SINC AGENCY
The differences between brain activity in conscious state at rest and allow a group of researchers found a “signature of consciousness” that could be applied in cases of patients in a coma or anesthetized for surgery . Conscious brain activity is characterized by the diversity and dynamism of their connections.
Experiments with monkeys reveal significant differences between states of consciousness and sleep. An anesthetized brain shows rigid connections linked to anatomical map, while consciousness presents a dynamic activity, according to research by Argentine and French scientists has published the journal Proceedings of the National Academy of Sciences of the United States of America (PNAS).
The goal of researchers is to detect the state of consciousness of a person through physiological measurements, which may have important clinical applications, for example, to know the cognitive status of persons coma or anesthesia monitor patients during surgery.
Paul Barttfeld, expert from the National Research Council (CONICET) and lead author of the publication, explained that in this work is measured “how different brain areas are synchronized and unsynchronized time, form networks within seconds diluted to lead to other, dynamically “. It is what they call “the signing of consciousness”.
To characterize the temporal variability of connections, researchers look for recurring patterns of connectivity and stable called “brain states”. When subjects are aware show a great diversity of these brain states, which are scanned sequentially and seemingly random.
However, when those same individuals are anesthetized into oblivion diversity low states drastically . some are very sparingly and still others are completely lost
A reflection of anatomical “wiring”
Under anesthesia, brain states are “very particular” says Paul Barttfeld, connections are weak and inefficient form a network compared to consciousness. In any case, the most interesting is that the dominant states under anesthesia reflect the “structural”, ie connectivity “anatomical wiring white matter that connects distant brain regions.” The closer is a brain state, the more likely underlying white matter is that occur under anesthesia.
This result suggests that those connections that remain under anesthesia are passively reflecting the anatomical “wiring” brain. In conscious states is not, the resemblance between functional and structural connection connection does not affect the probability of a particular brain configuration.
To perform these experiments, scientists used macaque monkeys awake and anesthetized whose activity was analyzed using functional magnetic resonance neuroimaging technique. “We looked at how they change over time connections,” says the specialist, “sometimes two brain regions are synchronized and unsynchronized few seconds later.”
The work published in PNAS experimentally confirmed mathematical models predicted brain dynamics has been found now. Another Argentine researcher, Gustavo Deco, one who had made a more relevant theoretical work in this regard, as acknowledged by the Paul Barttfeld.
Clinical Tool
The goal marked from scientists now is to replicate these same results in humans and verify their future as a clinical tool. “A smaller variety of brain configurations and greater similarity to the cerebral white matter, among other measures, awareness should indicate at least reduced,” says the scientist. Therefore, believes that understanding the pathophysiology of brain activity in cases such as patients in a vegetative state, for example, will “not only diagnose the state of consciousness, but project the clinical evolution and design new therapeutic strategies.”
In any case, in this research there are some areas for improvement, for example, the analysis tools. In this sense, “the definition of brain state has a cognitive grip” point, “but is calculated automatically according to the statistical properties of the data.” Therefore, in future experiments, “states seek to relate the brain explores mental states that the subject experiences simultaneously”
Bibliographic reference:.
– Signature of consciousness in the dynamics of resting -state brain activity. Paul Barttfeld, Lynn Uhrig, James D. Sitt, Mariano Sigman, Bechir Jarraya, Stanislas Dehaene. PNAS, 2015 DOI: 10.1073 / pnas.1418031112
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