Brain Mysteries
Recent News |  Archives |  Tags |  Newsletter |  Message Board/Forum |  About |  Links |  Subscribe to BrainMysteries.com RSS Feed Subscribe


More Articles
Songbird student pilots delay departure and make frequent stopovers during first migrationSongbird student pilots delay departure and make frequent stopovers during first migration

Researchers develop models to study polyelectrolytes, including DNA and RNAResearchers develop models to study polyelectrolytes, including DNA and RNA

Water leads to chemical that gunks up biofuels productionWater leads to chemical that gunks up biofuels production

Conclusive evidence on role of circulating mesenchymal stem cells in organ injuryConclusive evidence on role of circulating mesenchymal stem cells in organ injury

Enabling a new future for cloud computingEnabling a new future for cloud computing

Paleontologists describe a possible dinosaur nest and young 'babysitter'Paleontologists describe a possible dinosaur nest and young 'babysitter'

Nanodiamonds are foreverNanodiamonds are forever

Parents, listen next time your baby babblesParents, listen next time your baby babbles

Yellowstone supereruption would send ash across North AmericaYellowstone supereruption would send ash across North America

Plug n' play protein crystalsPlug n' play protein crystals

Cool moleculesCool molecules

Tilted acoustic tweezers separate cells gentlyTilted acoustic tweezers separate cells gently

A spectacular landscape of star formationA spectacular landscape of star formation

Study: Earth can sustain more terrestrial plant growth than previously thoughtStudy: Earth can sustain more terrestrial plant growth than previously thought

Evolutionary history of honeybees revealed by genomicsEvolutionary history of honeybees revealed by genomics

Bombarded by explosive waves of information, scientists review new ways to process and analyze Big DataBombarded by explosive waves of information, scientists review new ways to process and analyze Big Data

Key to speed? Elite sprinters are unlike other athletes -- deliver forceful punch to groundKey to speed? Elite sprinters are unlike other athletes -- deliver forceful punch to ground

Abusive leadership infects entire teamAbusive leadership infects entire team

Hot-spring bacteria reveal ability to use far-red light for photosynthesisHot-spring bacteria reveal ability to use far-red light for photosynthesis

Program earns kudos for improving grades, retaining studentsProgram earns kudos for improving grades, retaining students

Common household chemicals decrease reproduction in mice, study findsCommon household chemicals decrease reproduction in mice, study finds

A self-organizing thousand-robot swarmA self-organizing thousand-robot swarm

Crash-testing rivetsCrash-testing rivets

Scientists discover the miracle of how geckos move, cling to ceilingsScientists discover the miracle of how geckos move, cling to ceilings

Geography matters: Model predicts how local 'shocks' influence U.S. economyGeography matters: Model predicts how local 'shocks' influence U.S. economy

A healthy lifestyle adds years to lifeA healthy lifestyle adds years to life

Strict diet suspends development, doubles lifespan of wormsStrict diet suspends development, doubles lifespan of worms

Identified for the first time what kind of explosive has been used after the detonationIdentified for the first time what kind of explosive has been used after the detonation

Copied from nature: Detecting software errors via genetic algorithmsCopied from nature: Detecting software errors via genetic algorithms

Scientists solving the mystery of human consciousness (4/13/2012)

Tags:
anesthesia, consciousness
This image shows one returning from oblivion -- imaging the neural core of consciousness. Positron emission tomography (PET) findings show that the emergence of consciousness after anesthesia is associated with activation of deep, phylogenetically old brain structures rather than the neocortex. Left: Sagittal (top) and axial (bottom) sections show activation in the anterior cingulate cortex (i), thalamus (ii) and the brainstem (iii) locus coeruleus/parabrachial area overlaid on magnetic resonance image (MRI) slices. Right: Cortical renderings show no evident activations. -  Turku PET Center
This image shows one returning from oblivion -- imaging the neural core of consciousness. Positron emission tomography (PET) findings show that the emergence of consciousness after anesthesia is associated with activation of deep, phylogenetically old brain structures rather than the neocortex. Left: Sagittal (top) and axial (bottom) sections show activation in the anterior cingulate cortex (i), thalamus (ii) and the brainstem (iii) locus coeruleus/parabrachial area overlaid on magnetic resonance image (MRI) slices. Right: Cortical renderings show no evident activations. - Turku PET Center

Awakening from anesthesia is often associated with an initial phase of delirious struggle before the full restoration of awareness and orientation to one's surroundings. Scientists now know why this may occur: primitive consciousness emerges first. Using brain imaging techniques in healthy volunteers, a team of scientists led by Adjunct Professor Harry Scheinin, M.D. from the University of Turku, Turku, Finland in collaboration with investigators from the University of California, Irvine, USA, have now imaged the process of returning consciousness after general anesthesia. The emergence of consciousness was found to be associated with activations of deep, primitive brain structures rather than the evolutionary younger neocortex.

These results may represent an important step forward in the scientific explanation of human consciousness. The study was part of the Research Programme on Neuroscience by the Academy of Finland.

"We expected to see the outer bits of brain, the cerebral cortex (often thought to be the seat of higher human consciousness), would turn back on when consciousness was restored following anesthesia. Surprisingly, that is not what the images showed us. In fact, the central core structures of the more primitive brain structures including the thalamus and parts of the limbic system appeared to become functional first, suggesting that a foundational primitive conscious state must be restored before higher order conscious activity can occur" Scheinin said.

Twenty young healthy volunteers were put under anesthesia in a brain scanner using either dexme-detomidine or propofol anesthetic drugs. The subjects were then woken up while brain activity pictures were being taken. Dexmedetomidine is used as a sedative in the intensive care unit setting and propofol is widely used for induction and maintenance of general anesthesia. Dexmedetomidineinduced unconsciousness has a close resemblance to normal physiological sleep, as it can be reversed with mild physical stimulation or loud voices without requiring any change in the dosing of the drug. This unique property was critical to the study design, as it enabled the investigators to separate the brain activity changes associated with the changing level of consciousness from the drugrelated effects on the brain. The staterelated changes in brain activity were imaged with positron emission tomography (PET).

The emergence of consciousness, as assessed with a motor response to a spoken command, was associated with the activation of a core network involving subcortical and limbic regions that became functionally coupled with parts of frontal and inferior parietal cortices upon awakening from dexme-detomidine-induced unconsciousness. This network thus enabled the subjective awareness of the external world and the capacity to behaviorally express the contents of consciousness through voluntary responses.

Interestingly, the same deep brain structures, i.e. the brain stem, thalamus, hypothalamus and the anterior cingulate cortex, were activated also upon emergence from propofol anesthesia, suggesting a common, drugindependent mechanism of arousal. For both drugs, activations seen upon regaining consciousness were thus mostly localized in deep, phylogenetically old brain structures rather than in the neocortex.

The researchers speculate that because current depth-of-anesthesia monitoring technology is based on cortical electroencephalography (EEG) measurement (i.e., measuring electrical signals on the sur-face of the scalp that arise from the brain's cortical surface), their results help to explain why these devices fail in differentiating the conscious and unconscious states and why patient awareness during general anesthesia may not always be detected. The results presented here also add to the current understanding of anesthesia mechanisms and form the foundation for developing more reliable depth-of-anesthesia technology.

The anesthetized brain provides new views into the emergence of consciousness. Anesthetic agents are clinically useful for their remarkable property of being able to manipulate the state of consciousness. When given a sufficient dose of an anesthetic, a person will lose the precious but mysterious capacity of being aware of one's own self and the surrounding world, and will sink into a state of oblivion. Conversely, when the dose is lightened or wears off, the brain almost magically recreates a subjective sense of being as experience and awareness returns. The ultimate nature of consciousness remains a mystery, but anesthesia offers a unique window for imaging internal brain activity when the subjective phenomenon of consciousness first vanishes and then re-emerges. This study was designed to give the clearest picture so far of the internal brain processes involved in this phenomenon.

The results may also have broader implications. The demonstration of which brain mechanisms are involved in the emergence of the conscious state is an important step forward in the scientific explanation of consciousness. Yet, much harder questions remain. How and why do these neural mechanisms create the subjective feeling of being, the awareness of self and environment the state of being conscious?

Note: This story has been adapted from a news release issued by the Academy of Finland

Post Comments:

Search
New Articles
The striatum acts as hub for multisensory integrationThe striatum acts as hub for multisensory integration

'Haven't my neurons seen this before?''Haven't my neurons seen this before?'

In our digital world, are young people losing the ability to read emotions?In our digital world, are young people losing the ability to read emotions?

Driving brain rhythm makes mice more sensitive to touchDriving brain rhythm makes mice more sensitive to touch

Objectification in romantic relationships related to sexual pressure and coercion

Influenced by self-interest, humans less concerned about inequity to others

Mindfulness-based depression therapy reduces health care visits

Learning to play the piano? Sleep on it!

Geniposide protects hippocampal neurons via the non-classical estrogen signaling pathwayGeniposide protects hippocampal neurons via the non-classical estrogen signaling pathway

Maturing brain flips function of amygdala in regulating stress hormones

Targeted brain training may help you multitask better

New gene technique identifies previously hidden causes of brain malformation

Love makes sex better for most women

Study suggests hatha yoga boosts brain function in older adultsStudy suggests hatha yoga boosts brain function in older adults

New research sheds light on how children's brains memorize facts



Archives
September 2014
August 2014
July 2014
June 2014
May 2014
April 2014
March 2014
February 2014
January 2014
December 2013
November 2013
October 2013
September 2013
August 2013
July 2013
June 2013
May 2013
April 2013
March 2013
February 2013
January 2013
December 2012
November 2012
October 2012
September 2012
August 2012
July 2012
June 2012
May 2012
April 2012
March 2012
February 2012
January 2012
December 2011
November 2011
October 2011
September 2011
August 2011
July 2011
June 2011
May 2011
April 2011
March 2011
February 2011
January 2011
December 2010
November 2010
October 2010
September 2010
August 2010
July 2010
June 2010
May 2010
April 2010
March 2010
February 2010
January 2010
December 2009
November 2009
October 2009
September 2009
August 2009
July 2009
June 2009
May 2009
April 2009
March 2009
February 2009
January 2009
December 2008
November 2008
October 2008
September 2008
August 2008
July 2008
June 2008
May 2008
April 2008
March 2008
February 2008
January 2008
December 2007
November 2007
October 2007
September 2007
August 2007
July 2007
June 2007


Science Friends
Agricultural Science
Astronomy News
Sports Tech
Biology News
Biomimicry Science
Chemistry News
Tissue Engineering
Cancer Research
Cybernetics Research
Electonics Research
Forensics Report
Fossil News
Genetic Archaeology
Genetics News
Geology News
Microbiology Research
Nanotech News
Parenting News
Physics News


  Archives |  Submit News |  Advertise With Us |  Contact Us |  Links
Use of this site constitutes acceptance of our Terms of Service and Privacy Policy. All contents © 2000 - 2015 Web Doodle, LLC. All rights reserved.