Ketamine's antidepressant effects last much longer than its short half-life because the drug becomes trapped in NMDA receptors in the lateral habenula, and its release depends on neural activity. In mice, a single injection suppressed burst firing and blocked NMDA receptors in the lateral habenula for up to 24 hours. This sustained action results from use-dependent trapping, not endocytosis. By activating the lateral habenula and opening local NMDA receptors at different plasma ketamine concentrations, the duration of antidepressant effects could be shortened or prolonged. These findings explain the mechanism behind ketamine's sustained effects and suggest ways to modulate its therapeutic duration.
Structured visual streams containing regularities—whether perceptual (shape, motion) or semantic (idioms)—dominate over unstructured streams in the competition for visual awareness during binocular rivalry. Perceptual- and semantic-level regularities produce rivalry advantages that dissociate: perceptual regularities operate via nonconscious temporal integration and are vulnerable to disruptions of the spatiotemporal integration window, whereas semantic regularities operate via conscious temporal integration and are not. These findings indicate that structure-guided information integration across time contributes to visual awareness through at least two distinct mechanisms, supporting theories that link integration to conscious experience.