Our Variety's Showing: A Sampler of New Work
Date: November 29, 2010
When Miss Daisy changes lanes
Lane-changing is one of the most dangerous maneuvers in ordinary driving; more than 250,000 U.S. road accidents occur yearly from errors in what looks like a simple move-over.
For drivers of any age, not paying enough attention sets them up for trouble. But cognitive neuropsychologist Cynthia Munro was interested specifically in seniors. She and collaborators studied more than a thousand drivers over age 67 who participated in a Maryland longitudinal study of vision, cognition, mood and driving.
Car monitors tracked their driving performance. And, as well as measures of mood, visual acuity and field perception, the researchers gave drivers cognitive tests, including the Mini-Mental State Exam (for overall cognition), the Brief Test of Attention and the Beery-Buktenicka Test of Visual-Motor Integration (for auditory attention and visual perception).
What was most important? Surprisingly, not the drivers’ state of stress or their overall cognitive function. Safe lane-changing apparently mostly lies in the ability to apply what your visual perception tells you (visuoconstruction) and—surprisingly—in your auditory attentiveness. For information: 410-614-7785.
A “benzo” without drawbacks?
When benzodiazepines like Librium or Valium came out in the 1960s, they seemed nothing short of heaven-sent for anxiety: They worked—quickly—were well-tolerated and overdose wasn’t a particular worry. Yet their downside in having a high potential for abuse and dependence not only marked them as a controlled substance but, after two decades, made physicians wary. So the search has been on for an agent with benzodiazepines’ calming effect but fewer or no drawbacks. In a recent issue of The Journal of Pharmacology and Experimental Therapeutics, Nancy Ator and colleagues reported primate-testing TPA023—a compound more selective in the subtypes of GABA receptors it stimulates than prescribed benzodiazepines. Not only did the drug appear non-addictive, but the animals could ease off it with only a shadow of withdrawal. “This warrants more study,” says Ator. For information: 410-550-2773.
Heart risk: Not just depression
Pointing out the tie between depression and cardiovascular disease has been much in the news lately. And a few studies say it’s not just depression that raises the risk of circulatory troubles: Some suggest a similar link with bipolar disorder. But if the latter’s true, asks psychiatrist Hochang Lee, is it because of the depression that bipolar patients suffer? The mania? Both? Neither?
For answers, Lee used the same large, ongoing survey of Baltimore residents that Hopkins colleagues analyzed for the earlier depression-alone work—the Baltimore Epidemiologic Catchment Area Follow-up Study. His team noted incidence of heart attacks or congestive heart failure in those with a history of mania or hypomania, those who’d had major depression alone or those with neither. The result? Having mood highs also appears linked with risk to the heart—possibly more than major depression. E-mail: Hochang@jhmi.edu
Drugs and dicey decisions
Should I have unprotected sex or use a condom? When some people make that decision, they show a thought process not so different from one food-foraging animals use, explains behavioral psychologist Matthew Johnson. He’s been studying decision-making in the cocaine-addicted—a group with high HIV rates. In the pattern, hyperbolic delay discounting, waiting for a distant but preferable option gets harder the closer you are to a tempting but less-beneficial one. When temptation draws near, you’re more likely to jettison your resolve to wait. But this animal-like way of deciding, which cocaine-users can adopt to “a drastic degree,” means sabotage for responsible sex practices says Johnson. He’s the first to apply decision studies to sexual behavior in people dependent on cocaine; his insights could help tailor education to prevent HIV. E-mail: firstname.lastname@example.org
Giving the brain a different buzz
Transcranial magnetic stimulation (TMS) is already proving itself in Hopkins’ new clinic for patients with resistant depression. But now another noninvasive way to deliver therapy for that disorder and other specific psychiatric illness is showing potential, though it’s still on the workbench. Transcranial direct current stimulation (tDCS) employs weak electrical energy, rather than magnetic, applied to the scalp via electrodes. “We think tDCS works by altering the resting potential of large numbers of brain neurons,” says David Schretlen, who partnered with Tracy Vannorsdall to study the technique.
Unlike TMS, tDCS doesn’t directly prompt neurons’ firing, but shifts their excitability up or down, depending on the polarity of the current and where it’s placed. The resulting brain changes aren’t tightly focused but are likely broader in effect.
The research group—it’s headed by Neurology’s Barry Gordon—is using tDCS to explore the basics of language production. The hint that it improves types of verbal fluency in healthy adults is prompting studies in patients with autism or post-stroke speech loss. For information: 410-955-3268.
Catastrophizers: A way out is delayed
People with chronic pain know intuitively that distractions are a help. And science at Hopkins and elsewhere backs this up. In experiments that mete out some surface skin pain to healthy volunteers—often via capsaicin, the chili pepper molecule—distracting mental tasks can bring significant relief. The analgesia also holds for patients in chronic pain. Further, brain imaging shows there’s an underlying biology to distraction; it may tap the body’s native opioid system.
But Psychiatry’s Claudia Campbell has found that personality can add a layer of complexity. People who “catastrophize”—a not-uncommon group with an especially negative set of thought and emotional responses to pain—may respond differently. In Campbell’s study, healthy subjects were exposed, in random order, to capsaicin while they played video games like PacMan, to capsaicin skin cream alone, and to the games alone. High catastrophizers reported, expectedly, that their pain increased with time. And though they, too, benefitted from distraction, it took longer to kick in. For information: 410-550-7989.