Science Update - Diseases of the Brain

27 May 2007

Interview with

Chelsea Wald and Bob Hirshon

Bob - This week for the Naked Scientists, we're going to talk about new research on diseases of the brain. I'm going to report on scientists are learning about the connection between schizophrenia and depression. But first, Chelsea has this story about a surprising new diagnostic tool...Brain

Chelsea - In the future, neurologists may stockpile canisters of nasty odors, like those of pungent cheese, rotten meat, or skunk. They'd be used to screen for degenerative brain diseases like Alzheimer's. University of Cincinnati psychologist Robert Frank says the sense of smell is often a first casualty of these diseases. So he and biologist Robert Gesteland invented a simple sniff test.

Robert Frank (University of Cincinnati): And it's all based on the observation that if you're sniffing and you don't encounter a smell, you take bigger sniffs than when you're sniffing and you do encounter a smell.

Chelsea - Their device measures the air pressure created by a sniff and compares how hard a patient sniffs at a strong odor versus an empty canister. They use all kinds of smells, but Frank says unpleasant odors are especially useful.

Robert - If you just reflect on your experience in life, and you imagine yourself testing the milk for whether it's sour, or entering into a public restroom that's particularly odiferous, you can appreciate that those kinds of smells are very effective at suppressing your desire to sniff.

Chelsea - If the patient sniffs just as hard at odors like that as he does at any empty canister, further testing would determine whether it's a result of nasal problems, simple aging, or the start of more serious brain damage.

Bob - Thanks, Chelsea. Schizophrenia and mood disorders like depression tend to run in the same families. A recent report in the journal 'Neuron' shows how different kinds of damage to a single gene, called DISC1, may lead to one illness or the other. The researchers bred two strains of mice, each with a different type of DISC1 damage. According to medical geneticist David Porteous at the University of Edinburgh in Scotland, the two strains developed very different symptoms.

David Porteous (University of Edinburgh): So that we had on the one hand, mice that were hyper-excitable and unable to mask out auditory stimulation. And on the other, we had mice that were behaving as if they had a depressed mood and low sociability.

Bob - They then tested the mice on different types of psychiatric drugs.

David - The ones with the more schizophrenia-like behavior responded positively to the treatment with the antipsychotic and those with the mood disorder responded to the treatment with an antidepressant.

Bob - It's not yet known what causes the damage, when it happens, or how each type of damage leads to such different symptoms. But it's hoped that solving these mysteries will help doctors spot the illnesses earlier and treat them more effectively.

Chelsea - Thanks, Bob. Next time, we'll tell you how physicists are combining diamonds and lasers to simulate the insides of giant planets. Until then, I'm Chelsea Wald...

Bob - ...and I'm Bob Hirshon, for AAAS, The Science Society. Back to you, Naked Scientists!

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