The Brain Unveiled

By Emily Singer
MIT Technology Review, November/December 2008

Edited by Andy Ross

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Images by Van Wedeen, Ruopeng Wang, Jeremy Schmahmann, and Guangping Dai of the MGH Martinos Center for Biomedical Imaging in Boston, MA; Patric Hagmann of EPFL and CHUV, Lausanne, Switzerland; and Jon Kaas of Vanderbilt University, Nashville, TN.

Brain Connections
Diffusion spectrum imaging, developed by Van Wedeen at Massachusetts General Hospital, analyzes magnetic resonance imaging (MRI) data in new ways, letting scientists map the nerve fibers that carry information between cells. These images, generated from a living human brain, show a reconstruction of the entire brain (1) and a subset of fibers (2). The red fibers in the middle and lower left of both images are part of the corpus callosum connecting the brain hemispheres.

Mapping Diffusion
Neural fibers in the brain are too tiny to image directly, so scientists map them by measuring the diffusion of water molecules along their length. The scientists first break the MRI image into voxels (3D pixels) and calculate the speed at which water is moving through each voxel in every direction. Then they can infer the most likely path of the various nerve fibers (red and blue lines) passing through that spot. The result is a detailed diagram like that of the brain stem (3).

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Buffing the Brain

By Bryan Appleyard
The Sunday Times, November 16, 2008

Edited by Andy Ross

The brain is crème caramel mix of fat, water, and proteins. This is a problem for baby-boomers. The selves they love are just so many crème caramels soon to pass their sell-by date.

In the early 1990s, with the development of magnetic resonance imaging (MRI), we found out how to watch the brain at work. If MRI delivers half of what many people expect it to deliver, these could turn out to be the most revolutionary machines in human history.

Mark Jung Beeman, a professor of psychology at Northwestern University in Illinois, is one of a group trying to understand genius using MRI and EEG. There are two ways of solving problems: analytic and inspirational. With analytic you just plod your way through the work, reasoning your way to the solution. When you stop, new connections can be formed. Finally you reach the eureka moment, you say "Aha!" and your problem is solved.

Beeman: "Although all problem-solving relies on a largely shared cortical network, the sudden flash of insight occurs when solvers engage distinct neural and cognitive processes that allow them to see connections that previously eluded them."

The process seems to be centred on the anterior superior temporal gyrus. At Goldsmiths College in London, Dr Joydeep Bhattacharya says the real issue is not the "Aha!" moment itself, but the way it is produced in the brain: "We need to know the brain processes involved, to find how this moment is strong enough to reach consciousness. We know insight does not come from the sky."

There is a link between musical improvisation and the "Aha!" moment. Improvisation is found to be accompanied by a dissociated pattern of activity in the prefrontal cortex. The prefrontal cortex is to the brain what a conductor is to an orchestra. It pulls the whole show together.

The dissociated pattern echoes the loosening of connections that precedes the "Aha!" moment. Insight and creativity, perhaps even genius, seem to be linked to a brain that can disorganise itself and freewheel, making new and unexpected connections. Divergent thinkers habitually wander around their own minds, looking for links, however absurd or surreal.

In 1788, one of the greatest of all examples of divergent thinking came into the world. It was Mozart's last symphony, the Jupiter.

There has always been a link between madness and genius, and too much divergence can undoubtedly drive you crazy. High creativity is not linked with schizophrenia but with mood disorders — notably bipolar disorder or manic depression.

For a boomer with brain rot, the short answer is use it or lose it. The plasticity of the brain means that it is able, in the face of injury or decay, to find ways of adapting itself to preserve strong patterns of activity. Read good books — nothing works better.

In the end you die, and your crème caramel dies with you. Mozart spent most of his 35 years giving the best ever account in music of why your life is worth living.
 

A New Theory of Mental Disorders

By Benedict Carey
The New York Times, November 10, 2008

Edited by Andy Ross

Bernard Crespi, a biologist at Simon Fraser University in Canada, and Christopher Badcock, a sociologist at the London School of Economics, have published a theory of brain development that may change the way mental disorders like autism and schizophrenia are understood.

Their idea is that an evolutionary tug of war between genes from the father's sperm and the mother's egg can tip brain development in one of two ways. A strong bias toward the father pushes a developing brain along the autistic spectrum, toward a fascination with objects, patterns, mechanical systems, at the expense of social development. A bias toward the mother moves the growing brain along a psychotic spectrum, toward hypersensitivity to mood, increasing a child's risk of developing schizophrenia later on, or of mood problems like bipolar disorder and depression.

Autism and schizophrenia are at opposite ends of a spectrum that includes most psychiatric and developmental brain disorders. Emotional problems like depression, anxiety and bipolar disorder appear with schizophrenia on Mom's side, while Asperger's syndrome and other social deficits are on Dad's.

The theory leans heavily on the work of David Haig of Harvard, who argued in the 1990s that pregnancy was in part a biological struggle for resources between the mother and unborn child. Natural selection should favor mothers who limit the nutritional costs of pregnancy and have more offspring, but it should also favor fathers whose offspring maximize the nutrients they receive during gestation.

Evidence that this struggle is being waged at the level of individual genes is accumulating. An epigenetic effect changes the behavior of the gene without altering its chemical composition. This occurs by muffling a gene with a marker that makes it hard for the cell to read the genetic code.

To illustrate how such genetic reshaping works, Crespi and Badcock point to a remarkable group of children. Those with the genetic disorder called Angelman syndrome typically have a jerky gait, appear unusually happy and have difficulty communicating. Those born with a genetic problem known as Prader-Willi syndrome often are placid and compliant as youngsters.

These two disorders stem from disruptions of the same genetic region on chromosome 15. If the father's genes dominate in this location, the child develops Angelman syndrome. If the mother's do, the result is Prader-Willi syndrome. The former is associated with autism, and the latter with mood problems and psychosis later on, just as the new theory predicts.