Effect of bilingualism on infants’ cognitive flexibility

Research suggests that bilinguals often outperform monolinguals on tasks that tap into executive functions, such as those requiring conflict resolution and cognitive flexibility. Recently, better attentional control has been detected in infants as young as 6 months, thereby providing a possible basis for a cognitive benefit before language production. The goal of the present study was to examine if cognitive flexibility is more advanced in bilingual infants. A detour reaching task assessing conflict resolution, a delayed response task assessing shifting, and a multiple location task assessing maintaining, were administered to 17-month-old infants. The main findings revealed that being bilingual did not improve performance on any of the executive function tasks. Furthermore, current exposure to a second language or language proficiency did not impact executive functioning. We conclude that a bilingual advantage in cognitive flexibility may not be present before children have enough experience in code switching.

Maternal Choline Supplementation as a Potential Therapy for Down Syndrome: Assessment of Effects Throughout the Lifespan

Maternal choline supplementation (MCS) has emerged as a promising therapy to lessen the cognitive and affective dysfunction associated with Down syndrome (DS). Choline is an essential nutrient, especially important during pregnancy due to its wide-ranging ontogenetic roles. Using the Ts65Dn mouse model of DS, our group has demonstrated that supplementing the maternal diet with additional choline (4-5 × standard levels) during pregnancy and lactation improves spatial cognition, attention, and emotion regulation in the adult offspring. The behavioral benefits were associated with a rescue of septohippocampal circuit atrophy. These results have been replicated across a series of independent studies, although the magnitude of the cognitive benefit has varied. We hypothesized that this was due, at least in part, to differences in the age of the subjects at the time of testing. Here, we present new data that compares the effects of MCS on the attentional function of adult Ts65Dn offspring, which began testing at two different ages (6 vs. 12 months of age). These data replicate and extend the results of our previous reports, showing a clear pattern indicating that MCS has beneficial effects in Ts65Dn offspring throughout life, but that the magnitude of the benefit (relative to non-supplemented offspring) diminishes with aging, possibly because of the onset of Alzheimer's disease-like neuropathology. In light of growing evidence that increased maternal choline intake during pregnancy is beneficial to the cognitive and affective functioning of all offspring (e.g., neurotypical and DS), the addition of this nutrient to a prenatal vitamin regimen would be predicted to have population-wide benefits and provide early intervention for fetuses with DS, notably including babies born to mothers unaware that they are carrying a fetus with DS.

Meta-Analysis on Cognitive Benefit of Exercise after Stroke

ObjectiveThe objective of this paper is to evaluate the cognitive benefit of exercise after stroke, so as to provide more accurate and reliable guidance for targeted exercise intervention. Methods. Randomized controlled trials of the relationship between exercise and cognition after stroke were identified in Cochrane Library and PubMed. Methodological quality was assessed using the Cochrane tool of bias. SMD and 95% confidence intervals were calculated, and Chi-squared test (Q) was adopted to estimate the heterogeneity. Results. (a) Twenty-three studies met inclusion criteria, including 1528 participants. Heterogeneity was from low to high such as attention (I2 = 0.00%), executive function (I2 = 0.00%), cognition (I2 = 64%), and working memory (I2 = 77%). (b) The overall effect on cognition was small (SMD = 0.16 [0.04, 0.28]) but significant and there is a difference between cognitive domains in attention (SMD = −0.35 [−0.57, −0.14]), executive function (SMD = −0.24 [−0.40, −0.08]), and working memory (SMD = 0.36 [0.20, 0.53]). (c) Exercise training was less effective before the 18th month after stroke. Higher benefits on cognition were found after combined therapy compared with other exercise programs, and the older the stroke survivors, the less the cognitive benefit of exercise. Conclusion. Small-to-moderate effect of exercise on cognitive benefit after stroke was found, and the effect was moderated by treatment protocols and sample characteristics.

When Culture Influences Genes: Positive Age Beliefs Amplify the Cognitive-Aging Benefit of APOE ε2

Objectives Most studies of aging cognition have focused on risk factors for worse performance and on either genetic or environmental factors. In contrast, we examined whether 2 factors known to individually benefit aging cognition may interact to produce better cognition: environment-based positive age beliefs and the APOE ε2 gene. Method The sample consisted of 3,895 Health and Retirement Study participants who were 60 years or older at baseline and completed as many as 5 assessments of cognition over 8 years. Results As predicted, positive age beliefs amplified the cognitive benefit of APOE ε2. In contrast, negative age beliefs suppressed the cognitive benefit of APOE ε2. We also found that positive age beliefs contributed nearly 15 times more than APOE ε2 to better cognition. Discussion This study provides the first known evidence that self-perceptions can influence the impact of a gene on cognition. The results underscore the importance of combined psychosocial and biological approaches to understanding cognitive function in older adults.

Combined adult neurogenesis and BDNF mimic exercise effects on cognition in an Alzheimer’s mouse model

Adult hippocampal neurogenesis (AHN) is impaired before the onset of Alzheimer’s disease (AD) pathology. We found that exercise provided cognitive benefit to 5×FAD mice, a mouse model of AD, by inducing AHN and elevating levels of brain-derived neurotrophic factor (BDNF). Neither stimulation of AHN alone, nor exercise, in the absence of increased AHN, ameliorated cognition. We successfully mimicked the beneficial effects of exercise on AD mice by genetically and pharmacologically inducing AHN in combination with elevating BDNF levels. Suppressing AHN later led to worsened cognitive performance and loss of preexisting dentate neurons. Thus, pharmacological mimetics of exercise, enhancing AHN and elevating BDNF levels, may improve cognition in AD. Furthermore, applied at early stages of AD, these mimetics may protect against subsequent neuronal cell death.

RNA-dependent intergenerational inheritance of enhanced synaptic plasticity after environmental enrichment

ABSTRACTPhysical exercise in combination with cognitive training is known to enhance synaptic plasticity, learning & memory and lower the risk for various complex diseases including Alzheimer’s disease. Here we show that exposure of adult male mice to an environmental enrichment paradigm leads to enhancement of synaptic plasticity and cognition also in the next generation. We show that the effect is mediated through sperm RNA and is explained by microRNAs 212/132. In conclusion, our study reports intergenerational inheritance of an acquired cognitive benefit and points to specific microRNAs as candidates mechanistically involved in this type of transmission.