It’s a dangerous game – playing around with memories – but someone’s got to do it. MIT researchers have just found out where memories are stored – in individual neurons. Not only that, by selectively activating and deactivating certain neurons or group of neurons, the MIT team could either fire or erase certain memories. “Eternal Sunshine of the Spotless Mind” fans might have known this coming for a long time, but this is the first time this kind of manipulation is being made possible.
The team experimented on mice. They drilled a small hole through the skull and then aimed their lasers at very specific areas in the brain. So that the neurons responded to light signals, the researchers used optogenetically modified neurons. This allowed the scientists to play around with thoughts using electric signals as well as laser light.
One of the demonstrations involved creating a feeling of fear in the mice. The scientists triggered off a very specific area of the hippocampus of the brain using electric signals. This created a fear memory! The team then fired off lasers in order to activate this memory centre and immediately found that the mouse had gone into a “defensive, immobile crouch”, paralysed by fear. However, we still don’t know what the exact memory was; we just know its nature.
Just to ram home the point: scientists can pinpoint certain regions of the brain and create memories of very specific emotions. They can then ‘replay’ these memories, forcing the individual to react to these memories. Till now, the emotions need to be very simple! Remember that these memories can be very false! However, we still cannot manufacture specific detailed filled memories.
Though these experiments have been done only on mice, human brains are not too different, except that it is a lot more complicated. Scientists think that these can be replicated in humans, but no human subjects have been used for experiment, and none will be used in the near future.
This answers the old question of what memories are in the brain. They are not merely concepts – they are physical objects, represented by individual neurons. The next question to be answered is this: how are memories formed? Also, why do we remember a scene like we do, rather than in greater detail? Also, how are memories encoded? Is it possible to create a computer program to bestow a certain set of memories to an individual? The MIT team may be close to answering that.
Memories are more mundane than one might have thought, proves the MIT team. Remember that!