Région (macroscopique) de convergence-divergence
Dr. Antonio Damasio, a behavioral neurobiologist at the University of Southern California who has studied the neural systems behind memory for years, says that memory is actually a complex process where the brain scatters information across its neurons and then reconnects it using sequential cues. Our brains are not at all like video cameras, he says; they don't have the capacity to keep exact film-like representations of everything that happens in our lives. Instead, the brain records conjunctions of details and events in what Damasio calls "convergence/divergence zones." When we experience something, our neurons create a code to represent a series of disparate facts about the scene or idea that live in different areas of our brains. Recalling specific events or "memories" is actually a process of pulling together these details to essentially reconstruct a version of reality. "When you are asked to remember a certain experience that you had today in which you’re talking with person A, listening to the person’s voice, but you also are in a certain context, B, which is the context of a certain room in a certain building," says Damasio, as an example. "You are going to have the separate recordings of the voice of the person, the sight of the person, the place—but those recordings are going to be reactivated only if another recording of the simultaneity of the event has been made in a convergence/divergence zone." And so the brain sends signals forward through convergence, then divergence allows for the process of "retro-activation," where a memory is called up by putting all of the pieces back together in the mind. A memory is recalled simultaneously in different places, or in rapid sequence in those places, and the different aspects of it come together and can make a record of the proximity and simultaneity of these factors. Doing it this way solves a great problem of economy for the brain, says Damasio: "Instead of having to record every event that you are going through in your life every day with every kind of person, with the books you read, the things you see and hear and touch and smell, what you need to do is record conjunctions of the occurrence of certain events. And then out of the conjunction, you can replay, you can reconstruct. And so, memory in this perspective is always reconstructive. You’re always trying to get at some approximation of what went on rather than an exact recording of what went on.".
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