Abnormalities of thalamus volume and resting state functional connectivity in primary insomnia patients.

Primary insomnia (PI) is associated with deteriorating attention, memory, physical and mood complaints. Based on the extensive literature demonstrating the critical roles of the thalamus in sleep regulation, we hypothesized that insomnia would be associated with functional and structural changes of the thalamus. This information is needed to better understand the neural mechanisms of insomnia, and would be useful for informing future attempts to alleviate or treat insomnia symptoms. Twenty-seven PI patients and 39 matched healthy controls were included in the present study. Subcortical volume and resting state functional connectivity (RSFC) of thalamus were compared between groups, and the relationships between neuroimaging differences and clinical features, including the Pittsburgh Sleep Quality Index (PSQI), the Insomnia Severity Index Scale (ISI), the Self-Rating Anxiety Scale (SAS) and the Self-Rating Depression Scale (SDS), also be explored. Compared with the control group, the PI group showed significantly reduced volume of thalamus. In addition, several brain regions showed reduced RSFC with thalamus in PI patients, such as anterior cingulate cortex (ACC), orbitofrontal cortex, hippocampus, caudate and putamen. Correlation analyses revealed that, several of these RSFC patterns were negatively correlated with PSQI score among PI patients, including thalamic connections with the putamen, caudate, hippocampus. Negative correlation was also observed between the RSFC strength of right thalamus-right ACC and SDS score in PI patients. This work demonstrates the structural and functional abnormalities of the thalamus in PI patients that were associated with key clinical features of insomnia. These data further highlight the important role of the thalamus in sleep and PI.

Reduced Thalamus Volume May Reflect Nicotine Severity in Young Male Smokers.

Introduction: Nicotine acts as an agonist at presynaptic nicotinic acetylcholine receptors and to facilitate synaptic release of several neurotransmitters including dopamine and glutamate. The thalamus has the highest density of nicotinic acetylcholine receptors in the brain, which may make this area more vulnerable to the addictive effects of nicotine. However, the volume of thalamus abnormalities and the association with smoking behaviors in young smokers remains unknown. Methods: Thirty-six young male smokers and 36 age-, gender- and education-matched nonsmokers participated in the current study. The nicotine dependence severity and cumulative effect were assessed with the Fagerström test for nicotine dependence (FTND) and pack-years. We used subcortical volume analyses method in FreeSurfer to investigate the thalamus volume differences between young smokers and nonsmokers. Correlation analysis was used to investigate the relationship between thalamus volume and smoking behaviors (pack-years and FTND) in young smokers. Results and Conclusions: Relative to nonsmokers, the young smokers showed reduced volume of bilateral thalamus. In addition, the left thalamus volume was correlated with FTND in young smokers. It is hoped that our findings can shed new insights into the neurobiology of young smokers. Implications: In this article, we investigated the changes of thalamus volume in young male smokers compared with nonsmokers. Reduced left thalamus volume was correlated with FTND in young smokers, which may reflect nicotine severity in young male smokers.

Expertise modulates local regional homogeneity of spontaneous brain activity in the resting brain: an fMRI study using the model of skilled acupuncturists.

Studies on training/expertise-related effects on human brain in context of neuroplasticity have revealed that plastic changes modulate not only task activations but also patterns and strength of internetworks and intranetworks functional connectivity in the resting state. Much has known about plastic changes in resting state on global level; however, how training/expertise-related effect affects patterns of local spontaneous activity in resting brain remains elusive. We investigated the homogeneity of local blood oxygen level-dependent fluctuations in the resting state using a regional homogeneity (ReHo) analysis among 16 acupuncturists and 16 matched nonacupuncturists (NA). To prove acupuncturists' expertise, we used a series of psychophysical tests. Our results demonstrated that, acupuncturists significantly outperformed NA in tactile-motor and emotional regulation domain and the acupuncturist group showed increased coherence in local BOLD signal fluctuations in the left primary motor cortex (MI), the left primary somatosensory cortex (SI) and the left ventral medial prefrontal cortex/orbitofrontal cortex (VMPFC/OFC). Regression analysis displayed that, in the acupuncturists group, ReHo of VMPFC/OFC could predict behavioral outcomes, evidenced by negative correlation between unpleasantness ratings and ReHo of VMPFC/OFC and ReHo of SI and MI positively correlated with the duration of acupuncture practice. We suggest that expertise could modulate patterns of local resting state activity by increasing regional clustering strength, which is likely to contribute to advanced local information processing efficiency. Our study completes the understanding of neuroplasticity changes by adding the evidence of local resting state activity alterations, which is helpful for elucidating in what manner training effect extends beyond resting state.

Length of Acupuncture Training and Structural Plastic Brain Changes in Professional Acupuncturists.

BACKGROUND: The research on brain plasticity has fascinated researchers for decades. Use/training serves as an instrumental factor to influence brain neuroplasticity. Parallel to acquisition of behavioral expertise, extensive use/training is concomitant with substantial changes of cortical structure. Acupuncturists, serving as a model par excellence to study tactile-motor and emotional regulation plasticity, receive intensive training in national medical schools following standardized training protocol. Moreover, their behavioral expertise is corroborated during long-term clinical practice. Although our previous study reported functional plastic brain changes in the acupuncturists, whether or not structural plastic changes occurred in acupuncturists is yet elusive. METHODOLOGY/PRINCIPAL FINDINGS: Cohorts of acupuncturists (N = 22) and non-acupuncturists (N = 22) were recruited. Behavioral tests were delivered to assess the acupuncturists' behavioral expertise. The results confirmed acupuncturists' tactile-motor skills and emotion regulation proficiency compared to non-acupuncturists. Using the voxel-based morphometry technique, we revealed larger grey matter volumes in acupuncturists in the hand representation of the contralateral primary somatosensory cortex (SI), the right lobule V/VI and the bilateral ventral anterior cingulate cortex/ventral medial prefrontal cortex. Grey matter volumes of the SI and Lobule V/VI positively correlated with the duration of acupuncture practice. CONCLUSIONS: To our best knowledge, this study provides first evidence for the anatomical alterations in acupuncturists, which would possibly be the neural correlates underlying acupuncturists' exceptional skills. On one hand, we suggest our findings may have ramifications for tactile-motor rehabilitation. On the other hand, our results in emotion regulation domain may serve as a target for our future studies, from which we can understand how modulations of aversive emotions elicited by empathic pain develop in the context of expertise. Future longitudinal study is necessary to establish the presence and direction of a causal link between practice/use and brain anatomy.