The way the primates' brains look

The primates' brains see the world through triangular grids, according to a new study published online October 28 in the journal Nature.

Scientists at Yerkes National Primate Research Center, Emory University, have identified grid cells in the brains of brown monkeys. These neurons excite in repeated triangular patterns when the eye explores images.

The findings have implications for understanding how people form, and remember thinking patterns about the world, as well as how neurodegenerative diseases such as Alzheimer's disease undermine possibilities. there. This is the first time that grid cells have been discovered directly in primates.

Grid cells were identified in mice in 2005, and the existence of these cells in the human brain was deduced indirectly through magnetic resonance imaging.

The electrical activity of reticular cells, recorded by introducing electrodes into the entorhinal cortex of monkeys - an area of ​​the brain in the medial temporal lobe. At the same time, the monkey watches a lot of images on the computer screen and explores those images with their eyes. Eye infrared monitoring, allowing scientists to track parts of the image of the monkey's eyes have focused on. A single grid cell stimulates when the eyes focus on many discrete positions creating a grid pattern.

'Entorhinal cortex is one of the first areas of the brain to lead to degeneration in Alzheimer's disease, so our results may help explain why disorientation is one of the behavioral cues. First of Alzheimer's disease , 'said Dr. Dr. Christian Buffalo, associate professor of neurology at Emory University, and the University of Medical and National Primate Research Center, Yerkes. ' We think these neurons help provide a scene or a structure for the visual experiences stored in memory'.

The discovery of grid cells in our primates is a big step in understanding how our brains form memories of visual information, the first author Nathan Killian, one graduate students at Georgia Institute of Technology and Emory University said.

'This is an interesting way of thinking about memory that can lead to new treatments for neurodegenerative diseases'.

In experiments where mouse grid cells were identified, the cells were stimulated whenever the mice crossed the lines on an invisible triangular grid.

"What's amazing is that we can identify cells that work in the same way when monkeys simply move their eyes ," Buffalo said, suggesting that primates are not. 'visit' a place to build the same kind of intellectual map.

Another aspect of mesh cells that was not previously seen in rodents is that the cellular response changes when the monkey is seeing a second repetitive image. Specifically, mesh cells reduce their excitation rate when a repeating image is seen. Moving from the back (back) toward the front (front) of the cerebral entorhinal, more neurons express memory responses.

"These results demonstrate that grid cells participate in memory, not just visual mapping , " Killian said.