Understanding the human brain is undoubtedly one of the most difficult tasks of modern science. The leading approach for most of the past 200 years has been to link brain functions to different regions of the brain, or even individual neurons (brain cells). But more and more recent research indicates that we may be going completely wrong in trying to understand the human mind.
The idea that the brain is made up of multiple regions that perform specific tasks is called modularity. At first, it seemed quite successful. For example, it can explain how we recognize faces by activating a chain of specific brain regions in the occipital and temporal lobes. Bodies, however, are processed by a completely different set of brain regions. And scientists believe that other areas - areas of memory - help combine these perceptual stimuli to create holistic representations of people. The activity of certain areas of the brain has also been associated with specific conditions and diseases.
The reason this approach has been so popular is partly because of the technology that gives us an unprecedented cut of the brain. Functional magnetic resonance imaging (fMRI), which tracks changes in blood flow in the brain, allows scientists to see how areas of the brain are activated in response to actions - allowing them to map functions. Optogenetics, meanwhile, a technique that uses genetic modification of neurons to control their electrical activity by pulses of light, could help us investigate their specific contribution to brain function.
While both approaches produce extremely interesting results, it is unclear if they will ever provide us with a meaningful understanding of the brain. A neurophysiologist who finds a correlation between a neuron or region of the brain and a specific but in principle arbitrary physical parameter, such as pain, may infer that this neuron or this part of the brain controls pain. And this is ironic, because even the brain itself has the task of finding correlations in everything it does.
But what if we instead consider the possibility that all brain functions are distributed throughout the brain and that all parts of the brain contribute to all of these functions? If so, the correlations found could be the perfect intelligence trap. And then we need to solve the problem of how a region or type of neuron with a specific function interacts with other parts of the brain in order to form meaningful integrated behavior. Until now, there is no general solution to this problem - only hypotheses for specific cases, for example, recognizing people.
This problem can be well illustrated by a recent study that showed that the psychedelic drug LSD could disrupt the modular organization that explains vision. Moreover, the level of disorganization is related to the degree of “personality disorder” that people have at the time of taking the drug. Research has shown that the drug affects how several areas of the brain interact with the rest of the brain, increasing their level of connectivity. So if we ever want to understand what our sense of self really is, we have to understand the connections that run deep between brain regions as part of a complex network.
Promotional video:
The way forward?
Today, some researchers believe that the brain and its diseases as a whole can only be understood as an interaction between a huge number of neurons distributed throughout the central nervous system. The function of any single neuron depends on the functions of all the thousands of neurons with which it is associated. They, in turn, depend on others. The same region or the same neuron can be involved in a large number of contexts, but have different specific functions depending on the context.
It is possible that it is tiny disruptions in these interactions between neurons that cause avalanche effects in networks that lead to the development of depression or Parkinson's disease. In any case, we need to understand the mechanisms of these networks in order to understand the causes and symptoms of these diseases. Without a complete picture, we are unlikely to be able to successfully treat these and many other conditions.
Specifically, neuroscience must begin to explore how network configurations emerge from the brain's continuous attempts to make sense of the world. We also need to get a clear picture of how the cortex, brainstem, and cerebellum interact with muscles and tens of thousands of optical and mechanical sensors throughout our body to create a unified picture.
Connecting to physical reality is the only way to understand how information is presented in the brain. One of the reasons we have a nervous system in the first place is that the evolution of mobility requires a governing system. Cognitive, mental functions - and even thoughts - can be thought of as mechanisms that have evolved to better plan for the consequences of movements and actions.
Thus, the path of neuroscience may be more focused on general neural recordings (using optogenetics or fMRI), when the goal is not to assign each neuron or brain region to any particular function. This can be used in theoretical network studies that account for various observations and provide an integrated functional explanation. But theory should help us design experiments, not just beat around the bush.
Major obstacles
It won't be easy. Modern technologies are expensive - large financial resources are invested in them, as well as national and international prestige. Another obstacle is that the human mind tends to prefer simpler solutions to more complex ones, even if the former may not explain the results as broadly as the latter.
All relationships between neuroscience and the pharmaceutical industry are also built on a modular model. Typical strategies when it comes to common neurological and mental illnesses are to identify one type of receptor in the brain that a drug can target to address the entire problem.
For example, SSRIs (selective serotonin reuptake inhibitors), which block the absorption of serotonin in the brain so that more are readily available, are currently used to treat a number of different mental health problems, including depression. But they don't work for many patients and can create a placebo effect.
Likewise, epilepsy is now considered a distinct disease and is treated with anticonvulsants, which suppress the activity of all neurons. These drugs don't work for everyone. Any instant disruption in the brain's circuitry - and each patient may have a thousand unique triggering mechanisms - can send the brain into an epileptic state.
From this point of view, neuroscience is gradually losing the compass needle on the way to understanding the brain. We absolutely need to change that. Not only can this be the key to understanding some of the most serious mysteries known in science, such as consciousness, but it will also help in the treatment of many different diseases and health problems, both physical and mental.
ILYA KHEL