The brain may maintain optimal information transmission even when its functional connectivity is drastically altered. The psychedelic compound ibogaine, which induces an altered state of consciousness, fundamentally changes functional connectivity in the retrosplenial cortex of mice. Despite these changes, the scale-free statistics of movement and of neuronal avalanches among behaviorally related neurons remain largely unaltered. This suggests that the propagation of information within biological neural networks is robust to changes in the functional organization of neuronal subpopulations, offering a new perspective on how adaptive functional networks may support optimal information transmission.
Psilocybin, a classic psychedelic, reduces the spatial specificity and stability of neural activity in the retrosplenial cortex of mice navigating a treadmill. Place-related firing of neurons became less selective for distinct locations, and the consistency of this activity across trials decreased. Functional connectivity between simultaneously recorded neurons also declined. Most of these effects were blocked by the serotonin 2A receptor antagonist ketanserin, implicating 5-HT2AR signaling. The findings align with the proposal that psychedelics increase neural entropy and may explain the disorientation often reported by humans after taking such drugs.