Thursday, January 31, 2013

Pavlovian Mice Help Neuroscientists Locate Fear "Memory" In The Amygdala

A new study released by a neuroscience group at Cold Spring Harbor Laboratory (CSHL) examines how fear responses are learned, controlled and memorized, showing that a particular class of neurons in a subdivision of the amygdala place an active role in these processes...The team trained a strain of mice to respond in a Pavlovian manner to auditory cues, in order to examine the behavior of the animals undergoing a fear test. When the mice heard one of the sounds they had been taught to fear, they began to “freeze,” a very common fear response. The team wanted to study the particular neurons involved. They employed several methods to do this, and to understand the neurons in relation to the fear-inducing auditory cue. One method involved delivering a gene that encodes for a light-sensitive protein into the specific neurons they wanted to examine. The team then implanted a very thin fiber-optic cable directly into the area with the photosensitive neurons. This allowed them to shine colored laser light with pinpoint accuracy onto the cells, activating them. This technique is known as optogenetics. Changes in the behavior of the mice in response to the laser were monitored. more

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