Conscious perception is a matter of global neural networks

June 13, 2012, Max Planck Society
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

Silence is golden when it comes to how our brains work

June 18, 2018
It's the comparative silence between the firing spikes of neurons that tells what they are really up to, scientists report.

Observing brain plasticity during cello training

June 15, 2018
Music acquisition provides an excellent model of neural plasticity, and has become a hot research subject in neurology. Music performance provides an unmatched array of neural complexities revealing how neural networks are ...

New discovery about the brain's water system may prove beneficial in stroke

June 15, 2018
Water is transported from the blood into the brain via an ion transporter, according to a new study on mice conducted at the University of Copenhagen. If the mechanism can be targeted with medicine, it may prove relevant ...

Study shows how intensive instruction changes brain circuitry in struggling readers

June 14, 2018
The early years are when the brain develops the most, forming neural connections that pave the way for how a child—and the eventual adult—will express feelings, embark on a task, and learn new skills and concepts.

When emotional memories intrude, focusing on context could help, study finds

June 14, 2018
When negative memories intrude, focusing on the contextual details of the incident rather than the emotional fallout could help minimize cognitive disruption and redirect the brain's resources to the task at hand, suggests ...

The neurons that rewrite traumatic memories

June 14, 2018
Memories of traumatic experiences can lead to mental health issues such as post-traumatic stress disorder (PTSD), which can destroy a person's life. It is currently estimated that almost a third of all people will suffer ...

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.