The synthetic psychedelic 25CN-NBOH, which binds strongly to serotonin type 2A receptors, has a dual effect on neurons in the mouse medial prefrontal cortex. Acute application of a high concentration (10 µM) increased the frequency of spontaneous excitatory postsynaptic currents, an effect dependent on serotonin 2A receptor activation and not seen with chronic exposure or a lower concentration (200 nM). However, both concentrations suppressed the firing rate of pyramidal neurons after acute and one-hour exposure. This suppression was independent of serotonin 2A receptors but mediated by M-current channels, as blocking M-currents reversed it. The compound thus enhances excitatory transmission while reducing overall excitability, revealing complex cellular actions that may underlie its therapeutic effects.
Esketamine, the right-handed form of ketamine, blocks the NMDA receptor and is used as an anesthetic that reduces postoperative pain and opioid use. It also shows fast-acting antidepressant effects. Beyond anesthesia, esketamine has anti-inflammatory, antiapoptotic, and antioxidant properties in various diseases. This review describes esketamine's neuroprotective effects in central nervous system disorders, detailing how it influences neuronal apoptosis, microglial polarization, and astrocytic functions. The underlying molecular mechanisms involve inflammatory pathways and signaling cascades in neurological disorders.
Mindfulness meditation may improve neurovascular health in older adults through three potential mechanisms: directly increasing resting-state cerebral blood flow, indirectly reducing neuroinflammation via stronger default-mode network connectivity, and a top-down control pathway that combines both direct and indirect effects. This review first examines resting-state fMRI studies in older adults, then uses those findings to interpret task-based fMRI studies in clinical and healthy adult samples. The proposed mechanisms offer a framework for understanding how mindfulness could counteract age-related neurovascular decline.
Internet addiction is linked to altered communication patterns across the whole brain. Individuals with internet addiction showed increased functional connectivity density in regions involved in cognitive control and the default mode network, including the right dorsolateral prefrontal cortex, left parahippocampal gyrus, cerebellum, bilateral middle cingulate cortex, and superior temporal pole. Decreased connectivity density appeared in the right inferior parietal lobe and bilateral calcarine and lingual gyrus, areas tied to visual attention. Scores on the Internet Addiction Test correlated with connectivity changes in the left parahippocampal gyrus and bilateral superior temporal pole. These patterns resemble those seen in substance addiction and share neurobiological features with attention deficit/hyperactivity disorder.