Health

Scientists have captured the brain that makes memories for the first time

A team of researchers at the University of Southern California has imaged 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 PTSD.

With the help of a specially designed microscope, the researchers were able to record how the fish’s brain cells – which are transparent when young – lit up like Times Square on New Year’s Eve during the experiment.

The study, which mapped changes in the brain, made the surprising discovery that making memories appears to create new synapses — connections between neurons — or make them disappear altogether. The widely accepted theory that learning and memories strengthen synapses has not been clear.

“For the past 40 years, common wisdom has been that you learn by changing the strength of synapses but that is not what we found in this case,” Karl Kisselmann said in a press release.

Scroll down for the video

A team of researchers at the University of Southern California has imaged the brains of zebrafish to show how the brain processes and stores memories. Pictured is a survey of young zebrafish using a specially designed USC microscope

With the help of a specially designed microscope, the researchers were able to record how the fish's brain cells — which are transparent when young — lit up like Times Square on New Year's Eve (pictured) during the experiment.

With the help of a specially designed microscope, the researchers were able to record how the fish’s brain cells — which are transparent when young — lit up like Times Square on New Year’s Eve (pictured) during the experiment.

Lead author Professor Don Arnold at the University of Southern California added: “This was the best possible result we could have because we saw this dramatic change in the number of synapses – some disappearing, some forming, and we saw it in a very distinct part of the brain.

The belief was that synapses change their strength. But I was surprised to see the phenomenon of push and pull, and that we didn’t see a change in the strengths of the synapses.

By allowing scientists to track and name synaptic changes, the experiment may help show how memories form and why certain types of memories are stronger than others.

Researchers believe this could offer a breakthrough in new treatments for post-traumatic stress syndrome (PTSD) and neurodegenerative diseases.

The study, which mapped changes in the brain, made the surprising discovery that making memories appears to create new synapses — connections between neurons — or make them disappear altogether.  The picture is a clip from the study

The study, which mapped changes in the brain, made the surprising discovery that making memories appears to create new synapses — connections between neurons — or make them disappear altogether. The picture is a clip from the study

By allowing scientists to track and name synaptic changes, the experiment may help show how memories form and why certain types of memories are stronger than others.

By allowing scientists to track and name synaptic changes, the experiment may help show how memories form and why certain types of memories are stronger than others.

Researchers believe this could offer a breakthrough in new treatments for post-traumatic stress syndrome (PTSD) and neurodegenerative diseases.

Researchers believe this could offer a breakthrough in new treatments for post-traumatic stress syndrome (PTSD) and neurodegenerative diseases.

He finds that negative memories appear to form in a different part of the brain than most other memories - the amygdala, which is responsible for emotional responses including fight or flight.

He finds that negative memories appear to form in a different part of the brain than most other memories – the amygdala, which is responsible for emotional responses including fight or flight.

He found that negative memories appear to form in a different part of the brain than most other memories – the amygdala, which is responsible for emotional responses including fight or flight.

“Memory formation has been thought to involve primarily the remodeling of existing synaptic connections while in this study, we found formation and removal of synapses, but we only saw small, random changes in the synaptic strength of existing synapses,” Arnold explained.

This may 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, the amygdala, versus the hippocampus for most other memories. This may one day have a connection to PTSD, which is thought to be mediated through the formation of associative memories.

The study used zebrafish because their brains are similar to those of humans, both genetically and cellularly, but the young fish are transparent – allowing an unaltered look at their living brains.

“Our sensors can label synapses in a living brain without changing their structure or function, which was not possible with previous tools,” Professor Arnold said.

Using a new advanced microscope, invented at the University of Southern California, they were able to study fish brains over time and compare synapses and synaptic changes in the same brains – a ‘breakthrough in the field of neuroscience’.

Co-author Professor Scott Fraser added: “The microscope we built is designed to solve this imaging challenge and extract the knowledge we need.”

Sometimes you try to get such an amazing photo that kills what you are looking at. For this experiment, we had to find the right balance between getting an image that was good enough to get answers, but not so amazing that we’re killing the fish with photons.

The study used zebrafish because their brains are similar to those of humans, both genetically and cellularly, but the young fish are transparent - allowing an unaltered look at their living brains.  Pictured is a small zebrafish

The study used zebrafish because their brains are similar to those of humans, both genetically and cellularly, but the young fish are transparent – allowing an unaltered look at their living brains. Pictured is a small zebrafish

Using a new advanced microscope (pictured) invented at the University of Southern California, they were able to study fish brains over time and compare synapses and synaptic changes in the same brains - a 'breakthrough in the field of neuroscience'

Using a new advanced microscope (pictured) invented at the University of Southern California, they were able to study fish brains over time and compare synapses and synaptic changes in the same brains – a ‘breakthrough in the field of neuroscience’

The results were analyzed in a group led by Kiselman that developed new algorithms to monitor changing entanglement patterns.

The results were analyzed in a group led by Kiselman that developed new algorithms to monitor changing entanglement patterns.

Previous experiments were done on dead specimens while this experiment means they have hundreds of images of the neural activity of the same fish.

“This is a depiction of a ninja, we sneak inside without noticing,” Fraser said.

During six years of research, Fraser, Arnold and Kesselman have trained zebrafish to associate the light being played with the irritating sensation of heating infrared lasers in their heads.

The fish, whose DNA has been altered so that synapses can be distinguished by a fluorescent protein that glows when scanned with a laser, will try to avoid the laser by swimming away.

The fish that remembered the bond flicked its tail when the light shone, even without the laser.

Five hours after the initial laser exposure, the researchers measured dramatic changes in the animal’s synapsis and neuronal function.

The results were analyzed in a group led by Kiselman that developed new algorithms to monitor shifting synaptic patterns.

What is Post Traumatic Stress Disorder (PTSD)?

Post-traumatic stress disorder (PTSD) is an anxiety disorder caused by extremely stressful, frightening, or traumatic events.

People with PTSD often have nightmares and flashbacks of the traumatic event and can experience insomnia and an inability to concentrate.

Symptoms are often severe enough to have a serious impact on a person’s daily life, and they can appear immediately after the traumatic event or years later.

PTSD is thought to affect about 1 in 3 people who have a traumatic experience, and it was first documented in World War I in soldiers who sustained shell shock.

People who are concerned that they may have PTSD should see their GP, who may recommend a course of psychotherapy or antidepressants.

Combat Stress operates a 24-hour helpline for veterans, which can be reached at 0800138 1619.

.

Leave a Reply

Your email address will not be published. Required fields are marked *