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Finding ‘you’ in your brain
Brett Smith for redOrbit.com – Your Universe Online
We all know that who we are, our consciousness, resides somewhere within our brain. We just don’t know where.
Now, a team at Vanderbilt University is trying to find out how our brains make us self aware and their newly published study in the Proceedings of the National Academy of Sciences takes us one step closer to finding out.
Current theories on the neural foundation of consciousness typically fall one of two ways: focal or global. Focal theories argue that there are particular areas of the brain that are important for producing consciousness. Global theories claim consciousness comes from large-scale brain activities. The new Vanderbilt study applied an evaluation model called graph theory to investigate the validity of the two theories.
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“With graph theory, one can ask questions about how efficiently the transportation networks in the United States and Europe are connected via transportation hubs like LaGuardia Airport in New York,” said study author Douglass Godwin, a graduate student at Vanderbilt. “We can ask those same questions about brain networks and hubs of neural communication.”
Confidence is key
In the study, scientists enlisted 24 people from the university community to take part in a functional magnetic resonance imaging (fMRI) trial. While in the fMRI scanner, volunteers were asked to recognize a disk that was quickly flashed on a screen. In each session, volunteers responded if they were capable of recognizing the target disk and how much confidence they had in their answer. Researchers then evaluated the results of the high-confidence trials, including both when the target was detected and when it was missed by volunteers.
Study author René Marois, chair of the psychology department at Vanderbilt University, told redOrbit that this method for using high-confidence answers for comparing “aware” versus “unaware” is typical in the field.
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“Using only high confidence trials (for both hits and misses) means that we do not include trials in which subjects were not really sure if they saw the target and just guessed,” Marois said, “including low confidence trials would just add noise to the brain data analysis.”
The study team found that no single area or network of areas of the brain jumped out during awareness of the target. The researcher said the entire brain appeared to become more networked after reports of awareness.
“We know there are numerous brain networks that control distinct cognitive functions such as attention, language, and control, with each node of a network densely interconnected with other nodes of the same network, but not with other networks,” Marois said. “Consciousness appears to break down the modularity of these networks, as we observed a broad increase in functional connectivity between these networks with awareness.”
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“We take for granted how unified our experience of the world is. We don’t experience separate visual and auditory worlds, it’s all integrated into a single conscious experience,” Godwin said. “This widespread cross-network communication makes sense as a mechanism by which consciousness gets integrated into that singular world.”
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Source: http://www.redorbit.com/news/science/1113351161/finding-%e2%80%98you%e2%80%99-in-your-brain-031215/
