Which types of brain activity support conscious experiences?
Researchers build artificial time-evolving networks to search for the
brain's dynamic structures underpinning consciousness.

Date:
September 21, 2021
Source:
American Institute of Physics
Summary:
Our subjective experience appears to us in a continuous stream of
integrated information, and researchers now explore the question:
Which characteristics should brain activity have to support this
type of conscious experiences? The group searched for integrated
structures that encompass most of the brain but change configuration
from time to time.

Their hypothesis was these structures should vanish during states
of deep unconsciousness, such as deep sleep or while under general
anesthetics.



FULL STORY ========================================================================== Consciousness remains one of the brain's biggest mysteries. We know
very little about how it emerges from activity within the brain, but
most neuroscientists agree consciousness is dynamic in nature.


==========================================================================
Our subjective experience doesn't appear to us like a sequence of
disjointed snapshots. Instead, we feel the world as a continuous stream
of information.

This information is integrated, since we don't perceive a different stream
per sensory modality -- one for vision, one for hearing, and so forth --
but as a single one where all percepts merge.

In Chaos, from AIP Publishing, researchers explore the question:
Which characteristics should brain activity have to support this type
of conscious experiences? "We conclude that brain activity should be integrated, with multiple regions 'talking to each other' frequently,"
said Enzo Tagliazucchi, a co-author from Universidad Adolfo Iban~ez and
the Latin American Brain Health Institute in Santiago, Chile. "At the same time, the regions involved should change continuously, accounting for
the multiplicity of contents that appear in our conscious experience."
The group searched for integrated structures that encompass most of the
brain but change configuration from time to time. Their hypothesis was
these structures should vanish during states of deep unconsciousness,
such as deep sleep or while under general anesthetics.

"In the case of the brain, nodes are specific anatomical regions and
links indicate brain activity measured at those regions is significantly synchronized," said Tagliazucchi. "At a given time, we have a network describing how brain regions are synchronized, and this network changes
in time as brainwide communication patterns also change." The group
wanted to zero in on groups of nodes tightly coupled together (modules)
that maintain their identity over time, yet the involved nodes change
as time progresses.

"We hypothesize that the largest of these modules is important for consciousness, since it is both dynamic and integrates a large proportion
of brain regions," Tagliazucchi said.

To put it to the test, they developed a way to detect these structures
within temporal networks by using current algorithms within certain
parameters. The researchers built artificial time-evolving networks to
test and benchmark these algorithms and find the optimal parameters.

They applied algorithms using these parameters to brain imaging data
and confirmed several hypotheses.

Brain activity during conscious wakefulness presents large integrated and dynamic network modules. These modules tend to vanish or fragment during
sleep or under general anesthesia. These changes are similar between
both conditions, suggesting unconsciousness occurs in both situations
following the same mechanism.

"We expect our methodological advances will help other scientists
detect integrated structures within other temporal networks
by means of hypothesis- driven parameter optimization," said
Tagliazucchi. "Concerning the neurobiological significance of our
findings, I would like to see our results replicated in other unconscious
brain states and different modal organisms and be validated using metrics
that do not come from neuroimaging, such as behavioral observations." ========================================================================== Story Source: Materials provided by American_Institute_of_Physics. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Sofi'a Morena del Pozo, Helmut Laufs, Vincent Bonhomme, Steven
Laureys,
Pablo Balenzuela, Enzo Tagliazucchi. Unconsciousness reconfigures
modular brain network dynamics. Chaos: An Interdisciplinary Journal
of Nonlinear Science, 2021; 31 (9): 093117 DOI: 10.1063/5.0046047 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/09/210921172711.htm

--- up 2 weeks, 5 days, 8 hours, 25 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1:317/3)