Cerebral cortex最新文献

Hypnosis is a state of consciousness spontaneously occurring or induced through various techniques. Its occurrence is more likely in individuals with high scores of hypnotizability (highs) than in low hypnotizables (lows). The study aimed to assess the topological homogeneity within highs and lows during neutral hypnosis, and the EEG topological characteristics of highs and lows before and after hypnotic induction experienced as an altered state of consciousness only by highs. Sixteen highs and 16 lows were enrolled, informed that they would be submitted to hypnotic induction and studied across a session including open and closed eyes waking rest, hypnotic induction, neutral hypnosis, and post hypnosis open eyes rest. EEG was monitored throughout the session. Network analysis showed greater identifiability (less homogeneity) among lows than among highs. It revealed a similar pattern of changes in functional connectivity and topological properties-homological persistence and persistent entropy, which describe multiscale integration patterns-in the two groups across the session. Findings suggest that neutral hypnosis represents a modulation of the ordinary consciousness within its physiological variability rather than a distinct physiological state. Neither network nor topological differences account for the different subjective experiences of highs and lows.

In this functional magnetic resonance imaging study, we investigated whether language production and understanding recruit similar phoneme-specific networks. We did so by comparing the brain's response to different phoneme categories in minimal pairs: Bilabial-initial words (eg "monkey") were contrasted to alveolar-initial words (eg "donkey") in 37 participants performing both language production and comprehension tasks. Individual-specific region-of-interest analyses showed that the same sensorimotor networks were activated across the language modalities. In motor regions, word production and comprehension elicited the same phoneme-specific topographical activity patterns, with stronger haemodynamic activations for alveolar-initial words in the tongue cortex and stronger activations for bilabial-initial words in the lip cortex. In the posterior and middle superior temporal cortex, production and comprehension likewise resulted in similar activity patterns, with enhanced activations to alveolar- compared to bilabial-initial words. These results disagree with the classical asymmetry between language production and understanding in neurobiological models of language, and instead advocate for a cortical organization where phonology is carried by similar topographical activations in motor cortex and distributed activations in temporal cortex across the language modalities.

Dyslexia is a neurobiological disorder characterized by reading difficulties, yet its causes remain unclear. Neuroimaging and behavioral studies found anomalous responses in tasks requiring phonological processing, motion perception, and implicit learning, and showed gray and white matter abnormalities in dyslexics compared to controls, indicating that dyslexia is highly heterogeneous and promoting a multifactorial approach. To evaluate whether combining behavioral and multimodal MRI improves sensitivity in identifying dyslexia neurocognitive traits compared to monocomponential approaches, 19 dyslexic and 19 control subjects underwent cognitive assessments, multiple (phonological, visual motion, rhythmic) mismatch-response functional MRI tasks, structural diffusion-weighted imaging (DWI) and T1-weighted imaging. Between group differences in the neurocognitive measures were tested with univariate and multivariate approaches. Results showed that dyslexics performed worse than controls in phonological tasks and presented reduced cerebellar responses to mismatching rhythmic stimuli, as well as structural disorganization in white matter tracts and cortical regions. Most importantly, a machine learning model trained with features from all three MRI modalities discriminated between dyslexics and controls with greater accuracy than single-modality models. The individual classification scores in the multimodal machine learning model correlated with behavioral reading accuracy. These results characterize dyslexia as a composite condition with multiple distinctive cognitive and brain traits.

To date, the neurobiological principles that underlie poor motor imagery (MI) performance in children with developmental coordination disorder (DCD) remain poorly understood. To provide new insights into the neuro-structural correlates of MI performance in DCD, this study examined the association between the volume of gray matter regions and MI performance in a sample of 65 children (33 females, 24 children with DCD) aged 6 to 14 yr (mean age = 10.07, SD = 2.64). Implicit MI performance was assessed using a hand laterality judgment task. Regional volumes of frontal-motor, parietal, and cerebellar regions were derived from T1-weighted neuroimaging data. Relative to typically developing children, children with DCD showed less efficient MI performance on the hand laterality judgment task and had smaller cortical volumes in frontal and cerebellar regions. Partial correlations demonstrated that smaller gray matter volumes in frontal and parietal regions were associated with less efficient MI performance in children with and without DCD. These findings provide novel insight into the neurobiological basis of MI performance in children with and without DCD and highlight the possible contribution of gray matter morphological properties to compromised internal models in children with DCD.

Mild levels of stress may lead to compensatory changes in perceptual strategies, especially during social affective stroking. We recruited 17 healthy adults with moderate levels of psychological stress, as assessed by the PSM-25 questionnaire and clinical interviews, and 17 participants with low levels of stress. Tactile stimulation involved slow gentle stroking by the researcher's hand of two areas: the foot and the shin. We analyzed the regions of interest signal by examining all activated clusters in 34 participants and also analyzed group-specific BOLD signals. Our findings suggest an increased sensitivity to social tactile stroking in stressed individuals, which correlated with increased activity in areas related to tactile perception, including the left parietal and central operculum, as well as the left precentral gyrus. Additionally, we observed activation in brain regions involved in inhibitory control and theory of mind, such as the left caudate nucleus, left middle cingulate cortex, left anterior insula, and left superior temporal gyrus. Sex differences were also noted: compared to women, men showed higher activation in the middle occipital gyrus, superior parietal lobe and left middle frontal gyrus. This study sets the stage for future research into perceptual strategies and their biochemical correlates in highly stressed or distressed participants.

Inhibiting inappropriate prepotent responses is fundamental to goal-directed behavior, allowing individuals to adapt to changing environmental demands. Recent conceptualization of neural activity during cognitive control has suggested a close interplay of theta and alpha band activity and their role in information flow across cortical regions. In a sample of n = 104 healthy participants, we employed established experimental procedures and combined beamforming and directed connectivity (information flow) analysis in alpha and theta band activities to do this. The results showed that the insular cortex consistently emerged as a central hub, coordinating a flow of information between the anterior temporal lobe, the inferior frontal cortex, and the superior-medial frontal gyrus through alpha and theta oscillations. Alpha activity is implicated in selecting relevant stimuli, while theta band activity is key in reconfiguring perception-action associations during response inhibition. Increased directed connectivity towards the superior/middle frontal gyrus during response inhibition suggests its involvement in implementing inhibitory control. Notably, there was a directed flow of information from theta to alpha band activity within the insular cortex when cognitive control demands were elevated. The findings provide novel mechanistic insights into how the insular cortex modulates stimulus-response mappings and perception-action reconfiguration through directed information exchange between neural activity patterns.

The ability to choose adaptively between rewards differing in magnitude and delay (intertemporal choice) is critical for numerous life outcomes. Compared to younger adults, older adults tend to exhibit greater preference for large, delayed over small, immediate rewards (ie less delay discounting), which could lead to missed opportunities to obtain resources necessary for quality of life. Intertemporal choice is mediated by the prefrontal cortex, but how this is impacted by advanced age is not well understood. We used optogenetic inactivation to investigate contributions of medial prefrontal cortex (mPFC) during distinct components of an intertemporal choice task in young and aged rats. mPFC inactivation during deliberation (during decisions between small, immediate vs. large, delayed rewards) increased preference for large, delayed rewards in both age groups. In contrast, inactivation during delays prior to large reward delivery increased preference for large, delayed rewards only in aged rats. Choices were unaffected by inactivation during other task phases. Results suggest that mPFC integrates information regarding anticipated outcomes into the decision process across the whole lifespan, but that only in aging is mPFC critical for consolidating information regarding reward delays into the decision structure in order to modulate choice behavior.

Previous studies have shown that individuals with internet gaming disorder (IGD) and tobacco use disorder (TUD) represent nonsubstance and substance-related addictions, respectively. Identifying neuroimaging differences is essential for detecting and intervening in these disorders. 44 IGD participants, 73 TUD participants, and 33 healthy controls (HCs) were scanned with resting-state fMRI (rs-fMRI). We used independent component analysis (ICA) to identify regions of interest and compared the functional connectivity between groups using a false discovery rate correction. Rs-fMRI revealed increased functional connectivity in the precuneus cortex, left postcentral gyrus, and right superior frontal gyrus in the dorsal attention network (DAN) in the IGD group in contrast to HC group. In the TUD group, increased functional connectivity was observed in the superior frontal gyrus, supplementary motor cortex, right precentral gyrus, cingulate gyrus, anterior division, postcentral gyrus, thalamus r, and thalamus I. In contrast, decreased functional connectivity was observed in the right lateral occipital cortex (the inferior and superior division), right occipital fusiform gyrus, and the right occipital pole. Our results indicate distinct alterations in the DAN associated with IGD and TUD, suggesting divergent mechanisms in behavioral versus substance-related addictions.

Metacognition enables adaptive behavior through the self-evaluation of our cognitions. An unresolved question is whether metacognition relies on domain-general or domain-specific mechanisms. The domain-general account proposes that shared prefrontal resources support metacognition across all cognitive functions. This predicts that metacognitive abilities should correlate across cognitive tasks and show uniform age-related decline, as aging would affect this shared system. However, behavioral results show inconsistent cross-domain correlations and age-related decline, often confounded by methodological differences between tasks. The neural oscillations supporting metacognition also remain unclear, though electroencephalography (EEG) studies suggest theta oscillations as a potential mechanism in specific domains. No study has compared both behavioral and oscillatory patterns across domains using matched tasks. We addressed this by recording EEG from younger and older-adults during matched perceptual and visual short-term memory tasks. Despite equivalent task performance, aging selectively impaired metacognition in perception and not memory, revealing behavioral decoupling between domains. This dissociation was mirrored in oscillatory dynamics. Younger adults showed stronger occipital theta-synchronization supporting perceptual metacognition, while older adults engaged compensatory frontal beta-desynchronization. During memory, older adults' metacognition was supported by occipital alpha-desynchronization. These findings reveal the domain-specific oscillatory mechanisms supporting metacognition, each tuned to computational demands of the cognitive domain and age-group.

Using diffusion-weighted imaging, we quantified the microstructure of U-shaped fiber bundles connecting the primary motor and somatosensory cortices in chimpanzees. We tested for sex and age effects, lateralization, and associations with manual and orofacial motor functions. Manual skills were assessed with a tool-use task; orofacial communication was assessed by individual variation in attention-getting sound production. Chimpanzees showed population-level leftward asymmetries in fractional anisotropy in U-fibers connecting central and inferior cortices, especially in females. Age was inversely associated with radial, axial, and mean diffusivity in these bundles. Right-handed motor skill was linked to stronger leftward fractional anisotropy asymmetries in superior regions. In contrast, more frequent attention-getting sound production was associated with increased leftward asymmetries in inferior regions. These findings show that different motor functions in chimpanzees are linked to region-specific variation in U-fiber integrity along the dorsal-ventral axis, aligning with previous representations of the chimpanzee motor "homunculus." The observed association between orofacial skill and leftward asymmetry in inferior sensorimotor regions suggests a potential preadaptation for the lateralized speech functions found in modern humans.