Prenatal Activation of Microglia Induces Delayed Impairment of Glutamatergic Synaptic Function

BACKGROUND: Epidemiological studies have linked maternal infection during pregnancy to later development of neuropsychiatric disorders in the offspring. In mice, experimental inflammation during embryonic development impairs behavioral and cognitive performances in adulthood. Synaptic dysfunctions may be at the origin of cognitive impairments, however the link between prenatal inflammation and synaptic defects remains to be established. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we show that prenatal alteration of microglial function, including inflammation, induces delayed synaptic dysfunction in the adult. DAP12 is a microglial signaling protein expressed around birth, mutations of which in the human induces the Nasu-Hakola disease, characterized by early dementia. We presently report that synaptic excitatory currents in mice bearing a loss-of-function mutation in the DAP12 gene (DAP12(KI) mice) display enhanced relative contribution of AMPA. Furthermore, neurons from DAP12(KI) P0 pups cultured without microglia develop similar synaptic alterations, suggesting that a prenatal dysfunction of microglia may impact synaptic function in the adult. As we observed that DAP12(KI) microglia overexpress genes for IL1beta, IL6 and NOS2, which are inflammatory proteins, we analyzed the impact of a pharmacologically-induced prenatal inflammation on synaptic function. Maternal injection of lipopolysaccharides induced activation of microglia at birth and alteration of glutamatergic synapses in the adult offspring. Finally, neurons cultured from neonates born to inflamed mothers and cultured without microglia also displayed altered neuronal activity. CONCLUSION/SIGNIFICANCE: Our results demonstrate that prenatal inflammation is sufficient to induce synaptic alterations with delay. We propose that these alterations triggered by prenatal activation of microglia provide a cellular basis for the neuropsychiatric defects induced by prenatal inflammation

Inhibitory control, but not prolonged object-related experience appears to affect physical problem-solving performance of pet dogs

Human infants develop an understanding of their physical environment through playful interactions with objects. Similar processes may influence also the performance of non-human animals in physical problem-solving tasks, but to date there is little empirical data to evaluate this hypothesis. In addition or alternatively to prior experiences, inhibitory control has been suggested as a factor underlying the considerable individual differences in performance reported for many species. Here we report a study in which we manipulated the extent of object-related experience for a cohort of dogs (Canis familiaris) of the breed Border Collie over a period of 18 months, and assessed their level of inhibitory control, prior to testing them in a series of four physical problem-solving tasks. We found no evidence that differences in object-related experience explain variability in performance in these tasks. It thus appears that dogs do not transfer knowledge about physical rules from one physical problem-solving task to another, but rather approach each task as a novel problem. Our results, however, suggest that individual performance in these tasks is influenced in a complex way by the subject’s level of inhibitory control. Depending on the task, inhibitory control had a positive or a negative effect on performance and different aspects of inhibitory control turned out to be the best predictors of individual performance in the different tasks. Therefore, studying the interplay between inhibitory control and problem-solving performance will make an important contribution to our understanding of individual and species differences in physical problem-solving performance

Prospective Study of New Participants in a Community-based Mind-body Training Program

BACKGROUND: Mind-body practices such as yoga are widely popular, but little is known about how such exercises impact health-related quality of life. OBJECTIVE: To measure changes in health-related quality of life associated with 3 months of mind-body training as practiced in community-based settings. DESIGN: Prospective cohort study. SETTING: Eight centers for practice of mind-body training. PARTICIPANTS: One hundred ninety-four English-speaking adults who had taken no more than 10 classes at the centers prior to enrollment in the study. One hundred seventy-one (88%) returned the 3-month follow-up questionnaire. INTERVENTION: Administration of the SF-36 questionnaire at the start of training and after 3 months. MEASUREMENTS AND MAIN RESULTS: At baseline, new participants in mind-body training reported lower scores than U.S. norms for 7 of 8 domains of the SF-36: mental health, role emotional, social, vitality, general health, body pain, and role physical (P < .002 for all comparisons). After 3 months of training, within-patient change scores improved in all domains (P < .0001), including a change of +15.5 (standard deviation ±21) in the mental health domain. In hierarchical regression analysis, younger age (P= .0003), baseline level of depressive symptoms (P= .01), and reporting a history of hypertension (P= .0054) were independent predictors of greater improvement in the SF-36 mental health score. Five participants (2.9%) reported a musculoskeletal injury. CONCLUSIONS: New participants in a community-based mind-body training program reported poor health-related quality of life at baseline and moderate improvements after 3 months of practice. Randomized trials are needed to determine whether benefits may be generalizable to physician-referred populations