The Optogenetics Quiz: Six Questions on the Medicine Nobel

October brings Stockholm's annual parade of prize announcements, and this week's medicine award makes a perfect subject for an optogenetics quiz. The Nobel Assembly at the Karolinska Institutet announced that Stanford researcher Karl Deisseroth and German scientists Peter Hegemann and Georg Nagel will share the Nobel Prize in Physiology or Medicine for their pioneering work on light-gated ion channels and the method known as optogenetics, according to Nexa News.

The basic idea sounds like science fiction. Hegemann and Nagel found a light-sensitive protein called channelrhodopsin in a type of green algae. Deisseroth then showed that the protein could be installed in animal cells genetically, so that flashes of light would trigger a nerve signal in rats and mice, phys.org reported. By adjusting the light, scientists can flip a neuron's signal on or off with extremely fine precision, so they can trace which circuits drive which behaviors, phys.org reported. That light-switch trick is the science this optogenetics quiz tests.

The method has already changed how neuroscience labs work, and researchers see possible paths toward future treatments for conditions such as dementia, depression, and blindness. Imperial College London neurotechnology professor Simon Schultz described the ability to manipulate cells with light and genetics as transformational across the biological sciences. The optogenetics quiz below asks six questions about the science behind the award. Answers and explanations wait at the end.

The optogenetics quiz questions

Question one. Which trio of researchers will share this year's Nobel Prize in Physiology or Medicine for their optogenetics discoveries? A) Karl Deisseroth, Peter Hegemann, and Georg Nagel. B) Aiko Tanaka, Lars Bergstrom, and Maria Rossi. C) David Kim, Sofia Almeida, and James Okafor.

Question two. In which kind of organism did Hegemann and Nagel first discover channelrhodopsin, the light-sensitive protein at the heart of the technique? A) A type of green algae. B) A deep-sea jellyfish. C) A desert beetle.

Question three. How did Deisseroth demonstrate that optogenetics actually works? A) He introduced the protein into cells genetically and stimulated them with light, triggering a nerve signal in rats and mice. B) He transplanted whole algae into mouse brains and shone sunlight on them. C) He mapped the protein's shape with X-rays and simulated it on a computer.

Question four. Once channelrhodopsin is in place in a neuron, what can scientists do by controlling the light? A) Switch the neuron's signal on or off with extremely fine precision. B) Only dim overall brain activity in broad regions. C) Permanently rewire the neuron's connections to its neighbors.

Question five. Nobel medicine committee member and neuroscientist Abdel El Manira introduced the prize by noting the discovery illuminates behaviors from parental care and aggression to which basic drives? A) Thirst and water intake. B) Hibernation and migration. C) Courtship and nest building.

Question six. Optogenetics is seen as a path toward future treatments for which group of conditions? A) Dementia, depression, and blindness. B) Asthma, diabetes, and gout. C) Hay fever, fractures, and eczema.

Answers and explanations

Here is how the optogenetics quiz shakes out. Each answer below restates the fact behind the question.

Answer to question one: A. The Nobel Assembly at the Karolinska Institutet named Karl Deisseroth of Stanford and Peter Hegemann and Georg Nagel of German academic institutions as this year's laureates, according to Nexa News. The other trios are invented for this optogenetics quiz.

Answer to question two: A. Hegemann and Nagel discovered channelrhodopsin in a type of green algae growing in Peter Hegemann's Berlin laboratory, phys.org reported. The algae protein responds to light, which makes it the perfect natural light switch for the technique.

Answer to question three: A. Deisseroth introduced the algae protein into animal cells genetically and stimulated them with light, which triggered a nerve signal in rats and mice, according to phys.org. That experiment proved researchers could control living neurons with flashes of light.

Answer to question four: A. By adjusting the light, scientists can switch a neuron's signal on or off with extremely fine precision, phys.org reported. Turning selected neurons off and watching what changes lets researchers trace which circuits control which functions.

Answer to question five: A. Abdel El Manira, the committee member who introduced the prize, said the discovery sheds light on functions ranging from parental behavior and aggression to anxiety and fear, along with basic drives such as thirst and water intake, phys.org reported.

Answer to question six: A. Controlling neurons with light could eventually open new approaches to conditions such as dementia, depression, and blindness, according to phys.org. The science is still young, but the prize signals that the committee sees deep clinical promise. That is why this optogenetics quiz ends with the clinical question: the real payoff may belong to future patients.

That science is still young, but the prize signals that the committee sees deep clinical promise behind it. If this optogenetics quiz left you curious about prize season, read the op-ed on why DNA sequencing deserved the chemistry prize, the take on this year's ghost-particle physics award, or try another science brain teaser with the exoplanet aurora quiz.