Scientists from the Northeastern University (USA) have concluded that the human brain does not simply react to the external stimuli of the surrounding world, but actively predicts what will happen. The results of the study were published in the journal Nature Reviews Neuroscience (NRN).
The authors questioned the classic "stimulus-cognition-response" model, which assumes that a person first receives sensory information, then processes it and only then makes a decision. According to their data, the brain works differently. even before receiving sensory signals, it forms expectations and prepares possible actions based on past experiences and current tasks.
This means that the perception of the world is highly context dependent. For example, in an unfamiliar place, a person may interpret a dog as a potential threat and "prepare" an escape strategy in advance. In a familiar environment, the same object will be perceived differently as safe.
The researchers explain this with the features of brain function. The cerebral cortex is dominated by so-called top-down connections, from memory areas to sensory areas. The authors estimate that up to 90% of synapses in the visual cortex act in this direction, allowing the brain to "filter" incoming signals through the lens of past experience.
Additional MRI studies have shown that different types of brain waves are involved in this process. Beta waves, which are associated with planning and anticipation, can suppress gamma waves, which are responsible for processing sensory information. If the prediction turns out to be wrong, the brain registers the error and adjusts its models, thus learning occurs.
The new concept also helps explain the characteristics of certain mental states. For example, in depression, the brain may overgeneralize situations, perceiving them as threatening, while in autism, the opposite problem is observed: poor generalization and difficulty adapting to new situations.
