Conscious perception is a matter of global neural networks

June 13, 2012
Neurons in the lateral prefrontal cortex represent the content of consciousness. The red trace depicts neural activity (neuronal discharges) in the lateral prefrontal cortex when a stimulus is consciously perceived for 1 second while the green trace depicts neural activity when the same stimulus is suppressed from awareness. Credit: MPI for Biological Cybernetics

(Medical Xpress) -- Consciousness is a selective process that allows only a part of the sensory input to reach awareness. But up to today it has yet to be clarified which areas of the brain are responsible for the content of conscious perception. Theofanis Panagiotaropoulos and his colleagues - researchers at the Max Planck Institute for Biological Cybernetics in Tübingen and University Pompeu Fabra in Barcelona - have now discovered that the content of consciousness is not localized in a unique cortical area, but is most likely an emergent property of global networks of neuronal populations.

The question which parts of the brain are responsible for the things that reach our awareness is one of the main puzzles in neurobiology today. Previous research on the brains of primates has shown that neurons in primary and secondary cortices provide poor representation of visual consciousness. In contrast, the neurons in the temporal lobe seem to reliably reflect the actual of a visual stimulus. These findings indicated that not all parts of the brain are responsible for the content of conscious awareness. Nevertheless, the question whether only one of the brain's areas is responsible for the content of perception or whether more regions are involved in the process has so far remained unanswered.

The Max Planck scientists in Tübingen led by Nikos Logothetis have now addressed this issue using electrophysiological methods to monitor the in the lateral prefrontal cortex of macaque monkeys during ambiguous visual stimulation. The visual stimuli used allow for multiple perceptual interpretations, even though the actual input remained the same. In doing so, Panagiotaropoulos and his team were able to show that the electrical activity monitored in the lateral prefrontal cortex correlates with what the macaque monkeys actually perceive.

They thus concluded that is not only reliably reflected in the temporal lobe, but also in the lateral prefrontal cortex of primates. The results depict that the neuronal correlates of are embedded in this area, which has a direct connection to premotor and motor areas of the brain, and is therefore able to directly affect motor output. These findings support the “frontal lobe hypothesis” of conscious visual perception established in 1995 by the researchers Crick (the co-discoverer of the structure of the DNA molecule) and Koch that awareness is related to neural activity with direct access to the planning stages of the brain.

The results support this theory in so far as they show that the lateral prefrontal cortex is involved in the process of visual awareness. However, the fact that neural activity in two different cortical areas reflects conscious perception shows that the decision which reaches our awareness is most likely not made in a unique cortical area but, rather, that a global network of neurons from different areas of the brain is responsible for it. “Our results therefore broaden the hypothesis and create new questions regarding the cortical mechanisms of visual awareness”, Panagiotaropoulos explains. In the near future the group is going to record the electrical activity in both regions simultaneously.

By this they will try to find out which of the two areas is activated first and draw conclusions on how the two areas interact with each other during conscious perception. This may lead to a better understanding of why only certain things reach our and others remain suppressed.

Explore further: Study suggest that conscious perception has little to do with the primary visual cortex

More information: Theofanis I. Panagiotaropoulos, et al, Visual Consciousness in the Lateral Prefrontal Cortex, Neuron, Volume 74, Issue 5, 924-935, June 7th, 2012, 10.1016/j.neuron.2012.04.013

Related Stories

Study suggest that conscious perception has little to do with the primary visual cortex

March 5, 2012
From a purely intuitive point of view, it is easy to believe that our ability to actively pay attention to a target is inextricably connected with our capacity to consciously perceive it. However, this proposition remains ...

Attention and awareness uncoupled in brain imaging experiments

November 10, 2011
In everyday life, attention and awareness appear tightly interwoven. Attending to the scissors on the right side of your desk, you become aware of their attributes, for example the red handles. Vice versa, the red handles ...

Deeper insight in the activity of cortical cells

July 12, 2011
Visual and tactile objects in our surroundings are translated into a perception by complex interactions of neurons in the cortex. The principles underlying spatial and temporal organization of neuronal activity during decision-making ...

Recommended for you

Neuroscientists build case for new theory of memory formation

October 23, 2017
Learning and memory are generally thought to be composed of three major steps: encoding events into the brain network, storing the encoded information, and later retrieving it for recall.

Running on autopilot: Scientists find important new role for 'daydreaming' network

October 23, 2017
A brain network previously associated with daydreaming has been found to play an important role in allowing us to perform tasks on autopilot. Scientists at the University of Cambridge showed that far from being just 'background ...

Rhythm of memory: Inhibited neurons set the tempo for memory processes

October 23, 2017
The more we know about the billions of nerve cells in the brain, the less their interaction appears spontaneous and random. The harmony underlying the processing of memory contents has been revealed by Prof. Dr. Marlene Bartos' ...

Researchers demonstrate 'mind-reading' brain-decoding tech

October 23, 2017
Researchers have demonstrated how to decode what the human brain is seeing by using artificial intelligence to interpret fMRI scans from people watching videos, representing a sort of mind-reading technology.

Research revises our knowledge of how the brain learns to fear

October 23, 2017
Our brains wire themselves up during development according to a series of remarkable genetic programs that have evolved over millions of years. But so much of our behavior is the product of things we learn only after we emerge ...

Scientists use supercomputer to search for "memory molecules"

October 23, 2017
Until now, searching for genes related to memory capacity has been comparable to seeking out the proverbial "needle in a haystack." Scientists at the University of Basel made use of the CSCS supercomputer Piz Daint to discover ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.