Internally Organized Cell Assembly Trajectories

Abstract

Sequences of neuronal patterns are not always imposed on brain circuits in an outside-in manner by the sensory inputs. Internally organized processes can sustain self-organized and coordinated neuronal activity even without external inputs. A prerequisite of cognition is the availability of internally generated neuronal sentences. Self-generated, sequentially evolving activity is the default state of affairs in most neuronal circuits. Neuronal activity moves perpetually, and its trajectory depends only on initial conditions. Large recurrent networks can generate an enormous number of trajectories without prior experience. On the other hand, each is available to be matched by experience to “represent” something useful for the downstream reader mechanisms. The richness of the information depends not on the numbers of generated sequences but on the reader mechanisms. It is typically the reader structure that initiates the transfer of information, coordinating the onset of messages from multiple senders.