Time-locked multiregional retroactivation: a systems-level proposal for the neural substrates of recall and recognition.
This article outlines a theoretical framework for the understanding of the neural basis of memory and consciousness, at systems level. It proposes an architecture constituted by: (1) neuron ensembles located in multiple and separate regions of primary and first-order sensory association cortices ("early cortices") and motor cortices; they contain representations of feature fragments inscribed as patterns of activity originally engaged by perceptuomotor interactions; (2) neuron ensembles located downstream from the former throughout single modality cortices (local convergence zones); they inscribe amodal records of the combinatorial arrangement of feature fragments that occurred synchronously during the experience of entities or events in sector (1); (3) neuron ensembles located downstream from the former throughout higher-order association cortices (non-local convergence zones), which inscribe amodal records of the synchronous combinatorial arrangements of local convergence zones during the experience of entities and events in sector (1); (4) feed-forward and feedback projections interlocking reciprocally the neuron ensembles in (1) with those in (2) according to a many-to-one (feed-forward) and one-to-many (feedback) principle. I propose that (a) recall of entities and events occurs when the neuron ensembles in (1) are activated in time-locked fashion; (b) the synchronous activations are directed from convergence zones in (2) and (3); and (c) the process of reactivation is triggered from firing in convergence zones and mediated by feedback projections. This proposal rejects a single anatomical site for the integration of memory and motor processes and a single store for the meaning of entities of events. Meaning is reached by time-locked multiregional retroactivation of widespread fragment records. Only the latter records can become contents of consciousness.
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D000818:Animals; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping; D006801:Humans; D008568:Memory / Q000502:physiology*; D011939:Mental Recall / Q000502:physiology*; D010465:Perception / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*; D012153:Retention, Psychology / Q000502:physiology*