What happens in the brain when faced with complex challenges? Researchers have gained new insights into how an area works that enables us to speak, empathize, and pay attention. They were able to confirm the importance of this so-called inferior parietal lobe as an “interpretation center” of the brain and show more precisely how ingeniously this area works when we have to interpret complex information.
Brain research has made great strides in recent years and has unlocked many secrets from our thinking organ. For example, different areas in the cerebrum could be assigned to specific tasks. For example, they process our movements or what we see or hear. These regions are therefore responsible for comparatively clear functions and react to specific influencing factors. But the human brain is known to have far more complex abilities, the fundamentals of which remain mysterious. So it is still largely unclear which processing processes underlie the higher mental performance that characterizes humans.
How is complex processing processed?
It seems clear that the brain is accessing information that has already been preprocessed – that is, that is already on an abstract level. Previous studies have shown that there are certain areas in the brain that are responsible for these integration processes. Accordingly, the inferior parietal lobe (IPL) in the parietal lobe also plays such a role: There were indications that it is responsible for functions such as attention, language and social cognition – i.e. the ability to empathize with other people. So far, however, it has remained unclear how this center is able to take on such very different roles, explain the researchers led by Ole Numssen from the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig. That is why they have now devoted a detailed study to this interesting area of the brain.
They studied the brain activities of volunteers who were supposed to do mental tasks while they were in an MRI scanner. First of all, they should put their understanding of the language to the test. In addition, they saw words with meanings such as “dove” and “house”, but also meaningless words such as “pulre”. The task was to assign whether it was a real word or not. Subsequently, the ability to visual-spatial attention was asked: the study participants should react to stimuli on one side of a screen, although they expected something to happen on the other. In the third task, the so-called Sally Anne test was used as a challenge for social cognitive skills. The test subjects saw a comic in which two people interacted with each other. At the end there was a question that could only be answered correctly if the test person was able to empathize with the experiences of the people portrayed.
Divided and cleverly wired
As the researchers report, it became apparent in the evaluations of the brain scans that the IPL has subdivisions – it is divided into areas with different responsibilities. When it comes to language comprehension, the front part of the IPL in the left hemisphere becomes active. When paying attention, however, it is the front part on the right side of the brain. If social skills are required, cooperation is obviously necessary: The posterior IPL parts in both hemispheres come into action together. “Social cognition requires the most interpretation. In this case, the IPL parts therefore presumably work together on both sides of the brain, ”explains Numssen.
The individual sub-areas of the IPL then work together with different regions of the rest of the brain, according to the analyzes of the brain activity. When it comes to attention and language, it is mainly linked to areas on one side of the brain. When it comes to social skills, there are areas on both sides. Here, too, the following seems to apply: the more complex the task, the more intensive the cooperation with other areas. “Our results provide insights into the basic functioning of the human brain. They show how it reacts dynamically to changing requirements. To do this, it links specialized individual areas such as the IPL with other more general regions, ”summarizes Numssen. “The more demanding the tasks, the more intensively the individual areas network with one another.” This makes highly complex functions such as language or social skills possible, according to Numssen.
The researchers say that the IPL is a brain area with particularly human functions. According to them, this fits in with early studies of its counterpart in great apes. Accordingly, the IPL is also responsible for their sometimes considerable cognitive performance in our closest relatives in the animal kingdom. But there are structures in our IPL that are not found in the great apes. This suggests that the brain area has developed further in human evolution and today enables key functions of human cognition. “Ultimately, the IPL is the area with which we interpret the world in our human way,” concludes Numssen.
Max Planck Institute for Human Cognitive and Brain Sciences, specialist article: elife, doi: 10.7554 / eLife.63591