A new technique that lights up dopamine-releasing neurons in the brain will help scientists understand how dopamine affects us. (Photo: Colourbox)

Manipulated mouse brains help us understand ADHD

A Danish professor is lighting up mouse brains to better understand how nerve cells are affected by dopamine. The researchers behind the technique – optogenetics – were recently awarded a prestigious Danish research prize.

Optogenetics is a new technique used in behavioral neuroscience. The method combines techniques from optics and genetics to control the activity of individual neurons in living tissue and to measure the effects of those manipulations.

Danish researchers are now using this technique in a project that could prove crucial for how ADHD is diagnosed and treated in the future.

“We believe that people with ADHD release less dopamine in the brain than what’s normal. They also have a reduced ability to focus and concentrate,” says Professor Ulrik Gether, of Copenhagen University’s Department of Neuroscience and Pharmacology.

”By using optogenetics we can find some answers to how dopamine affects the brain’s visual attention and thus also its ability to focus.”

A flash of light can activate the cells

Optogenetic control of nerve cells is arguably the most important technical advance in neuroscience in the past 40 years.

Professor Colin Blakemore

Dopamine is a neurotransmitter that is released by a special group of brain cells. It plays a key role in our ability to learn, our ability to control our movements, our focus, tone of voice, thinking activity and memory.

Gether and his colleagues are currently in the process of genetically modifying dopamine-releasing cells in the brains of lab mice to find out how they are affected by dopamine.

Light switches brain cells on and off

Sensitising the neurons in the mouse brains to light enables the researchers to turn them on and off through an implanted optical fibre. A flash of light can e.g. cause the cells to release dopamine.

This gives the researchers an accurate picture of how dopamine works, and it enables them to study what goes on inside the heads of people who for instance have concentration problems.

Optogenetics involves the use of light to control neurons.

Neurons can be genetically modified and made light sensitive.

Then, when these neurons are stimulated by specific wavelengths of light, they can be switched either on or off.

“The better we get at understanding how the brain works, the more accurate our diagnoses will be. Optogenetics can revolutionise our understanding of a number of diseases,” says Gether.

“Not only can the technique improve our understanding of ADHD, it’s also relevant for a long series of other neuropsychiatric disorders such as Parkinson’s, Alzheimer’s and depression.”

Optogenetics wins major Danish prize

Optogenetics was developed about seven years ago by a group of European and US researchers. These researchers were recently awarded the prestigious Danish €1 million brain research award, The Brain Prize

”Optogenetic control of nerve cells is arguably the most important technical advance in neuroscience in the past 40 years,” Professor Colin Blakemore, the Chair of the Grete Lundbeck European Brain Research Prize Foundation’s selection committee, writes in a press release.

“It offers a revolution in our understanding of the way in which circuits of neurons carry out complex functions, such as learning and controlling movement,” he adds.”And it could provide an entirely new approach to the restoration of function in blindness or brain degeneration, and to the treatment of a variety of other neurological and psychiatric disorders.”

Prize for outstanding brain research

The Brain Prize is awarded annually to one or more researchers who have distinguished themselves by an outstanding contribution to European neuroscience.

This year’s prize was awarded to the six researchers who invented optogenetics. They are Gero Miesenböck from Austria, the three Germans Ernst Bamberg, Peter Hegemann and Georg Nagel and two Americans, Ed Boyden og Karl Deisseroth.


Read the Danish version of this article at videnskab.dk

Translated by: Dann Vinther

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