CONCEPT
The Cell Assembly (Hebb)
Donald Hebb's 1949 proposal that a thought is not a cell but a coalition—a distributed pattern of neurons welded by experience into a tightly interconnected group that fires as a unit—and the direct conceptual ancestor of the distributed representations that encode all knowledge in contemporary neural networks.
The cell assembly is
Donald Hebb's answer to one of the oldest puzzles in the study of the mind: how does a brain made of isolated neurons hold a thought? His answer: it does not, and the premise is wrong. No single neuron means anything. Meaning lives in groups. Repeated experience strengthens the connections among cells that are active together, welding them into tightly interconnected coalitions that tend to fire as a unit. Activate enough members of such a coalition and the whole ignites, because the strengthened internal connections carry the activation around the loop. An assembly is the physical embodiment of an idea or a percept: not a grandmother cell that fires for your grandmother, but a distributed coalition of cells whose joint activity is the thought of her. The concept does not live in any one neuron; it lives in the pattern across many.