Traumatic brain injury (TBI) causes a neurological impairment of the central nervous system that may induce severe motor deficits. In this study, human cranial bone-derived mesenchymal stem cells (hcMSCs) were transplanted into a mouse TBI model, and the effects of differences in exercise frequency were examined as a rehabilitation approach to improve motor function after cell transplantation. Twenty-four hours after TBI induction, phosphate-buffered saline or hcMSCs were intravenously injected into mice that were divided into a non-exercise group, a low-frequency exercise group (LF Ex), and a high-frequency exercise group (HF Ex). Beam walking tests and rotarod tests were performed over time to assess motor function. Injured brain tissues were collected for mRNA and protein expression analysis on days 8 and 35 after TBI induction. On days 28 and 35 after TBI induction, significant associations were found between hcMSC transplantation (T) and exercise factors. Notably, the T + HF Ex group exhibited a significant improvement in motor function compared with the other groups. Moreover, we found that the mRNA and protein expression levels of growth associated protein 43 (GAP-43), hepatocyte growth factor (HGF), and nerve growth factor (NGF) were significantly higher in the T + HF Ex group than in other groups. Increased expression of GAP-43 enhances synaptic regeneration and promotes functional recovery. High expression of NGF accelerates neural differentiation, and HGF ensures the efficacy of hcMSCs. These data suggest that hcMSC transplantation combined with high-frequency exercise is a promising option for TBI treatment.
Theory of mind (ToM), the ability to attribute mental states to others, is fundamental to human socio-cognition. In child development, a full or explicit understanding of false beliefs (FB) and their impact on action emerges around the age of 4 years. There is evidence of functional specialization of right hemispheric activity related to FB processing in adults and children. However, it remains unclear whether this specialization is the cause or the consequence of ToM development. The present exploratory study investigates the longitudinal relationship of resting-state electroencephalogram (rsEEG) alpha asymmetry measured in infancy/toddlerhood and behavioral false belief understanding (FBU) at the age of 4 years. Employing a longitudinal design, Study 1 assessed rsEEG alpha asymmetry across frontal and parietal electrode sites (N = 43), implicit FBU at 34 months (N = 38), and explicit FBU at age 4 (N = 22). Study 2 is another independent longitudinal dataset that included rsEEG alpha asymmetry at 14 months (N = 37) and explicit FBU at age 4 (N = 32). We found that superior explicit FBU at age 4 was associated with greater right frontal activity at an earlier age, and better implicit FBU was cross-sectionally related to greater right parietal activity. Given the limited sample size, these results should be viewed as preliminary and warrant replication in future studies. Interpreted cautiously, these findings may suggest that rsEEG alpha asymmetry in frontal regions may serve as an early-appearing neural marker of children's later explicit FBU.
The aim of this paper is to introduce and illustrate the use of Generalized Additive Mixed Models (GAMM) for analyzing intensive binary time-series eye-tracking data. The spatio-temporal GAMM was applied to intensive binary time-series eye-tracking data. In doing so, we reveal that both fixed condition effects, as well as previouslydocumented temporal contingencies in this type of data vary over time during speech perception. Further, spatial relationships between the point of fixation and the candidate referents on screen modulate the probability of an upcoming target fixation, and this pull (and push) on fixations changes over time as the speech is being perceived. This technique provides a way to not only account for the dominant autoregressive patterns typically seen in visual-world eye-tracking data, but does so in a way that allows modeling crossed random effects (by person and item, as typical in psycholinguistics datasets), and to model complex relationships between space and time that emerge in eye-tracking data. This new technique offers ways to ask, and answer new questions in the world of language use and processing.
Chronic morphine exposure affects neuroplasticity in the hippocampus, a key area for learning and memory. Since, novelty exploration influence rodent hippocampal plasticity, the aim of this study was to investigate the effects of habituation to novel contexts and odors on hippocampal plasticity in morphine-tolerant rats. For this purpose, neurogenesis markers, dendritic spine density and mRNA levels for various genes encoding neurotrophic factors were evaluated in the hippocampus tissue (ventral, vH vs. dorsal, dH) of male rats. Habituation to the new environment was established using animal models of morphine tolerance. Following multiple exposures to a novel context (open field habituation, OFH) or a series of novel odors (odor habituation, OH), markers (Ki67 or DCX) associated with neurogenesis were found to be lower in the morphine-tolerant rats that underwent habituation than the non-habituated morphine-tolerant rats, with specific regions (dH, vH), being differently influenced by specific type of habituation (OFH, OH, respectively). Further results showed subregion and habituation specific effects on the number of dendritic spines per spine type or levels of neurotropic factors including BDNF and TrkB mRNA levels in the dH and vH in morphine-tolerant rats that underwent habituation as compared to the non-habituated morphine-tolerant rats. We provide new evidence that habituation to novel contexts and novel odors appears to affect hippocampal plasticity in morphine-tolerant rats and that pro-plasticity molecules appear to mediate habituation effects on morphine tolerance plasticity.