Extracting collective variables from multivariate neural activity of place cells

We investigated the collective activity of the CA1 place field neurons of the mouse hippocampus during free exploration task. Using methods of nonlinear dimensionality reduction, we showed that the activity of a population of several hundred cells can be reduced to two collective variables that determine the position of the animal on the explored environment. Our results support the distributed coding hypothesis and can be used to analyze the collective activity of neurons in other brain regions.