Early-life education may help bolster declarative memory in old age, especially for women.

Although declarative memory declines with age, sex and education might moderate these weaknesses. We investigated effects of sex and education on nonverbal declarative (recognition) memory in 704 older adults (aged 58-98, 0-17 years of education). Items were drawings of real and made-up objects. Age negatively impacted declarative memory, though this age effect was moderated by sex and object-type: it was steeper for males than females, but only for real objects. Education was positively associated with memory, but also interacted with sex and object-type: education benefited women more than men (countering the age effects, especially for women), and remembering real more than made-up objects. The findings suggest that nonverbal memory in older adults is associated negatively with age but positively with education; both effects are modulated by sex, and by whether learning relates to preexisting or new information. The study suggests downstream benefits from education, especially for girls.

Asymmetry of the frontal aslant tract is associated with lexical decision.

The frontal aslant tract (FAT) is a recently documented white matter tract that connects the inferior and superior frontal gyri with a tendency to be more pronounced in the left hemisphere. This tract has been found to play a role in language functions, particularly verbal fluency. However, it is not entirely clear to what extent FAT asymmetry is related to performance benefits in language-related tasks. In the present study, we aimed to fill this gap by examining the correlations between asymmetric micro- and macro-structural properties of the FAT and performance on verbal fluency and lexical decision tasks. The results showed no correlation between the FAT and verbal fluency; however, lexical decision was correlated with FAT laterality. Specifically, greater left lateralization in both micro- and macro-structural properties was related to faster lexical decision response times. The results were not due merely to motor or decision-making processes, as responses in a simple discrimination control task showed no correlation with laterality. These data are the first to suggest a role for the FAT in mediating processes underlying lexical decision.

Working memory in older adults declines with age, but is modulated by sex and education.

Working memory (WM), which underlies the temporary storage and manipulation of information, is critical for multiple aspects of cognition and everyday life. Nevertheless, research examining WM specifically in older adults remains limited, despite the global rapid increase in human life expectancy. We examined WM in a large sample ( N = 754) of healthy older adults (aged 58-89) in a non-Western population (Chinese speakers) in Taiwan, on a digit n-back task. We tested not only the influence of age itself and of load (1-back vs. 2-back) but also the effects of both sex and education, which have been shown to modulate WM abilities. Mixed-effects regression revealed that, within older adulthood, age negatively impacted WM abilities (with linear, not nonlinear, effects), as did load (worse performance at 2-back). In contrast, education level was positively associated with WM. Moreover, both age and education interacted with sex. With increasing age, males showed a steeper WM decline than females; with increasing education, females showed greater WM gains than males. Together with other findings, the evidence suggests that age, sex, and education all impact WM in older adults, but interact in particular ways. The results have both basic research and translational implications and are consistent with particular benefits from increased education for women.

Decoding rule search domain in the left inferior frontal gyrus.

Traditionally, the left hemisphere has been thought to extract mainly verbal patterns of information, but recent evidence has shown that the left Inferior Frontal Gyrus (IFG) is active during inductive reasoning in both the verbal and spatial domains. We aimed to understand whether the left IFG supports inductive reasoning in a domain-specific or domain-general fashion. To do this we used Multi-Voxel Pattern Analysis to decode the representation of domain during a rule search task. Thirteen participants were asked to extract the rule underlying streams of letters presented in different spatial locations. Each rule was either verbal (letters forming words) or spatial (positions forming geometric figures). Our results show that domain was decodable in the left prefrontal cortex, suggesting that this region represents domain-specific information, rather than processes common to the two domains. A replication study with the same participants tested two years later confirmed these findings, though the individual representations changed, providing evidence for the flexible nature of representations. This study extends our knowledge on the neural basis of goal-directed behaviors and on how information relevant for rule extraction is flexibly mapped in the prefrontal cortex.

Structural hemispheric asymmetries underlie verbal Stroop performance.

Performance on tasks involving cognitive control such as the Stroop task is often associated with left lateralized brain activations. Based on this neuro-functional evidence, we tested whether leftward structural grey matter asymmetries would also predict inter-individual differences in combatting Stroop interference. To check for the specificity of the results, both a verbal Stroop task and a spatial one were administered to a total of 111 healthy young individuals, for whom T1-weighted magnetic resonance imaging (MRI) images were also acquired. Surface thickness and area estimations were calculated using FreeSurfer. Participants' hemispheres were registered to a symmetric template and Laterality Indices (LI) for the surface thickness and for the area at each vertex in each participant were computed. The correlation of these surface LI measures with the verbal and spatial Stroop effects (incongruent-congruent difference in trial performance) was assessed at each vertex by means of general linear models at the whole-brain level. We found a significant correlation between performance and surface area LI in an inferior posterior temporal cluster (overlapping with the so-called visual word form area, VWFA), with a more left-lateralized area in this region associated with a smaller Stroop effect only in the verbal task. These results point to an involvement of the VWFA for higher-level processes based on word reading, including the suppression of this process when required by the task, and could be interpreted in the context of cross-hemispheric rivalry.

Short-Term Memory Improvement After Simultaneous Interpretation Training.

Simultaneous interpretation (SI) is a cognitively demanding process that has been associated with enhanced memory and executive functions. It is unclear, however, if the previously evidenced interpreter advantages are developed through training and/or experience with SI or rather represent inherent characteristics that allow success in the field. The present study aimed to disentangle these possibilities through a longitudinal examination of students earning a Master of Conference Interpreting and two control populations. The students were tested at the beginning and end of their programs on measures of memory and executive functioning that have previously demonstrated an interpreter advantage. The results revealed no inherent advantage among the students of interpretation. However, an SI training-specific advantage was revealed in verbal short-term memory; the students of interpretation, but not the two control groups, showed a gain between the testing sessions. This controlled longitudinal study demonstrates that training in simultaneous interpretation is associated with cognitive changes.

Language control is not a one-size-fits-all languages process: evidence from simultaneous interpretation students and the n-2 repetition cost.

Simultaneous interpretation is an impressive cognitive feat which necessitates the simultaneous use of two languages and therefore begs the question: how is language management accomplished during interpretation? One possibility is that both languages are maintained active and inhibitory control is reduced. To examine whether inhibitory control is reduced after experience with interpretation, students with varying experience were assessed on a three language switching paradigm. This paradigm provides an empirical measure of the inhibition applied to abandoned languages, the n-2 repetition cost. The groups showed different patterns of n-2 repetition costs across the three languages. These differences, however, were not connected to experience with interpretation. Instead, they may be due to other language characteristics. Specifically, the L2 n-2 repetition cost negatively correlated with self-rated oral L2 proficiency, suggesting that language proficiency may affect the use of inhibitory control. The differences seen in the L1 n-2 repetition cost, alternatively, may be due to the differing predominant interactional contexts of the groups. These results suggest that language control may be more complex than previously thought, with different mechanisms used for different languages. Further, these data represent the first use of the n-2 repetition cost as a measure to compare language control between groups.

The interaction of process and domain in prefrontal cortex during inductive reasoning.

Inductive reasoning is an everyday process that allows us to make sense of the world by creating rules from a series of instances. Consistent with accounts of process-based fractionations of the prefrontal cortex (PFC) along the left-right axis, inductive reasoning has been reliably localized to left PFC. However, these results may be confounded by the task domain, which is typically verbal. Indeed, some studies show that right PFC activation is seen with spatial tasks. This study used fMRI to examine the effects of process and domain on the brain regions recruited during a novel pattern discovery task. Twenty healthy young adult participants were asked to discover the rule underlying the presentation of a series of letters in varied spatial locations. The rules were either verbal (pertaining to a single semantic category) or spatial (geometric figures). Bilateral ventrolateral PFC activations were seen for the spatial domain, while the verbal domain showed only left ventrolateral PFC. A conjunction analysis revealed that the two domains recruited a common region of left ventrolateral PFC. The data support a central role of left PFC in inductive reasoning. Importantly, they also suggest that both process and domain shape the localization of reasoning in the brain.

Development of allergic antibody to an enzyme in a body lotion: results of an 18-month clinical study.

Use of enzymes in cosmetic products is novel and the safety of these products is not well understood. The safety of a prototype enzyme-containing body moisturizer lotion was tested via measures of skin compatibility and potential to induce protease-specific IgE antibody in a clinical study. Female, atopic subjects (n = 1,100) used body lotion containing 100 ppm protease (Y217L BPN') for 5 consecutive days per month, for 18 months. Regular lotion was used the remaining days of each month. Skin evaluation and skin prick tests (SPT) were conducted every 3 months. Measures of skin hydration were made in a subset of subjects at 3-month intervals: skin biopsies occurred at baseline and at the first 3-month timepoint. Serum from SPT positive subjects was tested for specific IgE in an immunoCAP assay. Clinical evaluation and histopathology showed no skin irritation and increased hydration of the skin over time. Three of 864 subjects completing the study developed IgE antibody to the enzyme: 1 subject after 6 months product use and 2 subjects after 15 months product use. A fourth subject was found with IgE antibody 3 months after study termination. None had allergic symptoms associated with product use. Intermittent exposure to a low level of protease enzyme in a body lotion led to the development of specific IgE antibody in 0.46% of subjects. While this study showed favorable skin compatibility of the protease containing lotion, the occurrence of allergic antibody to the enzyme was unacceptable for product commercialization.