In Brief

  • High-fat diets might impair memory and learning by temporarily blocking the hormoneA high-fat diet might impair spatial learning, according to a new study. Previous research has found that obese mice suffer memory and learning impairments when navigating a maze. Researchers from CEU San Pablo University and Complutense University in Madrid wanted to see what triggered those impairments: the mice’s high fat diets or the metabolic changes related to obesity, such as insulin resistance, which can impair hippocampal function. They tested mice fed a high-fat diet in a maze and found that these mice did worse in the maze than controls, even before changes could be seen in their insulin levels. This suggests that high-fat diets influence memory and learning impairments in another way — possibly by temporarily increasing resistance to the hormone leptin, which is involved in hippocampal learning. (Neurobiology of Learning and Memory, Vol. 95, No. 1)
  • Healthy, well-fed cockroaches take more risks than malnourished ones, find researchers from the University of Lethbridge in Alberta, Canada. Two competing theories seek to explain how developmental environment influences risk-tasking: One says that animals that grow up in poor environments take more risks to improve their lot, while the other states that they take fewer risks because their lack of resources makes them more vulnerable than animals that grew up in better environments. The researchers raised cockroaches on high- and low-nutrition diets and found that the low-nutrition roaches took fewer risks while exploring and foraging, lending support to the second hypothesis. (In press in the Journal of Comparative Psychology)
  • A new vaccine blocks the effects of cocaine in mice, suggesting that a similar vaccine could help combat human cocaine addiction, according to researchers from Weill Cornell Medical College. The researchers developed the vaccine, which links a cocaine-mimicking chemical with an inactive strain of the common cold virus, to goad the immune system into making antibodies that block cocaine molecules from entering the brain. The technique has been shown to persistently reverse cocaine-based reward-seeking behavior in mice, and the authors are hopeful it will be translated into human medicine soon. (In press in Molecular Therapy)
  • The motion planning parts of the brain light up in smokers when they watch someone else take a puff, according to a new study. Researchers from Dartmouth College used fMRI to monitor the brains of smokers and nonsmokers watching a smoking scene from the move “Matchstick Men.” In smokers, they found greater activity in the parietal lobe and intraparietal sulcus — areas involved in the planning and coordination of hand and eye movement — than in the nonsmokers, and tellingly, the side of the brain that activated corresponded with the hand in which the smokers held their cigarettes. (The Journal of Neuroscience, Vol. 31, No. 3)
  • Having lots of close friends could boost your creativity.People with many close friends tend to be more creative than those with smaller social circles, finds a new study by Szabolcs Keri at the University of Szeged in Budapest, Hungary. The researcher analyzed traits such as IQ, inhibition and social network size among 111 participants and assessed their creativity by asking them about their creative achievements. Higher IQ and lower inhibition both contributed to more creative achievements, but the biggest predictor of creativity was the number of close friends. Having a large group of acquaintances and faint friends wasn’t associated with greater creativity. (In press in Psychology of Aesthetics, Creativity and the Arts)
  • Girls who start puberty early could be more likely to experience adolescent depression than girls whose puberty begins later, finds a new study led by developmental psychologist Carol Joinson, PhD, at Bristol University in the U.K. Joinson and colleagues surveyed teenagers and found that girls who began menstruating before age 11-and-a-half were at an increased risk of experiencing depression by age 13 or 14. Girls who began menstruating after age 13-and-a-half were at lower risk of experiencing depression over the same age range, the researchers found. Other researchers have theorized that the results could reflect the fact that girls who mature faster than their peers tend to have lower self-esteem and poorer body image. (British Journal of Psychiatry, Vol. 198, No. 1)
  • Men who sniff women’s tears experienceSniffing a woman’s tears might reduce arousal in men, suggests a new study by researchers from the Weizmann Institute in Rehovot, Israel. The researchers obtained tears from female volunteers watching a sad movie, then asked men to rate the attractiveness of images of women while sniffing either tears or a similar-smelling saline solution. The men rated women less attractive when they looked at them while sniffing tears. Further experiments showed that sniffing tears produced a dip in testosterone levels, and reduced activity in brain areas associated with sexual arousal. It’s unclear what chemicals in the tears might be involved in this process, the researchers say, but it reinforces the idea that unconscious chemical signals play a bigger role in our behaviors than we realize. (Science, Vol. 331, No. 6,014)
  • Fear might make us temporarily more observant, but it also gets in the way of our ability to evaluate our surroundings, according to a new study. Researchers from the University of Wisconsin-Madison took EMG readings of the brains of 32 participants who responded to images on a screen by pressing buttons that corresponded to the images’ placement in the scene. In some trials, participants were told they would receive a mild shock at some point, and in other trials, they were told they were safe from shocks. Brain recordings indicate that visual attention parts of the brain experienced increased activity under threat of shock, while visual processing parts showed reduced activity. The opposite occurred when participants knew they were safe. Researchers suggest that fear increases vigilance, and therefore the sheer amount of information to process, which can overload the brain’s ability to process that information. (Journal of Neuroscience, Vol. 31, No. 3)
  • The emotional damage of living through a hurricane is stillSome children who live through a hurricane show signs of post-traumatic stress as long as two years after the incident, according to a new study led by University of Miami psychologist Annette La Greca, PhD. She and her colleagues tested children for symptoms of post-traumatic stress nine months after a hurricane and again a year later. The symptoms included dreaming about the hurricane, difficulty sleeping, feeling tense and disconnected from others, and feeling sadder and more fearful than before. The researchers found that at nine months, 35 percent of children experienced moderate to severe levels of post-traumatic stress, while 29 percent did at 21 months. (Journal of Consulting and Clinical Psychology, Vol. 78. No. 6)
  • Irrelevant memories about events and people — such as the color of a person’s shirt or the way someone walks — might be recalled because they hitchhike on the memory formation process of more important recollections, say researchers from the Massachusetts Institute of Technology. The scientists found that when neurons are encoding pertinent information into long-term memories, minor details that are observed multiple times during the long-term memory formation process — which lasts about an hour and a half — get incorporated into the same synaptic circuit as the more pertinent memory. (Neuron, Vol. 69, No. 1)
  • Self-control measure scores from children as young as age 3 could predict those children’s health and legal troubles in adulthood, according to Duke University psychologists Terrie Moffitt, PhD, and Avshalom Caspi, PhD. The researchers looked at longitudinal data from more than 1,000 New Zealanders, about whom self-control information had been collected from parents, teachers, observers and the children themselves. By the time they reached age 32, those with the lowest scores on self-control measures were the most likely to have breathing problems, gum disease, sexually transmitted diseases, high cholesterol and blood pressure, as well as financial and legal problems such as massive debt and criminal records. However, those who improved their self-control scores throughout their young lives escaped that trend. (Proceedings of the National Academy of Sciences, Vol. 108, No. 4.)

—M. Price

“In Brief” reports on peer-reviewed research findings within the fields of psychology. These synopses are snapshots of larger ongoing investigations.