How does consciousness come about, and how can the brain create a world even when it is disconnected from the environment? Consciousness never fades when we are awake. However, when awakened from sleep, we sometimes recall dreams and sometimes recall no experiences. Traditionally, dreaming has been identified with rapid eye-movement (REM) sleep, characterized by wake-like, globally ‘activated’, high-frequency EEG activity. However, dreaming also occurs in non-REM (NREM) sleep, characterized by prominent low-frequency activity. Recent work using no-task, within-state paradigms has identified a ‘posterior hot zone’ where the EEG must be activated for subjects to experience dreams. Localized, content-specific activations occur depending on whether one dreams of faces, places, movement, and speech. These findings highlight the likely neural substrate of our own experiences and suggest some of the necessary and sufficient conditions for consciousness.
Giulio Tononi received his medical degree and specialized in psychiatry at the University of Pisa. After serving as an army medical officer, he obtained a Ph.D. in neuroscience at Sant'Anna School of Advanced Studies in Pisa. From 1990 to 2000, he was a member of The Neurosciences Institute, first in New York and then in San Diego. He is currently Professor of Psychiatry, Distinguished Professor in Consciousness Science, the David P. White Chair in Sleep Medicine at the University of Wisconsin–Madison, and the Director of the Wisconsin Institute for Sleep and Consciousness. In 2005 he received the NIH Director’s Pioneer Award for his work on sleep.
For further information, please contact Fiona Woods at the CNCB, University of Oxford.
