How does the brain infer the relationship between two things? Scientists recorded human brain activity through experimental tasks, created a unique database, and then used artificial intelligence (AI) to transform the data into clear high-dimensional geometric shapes, elucidating for the first time the neural processes of reasoning in the human brain. The research results were published online on the website of the journal Nature on the 14th. The Zuckerman Institute at Columbia University and the Sida Senai Medical Center team conducted EEG recordings of over 3000 neurons from 17 epilepsy patients who underwent invasive monitoring at the hospital to determine the source of their seizures. This dataset helped the team monitor the entire process of brain cells reasoning for the first time. The team released a simple reasoning task and simultaneously recorded neuronal activity. In the task, participants discovered the association between images and pressing the left or right button through repeated experimentation. Once participants learn the association between a set of images, the team will immediately switch contacts. After switching, participants will make incorrect judgments, but they can also quickly realize that all image button relationships have changed and infer new rules. The brain processing involved in this experimental task also frequently occurs in real life. In the study, the team revealed the physical expression of reasoning, inference, planning, and even emotion regulation in neuronal activity. They utilized carefully designed AI tools to integrate the recordings of previous neurons and convert participants' brain activity into geometric shapes. These shapes occupy astonishing thousands of dimensions, rather than the familiar three-dimensional (3D) presentation. The team stated that these high-dimensional geometric shapes cannot even be seen on computer monitors, but they can use mathematical techniques to see simplified versions of them in 3D demonstrations. The team found a significant difference in the shape of brain activity between successful and unsuccessful reasoning. In addition, they confirmed that the hippocampus not only depicts a "neural map" of physical space, but also constructs a "cognitive map" related to reasoning and learning. This study provides scientists with the first understanding of how the brain enables humans to learn and perform tasks flexibly, and respond to constantly changing conditions and experiences. The research findings can help guide scientists in finding intervention measures to treat neurological and psychiatric disorders related to memory and decision-making deficits. (New Society)