sciencehabit writes: The question of whether the human consciousness is subjective or objective is largely philosophical. But the line between consciousness and unconsciousness is a bit easier to measure. In a new study (abstract) of how anesthetic drugs affect the brain, researchers suggest that our experience of reality is the product of a delicate balance of connectivity between neurons—too much or too little and consciousness slips away. During wakeful consciousness, participants’ brains generated “a flurry of ever-changing activity”, and the fMRI showed a multitude of overlapping networks activating as the brain integrated its surroundings and generated a moment to moment “flow of consciousness.” After the propofol kicked in, brain networks had reduced connectivity and much less variability over time. The brain seemed to be stuck in a rut—using the same pathways over and over again.