Featured Research

from universities, journals, and other organizations

Where Does Consciousness Come From?

Date:
March 17, 2009
Source:
Public Library of Science
Summary:
A new paper suggests that four specific, separate processes combine as a "signature" of conscious activity. By studying the neural activity of people who are presented with two different types of stimuli -- one which could be perceived consciously, and one which could not -- researchers show that these four processes occur only in the former, conscious perception task.

New research suggests that four specific, separate processes combine as a "signature" of conscious activity.
Credit: iStockphoto/Linda Bucklin

Consciousness arises as an emergent property of the human mind. Yet basic questions about the precise timing, location and dynamics of the neural event(s) allowing conscious access to information are not clearly and unequivocally determined.

Related Articles


Some neuroscientists have even argued that consciousness may arise from a single "seat" in the brain, though the prevailing idea attributes a more global network property.

Do the neural correlates of consciousness correspond to late or early brain events following perception? Do they necessarily involve coherent activity across different regions of the brain, or can they be restricted to local patterns of reverberating activity?

A new paper suggests that four specific, separate processes combine as a "signature" of conscious activity. By studying the neural activity of people who are presented with two different types of stimuli – one which could be perceived consciously, and one which could not – Dr. Gaillard of INSERM and colleagues, show that these four processes occur only in the former, conscious perception task.

This new work addresses the neural correlates of consciousness at an unprecedented resolution, using intra-cerebral electrophysiological recordings of neural activity. These challenging experiments were possible because patients with epilepsy who were already undergoing medical procedures requiring implantation of recording electrodes agreed to participate in the study. The authors presented them with visually masked and unmasked printed words, then measured the changes in their brain activity and the level of awareness of seeing the words. This method offers a unique opportunity to measure neural correlates of conscious access with optimal spatial and temporal resolutions. When comparing neural activity elicited by masked and unmasked words, they could isolate four converging and complementary electrophysiological markers characterizing conscious access 300 ms after word perception.

All of these measures may provide distinct glimpses into the same distributed state of long-distance reverberation. Indeed, it seems to be the convergence of these measures in a late time window (after 300 ms), rather than the mere presence of any single one of them, which best characterizes conscious trials. "The present work suggests that, rather than hoping for a putative unique marker – the neural correlate of consciousness – a more mature view of conscious processing should consider that it relates to a brain-scale distributed pattern of coherent brain activation," explained neuroscientist Lionel Naccache, one of the authors of the paper.

The late ignition of a state of long distance coherence demonstrated here during conscious access is in line with the Global Workspace Theory, proposed by Stanislas Dehaene, Jean-Pierre Changeux, and Lionel Naccache.


Story Source:

The above story is based on materials provided by Public Library of Science. Note: Materials may be edited for content and length.


Journal Reference:

  1. Gaillard et al. Converging Intracranial Markers of Conscious Access. PLoS Biology, 2009; 7 (3): e61 DOI: 10.1371/journal.pbio.1000061

Cite This Page:

Public Library of Science. "Where Does Consciousness Come From?." ScienceDaily. ScienceDaily, 17 March 2009. <www.sciencedaily.com/releases/2009/03/090316201459.htm>.
Public Library of Science. (2009, March 17). Where Does Consciousness Come From?. ScienceDaily. Retrieved December 20, 2014 from www.sciencedaily.com/releases/2009/03/090316201459.htm
Public Library of Science. "Where Does Consciousness Come From?." ScienceDaily. www.sciencedaily.com/releases/2009/03/090316201459.htm (accessed December 20, 2014).

Share This


More From ScienceDaily



More Mind & Brain News

Saturday, December 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Researchers Test Colombian Village With High Alzheimer's Rates

Researchers Test Colombian Village With High Alzheimer's Rates

AFP (Dec. 19, 2014) In Yarumal, a village in N. Colombia, Alzheimer's has ravaged a disproportionately large number of families. A genetic "curse" that may pave the way for research on how to treat the disease that claims a new victim every four seconds. Duration: 02:42 Video provided by AFP
Powered by NewsLook.com
Double-Amputee Becomes First To Move Two Prosthetic Arms With His Mind

Double-Amputee Becomes First To Move Two Prosthetic Arms With His Mind

Buzz60 (Dec. 19, 2014) A double-amputee makes history by becoming the first person to wear and operate two prosthetic arms using only his mind. Jen Markham has the story. Video provided by Buzz60
Powered by NewsLook.com
Prenatal Exposure To Pollution Might Increase Autism Risk

Prenatal Exposure To Pollution Might Increase Autism Risk

Newsy (Dec. 18, 2014) Harvard researchers found children whose mothers were exposed to high pollution levels in the third trimester were twice as likely to develop autism. Video provided by Newsy
Powered by NewsLook.com
Yoga Could Be As Beneficial For The Heart As Walking, Biking

Yoga Could Be As Beneficial For The Heart As Walking, Biking

Newsy (Dec. 17, 2014) Yoga can help your weight, blood pressure, cholesterol and heart just as much as biking and walking does, a new study suggests. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins