Patients with disorders of consciousness (DOC) show reduced brain activity in midline regions (anterior and posterior cingulate cortex) during self-referential thinking tasks compared to healthy individuals. The degree of signal reduction in the perigenual anterior cingulate cortex predicts their level of consciousness. These same midline regions also display abnormal resting-state functional connectivity and low-frequency fluctuations. The findings link self-referential processing, resting-state brain activity, and consciousness, suggesting that neural abnormalities in these areas contribute to DOC.
Over the past 20 years, research on NMDA receptors as targets for depression treatment has grown steadily, with 5,092 publications identified. The United States leads in collaborations, publications, and citations. Co-cited reference analysis revealed 15 main clusters. Recent hotspots include ketamine (an NMDA receptor antagonist) for treatment-resistant depression, oxidative stress, synaptic plasticity, and neuroplasticity-related factors such as brain-derived neurotrophic factor. While ketamine's application and mechanisms in major depressive disorder remain a hot topic, its side effects have spurred investigation into new rapid-acting antidepressants.