Cerebral cortex最新文献

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.

A substantial body of literature has focused on neural signals evoked by errors emerging during the execution of goal-directed actions. It is still unclear how motor cortex activity during movement execution relates to feedback error processing. To investigate this, we recorded primary motor cortex (M1) single-unit activity in rats during a grasping task. About half of the recorded neurons showed modulation of their firing activity that did not depend on success or failure, which we termed outcome-independent neurons. Other neurons showed a difference in their discharge profile when comparing successful and unsuccessful trials, which we called outcome-dependent neurons. Among both outcome-dependent and -independent neurons, we further distinguished neurons presenting their maximum firing rate in specific epochs as defined by the task. We compared the cortical distribution of outcome-independent and outcome-dependent neurons to cortical maps of complex forelimb movements evoked by intracortical microstimulation in additional animals. The majority of outcome-independent neurons was localized within the limb extension and paw open-closure movement representations. Outcome-dependent neurons were not clearly associated to particular motor representations. Cortical arrangement of neurons, both outcome-independent and outcome-dependent, and their correlation with distinct movement representations, can serve as indicator for anticipating potential outcomes before the conclusion of an action.

Advanced meditation has been associated with long- and short-term psychological changes such as bliss, profound insight, and transformation of well-being. However, most advanced meditation neuroimaging analyses have implemented primarily spatially-localized approaches, focusing on discrete regional changes in activity rather than distributed dynamics. The present study uses a geometric eigenmode decomposition of ultrahigh field-strength 7T functional magnetic resonance imaging (fMRI) data from an intensely sampled case study to investigate the complex, distributed cortical dynamics associated with advanced concentrative absorption meditation. Geometric eigenmode decomposition of advanced concentrative absorption meditation and non-meditative control task fMRI data revealed elevated global brain state power and energy patterns of specific advanced concentrative absorption meditation states compared to controls, with mid-frequency spectrum brain state power and energy following a non-random, cubic trajectory through the advanced concentrative absorption meditation sequence. Further, these brain state differences were meaningfully associated with subjective phenomenological reports of attention, intensity of advanced concentrative absorption meditation quality, and sensations. This study unites precise methodological design, a novel fMRI decomposition framework, and rigorous phenomenology to provide valuable insights into the distributed neural signatures of highly refined conscious states. These results underscore similarities and differences between advanced concentrative absorption meditation and other altered states of consciousness like those induced by psychedelics-offering insights into refined conscious states and their implications for health and well-being.

We reported that in layer II pyramidal cells of rat somatosensory cortex, 10 μM serotonin (5-HT) alters miniature excitatory postsynaptic current frequency in a subset of cells (47%, "responders", RC; "non-responders", NC otherwise) via 5-HT2 receptors (5-HT2R) but in all pairs reduced evoked excitatory postsynaptic current amplitude by ~50% (Agahari FA, Stricker C. 2021. Serotonergic modulation of spontaneous and evoked transmitter release in layer II pyramidal cells of rat somatosensory cortex. Cereb Cortex. 31:1182-1200. https://doi.org/10.1093/cercor/bhaa285.) suggestive of preferential connectivity. We provide different lines of evidence that distinguish these subsets. First, after 5-HT exposure, changes in miniature excitatory postsynaptic current, spontaneous EPSC frequency, or whole-cell noise (σw) were restricted to postsynaptic cells in pairs (PO) and RC but absent in presynaptic (PR) and NC. Second, exposure caused a large change in holding current with a small variability in NC, but a small one with a large variability in PO/RC. In addition, ΔRin in PO/RC was larger than in PR/NC, with a negative correlation between ΔIhold and ΔRin in NC, a positive in PO, but none in RC. Third, an unbiased classifier identified most PO as RC and all PR as NC. Our data establish two distinct sets of pyramidal cells having a preferred connectivity from NC → RC. 5-HT2R-mediated modulation of transmitter release may likely reduce the signal-to-noise ratio in the ipsilateral but leave the output to the contralateral side unaffected.

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.