Assessment of Cooperative Firing in Groups of Neurons: Special Concepts for Multiunit Recordings from the Visual System

Progress in elucidating the cellular basis of visual perception has always depended on relating structure to function. At present, structure-function problems confront the field of cortical neurophysiology with the following types of questions: (a) what are the intrinsic dynamic operations in a local cortical module and what is its relevance for visual perception; (b) what are the principles of sensory processing within a single cortical area with its laminae, columns, and slabs; (c) what is the function of the distributed systems connecting the multiple visual areas? These problems are inherently population problems; i.e., to answer these questions, the dynamic interactions of neuron groups have to be studied. In our Marburg group we have developed (a) techniques for recording the spike trains from up to 19 single units; (b) computeraided procedures for the simultaneous visual stimulation of several units; and (c) real-time correlation methods to assess cooperative firing in groups of neurons.