Trait and state-related characteristics of thalamo-cortical circuit disruption in bipolar disorder: a prospective cross-sectional study.

Objective: The purpose of this study is to investigate the shared and distinct thalamic-cortical circuit between bipolar depression and remission, as well as to investigate the trait and state-related characteristics of the abnormal thalamic-cortical circuit in bipolar disorder. Methods: Resting-state functional magnetic resonance imaging was performed on 38 bipolar depression patients, 40 bipolar remission patients, and 39 gender-matched healthy controls (rsfMRI). The thalamic subregions were used as seed points to draw the functional connectivity of the entire brain, and then the shared and distinct thalamic-cortical circuits between bipolar depression and remission were compared. Results: When compared to the healthy group, both groups of patients had significantly lower functional connectivity between the rostral temporal thalamus and the lingual gyrus, the posterior parietal thalamus, the precuneus/cerebellum, and the occipital thalamus and the precuneus; however, functional connectivity between the premotor thalamus and the superior medial frontal was significantly lower in depression. Conclusion: This study discovered that both bipolar depression and remission had abnormal sensorimotor-thalamic functional connectivity, implying that it is a trait-related characteristic of bipolar disorder; however, the decline in prefrontal-thalamic connectivity exists specifically in bipolar depression, implying that it is a state-related characteristic of bipolar disorder.

Sex Differences in the Effects of Cognitive Reappraisal Training on Conditioned Fear Responses.

Sex differences in emotion regulation strategies may impact sex differences in affective disorders. Using cognitive reappraisal strategy in the discriminative task of conditioned fear was studied to understand how sex differences in emotion regulation impact on conditioned fear in men and women. College students with low cognitive reappraisal scores completed the task of conditioned fear during two days: acquisition and extinction at the first day, and re-extinction at the second day. The reappraisal training was carried out before conditioned fear task. The self-reported fear rating of the conditioned stimulus (CS) and US-expectancy in the conditioned fear (unconditioned stimulus, US) were analyzed. Results showed all subjects acquired conditional fear and successfully distinguished CS+ from CS-. Cognitive reappraisal significantly reduces the fear rating and improves the extinction of US-expectancy in both sexes, but the fear rating in female reappraisal group decreases more slowly than that in male reappraisal group, as well as the extinction of US-expectancy in woman requiring a longer time and more trials of extinction than that in men. For individuals with low cognitive reappraisal scores, cognitive reappraisal promotes the extinction of conditioned fear in both males and females. Because of the original gender difference of conditioned fear extinction and emotion regulation, the effect of cognitive reappraisal on conditioned fear is complex, which shows differently in influence speed and practice effect.

Exploring the Associations between Social Media Addiction and Depression: Attentional Bias as a Mediator and Socio-Emotional Competence as a Moderator.

Social media is used daily by a significant number of young people and can have an important influence on the well-being of its users. The aim of this study was to determine the motives for social media use among Chinese youth and whether social media addiction associates with depression. Another objective was to analyze possible mediating and moderating effects in explaining the association between social media addiction and depression. Participants were 1652 secondary school students (51.5% boys and 48.5% girls) aged 12-18 years in China. The results showed that attention bias mediated the association between social media addiction and depression when adolescents' socio-emotional competencies were low, but not as strong when their socio-emotional competencies were high. The findings not only provided theoretical support for preventing the negative effects of mobile social media addiction, but could also directly contribute to improving adolescents' quality of life.

The gain modulation by N-methyl-D-aspartate in the projection neurons of robust nucleus of the arcopallium in adult zebra finches.

The song of zebra finch is stable in life after it was learned successfully. Vocal plasticity is thought to be a motor exploration that can support continuous learning and optimization of performance. The activity of RA, an important pre-motor nucleus in songbird's brain, influences the song directly. This variability in adult birdsong is associated with the activity of NMDA receptors in LMAN-RA synapses, but the detailed mechanism is unclear. The control of gain refers to modulation of a neuron's responsiveness to input and is critically important for normal sensory, cognitive, and motor functions. Here, we observed the change of gain in RA projection neurons after exogenous NMDA was applied to activate NMDA receptors using the whole-cell current clamp recording. We found that NMDA substantially increased the slope (gain) of the firing rate-current relationship in RA projection neurons. The AMPA receptor-dependent excitability played a crucial role in the modulation of gain by NMDA. These results suggested that NMDA receptors may regulate the dynamics of RA projection neurons by input-output gain.

Electrophysiological properties of neurons in the robust nucleus of the arcopallium of adult male zebra finches.

Nucleus robust arcopallium (RA) of the songbird is a distinct forebrain region that is essential for song production. To explore the electrophysiological properties, whole cell recordings were made from adult zebra finch RA neurons in slice preparations. Based on the electrophysiological properties, neurons in RA were classified into two distinct classes. Type I neurons were spontaneously active. They had larger input resistance, longer time constant, larger time-peak of an afterhyperpolarization (AHP), and broader action potentials than those of the other class. A slow, time-dependent inward rectification was induced by hyperpolarizing current pulses in this type of neuron, and was blocked by external CsCl (2mM). Type II neurons had a more negative resting membrane potential than that of type I neurons. They were characterized by a steeper slope of the recovery from the peak of the AHP and frequency-current relationships, a higher firing threshold, and irregular spiking in response to depolarizing current injection.

Sexual dimorphism of the electrophysiological properties of the projection neurons in the robust nucleus of the arcopallium in adult zebra finches.

OBJECTIVE: To observe the sexual differences in electrophysiological properties of neurons in the robust nucleus of the arcopallium (RA) in adult zebra finches, and to provide the direct electrophysiological evidence for the sexual dimorphism of birdsong. METHODS: Whole-cell recording was used to record the spontaneous action potential firing rates from RA projection neurons in acute brain slices. RESULTS: The projection neurons of RA in male birds fired spontaneously at 10 Hz or above, while in female birds, the frequency was significantly lower, and even no firings could be detected. CONCLUSION: There is a sexual difference in electrophysiological properties of projection neurons in RA, which may result from the difference in the levels of steroid hormones in birds.