Our brain is exposed to far more sensory impressions and stimuli than we are aware of. In many cases, visual information reaches our brain and is processed there without our consciously perceiving it. How and where exactly it is decided which information reaches our consciousness and which does not, has not yet been clarified.
Researchers have now discovered that the content of our consciousness is not decided in a single brain region, but that an interplay between neurons from different brain regions is necessary for this.
Why only a certain part of the available sensory information reaches our consciousness is one of the most important questions in neurobiology today. Previous experiments on primate brains showed that neurons in the primary and secondary visual cortex (“visual cortex”) do not reflect actual perception. In contrast, this is the case in the temporal lobe. This research proves that not all brain regions play a role in conscious visual perception. However, it is questionable whether only the neurons in the temporal lobe are involved, or whether other regions play a role.
The scientists used electrophysiological methods to measure neuronal activity in the brains of macaques during visual stimulation. The researchers showed that the electrical activity measured in the lateral prefrontal part of the frontal lobe correlated with the monkeys’ actual perception. Thus, this brain region also appears to play a role in what impressions reach our consciousness. The results support the “frontal lobe hypothesis” for conscious visual perception put forward by scientists in 1995, according to which visual perception is directly related to neural activity that accesses the brain’s planning and decision-making units.
This is the case with the lateral part of the prefrontal frontal lobe. If we add the previously gained knowledge, the content of consciousness is thus reflected at least in two different brain regions. The decision which sensory impressions reach our consciousness is thus not made in a single brain region. Rather, an interplay of neurons in different brain regions seems to be responsible. Our findings extend rather than confirm the hypothesis and raise new questions about the mechanisms of visual consciousness.
In the future, he and his colleagues plan to record neuronal activity in the two brain regions simultaneously to find out which region is activated first after a stimulus and to what extent the two areas work together. In the long term, this could lead to a better understanding of the mechanisms that are crucial for the conscious perception of sensory impressions.
