Neuroscience

Is there a definitive test for mental illness? Not yet, but using advanced neuropsychiatric diagnostic tools including magnetic resonance imaging (MRI) and positron emission tomography (PET), mental health professionals at The Menninger Clinic in Houston are pinpointing the causes of behavioral and psychiatric problems in patients. “Even though a patient may have a straightforward mental health diagnosis or diagnoses, the neuropsychiatric approach can help us rule out medical or neurological reasons for the patient’s symptoms before we settle on a psychiatric reason,” says Florence Kim, M.D…

A variation in a gene called GRIK4 appears to make people with depression more likely to respond to the medication citalopram (Celexa) than are people without the variation, a study by the National Institute of Mental Health (NIMH) has found. The increased likelihood was small, but when people had both this variation and one in a different gene shown to have a similarly small effect in an earlier study, they were 23 percent more likely to respond to citalopram than were people with neither variation. The finding addresses a key issue in mental health research: the differences in people’s…

Jon-Kar Zubieta and colleagues have pinpointed a brain region central to the machinery of the placebo effect—the often controversial phenomenon in which a person’s belief in the efficacy of a treatment such as a painkilling drug influences its effect. The researchers said their findings with human subjects offer the potential of measuring the placebo effect and even modulating it for therapeutic purposes. They also said their findings could enable measurements of brain function that “would help determine dysfunctions in cerebral mechanisms that may impair recovery across a number of…

The link between alcohol and aggression is well known. What’s not so clear is just why drunks get belligerent. What is it about the brain-on-alcohol that makes fighting seem like a good idea" And do all intoxicated people get more aggressive" Or does it depend on the circumstances" University of Kentucky psychologist Peter Giancola and his student Michelle Corman decided to explore these questions in the laboratory. One theory about alcohol and aggression is that drinking impairs the part of the brain involved in allocating our limited mental resources—specifically attention and working…

The classic model of how brain cells communicate was put forth in 1943 by Warren McCulloch and Walter Pitts, at the time the first digital computers were being envisaged, and the McCulloch-Pitts model suggested that brain cells communicate in a binary fashion, represented by a “1” for firing and a “0” for not firing, much as a modern computer functions. While it is common to say that a mammalian brain functions like a computer, this is a somewhat faulty idea, in part because the observation from the Traub lab suggests that gap junctions cause “short circuiting” as part of the brain’s normal…

New research suggests that an eyedrop used to diagnose a rare syndrome in infants can cause severe lethargy lasting up to 10 hours and requiring hospital admission and oxygen administration. In the article “Adverse Effects of Apraclonidine Used in the Diagnosis of Horner Syndrome in Infants”, published in the June issue of Journal of the American Association for Pediatric Ophthalmology and Strabismus, Dr. Patrick Watts and coauthors described five cases of extreme drowsiness or unresponsiveness after infants under 6 months of age were administered 1% apraclonidine eyedrops. Apraclonidine was…

In some regions of Central Europe, salad dressing is made with pumpkin seed oil, which has a strong characteristic nutty flavor and striking color properties - in the bottle it appears red, but it looks green in a salad dressing. Samo and Marko Kreft's paper examines the remarkable two-tone (or dichromatic) color of pumpkin seed oil, by the use of a combination of imaging and CIE (International Commission on Illumination) chromaticity coordinates. The paper also explains why human vision perceives substances like pumpkin seed oil as dichromatic or polychromatic (exhibiting a variety of…

Salk Institute neurobiologists are beginning to tease apart the complex brain networks that enable humans and other higher mammals to fix our gaze on one object while independently directing attention to others - that pesky method mom used to always know you were doing something wrong when her back was turned. In a study published in the July 5, 2007 issue of Neuron, the researchers report two classes of brain cells with distinct roles in visual attention, and highlight at least two mechanisms by which these cells mediate attention. “This study represents a major advance in our understanding…

Researchers have come a step closer to understanding the incredible targeting system of human vision, namely how the brain and eye team up to spot an object in motion and follow it, a classic question of human motor control. The study shows that two distinctly different ways of seeing motion are used — one to catch up to a moving object with our eyes, a second to lock on and examine it. “Without the ability to lock our eyes onto a moving target, something called smooth pursuit, athletes cannot ‘keep their eye on the ball,’ and a person walking down the street cannot examine the facial…

A role for prion proteins, the much debated agents of mad cow disease and vCJD, has been identified. It appears that the normal prions produced by the body help to prevent the plaques that build up in the brain to cause Alzheimer’s disease. The possible function for the mysterious proteins was discovered by a team of scientists led by Medical Research Council funded scientist Professor Nigel Hooper of the University of Leeds. Alzheimer’s and diseases like variant Creutzfeldt-Jakob Disease follow similar patterns of disease progression and in some forms of prion disease share genetic features…