How do dreams differ from waking thoughts in terms of brain activity?

Dreams and waking thoughts are fundamentally different in terms of the brain activity that underlies them. While both involve the activity of neurons in the brain, the patterns of activity are distinct and reflect the unique cognitive and emotional processes that occur during each state.

During waking thought, the brain is highly active, with a variety of neural circuits engaged in processing sensory input, making decisions, and coordinating movements. Different regions of the brain are involved in different tasks, and the overall pattern of activity is complex and variable.

In contrast, the brain activity during dreaming is characterized by a more synchronized and consistent pattern of activity, with a relatively reduced activity in regions associated with cognitive control and attention. During REM sleep, when most dreaming occurs, the brain is highly active, with increased activity in regions associated with emotion, memory, and sensory processing.

One prominent theory of dreaming, known as the "activation-synthesis" hypothesis, proposes that dreams are essentially the brain's attempt to make sense of its own internal signals and sensory input. According to this theory, the random neural activity that occurs during REM sleep is interpreted by the mind as meaningful images and events, resulting in the often surreal and disjointed content of dreams.

Overall, the brain activity associated with dreaming is fundamentally different from that associated with waking thought. While waking thought is characterized by complex, variable patterns of activity associated with perception, decision-making, and action, dreaming is characterized by a more consistent, synchronized pattern of activity that reflects the brain's processing of internal signals and emotional content.