The process of awakening: a PET study of regional brain activity patterns mediating the re-establishment of alertness and consciousness
by
Balkin TJ, Braun AR, Wesensten NJ, Jeffries K,
Varga M, Baldwin P, Belenky G, Herscovitch P.
Department of Behavioral Biology,
Walter Reed Army Institute of Research,
Washington, DC 20307-5100, USA.
thomas.balkin@na.amedd.army.mil
Brain. 2002 Oct;125(Pt 10):2308-19

ABSTRACT

Awakening from sleep entails rapid re-establishment of consciousness followed by the relatively slow (20-30 min later) re-establishment of alertness--a temporal dissociation that facilitates specification of the physiological underpinnings of each of these facets of the awakening process. H(2)(15)O PET was used to assess changes in regional cerebral blood flow (rCBF) upon awakening from stage 2 sleep. Cerebral blood flow (CBF) was most rapidly re-established in centrencephalic regions (e.g. brainstem and thalamus), suggesting that the reactivation of these regions underlies the re-establishment of conscious awareness. Across the ensuing 15 min of wakefulness, further increases in CBF were evident primarily in anterior cortical regions, suggesting that the dissipation of sleep inertia effects (post-awakening performance and alertness deficits) is effected by reactivation of these regions. Concomitant shifts in correlation patterns of regional brain activity across the post-awakening period [in particular, a waning negative correlation between prefrontal cortex and mesencephalic reticular formation (RF) activity, and a waxing positive correlation between prefrontal cortex and ventromedial caudate nucleus (CAUD) activity] suggest that the post-awakening reversal of sleep inertia effects may be mediated by more than mere reactivation--it may also involve the functional reorganization of brain activity. Conversely, stable post-awakening correlations--such as those found between the anterior cingulate cortex (ACC) and most other brain regions--may denote the pattern of functional connectivity that underlies consciousness itself.

People
Awareness
Brain microtubules
Obstetric anaesthesia
Molecular mechanisms
The spongia somnifera
'My beloved chloroform'
'The secularisation of pain'
Functional neuroanatony of awareness
Intraoperative waking during anaesthesia
Awareness, muscle relaxants and balanced anaesthesia

Refs
and further reading

HOME
HedWeb
Nootropics
cocaine.wiki
Future Opioids
BLTC Research
MDMA/Ecstasy
Superhappiness?
Utopian Surgery?
The Good Drug Guide
The Abolitionist Project
The Hedonistic Imperative
The Reproductive Revolution
Critique of Huxley's Brave New World