<p>Information in the brain is encoded by large populations of neurons, i.e., neural ensembles. Place cells in hippocampal the CA1 field have become an experimental model for studying neural ensembles in the brain, as they provide a convenient research system. This review addresses the latest research on place cells in the CA1 field. The principles of the encoding of space by place cells, the mechanisms of control of place cell activity, and the anatomical and physiological features of place cells in different parts of the CA1 field are considered. Key findings: 1) Rate and phase encoding exist; 2) Dense local connections between pyramidal neurons can support information processing; 3) Interneurons are involved in the formation of both rate and phase codes by place cells; 4) Pyramidal neurons are anatomically and functionally subdivided into deep and superficial cells; 5) Generalization of spatial and non-spatial components of information occurs along the dorsoventral axis. the CA1 field has broad capabilities for signal processing and can implement computationally complex operations in the cognitive processes of the brain.</p>