Tag Archives: imaging

BigBang

Your Brain and Politics

New research out of the University of Exeter in Britain and the University of California, San Diego, shows that liberals and conservatives really do have different brains. In fact, activity in specific areas of the brain can be used to predict whether a person leans to the left or to the right with an accuracy of just under 83 percent. This means that a brain scan could more accurately predict your politics than the political persuasions of your parents (accurate around 70 percent of the time).

[div class=attrib]From Smithsonian:[end-div]

If you want to know people’s politics, tradition said to study their parents. In fact, the party affiliation of someone’s parents can predict the child’s political leanings about around 70 percent of the time.

But new research, published yesterday in the journal PLOS ONE, suggests what mom and dad think isn’t the endgame when it comes to shaping a person’s political identity. Ideological differences between partisans may reflect distinct neural processes, and they can predict who’s right and who’s left of center with 82.9 percent accuracy, outperforming the “your parents pick your party” model. It also out-predicts another neural model based on differences in brain structure, which distinguishes liberals from conservatives with 71.6 percent accuracy.

The study matched publicly available party registration records with the names of 82 American participants whose risk-taking behavior during a gambling experiment was monitored by brain scans. The researchers found that liberals and conservatives don’t differ in the risks they do or don’t take, but their brain activity does vary while they’re making decisions.

The idea that the brains of Democrats and Republicans may be hard-wired to their beliefs is not new. Previous research has shown that during MRI scans, areas linked to broad social connectedness, which involves friends and the world at large, light up in Democrats’ brains. Republicans, on the other hand, show more neural activity in parts of the brain associated with tight social connectedness, which focuses on family and country.

Other scans have shown that brain regions associated with risk and uncertainty, such as the fear-processing amygdala, differ in structure in liberals and conservatives. And different architecture means different behavior. Liberals tend to seek out novelty and uncertainty, while conservatives exhibit strong changes in attitude to threatening situations. The former are more willing to accept risk, while the latter tends to have more intense physical reactions to threatening stimuli.

Building on this, the new research shows that Democrats exhibited significantly greater activity in the left insula, a region associated with social and self-awareness, during the task. Republicans, however, showed significantly greater activity in the right amygdala, a region involved in our fight-or flight response system.

“If you went to Vegas, you won’t be able to tell who’s a Democrat or who’s a Republican, but the fact that being a Republican changes how your brain processes risk and gambling is really fascinating,” says lead researcher Darren Schreiber, a University of Exeter professor who’s currently teaching at Central European University in Budapest. “It suggests that politics alters our worldview and alters the way our brains process.”

[div class=attrib]Read the entire article following the jump.[end-div]

[div class=attrib]Image: Sagittal brain MRI. Courtesy of Wikipedia.[end-div]

BigBang

The Connectome: Slicing and Reconstructing the Brain

[tube]1nm1i4CJGwY[/tube]

[div class=attrib]From the Guardian:[end-div]

There is a macabre brilliance to the machine in Jeff Lichtman’s laboratory at Harvard University that is worthy of a Wallace and Gromit film. In one end goes brain. Out the other comes sliced brain, courtesy of an automated arm that wields a diamond knife. The slivers of tissue drop one after another on to a conveyor belt that zips along with the merry whirr of a cine projector.

Lichtman’s machine is an automated tape-collecting lathe ultramicrotome (Atlum), which, according to the neuroscientist, is the tool of choice for this line of work. It produces long strips of sticky tape with brain slices attached, all ready to be photographed through a powerful electron microscope.

When these pictures are combined into 3D images, they reveal the inner wiring of the organ, a tangled mass of nervous spaghetti. The research by Lichtman and his co-workers has a goal in mind that is so ambitious it is almost unthinkable.

If we are ever to understand the brain in full, they say, we must know how every neuron inside is wired up.

Though fanciful, the payoff could be profound. Map out our “connectome” – following other major “ome” projects such as the genome and transcriptome – and we will lay bare the biological code of our personalities, memories, skills and susceptibilities. Somewhere in our brains is who we are.

To use an understatement heard often from scientists, the job at hand is not trivial. Lichtman’s machine slices brain tissue into exquisitely thin wafers. To turn a 1mm thick slice of brain into neural salami takes six days in a process that yields about 30,000 slices.

But chopping up the brain is the easy part. When Lichtman began this work several years ago, he calculated how long it might take to image every slice of a 1cm mouse brain. The answer was 7,000 years. “When you hear numbers like that, it does make your pulse quicken,” Lichtman said.

The human brain is another story. There are 85bn neurons in the 1.4kg (3lbs) of flesh between our ears. Each has a cell body (grey matter) and long, thin extensions called dendrites and axons (white matter) that reach out and link to others. Most neurons have lots of dendrites that receive information from other nerve cells, and one axon that branches on to other cells and sends information out.

On average, each neuron forms 10,000 connections, through synapses with other nerve cells. Altogether, Lichtman estimates there are between 100tn and 1,000tn connections between neurons.

Unlike the lung, or the kidney, where the whole organ can be understood, more or less, by grasping the role of a handful of repeating physiological structures, the brain is made of thousands of specific types of brain cell that look and behave differently. Their names – Golgi, Betz, Renshaw, Purkinje – read like a roll call of the pioneers of neuroscience.

Lichtman, who is fond of calculations that expose the magnitude of the task he has taken on, once worked out how much computer memory would be needed to store a detailed human connectome.

“To map the human brain at the cellular level, we’re talking about 1m petabytes of information. Most people think that is more than the digital content of the world right now,” he said. “I’d settle for a mouse brain, but we’re not even ready to do that. We’re still working on how to do one cubic millimetre.”

He says he is about to submit a paper on mapping a minuscule volume of the mouse connectome and is working with a German company on building a multibeam microscope to speed up imaging.

For some scientists, mapping the human connectome down to the level of individual cells is verging on overkill. “If you want to study the rainforest, you don’t need to look at every leaf and every twig and measure its position and orientation. It’s too much detail,” said Olaf Sporns, a neuroscientist at Indiana University, who coined the term “connectome” in 2005.

[div class=attrib]Read the entire article after the jump.[end-div]

[div class=attrib]Video courtesy of the Connectome Project / Guardian.[end-div]