Cerebral cortex最新文献

Brain functional networks are associated with parkinsonism in observational studies. However, the causal effects between brain functional networks and parkinsonism remain unclear. We aimed to assess the potential bidirectional causal associations between 191 brain resting-state functional magnetic resonance imaging (rsfMRI) phenotypes and parkinsonism including Parkinson's disease (PD) and drug-induced parkinsonism (DIP). We used Mendelian randomization (MR) to assess the bidirectional associations between brain rsfMRI phenotypes and parkinsonism, followed by several sensitivity analyses for robustness validation. In the forward MR analyses, we found that three rsfMRI phenotypes genetically determined the risk of parkinsonism. The connectivity in the visual network decreased the risk of PD (OR = 0.391, 95% CI = 0.235 ~ 0.649, P = 2.83 × 10-4, P_FDR = 0.039). The connectivity of salience and motor networks increased the risk of DIP (OR = 4.102, 95% CI = 1.903 ~ 8.845, P = 3.17 × 10-4, P_FDR = 0.044). The connectivity of limbic and default mode networks increased the risk of DIP (OR = 14.526, 95% CI = 3.130 ~ 67.408, P = 6.32 × 10-4, P_FDR = 0.0437). The reverse MR analysis indicated that PD and DIP had no effect on brain rsfMRI phenotypes. Our findings reveal causal relationships between brain functional networks and parkinsonism, providing important interventional and therapeutic targets for different parkinsonism.

Although age differences in the dopamine system have been suggested to contribute to age-related cognitive decline based on cross-sectional data, recent large-scale cross-sectional studies reported only weak evidence for a correlation among aging, dopamine receptor availability, and cognition. Regardless, longitudinal data remain essential to make robust statements about dopamine losses as a basis for cognitive aging. We present correlations between changes in D2/3 dopamine receptor availability and changes in working memory measured over 5 yr in healthy, older adults (n = 128, ages 64 to 68 yr at baseline). Greater decline in D2/3 dopamine receptor availability in working memory-relevant regions (caudate, middle frontal cortex, hippocampus) was related to greater decline in working memory performance in individuals who exhibited working memory reductions across time (n = 43; caudate: rs = 0.494; middle frontal cortex: rs = 0.506; hippocampus; rs = 0.423), but not in individuals who maintained performance (n = 41; caudate: rs = 0.052; middle frontal cortex: rs = 0.198; hippocampus; rs = 0.076). The dopamine-working memory link in decliners was not observed in the orbitofrontal cortex, which does not belong to the core working memory network. Our longitudinal analyses support the notion that aging-related changes in the dopamine system contribute to working memory decline in aging.

Processing sensory information, generating perceptions, and shaping behavior engages neural networks in brain areas with highly varied representations, ranging from unimodal sensory cortices to higher-order association areas. In early development, these areas share a common distributed and modular functional organization, but it is not known whether this undergoes a common developmental trajectory, or whether such organization persists only in some brain areas. Here, we examine the development of network organization across diverse cortical regions in ferrets using in vivo wide field calcium imaging of spontaneous activity. In both primary sensory (visual, auditory, and somatosensory) and higher order association (prefrontal and posterior parietal) areas, spontaneous activity remained significantly modular with pronounced millimeter-scale correlations over a 3-wk period spanning eye opening and the transition to externally-driven sensory activity. Over this period, cortical areas exhibited a roughly similar set of developmental changes, along with area-specific differences. Modularity and long-range correlation strength generally decreased with age, along with increases in the dimensionality of activity, although these effects were not uniform across all brain areas. These results indicate an interplay of area-specific factors with a conserved developmental program that maintains modular functional networks, suggesting modular organization may be involved in functional representations in diverse brain areas.

Although inhibitory control is essential to goal-directed behavior, not all inhibition is the same: Previous research distinguished discarding an action plan from simply withholding it, suggesting separate neurophysiological mechanisms. This study tracks the neurophysiological signatures of both using time-frequency transformation and beamforming in n = 34 healthy individuals. We show that discarding an action plan reduces working memory load, with stronger initial theta band activity compared to withholding it. This oscillatory difference was localized in the (para-)hippocampus and anterior temporal lobe, likely reflecting the need to dissolve action plan features first to enable the following decrease of working memory load. Contrary, when exposed to the embedded stimulus, withholding was associated with higher theta, alpha, and beta band activity relative to discarding. This study advances our understanding of inhibition by revealing distinct neurophysiological mechanisms and functional neuroanatomical structures involved in withholding versus discarding an action.

As languages, mathematics is a biological product and thus based on causal processes of two time scales, namely neural mechanisms and evolution. In this commentary, I will try to figure out possible scenarios responsible for the chick mathematics raised by the target article, focusing on discreteness and transposability of natural numbers.

Is there an innate sense of number? Lorenzi et al. (2025) argue that the ability to extract numerical information from the environment is vital for a wide range of species, suggesting "a likely common origin". Studies in different species show that the neural mechanism for doing this-numerosity-selective neurons-can be found in animals with no opportunity to learn. This leaves open important questions: How do numerosity-selective neurons code for numerosities? Is the code the same in different species? How do the neurons participate in arithmetical operations?

The approximate number system or «sense of number» is a crucial, presymbolic mechanism enabling animals to estimate quantities, which is essential for survival in various contexts (eg estimating numerosities of social companions, prey, predators, and so on). Behavioral studies indicate that a sense of number is widespread across vertebrates and invertebrates. Specific brain regions such as the intraparietal sulcus and prefrontal cortex in primates, or equivalent areas in birds and fish, are involved in numerical estimation, and their activity is modulated by the ratio of quantities. Data gathered across species strongly suggest similar evolutionary pressures for number estimation pointing to a likely common origin, at least across vertebrates. On the other hand, few studies have investigated the origins of the sense of number. Recent findings, however, have shown that numerosity-selective neurons exist in newborn animals, such as domestic chicks and zebrafish, supporting the hypothesis of an innateness of the approximate number system. Control-rearing experiments on visually naïve animals further support the notion that the sense of number is innate and does not need any specific instructive experience in order to be triggered.

This study explored the differences in brain activation between individuals with and without Internet gaming disorder (IGD) through activation likelihood estimation analysis. In total, 39 studies were included based on the inclusion and exclusion criteria by searching the literature in the PubMed and Web of Science databases, as well as reading other reviews. The analysis revealed that the activated brain regions in IGD were the right inferior frontal gyrus, left cingulate gyrus, and left lentiform nucleus. In comparison, the activated brain regions in non-IGD were the left middle frontal, left inferior frontal, left anterior cingulate, left precentral, and right precentral gyri. The results of the present study on differences in activation further confirm existing theoretical hypotheses. Future studies should explore hemispheric differences in prefrontal brain function between IGD and non-IGD.

Optimal brain function is shaped by a combination of global information integration, facilitated by long-range connections, and local processing, which relies on short-range connections and underlying biological factors. With aging, anatomical connectivity undergoes significant deterioration, which affects the brain's overall function. Despite the structural loss, previous research has shown that normative patterns of functions remain intact across the lifespan, defined as the compensatory mechanism of the aging brain. However, the crucial components in guiding the compensatory preservation of the dynamical complexity and the underlying mechanisms remain uncovered. Moreover, it remains largely unknown how the brain readjusts its biological parameters to maintain optimal brain dynamics with age; in this work, we provide a parsimonious mechanism using a whole-brain generative model to uncover the role of sub-communities comprised of short-range and long-range connectivity in driving the dynamic compensation process in the aging brain. We utilize two neuroimaging datasets to demonstrate how short- and long-range white matter tracts affect compensatory mechanisms. We unveil their modulation of intrinsic global scaling parameters, such as global coupling strength and conduction delay, via a personalized large-scale brain model. Our key finding suggests that short-range tracts predominantly amplify global coupling strength with age, potentially representing an epiphenomenon of the compensatory mechanism. This mechanistically explains the significance of short-range connections in compensating for the major loss of long-range connections during aging. This insight could help identify alternative avenues to address aging-related diseases where long-range connections are significantly deteriorated.

Irony comprehension is challenging for both individuals with ASD and poor comprehenders (PCs). We aimed to examine the common and specific mechanisms underlying irony comprehension difficulty in the two populations. Both adolescents with ASD and PC showed lower performance in irony comprehension than an age-matched typical control group (TD). The ASD group also showed deficits in theory of mind (ToM), while the PC group showed impairments in structural language skills. In the brain, the ASD group showed reduced brain activation in the left inferior frontal gyrus (IFG) compared to both the TD and the PC group, suggesting ASD-specific differences, which was further found to be correlated with ToM deficits in ASD. Both the TD and the PC group showed greater activation for the ironic than the literal condition in the bilateral medial prefrontal cortex (mPFC), but the ASD group did not, suggesting ASD-specific difference in irony comprehension. The PC group showed reduced activation in the right cuneus compared to the TD, which was correlated with the language comprehension score, suggesting different mechanisms than ASD. Our findings provide insights about the neurocognitive mechanisms underlying impaired irony comprehension in ASD and PC.