Reliance on semantic and structural heuristics in sentence comprehension across the lifespan.

People sometimes misinterpret the sentences that they read. One possible reason suggested in the literature is a race between slow bottom-up algorithmic processing and "fast and frugal" top-down heuristic processing that serves to support fast-paced communication but sometimes results in incorrect representations. Heuristic processing can be both semantic, relying on world knowledge and semantic relations between words, and structural, relying on structural economy. Scattered experimental evidence suggests that reliance on heuristics may change from greater reliance on syntactic information in younger people to greater reliance on semantic information in older people. We tested whether the reliance on structural and semantic heuristics changes with age in 137 Russian-speaking adolescents, 135 young adults, and 77 older adults. In a self-paced reading task with comprehension questions, participants read unambiguous high- versus low-attachment sentences that were either semantically plausible or implausible: i.e., the syntactic structure either matched or contradicted the semantic relations between words. We found that the use of top-down heuristics in comprehension increased across the lifespan. Adolescents did not rely on structural heuristics, in contrast to young and older adults. At the same time, older adults relied on semantic heuristics more than young adults and adolescents. Importantly, we found that top-down heuristic processing was faster than bottom-up algorithmic processing: slower reading times were associated with greater accuracy specifically in implausible sentences.

Whisker trimming during infanthood modifies the development of spike-wave discharges and behavioral sequences in IntelliCage impulsivity paradigm in adult WAG/Rij rats.

Whisker system in rats undergoes rapid development during the first postnatal weeks. Neonatal whisker trimming increases excitability in the somatosensory cortex and affects exploratory behavior at adult ages. WAG/Rij rats are genetically predisposed to develop absence seizures in adulthood, and whisker trimming during three postnatal weeks aggravates epileptic activity in these rats. It is assumed that behavioral performance in adult WAG/Rij rats is influenced (1) by absence epilepsy and (2) by whisker trimming during the short period around the onset of active whisker movements, PN9-16. We examined the effect of whisker trimming in WAG/Rij rats during PN9-16 on spike-wave discharges (SWD, EEG hallmark of absence epilepsy). We found that 77% of WAG/Rij rats showed pronounced SWD (epileptic phenotype), and the rest did not (non-epileptic phenotype). At the age of 5 m, epileptic trimmed rats showed more SWD than epileptic control rats. Age-related increase of SWD was found only in the control group, suggesting that whisker trimming during PN9-16 led to an earlier maturation of SWD. Goal-directed behavior was examined in all rats at the age of 4-4.5 m using IntelliCage impulsivity paradigm. In order to optimize the analysis of behavioral data, we combined several Python packages into a single processing pipeline. Early life whisker trimming altered behavioral sequences and strategy of exploration in adulthood, suggesting reduced whisker sensitivity in the trimmed rats. Epileptic WAG/Rij rats at 4-4.5 months showed only a slight learning impairment during later stages of IntelliCage impulsivity paradigm, which may be associated with the early stage of development of SWD.

Molecular Surveillance of HIV-1 Infection in Krasnoyarsk Region, Russia: Epidemiology, Phylodynamics and Phylogeography.

BACKGROUND: The information about the dynamics of the viral population and migration events that affect the epidemic in different parts of the Russia is insufficient. Possibly, the huge size of the country and limited transport accessibility to certain territories may determine unique traits of the HIV-1 evolutionary history in different regions. OBJECTIVE: The aim of this study was to explore the genetic diversity of HIV-1 in the Krasnoyarsk region and reconstruct spatial-temporal dynamics of the infection in the region. METHODS: The demographic and virologic data from 281 HIV-infected individuals in Krasnoyarsk region collected during 2011-2016 were analyzed. The time to the most recent common ancestor, evolutionary rates, population growth, and ancestral geographic movements was estimated using Bayesian coalescent-based methods. RESULTS: The study revealed moderate diversity of the HIV-1 subtypes found in the region, which included A6 (92.3%), CRF063_02A (4.3%), B (1.1%), and unique recombinants (2.5%). Phylogenetic reconstruction revealed that the A6 subtype was introduced into Krasnoyarsk region by one viral lineage, which arose around 1996.9 (1994.5-1999.5). The phylogeography analysis pointed to Krasnoyarsk city as the geographical center of the epidemic, which further spread to central neighboring districts of the region. At least two epidemic growth phases of subtype A6 were identified which included exponential growth in early-2000s followed by the decline in the mid/late 2010s. CONCLUSION: This study demonstrates a change in the genetic diversity of HIV-1 in the Krasnoyarsk region. At the beginning of the epidemic, subtype A6 prevailed, subtypes B and CRF063_02A appeared in the region later.