Brain and Behavior



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Almost Half Will Have a Psychological Disorder
Using data from the National Comorbidity Survey Replication published in 2004, researchers estimate that the chance of being diagnosed with a psychological disorder during one's lifetime is 46.4%. Lifetime risk estimates for the most common disorders are: anxiety disorders, 28.8%; mood disorders, 20.8%; impulse-control disorders, 24.8%; substance use disorders, 14.6%. Half of all cases start by age 14 and three fourths by the age of 24. Women were more likely than men to be diagnosed with anxiety and mood disorders; impulse-control and substance use disorders were higher among men. Due to biasing factors such as reluctance to participate and exclusion of homeless individuals, the results are probably conservative. Archives of General Psychiatry, Vol 62, 593-602.

The Human Connectome Project
As our understanding of brain functions has matured, we have also recognized that our knowledge of the brain's interconnections is woefully inadequate. Now, a consortium of researchers spread across the country is undertaking a 5-year project to map these connections in 1200 healthy volunteers; the data will be made available to all qualified researchers as a step toward understanding both normal and disordered functioning. You can read more in Saint Louis's Post-Dispatch and at the Human Connectome Project website.

NIH Curtails Chimpanzee Research
Following a congressional investigation, the U.S. National Institutes of Health (NIH) commissioned a report on the use of chimpanzees in research. The report recommends sweeping changes in the care and use of chimps, and the NIH has suspended all new grants until the new standards are met. Ongoing research at sites not meeting the requirements will be phased out. The report notes that if the NIH's 17-year ban on breeding chimpanzees for research continues, the supply of animals will run out by 2037, raising the question whether NIH will revisit the ban. Science Insider, Dec. 15, 2011.

Autism Prevalence and Diagnostic Standards
The diagnosis of autism has been on the rise for several years, but it is unclear how much of the increase is due to environmental factors or greater awareness or changes in diagnostic standards. The criteria for diagnosing autism are very likely to be relaxed in the upcoming revision of the Diagnostic and Statistical Manual that sets these standards, a prospect that is already drawing criticism. More in Chapter 13 updates.

Update on Wakefield and Autism/Vaccine Link
Andrew Wakefield's report of a link between the measles, mumps, and rubella (MMR) vaccine and autism created a furor among parents of autistic children and a panic among parents of infants faced with immunization decisions. Twelve years later, the British medical journal Lancet retracted the article after determiining that the study was methodologically flawed (see p 418). Investigative reporter Brian Deer then documented numerous instances of fraud in the article, including the diagnoses of autism in the subjects and association of autism with MMR vaccinations and with colitis. (British Medical Journal, Vol 340, 838-841; Vol 342, 77-82.) As a result, Wakefield's license to practice medicine was revoked. He has now filed a libel suit against Deer, the British Medical Journal, and the journal's editor, Fiona Godlee. Wakefield also accused the journal of a conflict of interest because it receives money from vaccine makers GlaxoSmithKline and Merck. Wakefield also sued Deer in 2005 over a documentary accusing him of fraud, but withdrew the suit when the judge demanded more evidence. ScienceInsider, January 5, 2012.

Brain Characteristics Precede Addiction
Addicts typically have distinguishing brain anomalies, but it is difficult to know whether these contribute to a predisposition that leads to addiction or are the result of years of drug abuse. Researchers at the University of Cambridge found that addicts and their non-addicted siblings share deficits in white and gray matter as well as enlargement of areas associated with both addiction and learning and memory. Learn more in the Chapter 5 updates.

Former Players Suing NFL
Hundreds of former football players have filed suits against the National Football League for alleged negligence in failing to mitigate risks of head trauma and to inform players of the risks. Numerous former players are now suffering from dementia, Parkinson's disease, and amyotrophic lateral sclerosis (ALS, or Lou Gehrig's disease). A panel of judges has ruled that the individual and class action lawsuits will be consolidated in a federal court in Philadelphia. CNNHealth, February 5, 2012.

New Help for Stroke Victims
Researchers have thought that GABA released by the brain following traumatic injury to calm runaway activity also interferes with recovery, but blocking this inhibition has yielded mixed results. A drug that blocks GABA receptors on the cell but does not affect those at snapses may offer a solution. Drug-treated mice with experimenter-induced strokes regained 50% more function in their limbs than mice receiving control therapy. Nature, Vol 468, 305-309.

The Promise of Two-Photon Microscopy
A new version of two-photon microscopy, which uses fluorescent dyes to image specific types of tissue and even track neural activity, can image individual pairs of pre- and post-synaptic neurons and their connections. The developer has been able to follow changing connectivity in the mouse retina during the second week of life, and he hopes to refine our understanding of how the developing brain reorganizes its connections. Science Daily, October 31, 2010. Another researcher is imaging activity in neural networks of 1,000 neurons; he hopes to learn more about the neural replay that goes on in circuits following a learning experience, which is believed to be how the brain turns the neural information into a permanent memory. The Dana Foundation: Grants.

Clinical Trials With Human Embryonic Stem Cells
The U.S. Food and Drug Administration has approved a clinical trial testing the safety of human embryonic stem cell injections in patients with spinal cord injury; of course, the researchers will also test to see if the patients benefit from the therapy. Science Insider, October 12, 2010. The FDA has also approved a second trial to test stem cells in treating progressive loss of vision in children with advanced macular dystrophy. In earlier testing, the procedure prevented mice with a version of the disease from going blind. Science Insider, November 22, 2010. In the meantime, a district court judge issued an injunction against President Obama's lifting of the ban on federal funding, on the basis that federal funding violates the Dickey-Wicker Amendment; however, a U.S. Court of Appeals lifted that injunction. CNN U.S., April 29, 2011. Outcome in the courts may be important; research has found that adult stem cells do not proliferate as well as embryonic stem cells and they have a shorter life span. Stem Cells, February, 2010.

Treating Binge Drinking With Gene Therapy
Because the GABAA receptor is involved in producing alcohol's effects, addiction therapists often prescribe GABA blockers in the treatment of alcoholism. Now researchers have shown that genetic manipulation of the receptor can dramatically reduce binge drinking in rats bred to prefer alcohol (they don't typically imbibe). After RNA injections into the amygdala, GABAA receptor density decreased by 65%; binge drinking dropped profoundly in the ensuing 6 days and returned to previous levels by day 14. Proceedings of the National Academy of Sciences, Vol 108, 4465-4470.

Dramatic Increase in Diabetes Projected
The Centers for Disease Control and Prevention estimates that the number of new cases of diabetes will increase in the U.S. from its 2010 level of 14% to 25%-28% of the population by 2050, even if preventive interventions are undertaken. The projection is based on the incidence of prediabetes and diabetes, current life expectancy, and population increases among high-risk subgroups. Population Health Metrics, 2010, 8:29.

Sensing Dietary Deficits
Detection of nutrients often involves learned taste preference, but in other cases there is a more direct biological mechanism. When a rat eats a food lacking one of the indispensable amino acids (IACs, nine amino acids the body requires for synthesizing proteins) that it needs, activity increases in the anterior piriform cortex (APC); the rat will turn away from the food within 20 minutes. Even a slice of APC tissue will show an increase in excitatory postsynaptic potentials when placed in a nutrient bath missing any one of the IACs. This suggests that the APC can detect IAC levels directly, thus monitoring conditions in its own environment. Journal of Neuroscience, Vol 31, 1583-1590.

Childhood Predictors of Adult Homosexuality
The conclusion that children who later become homosexual typically show more gender nonconformity—behavior more typical of the other sex, along with a preference for other-sex playmates and companions—has been based on memories provided by the individuals and/or their families. When researchers at Northwestern University rated childhood videos of homosexual and heterosexual men and women for gender nonconforming behavior, the results indicated that both boys and girls who were homosexual as adults were less conforming than the other subjects. Developmental Psychology, Vol 44, 46-58.

Love Modifies Olfactory Responses to Other-Sex Friends
The attention hypothesis claims that sexual and romantic bonding increases attraction between the partners; according to the deflection hypothesis, it reduces attention to other members of the other sex. Results of a new study supported the deflection hypothesis: The higher women rated their romantic love for their boyfriends, the less able they were to distinguish the body odors of male friends from those of strangers; there was no effect on their ability to recognize their boyfriends' odors. Hormones and Behavior, Vol 55, 280-284.

Roots of Criminal Behavior in Childhood
Adult psychopaths have, on average, an 18% reduction in amygdala volume, which is associated with reduced fear responding; in a remarkable study, Raine followed 1800 children who showed impaired fear conditioning at age 3 and found that 20 years later they were much more likely to become criminal offenders. American Journal of Psychiatry, Vol 167, 56-60.

86-Country Study Finds No Math Gender Gap
Researchers at the University of Wisconsin have laid to rest any doubts that boys are inherently better than girls at mathematics. They used two international standardized tests and compared performance in elite competitions and on SAT math tests. In many of the countries there was no gap between boys and girls, either in average scores or in performance at top levels. In other countries, such as the United States, gaps that existed in the past had narrowed over time. In countries ranked higher on gender equity, math scores were higher for both boys and girls. However, women are still underrepresented among those pursuing careers in mathematics. Notices of the American Mathematical Society, Vol 59, 10-21.

Improving Learning and Memory
Memory tricks and drugs don't help very much, so researchers are excited about some promising results from electrical stimulation. Deep brain stimulation of the entorhinal cortex improved landmark learning in a virtual environment in epilepsy patients being prepped for surgery, and less invasive stimulation through electrodes on the scalp halved training time for Air Force operators controlling unmanned drones. Learn more in the Chapter 12 updates.

Restoring Vision
We finally have a 1500-electrode retinal implant (see p 300)! With it, a patient can read large print and identify common objects, such as a knife and cup. Proceedings of the Royal Society B, Vol 278, 1489-1497 (click here for video). Optogenetic restoration of sight has been found safe in mice and may enter human trials within two years. Molecular Therapy, doi:10.1038/mt.2011.69. You can see one of the mice locating the exit in a water maze here. Also, the U.S. FDA has approved clinical trials to determine the safety and tolerability of human embryonic stem cells in the treatment of macular degeneration. Advanced Cell Technology Press Release, May 16, 2011.

Spinal Stimulation Restores Movement in Paralyzed Man
For 4 years after being struck by a car, Rob Summers was paralyzed from the wait down; fortunately, some sensation remained, indicating that his spinal cord was not completely severed. Then in 80 sessions spread over 7 months, researchers delivered electrical pulses to electrodes implanted next to his spinal cord. Now during stimulation Rob is able to move his toes, feet, and legs, and to stand for several minutes and, with assistance, take a step. Even with the stimulation turned off, he reports improved bladder control and sexual function. Although generalization from one subject is difficult, the degree of recovery is remarkable and, perhaps, unprecedented. Lancet, Vol 377, 1938-1947.

Parkinson's Increases With Pesticide Exposure
Evidence continues to mount for pesticide exposure as a contributor to Parkinson's disease. Exposure to ziram and paraquat was associated with an 80% increase in risk, and the addition of maneb tripled the risk. Combinations of different pesticides apparently have a greater effect than a single pesticide because they affect different mechanisms leading to dopaminergic cell death. European Journal of Epidemiology, DOI 10.1007/s10654-011-9574-5.

Number of Late-Onset Alzheimer's Genes Doubles
Thanks to the efforts of the Alzheimer Disease Genetics Consortium, 5 new genes associated with late-onset Alzheimmer's disease have been identified, doubling the known number of genes. The two studies that identified the genes took the unusual step of replicating their initial results with two additional independent samples, providing strong assurance that the results are reliable. Both studies confirmed associations with CD2AP, CD33, EPHA1, and MS4A4/MS4A6E, and one of the studies also identified ABCA7. Nature Genetics, Vol 43, 429-435 and 436-441.

Alzheimer's Brain Deficient in β-Amyloid Clearance
It has long been believed that the accumulation of β-Amyloid in the Alzheimer's brain was due to overproduction, but there has been no direct evidence for this process. Using metabolic labeling, researchers at Washington University in Saint Louis found no differences between patients and controls in β-Amyloid production, but clearance was impaired in the patients. This information should be useful in devising treatments for the disease and, possibly, for earlier detection. Science, Vol 330, 1774.

Aging and the Brain
In a study of individuals over age 70 with mild cognitive impairment, treatment with folic acid and vitamins B6 and B12 slowed brain atrophy by 30%. PLoS ONE, Vol 5, e12244. In a second study, of individuals aged 72-92 years, connectivity throughout the whole brain network was associated with the maintenance of processing speed, visuospatial functions, and executive functioning (planning, behavioral monitoring and control). Journal of Neuroscience, Vol 31, 1204-1212.

Mice Explain Link Between Flu and Schizophrenia
We know that maternal influenza increases the risk for schizophrenia in offspring, but we haven't understood why. Researchers infected pregnant mice with a mouse-adapted influenza virus, then studied their adult offspring. The mice showed behavioral alterations, including reduced spontaneous locomotion, increased responsiveness to hallucinogens, and diminished antipsychotic-like effect of a glutamate agonist. Examination of their brains showed that the number and activity of 5-HT2A serotonin receptors was increased, while mGlu2 glutamate receptors were downregulated in frontal cortex. Journal of Neuroscience, Vol 31, 1863-1872.

Electrical and Genetic Treatments for Depression
Techniques for administering transcranial magnetic stimulation are improving, and gains are reported lasting as much as 3 years. Meanwhile, trials are underway with primates (following successes with mice) to determine effectiveness of treating depression by increasing the protein p11, which binds to serotonin receptors. More details in Chapter 14 updates.