(ORDO NEWS) — In the field of knowledge, people have no equal. After all, no other species has sent probes to other planets, produced life-saving vaccines, or created poetry. The question of how information is processed in the human brain to make this possible has attracted endless attention, but there are no definitive answers.
Our understanding of how the brain works has changed over the years. But current theoretical models describe the brain as a “distributed information processing system.”
This means that it has separate components that are closely interconnected through the wiring of the brain. In order to interact with each other, the regions exchange information through a system of input and output signals.
However, this is only a small part of a more complex picture. In a study published in the journal Nature Neuroscience , we have shown that there is more than just one type of information processing in the brain, based on data from different animal species and from different neuroscience disciplines.
The way information is processed is also different between humans and other primates, which may explain why our species’ cognitive abilities are so high.
To trace how the brain processes information, we borrowed concepts from the so-called mathematical foundation of information theory – the study of the measurement, storage and transmission of digital information, which is crucial for technologies such as the Internet and artificial intelligence. We found that different areas of the brain actually use different strategies for interacting with each other.
Some areas of the brain communicate with others in a very stereotypical way, using input and output. This ensures that signals are transmitted in a reproducible and reliable manner. This refers to areas that are specialized in sensory and motor functions (such as processing sound, visual, and motor information).
Take, for example, the eyes, which send signals to the back of the brain for processing. Most of the information sent is duplicated and transmitted by each eye. Half of this information, in other words, is unnecessary. Therefore, we call this type of input-output information processing “redundant”.
But redundancy provides strength and reliability – it is she who allows us to see with one eye. This ability is essential for survival. In fact, it is so important that the connections between these areas of the brain are anatomically rigidly fixed in the brain, like a telephone line.
However, not all information provided by the eyes is redundant. Combining information from both eyes ultimately allows the brain to process depth and distance between objects. Many types of 3D glasses in the cinema are based on this.
This is an example of a fundamentally different way of processing information that is greater than the sum of its parts. We call this type of information processing – when complex signals from different brain networks are integrated – “synergistic”.
Synergistic processing is most common in areas of the brain that support a wide range of more complex cognitive functions such as attention, learning, working memory, social and numerical cognition. It is not rigid in the sense that it can change depending on our experience, connecting different networks in different ways. This makes it easier to combine information.
Such areas where there is a lot of synergy – mainly in the front and middle cortex (the outer layer of the brain) – integrate various sources of information from the entire brain. Therefore, they are more widely and effectively connected to the rest of the brain than the areas that work with primary sensory and motor information.
Areas of high synergy that promote information integration also typically have many synapses, the microscopic connections that allow nerve cells to communicate.
Is synergy what makes us special?
Synergy (Greek συνεργία “collaboration, assistance, assistance, complicity, complicity” from other Greek σύν “together” + ἔργον “business, work, work, (impact) action”) – an enhancing effect of the interaction of two or more factors, characterized by the fact that the combined action of these factors significantly exceeds the simple sum of the actions of each of these factors, emergence.
We wanted to know if this ability to store and build information through complex networks in the brain differs between humans and other primates, which are our close evolutionary relatives.
To find out, we looked at brain imaging data and genetic analyzes from different species. We found that synergistic interactions account for a larger share of the total information flow in the human brain than in the brains of macaque monkeys. In contrast, the brains of both species are equal in how much they rely on redundant information.
However, we also looked at the prefrontal cortex, an area in the front of the brain that supports more advanced cognitive functions. In macaques, redundant information processing is more common in this area, while in humans it is an area where synergy predominates.
The prefrontal cortex has also undergone significant expansion over the course of evolution. When we looked at data from the chimpanzee brain, we found that the more an area of the human brain evolved in size compared to its chimpanzee counterpart, the more that area relied on synergy.
We also studied the results of genetic analysis of human donors. This showed that brain regions associated with synergistic information processing are more likely to express genes that are uniquely human and are associated with brain development and function, such as intelligence.
This led us to conclude that the extra human brain tissue acquired through evolution may be primarily intended for synergy.
In turn, it is tempting to speculate that the benefits of greater synergy may partly explain the additional cognitive abilities of our species. Synergy could add an important piece to the puzzle of human brain evolution that was previously missing.
Ultimately, our work shows how the human brain navigates the trade-off between reliability and information integration – we need both. It is important to note that the scheme we have developed promises to provide new critical knowledge on a wide range of neuroscience issues, ranging from general cognition to disorders.
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