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A transgenic mouse hippocampus

Update 12/2/xv: We've now followed upwards on this story: The more than we learn almost memory, the weirder it gets. The original continues below.

MIT researchers have shown, for the first time ever, that memories are stored in specific encephalon cells. Past triggering a small cluster of neurons, the researchers were able to force the subject to recall a specific memory. By removing these neurons, the subject would lose that memory.

Every bit you tin can imagine, the trick here is activating private neurons, which are incredibly modest and not really the kind of thing yous can adhere electrodes to. To practice this, the researchers used optogenetics, a bleeding edge sphere of science that involves the genetic manipulation of cells so that they're sensitive to calorie-free. These modified cells are and then triggered using lasers; you drill a hole through the subject's skull and point the light amplification by stimulated emission of radiation at a modest cluster of neurons.

At present, just to temper your excitement, we should annotation that MIT's subjects in this case are mice — but it's very, very likely that the human brain functions in the same manner. To perform this experiment, though, MIT had to breed genetically engineered mice with optogenetic neurons — and we're a long, long way off breeding humans with optogenetic brains.

In the experiment, MIT gave mice an electrical shock to create a fear retentivity in the hippocampus region of the brain (pictured to a higher place) — so afterward, using light amplification by stimulated emission of radiation calorie-free, activated the neurons where the memory was stored. The mice "quickly entered a defensive, immobile crouch," strongly suggesting the fear memory was being recalled.

Optogenetics

The principal significance hither is that nosotros finally have proof that memories (engrams, in neuropsychology speak) are physical rather than conceptual. Nosotros now know that, every bit in Eternal Sunshine of the Spotless Mind, specific memories could be erased. It as well gives the states further insight into degenerative diseases and psychiatric disorders, which are generally caused by the (faulty) interaction of neurons. "The more than we know about the moving pieces that make up our brains," says Steve Ramirez, co-author of the newspaper. "The amend equipped we are to figure out what happens when brain pieces break downwards."

Bear in mind, likewise, that this research follows on from MIT's discovery last year of Npas4, the gene that controls the formation of memories; without Npas4, you lot cannot recall anything. MIT has successfully bred mice without the Npas4 gene.

The question now, though, is how memories are actually encoded — can we programmatically create new memories and thus learn unabridged subjects by inserting a laser into our brain? Nosotros know that a cluster of neurons firing can trigger the memory of your showtime kiss — but why? How can 100 (or 100,000) neurons, firing in a specific order, conjure up a beautifully detailed epitome of an elephant? We've already worked out how images are encoded by the optic nerve, so hopefully MIT isn't too far away from finding out.

Read more at MIT or cheque out the research paper at Nature (paywalled)