Barlow versus Hebb: When is it time to abandon the notion of feature detectors and adopt the cell assembly as the unit of cognition?

Research on how information is encoded by the brain is largely based on studies of feature detector properties of single neurons, but considerable new data shows that single neurons in many brain areas have mixed selectivity for multiple features and change their tuning properties across realistic information processing situations. Here I consider new approaches that explore cell assemblies as the units of information processing and how these approaches are revealing the structure and organization of neural representations in perception and cognition.