In people with major depressive disorder, the balance between excitation and inhibition across the brain's cortex is disrupted, particularly in the parietal and prefrontal-cingulate regions. Using resting-state functional magnetic resonance imaging data from 254 patients and 451 healthy controls, the Hurst exponent—a proxy for excitation-inhibition balance—was found to be significantly reduced in patients. This imbalance was linked to specific gene expression related to neuronal structure, metabolism, and mitochondrial function, as well as to neurotransmitter systems including GABA, opioid, serotonin, and synaptic density. In a separate trial of 32 patients with treatment-resistant depression, ketamine increased the Hurst exponent in the anterior cingulate and medial prefrontal cortices, suggesting that restoring excitation-inhibition balance may underlie ketamine's antidepressant effects.
Mindfulness-based cognitive therapy (MBCT) reduced worry severity more than online psychoeducation in people with generalized anxiety disorder, but both interventions reduced anxiety to a similar degree overall. Among those who experienced childhood emotional abuse, MBCT was more effective at reducing anxiety than psychoeducation, and also more effective for anxiety in that subgroup compared to those without such abuse. The findings suggest MBCT's effect on anxiety depends on a history of childhood maltreatment, especially emotional abuse.
Closing the eyes alters resting-state brain activity in both sighted and congenitally blind individuals, suggesting that the effect is inherent to human nature rather than learned from vision. The study compared 21 congenitally blind participants with 21 sighted controls using functional MRI. In both groups, eye closure increased low-frequency fluctuations in sensorimotor and occipital regions and decreased them in the medial prefrontal cortex. No differences appeared between blind participants with and without light perception. Between-group differences in the posterior insula and fusiform were attributed to experience (nurture). The authors contend that volitional eye closure focuses attention inward and is a natural human action, not dependent on visual experience.