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. Author manuscript; available in PMC: 2013 Apr 1.
Published in final edited form as: Anesthesiology. 2012 Apr;116(4):946–959. doi: 10.1097/ALN.0b013e318249d0a7

Figure 2.

Figure 2

Schematic representing changes in responsiveness, neuromodulators and corticothalamic network connectivity with escalating propofol dose. Panel A: We define four particular states: awake, positive response on the isolate forearm technique (IFT +ve), dreaming and unconscious. With increasing doses of propofol (Panel B) patients transition through these states, first entering a state of environmentally connected consciousness (ECC = IFT +ve), then disconnected consciousness (DC = dreaming) before becoming unconscious. Panel B: depicts propofol dose. Panel C: Putative parallel changes in neuromodulators underlying behavioral changes with escalating doses of propofol. Ach = acetylcholine. Norepi = norepinephrine. ECC is hypothesized to require active norepinephrinergic and cholinergic signaling. Panel D: changes in corticothalamic network connectivity. Put-Amy = Putamen and Amygdala connectivity. CT-VATT = corticothalamic-ventral attention network connectivity. CT-Total = total corticothalamic connectivity. ECC requires adequate CT-Total and CT-VATT signaling.