Scientists at the University of Washington in St. Louis have studied how neurons in the visual cortex of the brain work.
Previously, it was believed that only neurons in the brain regions associated with smells and spatial memory change their responses to the same stimuli over time. Such features were not noticed behind the visual cortex.
We know that the brain is an ever-changing structure, so we expect neuronal activity to change over the course of a few days as we learn or gain new experiences. What really surprised us was that even in the absence of learning, neural activity in different areas of the brain continues to change.
Ji Xia, study co-author
During the new work, the authors conducted an experiment: they showed mice a short video and recorded the activity of several hundred of their neurons in the primary visual cortex using two-photon calcium imaging. This was repeated for seven days in a row.
As a result, the researchers found that the response of individual neurons to video was unstable for weeks, which means that they reacted differently to the same images.
Previously, a similar process for other groups of neurons was called “representative drift.” But the presence of drift in the visual cortex was a surprise for the authors of the work.