Automated parcellation and pattern recognition approaches were supplemented by voxelwise analyses of gray and white matter volumes to analyze magnetic resonance images. All analyses included age, sex, and total intracranial volume as covariates. SETTING Department of Psychiatry and Psychotherapy of the University of Freiburg Medical Center. PARTICIPANTS There were 28 patients with PI (10 males; 18 females; age 43.7 ± 14.2 y) and 38 healthy, good sleepers (17 males; 21 females; age 39.6 ± 8.9 y). INTERVENTIONS N/A. RESULTS No significant between-group differences were observed in any of the investigated brain morphometry variables. CONCLUSIONS Altered brain function in insomnia does not appear to have a substantial effect on brain morphometry on a macroscopic level.

Insomnia Disorder is Associated with Increased Amygdala Reactivity to Insomnia-Related Stimuli

STUDY OBJECTIVES Alterations in emotional reactivity may play a key role in the pathophysiology of insomnia disorder (ID). However, only few supporting experimental data are currently available. We evaluated in a hypothesis-driven design whether patients with ID present altered amygdale responses to emotional stimuli related and unrelated to the experience of insomnia and, because of chronic hyperarousal, less habituation of amygdala responses. DESIGN Case-control study. SETTING Departments of Psychiatry and Psychotherapy and of Radiology of the University of Freiburg Medical Center. PARTICIPANTS There were 22 patients with ID (15 females; 7 males; age 40.7 ± 12.6 y) and 38 healthy good sleepers (HGS, 21 females; 17 males; age 39.6 ± 8.9 y). INTERVENTIONS N/A. MEASUREMENTS AND RESULTS In a functional magnetic resonance imaging session, five different blocks of pictures with varying emotional arousal, valence, and content (insomnia-relatedness) were presented. Pictures were presented twice to test for habituation processes. Results showed that patients with ID, compared to HGS, presented heightened amygdala responses to insomnia-related stimuli. Moreover, habituation of amygdale responses was observed only in HGS, but not in patients with ID who showed a mixed pattern of amygdala responses to the second presentation of the stimuli. CONCLUSIONS The results provide evidence for an insomnia-related emotional bias in patients with ID. Cognitive behavior treatment for ID could benefit from strategies dealing with the emotional charge associated with the disorder. Further studies should clarify the role of ID with respect to habituation of amygdala responses.

Reduced anterior internal capsule white matter integrity in primary insomnia.

Chronic insomnia is one of the most prevalent central nervous system diseases, however, its neurobiology is poorly understood. Up to now, nothing is known about the integrity of white matter tracts in insomnia patients. In this study, diffusion tensor imaging (DTI) was used in a well‐characterized sample of primary insomnia (PI) patients and good sleeper controls to fill this void. Voxelwise between‐group comparisons of fractional anisotropy (FA) were performed in 24 PI patients (10 males; 14 females; 42.7 ± 14.5 years) and 35 healthy good sleepers (15 males; 20 females; 40.1 ± 9.1 years) with age and sex as covariates. PI patients showed reduced FA values within the right anterior internal capsule and a trend for reduced FA values in the left anterior internal capsule. The results suggest that insomnia is associated with a reduced integrity of white matter tracts in the anterior internal capsule indicating that disturbed fronto‐subcortical connectivity may be a cause or consequence of the disorder. Hum Brain Mapp 35:3431–3438, 2014.

Objective sleep disturbances are associated with greater waking resting-state connectivity between the retrosplenial cortex/hippocampus and various nodes of the default mode network

BACKGROUND Psychological models highlight the bidirectional role of self-referential processing, introspection, worry and rumination in the development and maintenance of insomnia; however, little is known about the underlying neural substrates. Default mode network (DMN) functional connectivity has been previously linked to these cognitive processes. METHODS We used fMRI to investigate waking DMN functional connectivity in a well-characterized sample of patients with primary insomnia (PI) and good sleeper controls. RESULTS We included 20 patients with PI (8 men and 12 women, mean age 42.7 ± 13.4 yr) and 20 controls (8 men and 12 women, mean age 44.1 ± 10.6 yr) in our study. While no between-group differences in waking DMN connectivity were observed, exploratory analyses across all participants suggested that greater waking connectivity between the retrosplenial cortex/hippocampus and various nodes of the DMN was associated with lower sleep efficiency, lower amounts of rapid eye movement sleep and greater sleep-onset latency. LIMITATIONS Owing to the cross-sectional nature of the study, conclusions about causality cannot be drawn. CONCLUSION As sleep disturbances represent a transdiagnostic symptom that is characteristic of nearly all psychiatric disorders, our results may hold particular relevance to previous findings of increased DMN connectivity levels in patients with psychiatric disorders.

Neuroimaging Studies in Insomnia

Chronic insomnia is one of the most prevalent psychiatric disorders and has a significant impact on individual’s health. However, the pathophysiology of the disorder is poorly understood. The current review focuses on neuroimaging findings in insomnia. In summary, the current data suggest the following: (1) insomnia is characterized by corticolimbic overactivity during sleep and wakefulness that interferes with sleep initiation and/or maintenance; (2) insomnia patients’ daytime performance is associated with a hypoactivation of task-related areas; (3) neurochemically, insomnia patients are probably characterized by reduced cortical GABA levels; (4) insomnia may be associated with abnormal brain morphometry in the frontal cortex, hippocampus and/or anterior cingulate cortex. Future investigations should include larger sample sizes or longitudinal within-subject comparisons. Other possible methodological improvements are discussed.

Interindividual synchronization of brain activity during live verbal communication

Verbal social interaction plays an important role both in the etiology and treatment of psychiatric disorders. However, the neural basis of social interaction has primarily been studied in the individual brain, neglecting the inter-individual perspective. Here, we show inter-individual neuronal coupling of brain activity during live verbal interaction, by investigating 11 pairs of good female friends who were instructed to speak about autobiographical life events during simultaneous fMRI acquisition. The analysis revealed that the time course of neural activity in areas associated with speech production was coupled with the time course of neural activity in the interlocutors auditory cortex. This shows the feasibility of the new methodology, which may help elucidate basic reciprocal mechanisms of social interaction and the underpinnings of disordered communication. In particular, it may serve to study the process of psychotherapy on a neuronal level.

Sleep-related arousal versus general cognitive arousal in primary insomnia.

STUDY OBJECTIVES The present study aimed at further investigating trait aspects of sleep-related cognitive arousal and general cognitive arousal and their association with both objective and subjective sleep parameters in primary insomnia patients. METHODS A clinical sample of 182 primary insomnia patients and 54 healthy controls was investigated using 2 nights of polysomnography, subjective sleep variables, and a questionnaire on sleep-related and general cognitive arousal. RESULTS Compared to healthy controls, primary insomnia patients showed both more sleep-related and general cognitive arousal. Furthermore, sleep-related cognitive arousal was closely associated with measures of sleep-onset and sleep-maintenance problems, while general cognitive arousal was not. CONCLUSIONS Cognitive-behavioral treatment for insomnia might benefit from dedicating more effort to psychological interventions that are able to reduce sleep-related cognitive arousal.

The impact of acamprosate on cue reactivity in alcohol dependent individuals: a functional magnetic resonance imaging study.

Abstract Alcohol cue–induced brain activation has been studied extensively in alcoholics. However, little is known about the impact of standard treatment protocols on this phenomenon. The current study aimed at investigating the impact of the anticraving substance acamprosate on alcohol cue–related brain activity. Patients underwent a functional magnetic resonance imaging investigation before the beginning of medication with acamprosate or placebo (T0) and 2 weeks later (T1). All patients also received psychiatric inpatient treatment including psychotherapeutic interventions. Twenty-nine patients were included in the T0 analysis and 22 patients in the T1 analysis. At T0, a cluster in the left and right posterior cingulate cortex, covering parts of the retrosplenial cortex, was significantly associated with alcohol versus neutral cue exposure. At T1, no significant cluster was found for the alcohol-versus-neutral contrast. The analysis of the impact of acamprosate on cue-related activity in the posterior cingulate cortex cluster revealed no significant difference to placebo. These results provide further evidence for the involvement of the posterior cingulate cortex in alcohol cue exposure. However, in comparison with psychiatric inpatient treatment alone, there was no additional effect of acamprosate on cue-related brain activity.