Based on her analysis of archaeological evidence from the excavations of Maya churches at Tipu and Lamanai, Elizabeth Graham seeks to understand why the Maya sometimes actively embraced Catholicism ...during the period of European conquest and continued to worship in this way even after the end of Spanish occupation. The Maya in Belize appear to have continued to bury their dead in Christian churchyards long after the churches themselves had fallen into disuse. They also seem to have hidden pre-Hispanic objects of worship in Christian sacred spaces during times of persecution, and excavations reveal the style of the early churches to be unmistakably Franciscan. The evidence suggests that the Maya remained Christian after 1700, when Spaniards were no longer in control, which challenges the widespread assumption that because Christianity was imposed by force it was never properly assimilated by indigenous peoples. Combining historical and archaeological data with her experience of having been raised as a Roman Catholic, Graham proposes a way of assessing the concept of religious experience and processes of conversion that takes into account the material, visual, sensual, and even olfactory manifestations of the sacred. A volume in the series Maya Studies, edited by Arlen Chase and Diane Z. Chase
Fluid intelligence (Gƒ) includes logical reasoning abilities and is an essential component of normative cognition. Despite the broad consensus that parieto‐prefrontal connectivity is critical for Gƒ ...(e.g. the parieto‐frontal integration theory of intelligence, P‐FIT), the dynamics of such functional connectivity during logical reasoning remains poorly understood. Further, given the known importance of these brain regions for Gƒ, numerous studies have targeted one or both of these areas with non‐invasive stimulation with the goal of improving Gƒ, but to date there remains little consensus on the overall stimulation‐related effects. To examine this, we applied high‐definition direct current anodal stimulation to the left and right dorsolateral prefrontal cortex (DLPFC) of 24 healthy adults for 20 min in three separate sessions (sham, left, and right active). Following stimulation, participants completed a logical reasoning task during magnetoencephalography (MEG). Significant neural responses at the sensor‐level were imaged using a beamformer, and peak task‐induced activity was subjected to dynamic functional connectivity analyses to evaluate the impact of distinct stimulation montages on network activity. We found that participants responded faster following right DLPFC stimulation vs. sham. Moreover, our neural findings followed a similar trajectory of effects such that left parieto‐frontal connectivity decreased following right and left DLPFC stimulation compared to sham, with connectivity following right stimulation being significantly correlated with the faster reaction times. Importantly, our findings are consistent with P‐FIT, as well as the neural efficiency hypothesis (NEH) of intelligence. In sum, this study provides evidence for beneficial effects of right DLPFC stimulation on logical reasoning.
Key points
Logical reasoning is an indispensable component of fluid intelligence and involves multispectral oscillatory activity in parietal and frontal regions.
Parieto‐frontal integration is well characterized in logical reasoning; however, its direct neural quantification and neuromodulation by brain stimulation remain poorly understood.
High‐definition transcranial direct current stimulation of dorsolateral prefrontal cortex (DLPFC) had modulatory effects on task performance and neural interactions serving logical reasoning, with right stimulation showing beneficial effects.
Right DLPFC stimulation led to a decrease in the response time (i.e. better task performance) and left parieto‐frontal connectivity with a marginal positive association between behavioural and neural metrics.
Other modes of targeted stimulation of DLPFC (e.g. frequency‐specific) can be employed in future studies.
figure legend Offline prefrontal high‐definition transcranial direct current stimulation (HD‐tDCS) modulated behavioural and network‐level neuronal activity underlying logical reasoning in healthy adults. The reaction time improved following right dorsolateral prefrontal cortex (DLPFC) stimulation, which was further associated with decreased left parieto‐frontal connectivity in the alpha/beta range compared to sham.
Dispersal is an essential process which influences the effects of stream restoration on aquatic insect communities, yet dispersal capabilities of many New Zealand taxa remain unknown. We estimated ...realised dispersal distances of New Zealand Ephemeroptera, Plecoptera, and Trichoptera taxa by benthic crawling and of Trichoptera by aerial flight in intermittent streams, which are recolonised after every dry period. Benthic crawling distances were not more than 200 m for most genera. In contrast, adult caddisflies were found up to 1500 m from permanent water, with at least one family carrying eggs the full distance. This suggests greater potential for insects to recolonise distant restored sites by aerial dispersal than by crawling. Our results are a first step towards identifying the dispersal pathways used by desired colonist taxa and the distances over which they can disperse. This information will improve our ability to design and implement effective restoration.
The ability to reorient attention within the visual field is central to daily functioning, and numerous fMRI studies have shown that the dorsal and ventral attention networks (DAN, VAN) are critical ...to such processes. However, despite the instantaneous nature of attentional shifts, the dynamics of oscillatory activity serving attentional reorientation remain poorly characterized. In this study, we utilized magnetoencephalography (MEG) and a Posner task to probe the dynamics of attentional reorienting in 29 healthy adults. MEG data were transformed into the time‐frequency domain and significant oscillatory responses were imaged using a beamformer. Voxel time series were then extracted from peak voxels in the functional beamformer images. These time series were used to quantify the dynamics of attentional reorienting, and to compute dynamic functional connectivity. Our results indicated strong increases in theta and decreases in alpha and beta activity across many nodes in the DAN and VAN. Interestingly, theta responses were generally stronger during trials that required attentional reorienting relative to those that did not, while alpha and beta oscillations were more dynamic, with many regions exhibiting significantly stronger responses during non‐reorienting trials initially, and the opposite pattern during later processing. Finally, stronger functional connectivity was found following target presentation (575‐700 ms) between bilateral superior parietal lobules during attentional reorienting. In sum, these data show that visual attention is served by multiple cortical regions within the DAN and VAN, and that attentional reorienting processes are often associated with spectrally‐specific oscillations that have largely distinct spatiotemporal dynamics.
The ability to execute a motor plan involves spatiotemporally precise oscillatory activity in primary motor (M1) regions, in concert with recruitment of “higher order” attentional mechanisms for ...orienting toward current task goals. While current evidence implicates gamma oscillatory activity in M1 as central to the execution of a movement, far less is known about top‐down attentional modulation of this response. Herein, we utilized magnetoencephalography (MEG) during a Posner attention‐reorienting task to investigate top‐down modulation of M1 gamma responses by frontal attention networks in 63 healthy adult participants. MEG data were evaluated in the time–frequency domain and significant oscillatory responses were imaged using a beamformer. Robust increases in theta activity were found in bilateral inferior frontal gyri (IFG), with significantly stronger responses evident in trials that required attentional reorienting relative to those that did not. Additionally, strong gamma oscillations (60–80 Hz) were detected in M1 during movement execution, with similar responses elicited irrespective of attentional reorienting. Whole‐brain voxel‐wise correlations between validity difference scores (i.e., attention reorienting trials—nonreorienting trials) in frontal theta activity and movement‐locked gamma oscillations revealed a robust relationship in the contralateral sensorimotor cortex, supplementary motor area, and right cerebellum, suggesting modulation of these sensorimotor network gamma responses by attentional reorienting. Importantly, the validity difference effect in this distributed motor network was predictive of overall motor function measured outside the scanner and further, based on a mediation analysis this relationship was fully mediated by the reallocation response in the right IFG. These data are the first to characterize the top‐down modulation of movement‐related gamma responses during attentional reorienting and movement execution.
Accurate repair of DNA double-strand breaks (DSBs) is essential for the maintenance of genome integrity, as failure to repair DSBs can result in cell death. The cell has evolved two main mechanisms ...for DSB repair: non-homologous end-joining (NHEJ) and homology-directed repair (HDR), which includes single-strand annealing (SSA) and homologous recombination (HR). While certain factors like age and state of the chromatin are known to influence DSB repair pathway choice, the roles of developmental stage, tissue type, and sex have yet to be elucidated in multicellular organisms. To examine the influence of these factors, DSB repair in various embryonic developmental stages, larva, and adult tissues in Drosophila melanogaster was analyzed through molecular analysis of the DR-white assay using Tracking across Indels by DEcomposition (TIDE). The proportion of HR repair was highest in tissues that maintain the canonical (G1/S/G2/M) cell cycle and suppressed in both terminally differentiated and polyploid tissues. To determine the impact of sex on repair pathway choice, repair in different tissues in both males and females was analyzed. When molecularly examining tissues containing mostly somatic cells, males and females demonstrated similar proportions of HR and NHEJ. However, when DSB repair was analyzed in male and female premeiotic germline cells utilizing phenotypic analysis of the DR-white assay, there was a significant decrease in HR in females compared to males. This study describes the impact of development, tissue-specific cycling profile, and, in some cases, sex on DSB repair outcomes, underscoring the complexity of repair in multicellular organisms.
Increasing spatial working memory (SWM) load is generally associated with declines in behavioral performance, but the neural correlates of load‐related behavioral effects remain poorly understood. ...Herein, we examine the alterations in oscillatory activity that accompany such performance changes in 22 healthy adults who performed a two‐ and four‐load SWM task during magnetoencephalography (MEG). All MEG data were transformed into the time‐frequency domain and significant oscillatory responses were imaged separately per load using a beamformer. Whole‐brain correlation maps were computed using the load‐related beamformer difference images and load‐related accuracy effects on the SWM task. The results indicated that load‐related differences in left inferior frontal alpha activity during encoding and maintenance were negatively correlated with load‐related accuracy differences on the SWM task. That is, individuals who had more substantial decreases in prefrontal alpha during high‐relative to low‐load SWM trials tended to have smaller performance decrements on the high‐load condition (i.e., they performed more accurately). The same pattern of neurobehavioral correlations was observed during the maintenance period for right superior temporal alpha activity and right superior parietal beta activity. Importantly, this is the first study to employ a voxel‐wise whole‐brain approach to significantly link load‐related oscillatory differences and load‐related SWM performance differences.
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