Featured Research

from universities, journals, and other organizations

The radical restructuring of brain networks in comatose patients

Date:
December 4, 2012
Source:
INSERM (Institut national de la santé et de la recherche médicale)
Summary:
Researchers have analyzed data from 17 comatose patients using functional MRI data. Their research reveals that the brain networks of these patients have been restructured. The results could help clinical practitioners diagnose comatose patients.

Brain imaging obtained from connectivity graphs.
Credit: © Sophie Achard – Petra Vertes

Researchers from Inserm, CNRS and the Université Joseph Fourier in Grenoble, in collaboration with Cambridge university, Strasbourg university and clinical practitioners from the Strasbourg University Hospital Centre, have analysed data from 17 comatose patients using functional MRI data. Their research reveals that the brain networks of these patients have been restructured. The results, published in PNAS on 26 November 2012, could help clinical practitioners diagnose comatose patients.

Related Articles


The researchers are focusing on analysing brain networks of brain-damaged comatose (non-traumatised) patients, a state where the individual is considered to be unconscious.

The authors of the study used an original graph theory-based methodology, where images were constructed using functional MRI data at rest and using robust statistical signal-processing methods. Local and overall effectiveness indices of functional brain networks were obtained for 17 brain-damaged patients and 20 healthy volunteers.Correlations in 417 brain regions were extracted to produce brain connection graphs using the statistically significant correlations.

Inserm unit 836 "Grenoble Institut des neurosciences," CNRS researchers from the "GIPSA lab" and from the Behavioural and Clinical Neuroscience Institute in Cambridge, in collaboration with clinical practitioners from the Strasbourg University Hospital Centre, have been able to highlight restructured brain networks in brain-damaged (non-traumatized) comatose patients.

Through comparisons with the healthy subjects, the results demonstrate that the overall cerebral connectivity is preserved in comatose patients. By analysing the connectivity at a local level, the authors of the study have observed that some brain regions ("hubs"), which are highly connected in healthy volunteers, are less well connected in comatose patients. Conversely, the less densely connected regions in the network in healthy subjects become "hubs" in comatose patients.

Brain imaging obtained from connectivity graphs

The connectivity graph method is used to summarize in a single image data acquired through MRI scanning. It translates the effectiveness of connections in a single region compared to all the others. By grouping the most interconnected regions, modules are revealed (each represented by a different colour). Patients and healthy volunteers both have different models in their spatial location, representing radical alterations to the brain connections.

According to current hypotheses, consciousness disorders in persistently comatose patients could be linked to disconnection phenomena between specific cortical regions, particularly the precuneus. The results of this study also point in this direction. "From an overall perspective, the topology of brain connections resists well to traumatism by reorganising the most interconnected regions in the network. It therefore seems that comas may be linked to changes in the location of "hubs" among the brain networks" suggests Chantal Delon Martin, an Inserm researcher.

An assessment of brain injury and comas

Patients with brain injury may go through various clinically-defined states: vegetative state that ischaracterized by the preserved sleep-wake cycle (eyes opening spontaneously, autonomous breathing, etc.); minimally conscious state where patients have partially preserved environmental consciousness (eye movement capacity, reaction to stimulation); locked in syndrome where the patient is paralysed but conscious (communication using eyes); brain death when the coma is irreversible flat line EEG, no blood flow).

Coma (from the Greek κῶμα kôma meaning "deep sleep") is one of the different states where self awareness and consciousness of the outside world is eradicated further to an accident (cerebral, cardiac, etc.). There are two coma phases: the "acute" coma phase (a few days after the accident) and the "chronic" phase (one month or more). Brain restructuring was observed by researchers during the "acute" phase, when it is not known which coma type the patient will develop.

Assessments of brain injuries in comatose patients are currently conducted through clinical examination, morphological MRI, evoked potentials and by SPECT (Single-photon emission computed tomography) or TEP (Positron emission tomography (PET). "The results of this study could help clinical practitioners in the difficult diagnosis process for comatose patients, since this method makes it possible to characterize each patient individually", conclude the researchers.


Story Source:

The above story is based on materials provided by INSERM (Institut national de la santé et de la recherche médicale). Note: Materials may be edited for content and length.


Journal Reference:

  1. S. Achard, C. Delon-Martin, P. E. Vertes, F. Renard, M. Schenck, F. Schneider, C. Heinrich, S. Kremer, E. T. Bullmore. Hubs of brain functional networks are radically reorganized in comatose patients. Proceedings of the National Academy of Sciences, 2012; DOI: 10.1073/pnas.1208933109

Cite This Page:

INSERM (Institut national de la santé et de la recherche médicale). "The radical restructuring of brain networks in comatose patients." ScienceDaily. ScienceDaily, 4 December 2012. <www.sciencedaily.com/releases/2012/12/121204145651.htm>.
INSERM (Institut national de la santé et de la recherche médicale). (2012, December 4). The radical restructuring of brain networks in comatose patients. ScienceDaily. Retrieved November 20, 2014 from www.sciencedaily.com/releases/2012/12/121204145651.htm
INSERM (Institut national de la santé et de la recherche médicale). "The radical restructuring of brain networks in comatose patients." ScienceDaily. www.sciencedaily.com/releases/2012/12/121204145651.htm (accessed November 20, 2014).

Share This


More From ScienceDaily



More Mind & Brain News

Thursday, November 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Kids React to Lammily, The Realistic Barbie Alternative

Kids React to Lammily, The Realistic Barbie Alternative

Buzz60 (Nov. 19, 2014) — Artist Nickolay Lamm's Kickstarter-funded Lammily doll, based on his 'What Would Barbie Look Like as a Real Woman' project, is finally available to buy. Jen Markham explains how the doll's realistic proportions are going over with a test group of second-graders who are used to the impossible measurements of Barbie dolls. Video provided by Buzz60
Powered by NewsLook.com
Trans-Fat Foods Now Linked To Poor Memory

Trans-Fat Foods Now Linked To Poor Memory

Newsy (Nov. 19, 2014) — A study presented at the American Heart Association Scientific Sessions shows a link between diets high in trans fats and decreased memory recall. Video provided by Newsy
Powered by NewsLook.com
Creating Lifelong Love of Science and Math

Creating Lifelong Love of Science and Math

AP (Nov. 18, 2014) — Kelly Mathews is a new mom on a mission to get girls interested in science, technology, engineering and math, and it starts with her own daughter. The Girl Scouts are doing their part, too, by promoting S.T.E.M. through badges and activities. (Nov. 18) Video provided by AP
Powered by NewsLook.com
3D Fun Improves Child Therapy in Poland

3D Fun Improves Child Therapy in Poland

Reuters - Innovations Video Online (Nov. 17, 2014) — Scientists in Poland are helping children with autism and Down's Syndrome better focus on therapeutic exercises by taking them out of their real world environment and into a specially-designed 3D cave in which their imagination can flourish. Jim Drury reports. Video provided by Reuters
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