Controlling Brain Circuits in Mice

NIH | MAY 22, 2015

Researchers developed a tool that can turn specific sets of neurons on and off in mice to affect behavior.

In 2007, a team of the University of North Carolina School of Medicine developed a technology dubbed DREADD—Designer Receptors Exclusively Activated by Designer Drugs. DREADDs are protein receptors altered in a lab so that only a specific synthetic chemical can bind and activate them.

Scientists can then create genetically modified animals in which only a specific set of neurons contains the receptor. Only neurons expressing the DREADD respond to the compound. Thus, scientists can explore what happens when those particular neurons are turned on or off.

Until recently, all DREADDs were activated by a chemical called clozapine-N-oxide (CNO).

A team of researchers developed a new DREADD by changing the structure of a naturally occurring receptor called the κ-opioid receptor (KOR).

To create a KOR DREADD, or KORD, the researchers mutated KOR so that it was activated by a synthetic chemical called salvinorin B. This chemical could only bind very weakly to KOR and not at all to other receptors in the body.

The researchers next created genetically modified mice whose brains contained a set of neurons expressing both KORD and a CNO-activated DREADD called hM3Dq. Both movement and feeding could be altered by giving the mice either salvinorin B or CNO. For the first time, scientists could use chemicals to control a neuronal circuit in 2 directions in the same animal.

YOU MAY ALSO LIKE

New Findings Reveal Surprising Role of the Cerebellum in Reward and Social Behaviors

A new study in rodents has shown that the brain’s cerebellum—known to play a role in motor coordination—also helps control the brain’s reward circuitry.

Pre-life building blocks spontaneously align in evolutionary experiment

When Earth was a lifeless planet about 4 billion years ago, chemical components came together in tiny molecular chains that would later evolve into proteins, which are crucial life building blocks. A new study has shown how some early predecessors of proteins may have fallen into line.

Eye cells may use math to detect motion

Our eyes constantly send bits of information about the world around us to our brains where the information is assembled into objects we recognize. Along the way, a series of neurons in the eye uses electrical and chemical signals to relay the information.

The Super-Earth that Came Home for Dinner

It might be lingering bashfully on the icy outer edges of our solar system, hiding in the dark, but subtly pulling strings behind the scenes: stretching out the orbits of distant bodies, perhaps even tilting the entire solar system to one side.

Algal Virus Infects, Affects Humans

A group led by Dr. Robert Yolken at Johns Hopkins University has been studying the links between viral infections and brain development. Unexpectedly, the researchers discovered genetic sequences from Acanthocystis turfacea chlorella virus 1, a type of Chlorovirus, which infects green algae. These viruses are common in fresh water, such as lakes and ponds, but weren’t thought to infect humans or animals.

Scientists generate key life event in artificial mouse ‘embryo’ created from stem cells

The creation of artificial embryos has moved a step forward after an international team of researchers used mouse stem cells to produce artificial embryo-like structures capable of ‘gastrulation’, a key step in the life of any embryo.