The brain’s ability to catch and correct its own processing errors deteriorates significantly after only a few drinks, researchers have concluded. According to a study in the November 8 Science, even relatively small amounts of alcohol can adversely affect the anterior cingulate cortex, a region of the brain that monitors errors in cognitive processing. Participants performed tasks under placebo or two different doses of alcohol, corresponding to blood alcohol concentrations of zero, 0.04%, and 0.10%, respectively. Electrical signals from the anterior cingulate cortex were significantly altered in the subjects who consumed alcohol. Unable to detect errors in their cognitive processing, these volunteers were also unable to make changes in their behavior to adjust their performance on the task.

The decay of brain cells in disorders such as Alzheimer’s disease may be caused by lack of iron, reported a study in the November 12 Proceedings of the National Academy of Sciences. In experiments involving human and animal brain cells, researchers discovered that reducing the production of heme led to degeneration similar to that caused by aging and Alzheimer’s disease. When the researchers tried to prompt the cells to multiply, those that were heme-deficient died. Additionally, interfering with heme caused cells to make abnormal versions of amyloid precursor protein, which accumulate to form the brain deposits seen in Alzheimer’s disease. Researchers feel that taking a multivitamin may serve as an “insurance pill” against heme deficiency.

The prevalence of epilepsy increases with socioeconomic deprivation, according to a study published in the November 2 BMJ. Researchers analyzed all incident cases of epilepsy in a community-based population in London and southeast England. The investigators obtained clinical and demographic data for each patient, and determined the degree of social deprivation for each patient. They analyzed 190 new cases of epilepsy and found a strong correlation between rate of epilepsy and socioeconomic deprivation, with the incidence in the most deprived fifth of the population more than twice the rate of the least deprived fifth of those studied.

Researchers have determined that levetiracetam, an antiepileptic drug commonly used in combination with other drugs, may be successful as monotherapy. In a study published in the October Epilepsy and Behavior, investigators analyzed 37 patients with epilepsy; for nine of the patients, levetiracetam was their first treatment for epilepsy. Of the seven patients who completed the six-month study, four became seizure-free and three had their seizures reduced by 75%. The remaining patients experienced difficult-to-control seizures and were unsatisfied with results from other antiepileptic drugs. Nearly 80% of these patients had their seizures reduced by half, and nine became seizure-free. The patients also reported fewer side effects that could hamper their quality of life.

A seemingly mild injury to the brain could sensitize neurons to attack using immune system proteins that are otherwise protective, according to a study in the October 24 Neuron. Researchers exposed cultures of neurons and astrocytes to levels of glutamine that would be generated by a mild brain injury. When they exposed the same cultures to a set of immune complement proteins, the neurons were preferentially killed. The investigators determined that the glutamate treatment sensitized neurons to attack by complements. These findings may explain why people with neurodegenerative diseases significantly worsen following brief seizures, mild head trauma, or stroke.

High-frequency stimulation of the subthalamic nucleus may relieve symptoms of obsessive-compulsive disorder, investigators reported in the October 26 Lancet. The researchers implanted electrodes in the subthalamic nucleus and zona incerta to alleviate parkinsonian symptoms in two patients with Parkinson’s disease and a history of obsessive-compulsive disorder. Two weeks after surgery, both patients stated that their compulsions disappeared and their obsessive symptoms improved. The investigators believe that “the disappearance of compulsions and amelioration of obsessions in both patients are unlikely to be caused by natural variations in the severity of obsessive-compulsive disorder,” as both patients’ symptoms had been stable for decades.

Older men with higher levels of free testosterone in their bloodstreams have better visual and verbal recall and perform spatial tasks more adeptly than their peers, stated an article in the November Journal of Clinical Endocrinology & Metabolism. Researchers evaluated the testosterone levels of 407 men 50 and older, and correlated free and total testosterone levels with the men’s performances on memory and other cognitive tests. They discovered that only free testosterone was significantly associated with higher scores on verbal, visual memory, and spatial tests. However, investigators cautioned that testosterone replacement therapy may not be advisable for older men because the effects of hormone supplementation remain unclear.

Inserting a low-flow ventriculoperitoneal shunt to drain cerebrospinal fluid in patients with Alzheimer’s disease is reasonably safe, concluded an article in the October 22 Neurology. Twenty-nine subjects with probable Alzheimer’s disease were randomized to receive treatment (a shunt) or no treatment. Both groups were assessed using the National Adult Reading Test, the Mattis Dementia Rating Scale, and the Mini-Mental State Exam. At the one-year follow-up, the shunt-treatment group showed little change in the total scores on the Mattis Dementia Rating Scale, compared with the control group, whose scores declined; in addition, the Mini-Mental State Examination scores supported a trend in favor of shunt treatment. Researchers did not observe any device-related adverse events or complications.

Investigators have discovered a method of causing human embryonic stem cells implanted into the brains and spinal cords of rats to differentiate into nerve cells, according to the November 11 online edition of Nature Neuroscience. The researchers primed the stem cells for nerve cell development and injected the cells into the central nervous system of healthy rats. The primed cells then developed into the appropriate neurons for the area into which they were implanted. Researchers explained that priming gets “the cells into a plastic intermediate stage, and then after they’re injected they acquire environmental cues and become specific kinds of neurons according to where they’re located.” The investigators are currently attempting to discover whether the neurons will make contact with the right targets.

The antibiotic geldanamycin averted the onset of neurodegenerative disease in fruit flies genetically predisposed to a disorder similar to Parkinson’s disease, reported an article in the November Nature Medicine. When researchers administered the drug to adult flies that would normally experience a 50% loss of dopaminergic neurons by 20 days of age, the flies maintained normal numbers of these neurons. Because geldanamycin modifies the activity of molecular chaperones, researchers theorized that neurodegenerative diseases may result from reduced chaperone levels and could be avoided by pharmacologically boosting chaperone activity.

Postmenopausal women with Alzheimer’s disease who undergo long-term estrogen replacement therapy may experience increased memory loss, according to the October Behavioral Neuroscience. Researchers had 40 female rats perform a water maze task to observe the interaction of two conditions known to exist in female patients with Alzheimer’s disease: the presence of chronic neuroinflammation and over- or underproduction of estrogen. Some rats were ovariectomized to mimic the changes seen in menopausal women, but this did not impair the rats’ performance in the maze. However, the introduction of either sustained estrogen replacement therapy or chronic brain inflammation did impair memory performance, and the occurrence of both conditions significantly worsened cognitive performance.

NR