How the brain unconsciously detects patterns

How the brain unconsciously detects patterns

Miriam Nadav & Nature Magazine

The human brain constantly recognizes patterns from everyday experiences. conscious thoughtfound a study of neural activity in people who had electrodes implanted in their brain tissue for medical reasons.

The study shows that neurons in key areas of the brain combine information about what happened and when, allowing the brain to recognize patterns of events as they unfold over time. It helps the brain predict future events, the authors say. The work was published today nature.

“The brain does many things that we are not consciously aware of,” says neuroscientist Edvard Moser of the Norwegian University of Science and Technology in Trondheim. “This is no exception.”

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blizzard of data

To understand the world around us, the brain needs to process large amounts of information about what, where, and when. The study’s authors wanted to investigate how the brain organizes this information over time, an important step. learning and memory.

The team studied 17 People with epilepsy who have electrodes implanted in their brains Preparing for surgical treatment. These electrodes allowed the authors to directly capture the activity of individual neurons in multiple brain regions.

Some of those areas are Hippocampus and entorhinal cortexis involved in memory, navigation. These regions contain time and place cells that act as the body’s internal clock and GPS system, encoding time and location. “Everything from the outside world that comes into our brain has to be filtered through that system,” says study co-author Itzhak Fried, a neurosurgeon and neuroscientist at the University of California, Los Angeles.

parade of faces

To prepare for the main experiment, the researchers showed each participant images of different faces. Scientists identified six things for each participant: The faces that caused individual neurons to fire in participants’ brains Strongly. For example, a participant might have a “man wearing sunglasses” neuron, a “woman wearing a hat” neuron, and four more neurons, each preferring a particular face.

The team placed six images of each participant in a triangle, one in each corner and one on each side. Each image was connected to the closest image by a line running down the sides and through the interior of the triangle.

In the experimental trial, participants viewed a series of facial images. A simple rule determines the order of the images. Each face is followed by the faces connected to it on the triangle. For example, if the first face is the face in the lower left corner of the triangle, the second face will be one of its two immediate neighbors. That is, the face at the center of the base of the triangle, or the face at the center of the left side of the triangle. The experimenter did not reveal this rule to the participants. Additionally, they distracted participants by asking questions about the content of the images during each trial.

During the experiment, neurons in each participant’s hippocampus and entorhinal cortex gradually began to respond not only to the face being presented, but also to the faces directly connected to it on the triangle. When asked if they noticed any patterns in the order of the images, participants said they had not. However, their brain cells are still learning patterns, showing that the brain can recognize patterns without consciously thinking about them. During breaks between experiments, the participants’ “face” neurons played back what they had learned, cycling through the patterns on their own without stimulation.

“It’s not explicit, it’s implicit, and the brain basically recognizes it very quickly and can see the changes in individual cells,” Fried says.

Neurons facing the future

The authors found that neurons can also predict what images will appear next, suggesting that the brain can learn to predict future events based on learned patterns.

“The fact that this is happening without any external motivation is really interesting,” said Matt Jones, a neuroscientist at the University of Bristol in the UK. “Many of the findings are strikingly consistent with predictions from rodent studies and highlight how hippocampal circuits have evolved to build our cognitive maps,” he added. Ta.

Understanding how the brain organizes information about sequences of events could lead to important clinical applications. for example, memory enhancement therapy Freed said it may focus on strengthening specific neuron patterns that represent important memories. “Ultimately, it’s a matter of putting things together in time. That’s really the core of memory.”

This article is reprinted with permission. first published September 25, 2024.