CSAIL Event Calendar: Previous Series
The Neocortical Microcircuit: Organization, Plasticity and Function
Speaker: Henry Markram , Weizmann Institute of Science
The neocortex subserves essentially all high-level cognitive functions. The elementary component of the neocortex is the neocortical microcircuit. The neocortical microcircuit is the product of a new evolutionary leap in the design the nervous system and it is the immense computational power of this microcircuit, which enables mammals their apparently limitless capacity to adapt. Despite this pivotal significance, we still do not know enough about the anatomy and physiology of the microcircuit in order to understand its function. No current model can capture even a miniscule fraction of the computational power of these microcircuits. This lecture will describe: (1) the intricate organizational rules that are active to build the microcircuit; (2) the rules that govern the plasticity at connections between different types of neurons; (3) the principles that govern retrieval of memory stored in neocortical synapses and their constraints on microcircuit operations; (4) principles of recruiting and applying inhibition and; (5) an algorithm for plasticity that generates a novel form of auto-associative, history-dependent memory structure with virtually unlimited information storage capacity. It is concluded that the recurrent microcircuit anatomy embodies sets of relational rules, that the essential physiological operations in the microcircuit enables selection of relationships, that learning involves activating new relationships, and that the potential computational and memory capacity is essentially unlimited.