Writing Memories to the Fly Brain
Researchers at the University of Oxford have elucidated the pathway by which experiences and memories are stored in the Drosphilia brain. By artificially activating dopaminergic pathways in the presence of certain odors, the research team was able to condition the flies to react adversely just as well as if the flies had been conditioned with electric shocks.
Fruit flies can be conditioned to react adversely to odors. It was known that dopaminergic receptors play a role in this learning process, but the study aimed to probe the details of this pathway. For a control group, the team placed flies in a T-shaped tube with a total of two scents, one at either end of the T. The control group was conditioned via electric shocks to react adversely to one of the scents.
The experimental group was genetically modified so that dopaminergic neurons near the brain center responsible for olfactory learning (the "mushroom body") expressed an ATP receptor that activated them. Next, a special form of ATP that remains inactive until exposed to light was injected into the flies' brains. The ATP could be activated by a pulse of laser light. The experimental group was conditioned to react adversely to one of the scents by aiming a small pulse of laser light at their head, which released the ATP, activating the dopaminergic neurons and "writing" an aversive reaction into the flies' brains. The experimental group exhibited the same scale of aversive response as the control group.
By silencing certain groups of neurons and examining tissues microscopically, the group was able to isolate a group of only 12 neurons that mediated the dopamine response to olfactory information. This group is known as the PPL1 neurons; they sit to the side of the mushroom body.
This is of interest because the formation of memories is not well understood, and the advancement of our knowledge of how the brain learns, stores experience information, and stores memories is exciting. From an engineering perspective, the small advances made in our understanding of memory formation give hope that one day we will be able to manipulate memories, though for the present this is a wild speculation. Our knowledge of this area is still very primitive, and engineering applications in humans of memory formation are not likely to be realized in my lifetime.
The citation to the original paper is as follows:
Claridge-Chang, Adam; Roorda, Robert D., et. al. Writing Memories with Light-Addressable Reinforcement Circuitry. Cell 139, 405-415.
There are a plethora of news sites/blogs that summarize this story. I used http://scienceblogs.com/neurophilosophy/2009/10/laser_light_false_memories_fruit_fly_brain.php.
Fruit flies can be conditioned to react adversely to odors. It was known that dopaminergic receptors play a role in this learning process, but the study aimed to probe the details of this pathway. For a control group, the team placed flies in a T-shaped tube with a total of two scents, one at either end of the T. The control group was conditioned via electric shocks to react adversely to one of the scents.
The experimental group was genetically modified so that dopaminergic neurons near the brain center responsible for olfactory learning (the "mushroom body") expressed an ATP receptor that activated them. Next, a special form of ATP that remains inactive until exposed to light was injected into the flies' brains. The ATP could be activated by a pulse of laser light. The experimental group was conditioned to react adversely to one of the scents by aiming a small pulse of laser light at their head, which released the ATP, activating the dopaminergic neurons and "writing" an aversive reaction into the flies' brains. The experimental group exhibited the same scale of aversive response as the control group.
By silencing certain groups of neurons and examining tissues microscopically, the group was able to isolate a group of only 12 neurons that mediated the dopamine response to olfactory information. This group is known as the PPL1 neurons; they sit to the side of the mushroom body.
This is of interest because the formation of memories is not well understood, and the advancement of our knowledge of how the brain learns, stores experience information, and stores memories is exciting. From an engineering perspective, the small advances made in our understanding of memory formation give hope that one day we will be able to manipulate memories, though for the present this is a wild speculation. Our knowledge of this area is still very primitive, and engineering applications in humans of memory formation are not likely to be realized in my lifetime.
The citation to the original paper is as follows:
Claridge-Chang, Adam; Roorda, Robert D., et. al. Writing Memories with Light-Addressable Reinforcement Circuitry. Cell 139, 405-415.
There are a plethora of news sites/blogs that summarize this story. I used http://scienceblogs.com/neurophilosophy/2009/10/laser_light_false_memories_fruit_fly_brain.php.
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