Signature of consciousness captured in brain scans
2009 11 13

By Anil Ananthaswamy | NewScientist.com


A telltale signature of consciousness has been detected that takes us a step closer to disentangling the brain activity underlying conscious and unconscious brain processes.

It turns out that there is a similar pattern of neural activity each time we become conscious of the same picture, but not if we process information from the image unconsciously. These contrasting patterns of activity can now be detected via brain scans, and could one day help determine if patients with brain damage are conscious. They might even be used to probe consciousness in animals.

"It's very exciting work," says neuroscientist Raphaël Gaillard of the University of Cambridge, who was not involved in the work. "The use of a reproducibility measure to disentangle conscious and non-conscious processes is genuinely new." Gaillard has previously shown that coordinated activity across the entire brain is one of the signatures of consciousness .

Consistent signals

So far, efforts to find a brain signature of consciousness have focused on the intensity of neural activity, how long it lasts, and whether signals tend to be synchronised across different regions of the brain.

"We were looking for something other than the intensity and duration of the neural activity that characterises conscious neural processing," says Aaron Schurger of Princeton University in New Jersey, who led the new work.

He and his colleagues hypothesised that when the brain is presented with the same sensory input – a picture, say – time after time, then conscious awareness of the picture should produce similar neural activity each time.

Conversely, if the sensory input did not enter conscious awareness, it should produce different brain activity each time because there would be other subconscious processes going on at the same time.

Invisible pictures

To test this hypothesis, Schurger and colleagues used functional magnetic resonance imaging (fMRI) to measure the brain activity in 12 volunteers who were asked to look at a series of images – some designed to elicit a conscious response, others a subconscious one.

The researchers invoked conscious processing simply by showing volunteers pictures of faces or houses. To invoke subconscious processing, the researchers presented volunteers with so-called "invisible stimuli".

These consist of two drawings, of either a house or a face, one shown to each eye. Crucially in each pair, one drawing is in pale orange on a pale green background, the other is the same drawing with the colours reversed. When the brain is confronted with such seemingly contradictory visual inputs it reconciles them by creating a yellow patch. So the volunteer consciously sees nothing but yellow, though the brain has subconsciously processed the face or house.

Probing anaesthesia

A set of fMRI recordings of subjects' temporal lobes backed up the team's hypothesis: each time a house or face was consciously processed by an individual, the resulting patterns in brain activity were similar. When the same image was processed subconsciously, the researchers found that the patterns of brain activity were much more variable. "Neural patterns were more reproducible when the drawings were seen consciously compared to when they were not," says Schurger.

The team thinks that reproducibility – the replication of similar neural patterns in the brain each time it becomes conscious of the same sensory input – gives us clues as to what consciousness is.

It could also be used in the future to tell if someone in a coma is conscious, or probe the consciousness of people under anaesthesia, something that also isn't well understood.

Article from: NewScientist.com

Image credit: HealthyJockey.com


Eldon Taylor - Subliminal Programming, Media Persuasion & Mind Control

Eldon Taylor - Mind Programming & How to Break Free from the Spell (Subscription)

Peter Russell - The Primacy of Consciousness

Peter Russell - Awareness, Presence & The Global Brain (Subscription)

Neil Kramer - Awakening, Eschatology & Entheogens

Neil Kramer - The Gates of Awakening & The Field Uplink

Steve Willner - Labyrinth of the Psychonaut

Michael Sharp - A Strong Theory of Consciousness and Creation

Michael Sharp - Consciousness & The Ascension Process




Related Articles
The Science of Brain Breathing
Doctors missing consciousness in vegetative patients
'Consciousness signature' discovered spanning the brain
'Consciousness meter' may predict coma recoveries
Systems Thinking: Ancient Maya’s Evolution of Consciousness and Contemporary
Toward a Science of Consciousness Conference 2009
Teenager who fell unconscious in bath is saved by twin sister's 'sixth sense'
A cyberpunk's search for consciousness
Neuroweapons, war crimes and the preconscious brain
Emotions Can Be Unconsciously And Subliminally Evoked, Study Shows
Forces of the Unconscious Mind
Transcendent Consciousness for Transcendent Technologies
The War on Consciousness
Red Ice Creations - Consciousness, OBE, RV, NDE, Entheogens and Altered States
What is Consciousness?
The Global Brain - Video
My Mystical Big Toe, A Strong Theory of Consciousness and Creation (pdf)


Latest News from our Front Page

If Someone Secretly Controlled What You Say, Would Anyone Notice?
2014 10 01
The subject enters a room in which a 12-year-old boy is seated. A 20-minute conversation ensues. The subject quizzes the boy about current events and other topics to get a sense of his intelligence and personality. But the boy is not what he appears to be. Unbeknownst to the subject, the boy is wearing a radio receiver in his ear, and ...
Obama has had accurate intelligence about ISIS since BEFORE the 2012 election, says administration insider
2014 10 01
‘President Barack Obama’s intelligence briefings have provided him with specific information since before he won re-election in 2012 about the growing threat of the terror group now known alternatively as ISIS and ISIL, an administration insider told MailOnline on Monday. ‘Unless someone very senior has been shredding the president’s daily briefings and telling him that the dog ate them, highly accurate ...
Can holding a magnet against your head help defeat depression?
2014 10 01
Former GP Sue Mildred suffered from crippling depression and anxiety for 20 years. On two occasions it was so severe that she ended up in hospital, and for 15 years she was unable to work. Sue, 51, has tried antidepressants, talking therapies and, out of desperation, even ECT (electro-convulsive therapy), where an electric current is passed through the brain. This did ...
Extremists to have Facebook and Twitter vetted by anti-terror police
2014 09 30
Theresa May to announce new Extremist Disruption Orders to strengthen counter-terrorism if the Tories win the next general election Extremists will have to get posts on Facebook and Twitter approved in advance by the police under sweeping rules planned by the Conservatives. They will also be barred from speaking at public events if they represent a threat to “the functioning of democracy”, ...
Scottish Independence: Protesters demand revote
2014 09 30
Pro-independence campaigners gathered outside the Scottish Parliament for the second day in a row, this time to demand a revote of the September 18 referendum. While yesterday’s “Rally For A Revote” saw the return of Saltires and Yes banners to Holyrood, it did not match the turnout for the “Voice Of The People” rally held on Saturday, when up 3000 people ...
More News »