The author argues that access consciousness and phenomenal consciousness, though conceptually distinct, might refer to the same brain process, similar to how water and H2O are different concepts of the same substance. However, recent work by Crick and Koch suggests that these two forms of consciousness may have distinct, albeit overlapping, neural correlates, even though Crick and Koch themselves implicitly reject this possibility.
Antidepressant drugs, including slow-acting types, fast-acting ketamine, and psychedelics, all promote neuronal plasticity through activation of BDNF signaling via its receptor TRKB, though each drug targets different cells. The authors propose that some antidepressants may directly bind to TRKB and allosterically enhance BDNF signaling. Activating TRKB in parvalbumin-containing interneurons disinhibits cortical networks and reopens a juvenile-like window of plasticity. This rewiring of faulty neural circuits, combined with environmental input, may explain clinical antidepressant effects. This hypothesis could guide development of new treatments.
Spontaneous brain activity before a stimulus influences whether it is consciously perceived. The prefrontal cortex and default mode network play active roles in shaping perception, not just in higher-level cognition. The findings suggest that prestimulus neural states in multiple brain networks modulate sensory processing and conscious awareness.