Release date: 2014-10-20
Researchers at the Department of Neuroscience and the Department of Psychology at the University of California, Davis, used light to eliminate specific memories in the mouse brain.
Recently, researchers at the University of California, Davis Center for Neuroscience and the Department of Psychology used light to eliminate specific memories in the mouse brain and proved a basic "how different parts of the brain work together to retrieve episodic memory." theory. The findings are published in the recent issue of Neuron.
Optogenetics, a new technology pioneered by Karl Diesseroth of Stanford University, uses light to manipulate and study nerve cells. Optogenetic technology is rapidly becoming the standard method for studying brain function.
Kazumasa Tanaka, Brian Wiltgen, and colleagues at the University of California, Davis, applied this technique to detect a long-standing idea of ​​memory retrieval. For about 40 years, Wiltgen says, neuroscientists believe that retrieving episodic memory—the memory of a particular place and event—coordinates coordination between the cerebral cortex and the hippocampus (a small structure deep in the brain).
Wiltgen said: "The theory holds that learning involves the processing in the cortex, and the hippocampus produces this pattern of activity during the retrieval process, allowing you to relive these events." If the hippocampus is damaged, the patient will lose decades. Memory.
But this model has been difficult to detect directly until the arrival of optogenetics.
Wiltgen and Tanaka use transgenic mice that, when activated, emit green fluorescence and express a protein that shuts down the cells. Therefore, they are able to fully follow which neurons in the cerebral cortex and hippocampus are activated to learn and remember to retrieve them directly through the light of the fiber optic cable.
They trained the mice and placed them in a cage for a slight electric shock. Often, mice placed in a new environment will sniff around and explore with the nose. However, when they are placed in a cage that has been shocked before, they freeze in a "fear reaction."
Tanaka and Wiltgen showed for the first time that they can label cells involved in learning and show that they can be reactivated during memory recovery. They then turned off specific nerve cells in the hippocampus, indicating that the mice lost memories of unpleasant events. They can also prove that shutting down other cells in the hippocampus does not affect the retrieval of those memories, and follows the fibers from the hippocampus to specific cells in the cerebral cortex.
Wiltgen said: "The cerebral cortex does not do this alone. It requires input from the hippocampus. For a long time, this has been a basic assumption in our field. Kazu's data provides direct evidence for the first time that this is true. ."
They can also see how specific cells in the cerebral cortex connect to the amygdala, a structure in the brain that participates in emotions and produces a frozen response.
Source: Biopass
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