Cerebral cortex最新文献

Our study investigates how language proficiency impacts cognitive processing in the brain. We focused on congenitally and early deaf adults, where individual differences in language access during development significantly influence language proficiency and cognitive function. This variability in language backgrounds and skills allows us to explore the influence of early language experience on the large-scale brain networks that support cognition. We used functional MRI in a group of deaf adults with diverse language backgrounds and a control group of hearing participants. We hypothesized that differences in language skills would modulate neural responses and functional connectivity in task-related networks during the execution of demanding working memory and planning tasks. Our study revealed that differences in language proficiency, independently of language modality (signed or spoken), are positively correlated with neural activity and functional connectivity within the task-positive network during working memory in deaf adults. Furthermore, compared to hearing participants, the deaf group showed distinct patterns of neural activity and connectivity in task-dependent regions in the working memory experiment. Our findings emphasize the profound impact of early environmental experiences on brain responses during cognitive processing. Specifically, they highlight the role of language proficiency in shaping and supporting higher-order cognition.

Theoretical models suggest that loneliness may be linked to abnormal social information processing and reduced emotion regulation capacity; yet these effects have mostly been investigated using self-report methods. Therefore, the current preregistered study examined whether loneliness is associated with objective and subjective markers of bottom-up emotional reactivity and cognitive reappraisal efficiency in a cohort of 150 young adults (18-35 years old) recruited to reflect the distribution of loneliness scores in the Polish population. Participants completed an emotion processing and regulation task with both social and nonsocial stimuli while their electroencephalography activity was recorded. Contrary to the hypotheses, when faced with socio-affective stimuli, lonelier individuals did not exhibit abnormal markers of early sensory processing, late sustained processing, or decreased efficiency in reappraisal use, as indicated by event-related potential markers. Only a weak association between loneliness and an increased P300 response to negative vs. neutral social stimuli was found. This pattern of findings did not align with subjective arousal reports, which suggested a decreased response to negative social stimuli and reduced cognitive reappraisal efficiency in lonelier participants. These results suggest that loneliness is linked to disruptions in emotional self-awareness rather than an abnormal response to socio-affective stimuli.

Psychological pain showed stronger predictive power for suicide attempts (SAs) than depression, even in patients with major depressive disorder (MDD). This study aimed to elucidate the compositional architecture of the pain network and quantify the explanatory power of this network versus the reward network in modeling suicide risk mechanisms. Resting-state functional magnetic resonance imaging data from MDD patients with SA, MDD patients without SA, and healthy controls (HCs) were analyzed using graph theoretical analysis. Partial least squares regression was used to assess suicide-related neural alterations in relation to depression and psychological pain. Compared with HCs, MDD patients exhibited reduced nodal centrality in both the reward and pain networks. Within MDD, individuals with SA exhibited changes primarily in the pain network, including a decrease in the betweenness centrality of the right anterior insula. Suicide-related alterations overlapped more with pain avoidance than with depression. Centrality in the right opercular inferior frontal gyrus, left medial superior temporal gyrus, and right anterior insula was associated with pain arousal, feelings, and avoidance, broadening the current understanding of the pain network. These findings extended the conceptualization of the pain network and highlight its pivotal role in suicide risk.

Auditory evoked responses undergo notable changes during childhood, likely reflecting modifications in synaptic signaling in the auditory cortex. Particularly robust response, observed around 200 to 300 ms post stimulus (N/M250), has been consistently reported in children but is absent in adults. This long-latency response, evoked even in passive listening conditions, may indicate heightened sensory pathway responsiveness, facilitating experience-driven cortical plasticity. However, it remains unclear whether this delayed activation pattern is an intrinsic, species-general feature of brain development. We recorded cortical auditory evoked responses to monaural sine-wave tones/click sounds in 3 age groups (preadolescents, adolescents, and young adults) of human subjects and rats. Following short-lived early responses, both species exhibited a long-latency (150 to 450 ms) response in the auditory cortex. In both species, the relative amplitude of the long-latency response, compared to early responses, was increased in younger individuals. In human children, single-trial analysis demonstrated more consistent trial-by-trial timing of the response in this later time window than in the adult-typical 100-ms response in the earlier time window. Given its emergence in purely passive conditions, and across species, the robust current activity in late time window could represent a distinct synaptic event and may serve as a marker of the maturational stage, particularly in GABAergic cortical circuits.

Previous research suggests that habit formation is associated with a decreasing control by the goal-directed system and increasing control of the habit-related brain systems. However, the causal contribution of these systems in human habit formation and expression remains unclear. In the current study, we applied 1-Hz inhibitory repetitive transcranial magnetic stimulation (rTMS) targeting the inferior parietal cortex (IPL) and the dorsal premotor cortex (PMC) to interfere with goal- and habit-related brain systems, respectively. Two groups of participants (IPL/PMC) received real or sham-rTMS on separate days prior to habit training. We found that TMS did not induce significant learning-related changes during habit learning. Importantly, we found a significantly increased habit expression during goal-habit competition following IPL stimulation. In contrast, while numerically, habit expression decreased following PMC stimulation, this effect did not reach statistical significance. Thereby, the current study provides direct causal evidence suggesting that habit expression is significantly influenced by the release of control from the goal-directed system, while evidence regarding the influence of the habit-related system remains less conclusive.

Basal forebrain cholinergic neurons (BFCNs) densely innervate auditory cortex (ACtx), conveying signals linked to internal brain states and external sensory cues. Acetylcholine (ACh) is known to rapidly modulate cortical circuits through nicotinic ACh receptor (nAChR)-mediated activation of layer 1 inhibitory neurons (L1-INs). However, BFCN terminals are also abundant in deeper layers, where their functional impact has received less attention. Using multi-plex in situ labeling across cortical layers and cell types, we found that layer 6 pyramidal neurons (L6-PNs) are highly enriched in diverse transcripts for nAChR subunits and muscarinic ACh receptors (mAChRs). In vivo optogenetic activation of BFCN axons revealed persistent modulation of regular spiking units in L2-6 but a rapid phasic activation only in L6. In acute slices, optogenetic activation of BFCN axons elicited fast nAChR-mediated excitatory post-synaptic potentials in L6-PNs, comparable to responses in L1-INs, and slower mAChR-mediated inhibitory responses. These findings identify L1-INs and excitatory L6-PNs as two major hubs for BFCN modulation of cortical circuits. By recruiting distinct receptor mechanisms and circuit motifs in L1 and L6, BFCNs may engage parallel pathways of cholinergic control that couple fast, transient modulation with slower, sustained regulation to shape cortical perception and plasticity.

Stress is a major risk factor for psychiatric disorders, with the timing of exposure critically shaping its neural and behavioral consequences. Here, we investigated how stress during adolescence or adulthood affects neuronal activity and oscillatory dynamics in the medial prefrontal cortex (mPFC) of rats. Animals were exposed to a combined footshock and restraint stress protocol during adolescence (postnatal days [PNDs] 31 to 40) or adulthood (PNDs 65 to 74). In vivo electrophysiological recordings of putative glutamate pyramidal neurons, Gamma-Aminobutyric Acid (GABA) interneurons, and local field potentials were performed 1 to 2 and 5 to 6 wk post-stress to evaluate both short- and long-term effects. Adolescent stress induced increases in pyramidal neuron firing rates and sustained elevations in interneuron burst activity that persisted into adulthood, accompanied by long-lasting reductions in mPFC gamma oscillations. These alterations point to enduring disruptions in excitatory-inhibitory balance and impaired network coordination. In contrast, adult stress produced no persistent changes in pyramidal neuron activity but caused transient increases in interneuron excitability and selective reductions in theta oscillatory power, suggesting temporary inhibitory dysfunction. These findings highlight adolescence as a critical window during which stress triggers enduring, cell-type-specific changes in cortical circuitry, whereas changes induced by adult stress are transient, potentially reflecting recovery mechanisms. Collectively, our results underscore the importance of developmental timing in determining stress outcomes, providing mechanistic insight into how adolescent stress may contribute to long-lasting cortical dysfunction and psychiatric disease risk, and informing the timing of potential preventive or therapeutic interventions.

Prior EEG research has shown that during working memory, alpha (8 to 14 Hz) and theta (4 to 8 Hz) oscillations tend to form a 2:1 frequency ratio. According to the Binary Hierarchy Brain Body Oscillation Theory (BHBBOT), a recent model grounded in mathematical analysis, this cross-frequency configuration reflects enhanced connectivity between brain regions generating these rhythms. However, this prediction has not yet been empirically tested. In this study, we leveraged high density EEG, source localization and connectivity metrics derived from Information Theory (IT) and the Theory of Weakly Coupled Oscillators (TWCO) to examine whether the previously observed alpha-theta cross-frequency dynamics during working memory are accompanied by changes in connectivity. Our results show that a significant increase in the proportion of 2:1 ratios between regions generating frontal theta and parietal alpha rhythms was accompanied by relative decreases in connectivity, as revealed by both IT and TWCO metrics. Furthermore, phase synchrony between these two regions was significantly reduced during working memory and correlated negatively with behavioral performance. In conclusion, our results show that the increased occurrence of 2:1 alpha:theta cross-frequency ratios during working memory reflects functional segregation (rather than integration) and therefore directly challenges some of the predictions of the BHBBOT.

Frontal midline theta oscillations are key neural markers for learning, set-shifting, and adaptive behavior, signaling cognitive control and the reorganization of neural representations. The present study explored how these oscillations mediate the extraction and updating of statistical regularities. We delivered 6-Hz in-phase or sham transcranial alternating current stimulation, synchronizing frontal midline theta during an eye-tracking probabilistic sequence learning task designed to test cognitive flexibility and assess changes in pre-stimulus gaze direction. A novel probabilistic sequence with a partially overlapping structure was introduced that allowed us to distinguish between the retention of old sequences and the acquisition of new ones. Following comparable statistical learning in both groups during the stimulation session, our results showed that frontal midline theta synchronization enhances the adaptation of predictive processes shown by the reduction of erroneous anticipations of previously learned regularities and more flexible anticipation of novel regularities. These results suggest a role of frontal midline theta in the flexible rewiring of the mental representations of prior probabilistic structures and in making predictions more accurate.