Neurophysiological data suggest that lucid dreaming involves increased activity in the prefrontal cortex, the area of the brain responsible for decision-making, planning, self-awareness, and controlling actions. There is also heightened activity in the hippocampus and other regions related to memory, orientation, and information processing. The increased levels of acetylcholine and other neurotransmitters associated with brain activity in the REM phase contribute to a more conscious state during sleep.