New Help for Stroke Victims
As if the damage from stroke or traumatic injury were not enough, a cascade of responses by the brain makes matters worse. First, the dying neurons release excess glutamate, which overstimulates nearby neurons; the resulting flood of calcium into those cells causes them to die as well (see p 80 of the text). The brain compensates somewhat by releasing large amounts of inhibitory GABA, which helps calm the runaway activity. However, researchers suspected that this inhibition later interferes with neural recovery, but their attempts to limit GABA activity met with mixed and confusing results. A team at UCLA thought the problem was the researchers' failure to distinguish between GABA-mediated phasic inhibition, which occurs at synapses, and tonic inhibition, which affects receptors elsewhere on the cell. They gave mice that had been subjected to experimentally-induced stroke a drug that blocks the tonic inhibition without affecting phasic inhibition. The idea was to administer the drug after tonic inhibition had protected as many neurons as possible, but before it could wreak too much damage. The drug-treated mice regained 50% more function in their limbs than mice receiving control therapy. How useful this approach will turn out to be is uncertain, but it does offer a new direction in a field that sorely needs new ideas. Nature, Vol 468, 305-309.
A Blood Test for Traumatic Brain Injury?
Too often, head trauma isn't taken seriously until the person begins to show symptoms of brain injury; by then, the best opportunity for minimizing long-term impairment has passed. Now military researchers think they have developed a blood test that will tell doctors whether someone has suffered a concussion or traumatic brain injury (TBI). The test relies on the fact that injured blood cells spill out their contents; two proteins are released in sufficient quantities to pass into the blood stream. The researchers hope to have clinical trials far enough along to go to the Food and Drug Administration for approval by the end of 2012. CNN Health, October 15, 2010. That won't come any too soon, for athletes as well as soldiers. As the text indicates, even athletes with no history of concussions are turning up with Alzheimer's-like brain pathology (see "Is the Brain too Fragile for Sports?" on p 81). The latest
example is former NFL lineman Shane Dronett, who became the 13th player out of 14 autopsied by Boston University School of Medicine's Center for the Study of Traumatic Encephalopathy to have brain pathology. Shortly after retiring from football, Shane began to have terrifying dreams, then went from being "the best dad in the world" to an unpredictable paranoid who could punch out a fast food server just for, according to his 16-year-old daughter, "shaking the ice weird or something." Within 3 years he had committed suicide. According to Shane's wife, Chris, he never let a concussion keep him from playing. CNN Health, April 1, 2011.
Brain Information Sways Jury
In 2005, Grady Nelson stabbed his wife 61 times, killing her, and stabbed and raped her mentally handicapped 11-year-old daughter. In December, 2010, a Miami jury convicted him of the crimes and sentenced him to life in prison. Six jurors voted for the death penalty, but two of those who voted against it said they were swayed by the testimony of Robert Thatcher, a neuroscientist. Using a technique called quantitative EEG, he showed that Nelson had large electrical spikes in the area of his frontal lobes. Thatcher said this indicated impaired frontal lobe functioning, due to three traumatic brain injuries. The jury's decision has not set well with some experts. Emory University neurologist Charles Epstein says the data were riddled with artifacts and the statistical analysis was flawed. According to Epstein, he had never seen such EEG spiking in people with head trauma, and the spikes looked more like blips caused by contractions of scalp muscles. Those criticisms aside, UCLA neurologist Andrew Leuchter cautioned that our present knowledge does not allow us to say that a person's behavior is due to his or her brain abnormality. An In the News feature in Chapter 8 reports that experts made a similar argument after an Italian court reduced the sentence of a murderer based on evidence that he had a gene that has been associated with violent behavior. So, while the public is showing more willingness to take biology into account in assigning responsibility for behavior, experts are urging us not to go beyond the data. Science Insider, December 14, 2010.