“Consciousness Lost and Found: Subjective Experiences in an Unresponsive State”, Valdas Noreika, Leila Jylhänkangas, Levente Móró, Katja Valli, Kimmo Kaskinoro, Riku Aantaa, Harry Scheinin, Antti Revonsuo2011-12 (anesthesia)⁠:

• Subjective experiences occurred in 59% of sedative unresponsiveness sessions.

• Dexmedetomidine sedation had more subjective experiences than propofol sedation.
• Sevoflurane induced more laboratory related experiences than dexmedetomidine.

• Subjective experiences were related to shallower level of dexmedetomidine sedation.

Anesthetic-induced changes in the neural activity of the brain have been recently used as a research model to investigate the neural mechanisms of phenomenal consciousness. However, the anesthesiology definition of consciousness as “responsiveness to the environment” seems to sidestep the possibility that an unresponsive individual may have subjective experiences.

The aim of the present study was to analyze subjective reports in sessions where sedation and the loss of responsiveness were induced by dexmedetomidine, propofol, sevoflurane or xenon in a nonsurgical experimental setting.

After regaining responsiveness, participants recalled subjective experiences in almost 60% of sessions. During dexmedetomidine sessions, subjective experiences were associated with shallower “depth of sedation” as measured by an electroencephalography-derived anesthesia depth monitor.

Our results confirm that subjective experiences may occur during clinically defined unresponsiveness, and that studies aiming to investigate phenomenal consciousness under sedative and anesthetic effects should control the subjective state of unresponsive participants with post-recovery interviews.

[Keywords: consciousness, responsiveness, subjective experiences, depth of sedation, dexmedetomidine]

See Also:

• General Anesthesia: A Probe to Explore Consciousness

• Inverse p-zombies: the other direction in the Hard Problem of Consciousness

• Real-time dialogue between experimenters and dreamers during REM sleep

• What I make up when I wake up: anti-experience views and narrative fabrication of dreams

• Simulated thought insertion: Influencing the sense of agency using deception and magic

• The varieties of contemplative experience: A mixed-methods study of meditation-related challenges in Western Buddhists

• Decreased Directed Functional Connectivity in the Psychedelic State

• The Unreliability of Naive Introspection