The Functional Anatomy of the Claustrum : The Net That Binds

Crick and Koch suggested in 2005 that the claustrum might be engaged in sensory binding operations related to consciousness. This might involve, they suggested, widespread waves of information traveling within the claustrum that might depend on networks of gap-junction linked neurons, which were especially sensitive to the timing of inputs. But they did not suggest any specific system to do this. The purpose of this present paper is to suggest what this mechanism might be. The basic thesis is that the claustrum is a spike coincidence–detecting device, constructed of large number of small simple identical nerve nets. These function as GABA-modulated ‘AND gates’ that convert the separate packets of unbound information in its inputs into an efferent signal that carries the binding information essential for consciousness and other brain functions. This function may also be relevant to processing of synchronized oscillation by the claustrum. Different anatomical regions of the claustrum may exert this function for sensory binding, computation of the significance of reinforcement in a complex environment, and other higher brain functions. We also suggest the outlines of a mechanism by which the cortex may process this input from the claustrum. We review the manner in which this hypothesis explains the present data. There is at present no other detailed hypothesis in this field.