Nasal esketamine, a rapid-acting antidepressant, alters brain network activity by reducing top-down control and shifting the excitation/inhibition balance toward excitation. In eight individuals with major depressive disorder, EEG recordings before and up to 90 minutes after esketamine administration showed decreased frontoparietal alpha power and central beta power, along with increased frontal midline delta and low gamma power. The aperiodic exponent decreased, indicating cortical disinhibition. These neural changes correlated with increased subjective ratings of highness and happiness and decreased tension, linking the drug's neurophysiological effects to the immediate subjective experience.
Two types of mantra meditation produce distinct brain activity patterns. Novice practitioners were randomly assigned to chant either the Hare Krishna (HK) or Sa-Ta-Na-Ma (SA) mantra. EEG measurements showed that HK meditation led to widespread decreases in alpha power and increases in alpha frequency during and after practice, suggesting a more activating, attentionally focused state. In contrast, SA meditation produced localized alpha power reduction and, after training, a significant decrease in alpha frequency, indicating a more relaxed state. Both groups reported reduced stress. These results challenge the idea that all mantra meditation is the same and underscore the need to differentiate practices for targeted mental health applications.