Post-traumatic stress disorder patients

Post-traumatic stress disorder patients

A team of researchers at the University of Southern California were able to image the brains of live zebrafish to show how the brain processes and stores memories in a groundbreaking study that could provide hope for new treatments for post-traumatic stress disorder (PTSD).

With the help of a specially designed microscope, the researchers were able to record how the fish's brain cells - which are transparent in their youth - lit up with millions of colors and lights during the experiment.

map of brain changes

The study, which mapped changes in the brain, led to the surprising discovery that the process of making memories appears to be done by creating new synapses, or connections between neurons, or making them disappear altogether, contrary to what the commonly accepted theory would imply. Broadly speaking, learning and memories strengthen connections, or synapses, between neurons.

The study used zebrafish because their brains are similar to human brains, both genetically and cellularly, and the young fish are transparent - allowing a look without having to make any changes to their live brains.

"For the past XNUMX years, the common wisdom has been that you learn by changing the strength of synapses, but what has been found is the opposite," researcher Karl Kelsman said in a press release.

Dramatic change

While lead researcher Professor Don Arnold, a professor at the University of Southern California, added: “The best possible result was achieved, because we could see this dramatic change in the number of synapses — some disappearing, some forming, and [which appeared] in a very distinct part of the brain.” . [The common belief] was that synapses change their strength. But the surprise was to see the phenomenon of push and pull, and there was no change in the strengths of the synapses.”

By allowing scientists to track and name changes in connections between neurons, the experiment could help show how memories are formed in the human brain and why certain types of memories are stronger than others, in what researchers believe could offer a breakthrough in new treatments for PTSD. Traumatic PTSD and Neurodegenerative Diseases.

In the amygdala, not the hippocampus

It turns out that negative memories appear to form in a different part of the brain than most other memories in the amygdala, which is responsible for emotional responses such as fight or flight.

Professor Arnold explained: “Memory formation was thought to primarily involve the remodeling of existing synaptic connections while in this study, we discovered that synapses are being formed and removed, while only small, random changes in synaptic strength [of neuronal networks] were seen. existing.”

This could be due to this study's focus on associative memories, which are much more powerful than other memories, and are formed in a different place in the brain, [specifically in] the amygdala, versus the hippocampus for most other memories. And [this discovery] may one day have a connection to PTSD, which is thought to occur through the formation of associative memories.

dazzling microscope

Using a new advanced microscope, invented at the University of Southern California, researchers were able for six years to study the brains of fish and compare the synapses and synaptic changes of neurons, leading to a "breakthrough in the field of neuroscience."
Co-author Professor Scott Fraser added that "the microscope [used in the study] is designed to solve the challenge of imaging and extract the knowledge that scientists need to access."

Laser, Fluorescent, and Algorithms

Fraser, Arnold and Kiselman trained zebrafish to associate the hotness of infrared laser light projected onto their heads with an unpleasant sensation. The fish, whose DNA has been altered so that synapses can be distinguished by a fluorescent protein that glows when illuminated by laser beams, try to avoid the laser by swimming away, and fish that remember the association flick their tails when the light is turned on even without the laser.

Five hours after the initial laser exposure, the researchers measured dramatic changes in fish brain neuron synapses and neuronal function. The results were analyzed with the help of new algorithms developed to monitor the changing interlocking patterns.

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