1. An integrated self-contained recorder of biological data for a small animal comprising: a converter for conversion of at least one biological signal to digital data, a data storage unit for storing the digital data, a data output for transporting the stored digital data from the recorder after a recording session, a power source, a head connector that attaches to the head of a small animal, the head connector comprising at least one sensor of a biological signal from the small animal, and an electrical connector for connecting the recorder with the head connector.