Frontiers in Psychology
When language switching has no apparent cost: Lexical access in sentence context
Bilinguals have the remarkable ability to switch from one language to the other. In a new study, Jason Gullifer and colleagues from Pennsylvania State University, USA, looked at whether language switching incurs a processing cost. They show that the mind has little difficulty in preventing such mix-ups between languages. When 26 North American Latino people were asked to read aloud an underlined word within a text that mixed English and Spanish, they did not think longer or make more mistakes than when the text was in a single language. Gullifer et al. conclude that voluntary language switching is a natural feature of bilingualism that requires little additional processing time by the mind.
Frontiers in Microbiology
Contrasting genomic properties of free-living and particle-attached microbial assemblages within a coastal ecosystem
In terms of environmental and economic impact, the Columbia River is the most important river in the US Pacific Northwest. To characterize the microbial diversity within its estuary, Holly M. Simon and colleagues from Oregon Health & Science University’s Center for Coastal Margin Observation and Prediction and the J. Craig Venter Institute, sequenced total DNA from water in four habitats: the Columbia River’s immediate outflow; the river plume that extends into Pacific Ocean; upwelling low-oxygen water off the coast; and the ocean bottom. They show that the Columbia River estuary is a complex region characterized by high turbidity (“cloudiness”), in which bacteria attached to solid particles suspended in the water are crucial for recycling organic matter.
Paradoxically, the turbidity blocks sunlight in these estuarine waters and makes it difficult for photosynthetic algae to grow there, yet light-dependent bacteria dominate these waters. These bacteria are known as photoheterotrophs because they use both organic substrates and light energy for growth and survival. They employ a protein that is related to light-sensitive pigments in mammalian eyes to generate energy from light, which helps them survive when nutrients are scarce. Habitat diversity, in the form of local variation in size and type of suspended particles, maintains the considerable bacterial biodiversity in the estuary of the Columbia River.
Frontiers in Neuroscience
Age-related similarities and differences in brain activity underlying reversal learning
Memories are constantly updated because surroundings are not static. One way that researchers have investigated memory updating is with “reversal learning” tasks in which participants learn as association (e.g., Mary is angry) and then update their response when contingencies change (e.g., Mary is no longer angry). Kaoru Nasiro at the Center for Vial Longevity at the University of Texas, Dallas and colleagues from the University of Southern California, USA, examined brain activity in younger (19-35 years) and older (61-78 years) adults while they were engaged in two types of reversal learning tasks in an fMRI scanner; one involved emotion and the other did not (e.g., who is angry? vs. who wears eye-glasses?).
During emotional reversal learning, both groups showed similar activity in the amygdala, a region critical for emotional memory, and the frontopolar/orbitofrontal cortex, which updates old emotional memory. During neutral reversal learning however, older adults showed greater activity in regions that control attention than did younger adults. The results suggest that brain mechanisms underlying emotional memory updating is little affected by age.
Frontiers in Psychology
Music training, cognition, and personality
Two key personality traits – openness-to-experience and conscientiousness – predict better than IQ who will take music lessons and continue for longer periods, according to a new study. A team of researchers, led by Glenn Schellenberg at the University of Toronto Mississaug, also found that when personality traits and demographic factors are considered, the link between cognitive ability and music training disappears. In separate groups of 167 10-12-year-olds and 118 university undergraduates, the researchers looked at how individual differences in cognitive ability and personality predict who takes up music lessons and for how long. They found that pre-existing differences in personality could explain why musically trained children have substantially higher IQs and perform better in school than other children.
Frontiers in Neuroscience
The role of the primary auditory cortex in the neural mechanism of auditory verbal hallucinations
How can healthy people who hear voices help those with schizophrenia? In a recently pubished study, Kristiina Kompus and colleagues analyzed data from a functional magnetic reasonance imaging (fMRI) study, to show that those with schizophrenia have a reduced ability to regulate the primary auditory cortex using cognitive control compared to those who hear voices but are otherwise healthy.