Kerri Smith

Neuroscience vs philosophy: Taking aim at free will

Scientists think they can prove that free will is an illusion. Philosophers are urging them to think again.

Brain imaging: fMRI 2.0

one led by Seiji Ogawa at Bell Laboratories in Murray Hill, New Jersey, the other by Kenneth Kwong at Massachusetts General Hospital in Charlestown, slid a handful of volunteers into giant magnets. With their heads held still, the volunteers watched flashing lights or tensed their hands, while the research teams built the data flowing from the machines into grainy images showing parts of the brain illuminated as multicoloured blobs. The results showed that a technique called functional magnetic resonance imaging (fMRI) could use blood as a proxy for measuring the activity of neurons — without the injection of a signal-boosting compound. It was the first demonstration of fMRI as it is commonly used today, and came just months after the technique debuted — using Functional magnetic resonance imaging is growing from showy adolescence into a workhorse of brain imaging. f MR I 2 .0

Neuroscience: Idle minds

For volunteers, a brain-scanning experiment can be pretty demanding. Researchers generally ask participants to do something — solve mathematics problems, search a scene for faces or think about their favoured political leaders — while their brains are being imaged. But over the past few years, some researchers have been adding a bit of down time to their study protocols. While subjects are still lying in the functional magnetic resonance imaging (fMRI) scanners, the researchers ask them to try to empty their minds. The aim is to find out what happens when the brain simply idles. And the answer is: quite a lot. Some circuits must remain active; they control automatic functions such as breathing and heart rate. But much of the rest of the brain continues to chug away as the mind naturally wanders through grocery lists, rehashes conversations and just generally daydreams. This activity has been dubbed the resting state. And neuroscientists have seen evidence that the networks it engages look a lot like those that are active during tasks. Resting-state activity is important, if the amount of energy devoted to it is any indication. Blood flow to the brain during rest is typically just 5–10% lower than during task-based experiments. And studying the brain at rest should help to show how the active brain works. NATURE.COM Listen to the Nature Podcast for more on the resting brain: go.nature.com/gww192 Neuroscientists are trying to work out why the brain does so much when it seems to be doing nothing at all. IDLE MINDS IL LU ST R AT IO N S B Y R YA N S N O O K

How to map the circuits that define us

Neuroscientists want to understand how tangles of neurons produce complex behaviours, but even the simplest networks defy understanding.Neuroscientists want to understand how tangles of neurons produce complex behaviours, but even the simplest networks defy understanding.

I can't imagine...

Brain damage that wipes out the past also takes out the future.

Mood makes food taste different

Taste test could be used to pinpoint chemical causes of depression.

Epigenome: The symphony in your cells

A slew of papers reveals the chemical tweaks to DNA in a wealth of different cells — as explained with the help of a small orchestra.

Neuroscience: Method man

first lab in 2004, he found himself replacing a high-profile tenant: Nobel-prize winning physicist Steven Chu. “His name was still on the door when I moved in,” says Deisseroth, a neuroscientist, of the basement space at Stanford University in California. The legacy has had its benefits. When chemistry student Feng Zhang dropped by looking for Chu, Deisseroth convinced him to stick around. “I don’t think he knew who I was. But he got interested enough.” Deisseroth is now a major name in science himself. He is associated with two blockbuster techniques that allow researchers to show how intricate circuits in the brain create patterns of behaviour. The development of the methods, he says, came from a desire to understand mechanisms that give rise to psychiatric disease — and from the paucity of techniques to do so. “It was extremely clear that for fundamental advances in these domains I would have to spend time developing new tools,” says Deisseroth. His measured tone and laid-back demeanour belie the frenzy that his lab’s techniques are generating in neuroscience. First came opto genetics, which involves inserting lightsensitive proteins from algae into neurons, allowing researchers to switch the cells on and off with light. Deisseroth developed the method shortly after starting his lab, working with Zhang and Edward Boyden, a close collaborator at the time. Opto genetics has since been adopted by scientists around the world to explore everything from the functions of neuron subtypes to the circuits altered in depression or autism. Deisseroth has lost count of how many groups are using it. “We sent clones Method man

Gorilla joins the genome club

Sequencing of gorilla genome adds to understanding of our evolutionary path

Don't wash those fossils!

Standard museum practice can wash away DNA.