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1.
Neuroimage ; 299: 120837, 2024 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-39241898

RESUMO

Sleep deprivation has been demonstrated to exert widespread and intricate impacts on the brain network. The human brain network is a modular network composed of interconnected nodes. This network consists of provincial hubs and connector hubs, with provincial hubs having diverse connectivities within their own modules, while connector hubs distribute their connectivities across different modules. The latter is crucial for integrating information from various modules and ensuring the normal functioning of the modular brain. However, there has been a lack of systematic investigation into the impact of sleep deprivation on brain connector hubs. In this study, we utilized functional connectivity from resting-state functional magnetic resonance imaging, as well as structural connectivity from diffusion-weighted imaging, to systematically explore the variation of connector hub properties in the cerebral cortex after one night of sleep deprivation. The normalized participation coefficients (PCnorm) were utilized to identify connector hubs. In both the functional and structural networks, connector hubs exhibited a significant increase in average PCnorm, indicating the diversity enhancement of the connector hub following sleep deprivation. This enhancement is associated with increased network cost, reduced modularity, and decreased small-worldness, but enhanced global efficiency. This may potentially signify a compensatory mechanism within the brain following sleep deprivation. The significantly affected connector hubs were primarily observed in both the Control Network and Salience Network. We believe that the observed results reflect the increasing demand on the brain to invest more effort at preventing performance deterioration after sleep loss, in exchange for increased communication efficiency, especially involving systems responsible for neural resource allocation and cognitive control. These results have been replicated in an independent dataset. In conclusion, this study has enhanced our understanding of the compensatory mechanism in the brain response to sleep deprivation. This compensation is characterized by an enhancement in the connector hubs responsible for inter-modular communication, especially those related to neural resource and cognitive control. As a result, this compensation comes with a higher network cost but leads to an improvement in global communication efficiency, akin to a more random-like network manner.


Assuntos
Conectoma , Imagem de Difusão por Ressonância Magnética , Imageamento por Ressonância Magnética , Rede Nervosa , Privação do Sono , Humanos , Privação do Sono/fisiopatologia , Privação do Sono/diagnóstico por imagem , Masculino , Adulto , Rede Nervosa/diagnóstico por imagem , Rede Nervosa/fisiopatologia , Rede Nervosa/fisiologia , Conectoma/métodos , Adulto Jovem , Feminino , Encéfalo/diagnóstico por imagem , Córtex Cerebral/diagnóstico por imagem , Córtex Cerebral/fisiopatologia , Córtex Cerebral/fisiologia
2.
Neuroimage ; 299: 120841, 2024 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-39244077

RESUMO

Working memory in attention deficit hyperactivity disorder (ADHD) is closely related to cortical functional network connectivity (CFNC), such as abnormal connections between the frontal, temporal, occipital cortices and with other brain regions. Low-intensity transcranial ultrasound stimulation (TUS) has the advantages of non-invasiveness, high spatial resolution, and high penetration depth and can improve ADHD memory behavior. However, how it modulates CFNC in ADHD and the CFNC mechanism that improves working memory behavior in ADHD remain unclear. In this study, we observed working memory impairment in ADHD rats, establishing a corresponding relationship between changes in CFNCs and the behavioral state during the working memory task. Specifically, we noted abnormalities in the information transmission and processing capabilities of CFNC in ADHD rats while performing working memory tasks. These abnormalities manifested in the network integration ability of specific areas, as well as the information flow and functional differentiation of CFNC. Furthermore, our findings indicate that TUS effectively enhances the working memory ability of ADHD rats by modulating information transmission, processing, and integration capabilities, along with adjusting the information flow and functional differentiation of CFNC. Additionally, we explain the CFNC mechanism through which TUS improves working memory in ADHD. In summary, these findings suggest that CFNCs are important in working memory behaviors in ADHD.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade , Memória de Curto Prazo , Animais , Transtorno do Deficit de Atenção com Hiperatividade/fisiopatologia , Transtorno do Deficit de Atenção com Hiperatividade/terapia , Ratos , Memória de Curto Prazo/fisiologia , Masculino , Modelos Animais de Doenças , Córtex Cerebral/fisiopatologia , Córtex Cerebral/diagnóstico por imagem , Ratos Sprague-Dawley , Rede Nervosa/fisiopatologia , Rede Nervosa/diagnóstico por imagem
3.
Cereb Cortex ; 34(9)2024 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-39270674

RESUMO

Brain network hubs are highly connected brain regions serving as important relay stations for information integration. Recent studies have linked mental disorders to impaired hub function. Provincial hubs mainly integrate information within their own brain network, while connector hubs share information between different brain networks. This study used a novel time-varying analysis to investigate whether hubs aberrantly follow the trajectory of other brain networks than their own. The aim was to characterize brain hub functioning in clinically remitted bipolar patients. We analyzed resting-state functional magnetic resonance imaging data from 96 euthymic individuals with bipolar disorder and 61 healthy control individuals. We characterized different hub qualities within the somatomotor network. We found that the somatomotor network comprised mainly provincial hubs in healthy controls. Conversely, in bipolar disorder patients, hubs in the primary somatosensory cortex displayed weaker provincial and stronger connector hub function. Furthermore, hubs in bipolar disorder showed weaker allegiances with their own brain network and followed the trajectories of the limbic, salience, dorsal attention, and frontoparietal network. We suggest that these hub aberrancies contribute to previously shown functional connectivity alterations in bipolar disorder and may thus constitute the neural substrate to persistently impaired sensory integration despite clinical remission.


Assuntos
Transtorno Bipolar , Imageamento por Ressonância Magnética , Rede Nervosa , Córtex Somatossensorial , Humanos , Transtorno Bipolar/fisiopatologia , Transtorno Bipolar/diagnóstico por imagem , Masculino , Feminino , Adulto , Córtex Somatossensorial/diagnóstico por imagem , Córtex Somatossensorial/fisiopatologia , Rede Nervosa/diagnóstico por imagem , Rede Nervosa/fisiopatologia , Rede Nervosa/fisiologia , Vias Neurais/fisiopatologia , Vias Neurais/diagnóstico por imagem , Conectoma , Pessoa de Meia-Idade , Encéfalo/fisiopatologia , Encéfalo/diagnóstico por imagem , Adulto Jovem
4.
PLoS Comput Biol ; 20(9): e1012415, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39226309

RESUMO

Revealing the relationship between neural network structure and function is one central theme of neuroscience. In the context of working memory (WM), anatomical data suggested that the topological structure of microcircuits within WM gradient network may differ, and the impact of such structural heterogeneity on WM activity remains unknown. Here, we proposed a spiking neural network model that can replicate the fundamental characteristics of WM: delay-period neural activity involves association cortex but not sensory cortex. First, experimentally observed receptor expression gradient along the WM gradient network is reproduced by our network model. Second, by analyzing the correlation between different local structures and duration of WM activity, we demonstrated that small-worldness, excitation-inhibition balance, and cycle structures play crucial roles in sustaining WM-related activity. To elucidate the relationship between the structure and functionality of neural networks, structural circuit gradients in brain should also be subject to further measurement. Finally, combining anatomical data, we simulated the duration of WM activity across different brain regions, its maintenance relies on the interaction between local and distributed networks. Overall, network structural gradient and interaction between local and distributed networks are of great significance for WM.


Assuntos
Memória de Curto Prazo , Modelos Neurológicos , Rede Nervosa , Memória de Curto Prazo/fisiologia , Rede Nervosa/fisiologia , Humanos , Biologia Computacional , Animais , Encéfalo/fisiologia , Simulação por Computador , Neurônios/fisiologia , Potenciais de Ação/fisiologia
5.
PLoS Comput Biol ; 20(9): e1012378, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39226313

RESUMO

Understanding the mechanism by which the brain achieves relatively consistent information processing contrary to its inherent inconsistency in activity is one of the major challenges in neuroscience. Recently, it has been reported that the consistency of neural responses to stimuli that are presented repeatedly is enhanced implicitly in an unsupervised way, and results in improved perceptual consistency. Here, we propose the term "selective consistency" to describe this input-dependent consistency and hypothesize that it will be acquired in a self-organizing manner by plasticity within the neural system. To test this, we investigated whether a reservoir-based plastic model could acquire selective consistency to repeated stimuli. We used white noise sequences randomly generated in each trial and referenced white noise sequences presented multiple times. The results showed that the plastic network was capable of acquiring selective consistency rapidly, with as little as five exposures to stimuli, even for white noise. The acquisition of selective consistency could occur independently of performance optimization, as the network's time-series prediction accuracy for referenced stimuli did not improve with repeated exposure and optimization. Furthermore, the network could only achieve selective consistency when in the region between order and chaos. These findings suggest that the neural system can acquire selective consistency in a self-organizing manner and that this may serve as a mechanism for certain types of learning.


Assuntos
Biologia Computacional , Modelos Neurológicos , Redes Neurais de Computação , Plasticidade Neuronal , Plasticidade Neuronal/fisiologia , Humanos , Aprendizado de Máquina não Supervisionado , Rede Nervosa/fisiologia , Encéfalo/fisiologia , Aprendizagem/fisiologia , Percepção/fisiologia
6.
PLoS Comput Biol ; 20(9): e1012401, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39226329

RESUMO

Neural activity in the cortex exhibits a wide range of firing variability and rich correlation structures. Studies on neural coding indicate that correlated neural variability can influence the quality of neural codes, either beneficially or adversely. However, the mechanisms by which correlated neural variability is transformed and processed across neural populations to achieve meaningful computation remain largely unclear. Here we propose a theory of covariance computation with spiking neurons which offers a unifying perspective on neural representation and computation with correlated noise. We employ a recently proposed computational framework known as the moment neural network to resolve the nonlinear coupling of correlated neural variability with a task-driven approach to constructing neural network models for performing covariance-based perceptual tasks. In particular, we demonstrate how perceptual information initially encoded entirely within the covariance of upstream neurons' spiking activity can be passed, in a near-lossless manner, to the mean firing rate of downstream neurons, which in turn can be used to inform inference. The proposed theory of covariance computation addresses an important question of how the brain extracts perceptual information from noisy sensory stimuli to generate a stable perceptual whole and indicates a more direct role that correlated variability plays in cortical information processing.


Assuntos
Potenciais de Ação , Biologia Computacional , Modelos Neurológicos , Neurônios , Neurônios/fisiologia , Humanos , Potenciais de Ação/fisiologia , Redes Neurais de Computação , Rede Nervosa/fisiologia , Aprendizagem/fisiologia , Animais , Simulação por Computador , Encéfalo/fisiologia
7.
Psychiatry Res Neuroimaging ; 344: 111880, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39217670

RESUMO

BACKGROUND: Major Depressive Disorder (MDD), as a chronic mental disorder, causes changes in mood, thoughts, and behavior. The pathophysiology of the disorder and its treatment are still unknown. One of the most notable changes observed in patients with MDD through fMRI is abnormal functional brain connectivity. METHODS: Preprocessed data from 60 MDD patients and 60 normal controls (NCs) were selected, which has been performed using the DPARSF toolbox. The whole-brain functional networks and topologies were extracted using graph theory-based methods. A two-sample, two-tailed t-test was used to compare the topological features of functional brain networks between the MDD and NCs groups using the DPABI-Net/Statistical Analysis toolbox. RESULTS: The obtained results showed a decrease in both global and local efficiency in MDD patients compared to NCs, and specifically, MDD patients showed significantly higher path length values. Acceptable p-values were obtained with a small sample size and less computational volume compared to the other studies on large datasets. At the node level, MDD patients showed decreased and relatively decreased node degrees in the sensorimotor network (SMN) and the dorsal attention network (DAN), respectively, as well as decreased node efficiency in the SMN, default mode network (DMN), and DAN. Also, MDD patients showed slightly decreased node efficiency in the visual networks (VN) and the ventral attention network (VAN), which were reported after FDR correction with Q < 0.05. LIMITATIONS: All participants were Chinese. CONCLUSIONS: Collectively, increased path length, decreased global and local efficiency, and also decreased nodal degree and efficiency in the SMN, DAN, DAN, VN, and VAN were found in patients compared to NCs.


Assuntos
Transtorno Depressivo Maior , Imageamento por Ressonância Magnética , Rede Nervosa , Humanos , Transtorno Depressivo Maior/diagnóstico por imagem , Transtorno Depressivo Maior/fisiopatologia , Imageamento por Ressonância Magnética/métodos , Feminino , Adulto , Masculino , Rede Nervosa/diagnóstico por imagem , Rede Nervosa/fisiopatologia , Encéfalo/diagnóstico por imagem , Encéfalo/fisiopatologia , Pessoa de Meia-Idade , Conectoma/métodos , Adulto Jovem
8.
Sleep Med ; 123: 42-48, 2024 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-39236464

RESUMO

BACKGROUND: Chronic insomnia disorder (CID) is commonly associated with mood disorders. The cingulate gyrus (CG) plays a critical role in the pathophysiology of CID and anxiety. However, the specific characteristics of altered brain networks in the CG in CID with anxiety remain unclear. This study aimed to investigate the characteristics of CG functional connectivity (FC) in CID with and without anxiety. METHODS: Resting-state functional magnetic resonance imaging was conducted on 92 CID and 36 healthy controls (HC). CID was divided into CID with anxiety (CID-A, N = 37) and CID without anxiety (CID-NA, N = 55) groups based on anxiety scores. Using the Human Brainnetome Atlas, the subregion CG FC network was constructed. RESULTS: Compared with HC, CID showed significantly decreased CG FC with the precuneus, middle frontal gyrus (MFG), and hippocampus, while showing significantly increased CG FC with the middle temporal gyrus (MTG)/superior temporal gyrus (STG). In contrast, CID-A showed significantly decreased CG FC with the salience network (insular, putamen) and default mode network (MTG/STG and inferior parietal lobule), while showing significantly increased CG FC with the thalamus and MFG compared to CID-NA. Further, CID-A and CID-NA could be classified with 84.21 % accuracy by using the CG FCs as features. Among these features, the CG FC with MFG, thalamus, and putamen had the highest contribution weights. CONCLUSION: This study revealed specific changes in the brain network of the CG subregion in CID-A. Understanding these CG FC alterations can help identify potential biomarkers specific to CID-A, which may be valuable for early detection and differentiation from other CID subtypes.


Assuntos
Giro do Cíngulo , Imageamento por Ressonância Magnética , Distúrbios do Início e da Manutenção do Sono , Humanos , Masculino , Distúrbios do Início e da Manutenção do Sono/fisiopatologia , Distúrbios do Início e da Manutenção do Sono/diagnóstico por imagem , Feminino , Giro do Cíngulo/fisiopatologia , Giro do Cíngulo/diagnóstico por imagem , Adulto , Ansiedade/fisiopatologia , Pessoa de Meia-Idade , Vias Neurais/fisiopatologia , Mapeamento Encefálico/métodos , Rede Nervosa/fisiopatologia , Rede Nervosa/diagnóstico por imagem
9.
Nat Commun ; 15(1): 8238, 2024 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-39300106

RESUMO

A general mathematical description of how the brain sequentially encodes knowledge remains elusive. We propose a linear solution for serial learning tasks, based on the concept of mixed selectivity in high-dimensional neural state spaces. In our framework, neural representations of items in a sequence are projected along a "geometric" mental line learned through classical conditioning. The model successfully solves serial position tasks and explains behaviors observed in humans and animals during transitive inference tasks amidst noisy sensory input and stochastic neural activity. This approach extends to recurrent neural networks performing motor decision tasks, where the same geometric mental line correlates with motor plans and modulates network activity according to the symbolic distance between items. Serial ordering is thus predicted to emerge as a monotonic mapping between sensory input and behavioral output, highlighting a possible pivotal role for motor-related associative cortices in transitive inference tasks.


Assuntos
Modelos Neurológicos , Humanos , Animais , Encéfalo/fisiologia , Aprendizagem/fisiologia , Redes Neurais de Computação , Rede Nervosa/fisiologia , Condicionamento Clássico/fisiologia
10.
BMC Ophthalmol ; 24(1): 411, 2024 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-39300474

RESUMO

BACKGROUND: The pathogenesis of intermittent exotropia (IXT) remains unclear. The study aims to investigate alterations of resting-state networks (RSNs) in IXT adult patients using resting-state functional magnetic resonance imaging (rs-fMRI) data to explore the potential neural mechanisms. METHODS: Twenty-six IXT adult patients and 22 age-, sex-, handedness-, and education-matched healthy controls (HCs) underwent fMRI scanning and ophthalmological examinations. Brain areas with significant functional connectivity (FC) differences between the IXT and HC groups were selected as regions of interest (ROI) and mean z-scores were calculated to control for individual differences. RESULTS: Compared with HCs, IXT patients exhibited altered FC in various brain regions within RSNs involved in binocular fusion, stereopsis, ocular movement, emotional processes and social cognition, including the default mode network (DMN), the dorsal attention network (DAN), the visual network (VN), the sensorimotor network (SMN), the executive control network (ECN), the frontoparietal network (FPN) and the auditory network (AN). The degree of exodeviation was positively correlated with FC value of left middle occipital gyrus (MOG) within the VN. Correspondingly, we found a negative correlation between the degree of exodeviation and the FC value of left angular gyrus (AG) within FPN (P < 0.05). The FNC analysis between different RSNs also provides evidence on visual-motor cortical plasticity. CONCLUSIONS: IXT patients showed widespread changes of brain activity within RSNs related to binocular fusion, stereopsis, oculomotor control, emotional processes, and social cognition. These findings extend our current understanding of the neuropathological mechanisms of IXT. TRIAL REGISTRATION: Beginning date of the trial: 2021-09-01. Date of registration:2021-07-18. Trial registration number: ChiCTR 2,100,048,852. Trial registration site: http://www.chictr.org.cn/index.aspx .


Assuntos
Exotropia , Imageamento por Ressonância Magnética , Humanos , Exotropia/fisiopatologia , Exotropia/diagnóstico por imagem , Masculino , Feminino , Imageamento por Ressonância Magnética/métodos , Adulto , Adulto Jovem , Rede Nervosa/fisiopatologia , Rede Nervosa/diagnóstico por imagem , Mapeamento Encefálico/métodos , Encéfalo/fisiopatologia , Encéfalo/diagnóstico por imagem , Descanso/fisiologia , Pessoa de Meia-Idade
11.
Hum Brain Mapp ; 45(14): e70030, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39301700

RESUMO

Psychosis implicates changes across a broad range of cognitive functions. These functions are cortically organized in the form of a hierarchy ranging from primary sensorimotor (unimodal) to higher-order association cortices, which involve functions such as language (transmodal). Language has long been documented as undergoing structural changes in psychosis. We hypothesized that these changes as revealed in spontaneous speech patterns may act as readouts of alterations in the configuration of this unimodal-to-transmodal axis of cortical organization in psychosis. Results from 29 patients with first-episodic psychosis (FEP) and 29 controls scanned with 7 T resting-state fMRI confirmed a compression of the cortical hierarchy in FEP, which affected metrics of the hierarchical distance between the sensorimotor and default mode networks, and of the hierarchical organization within the semantic network. These organizational changes were predicted by graphs representing semantic and syntactic associations between meaningful units in speech produced during picture descriptions. These findings unite psychosis, language, and the cortical hierarchy in a single conceptual scheme, which helps to situate language within the neurocognition of psychosis and opens the clinical prospect for mental dysfunction to become computationally measurable in spontaneous speech.


Assuntos
Imageamento por Ressonância Magnética , Transtornos Psicóticos , Fala , Humanos , Transtornos Psicóticos/diagnóstico por imagem , Transtornos Psicóticos/fisiopatologia , Transtornos Psicóticos/patologia , Masculino , Adulto , Feminino , Fala/fisiologia , Adulto Jovem , Rede Nervosa/diagnóstico por imagem , Rede Nervosa/fisiopatologia , Rede Nervosa/patologia , Córtex Cerebral/diagnóstico por imagem , Córtex Cerebral/fisiopatologia , Rede de Modo Padrão/diagnóstico por imagem , Rede de Modo Padrão/fisiopatologia
12.
CNS Neurosci Ther ; 30(9): e70029, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39302036

RESUMO

AIMS: The study aims to examine the changing trajectory characteristics of dynamic functional network connectivity (dFNC) and its correlation with lipid metabolism-related factors across the Alzheimer's disease (AD) spectrum populations. METHODS: Data from 242 AD spectrum subjects, including biological, neuroimaging, and general cognition, were obtained from the Alzheimer's Disease Neuroimaging Initiative for this cross-sectional study. The study utilized a sliding-window approach to assess whole-brain dFNC, investigating group differences and associations with biological and cognitive factors. Abnormal dFNC was used in the classification of AD spectrum populations by support vector machine. Mediation analysis was performed to explore the relationships between lipid-related indicators, dFNC, cerebrospinal fluid (CSF) biomarkers, and cognitive performance. RESULTS: Significant group difference concerning were observed in relation to APOE-ε4 status, CSF biomarkers, and cognitive scores. Two reoccurring connectivity states were identified: state-1 characterized by frequent but weak connections, and state-II characterized by less frequent but strong connections. Pre-AD subjects exhibited a preference for spending more time in state-I, whereas AD patients tended remain in state-II for longer periods. Group difference in dFNC was primarily found between AD and non-AD participants within each state. The dFNC of state-I yielded strong power to distinguish AD from other groups compared with state-II. APOE-ε4+, high polygenic score, and high serum lipid group were strongly associated with network disruption between association cortex system and sensory cortex system that characterized elevation of cognitive function, which may suggest a compensatory mechanism of dFNC in state-I, whereas differential connections of state-II mediated the relationships between APOE-ε4 genotype and CSF biomarkers, and cognitive indicators. CONCLUSION: The dysfunction of dFNC temporal-spatial patterns and increased cognition in individuals with APOE-ε4, high polygenic score, and higher serum lipid levels shed light on the lipid-related mechanisms of dynamic network reorganization in AD.


Assuntos
Doença de Alzheimer , Metabolismo dos Lipídeos , Imageamento por Ressonância Magnética , Humanos , Doença de Alzheimer/metabolismo , Doença de Alzheimer/líquido cefalorraquidiano , Masculino , Feminino , Idoso , Metabolismo dos Lipídeos/fisiologia , Estudos Transversais , Encéfalo/metabolismo , Encéfalo/diagnóstico por imagem , Idoso de 80 Anos ou mais , Rede Nervosa/metabolismo , Rede Nervosa/diagnóstico por imagem , Apolipoproteína E4/genética , Biomarcadores/líquido cefalorraquidiano , Biomarcadores/sangue , Pessoa de Meia-Idade
13.
PLoS One ; 19(9): e0308146, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39302961

RESUMO

Packet information encoding of neural signals was proposed for vision about 50 years ago and has recently been revived as a plausible strategy generalizable to natural and artificial sensory systems. It involves discrete image segmentation controlled by feedback and the ability to store and compare packets of information. This article shows that neurons of the cerebellum-like electrosensory lobe (EL) of the electric fish Gymnotus omarorum use spike-count and spike-timing distribution as constitutive variables of packets of information that encode one-by-one the electrosensory images generated by a self-timed series of electric organ discharges (EODs). To evaluate this hypothesis, extracellular unitary activity was recorded from the centro-medial map of the EL. Units recorded in high-decerebrate preparations were classified into six types using hierarchical cluster analysis of post-EOD spiking histograms. Cross-correlation analysis indicated that each EOD strongly influences the unit firing probability within the next inter-EOD interval. Units of the same type were similarly located in the laminar organization of the EL and showed similar stimulus-specific changes in spike count and spike timing after the EOD when a metal object was moved close by, along the fish's body parallel to the skin, or when the longitudinal impedance of a static cylindrical probe placed at the center of the receptive field was incremented in a stepwise manner in repetitive trials. These last experiments showed that spike-counts and the relative entropy, expressing a comparative measure of information before and after the step, were systematically increased with respect to a control in all unit types. The post-EOD spike-timing probability distribution and the relatively independent contribution of spike-timing and number to the content of information in the transmitted packet suggest that these are the constitutive image-encoding variables of the packets. Comparative analysis suggests that packet information transmission is a general principle for processing superposition images in cerebellum-like networks.


Assuntos
Cerebelo , Animais , Cerebelo/fisiologia , Potenciais de Ação/fisiologia , Órgão Elétrico/fisiologia , Neurônios/fisiologia , Peixe Elétrico/fisiologia , Gimnotiformes/fisiologia , Rede Nervosa/fisiologia
14.
Sci Adv ; 10(38): eadp5229, 2024 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-39303044

RESUMO

Changes in synaptic strength across timescales are integral to algorithmic operations of neural circuits. However, pinpointing synaptic loci that undergo plasticity in intact brain circuits and delineating contributions of synaptic plasticity to circuit function remain challenging. The whole-mount retina preparation provides an accessible platform for measuring plasticity at specific synapses while monitoring circuit-level behaviors during visual processing ex vivo. In this review, we discuss insights gained from retina studies into the versatile roles of short-term synaptic plasticity in context-dependent circuit functions. Plasticity at single synapse level greatly expands the algorithms of common microcircuit motifs and contributes to diverse circuit-level behaviors such as gain modulation, selective gating, and stimulus-dependent excitatory/inhibitory balance. Examples in retinal circuitry offer unequivocal support that synaptic plasticity increases the computational capacity of hardwired neural circuitry.


Assuntos
Plasticidade Neuronal , Retina , Sinapses , Plasticidade Neuronal/fisiologia , Retina/fisiologia , Animais , Humanos , Sinapses/fisiologia , Rede Nervosa/fisiologia
15.
Sci Adv ; 10(38): eadh3920, 2024 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-39292771

RESUMO

Frontal cortical circuits undergo prolonged maturation across childhood and adolescence; however, it remains unknown what specific changes are occurring at the circuit level to establish adult cognitive function. With the recent advent of circuit dissection techniques, it is now feasible to examine circuit-specific changes in connectivity, activity, and function in animal models. Here, we propose that the balance of local and long-range inputs onto frontal cognitive circuits is an understudied metric of circuit maturation. This review highlights research on a frontal-sensory attention circuit that undergoes refinement of local/long-range connectivity, regulated by circuit activity and neuromodulatory signaling, and evaluates how this process may occur generally in the frontal cortex to support adult cognitive behavior. Notably, this balance can be bidirectionally disrupted through various mechanisms relevant to psychiatric disorders. Pharmacological or environmental interventions to normalize or reset the local and long-range balance could hold great therapeutic promise to prevent or rescue cognitive deficits.


Assuntos
Cognição , Lobo Frontal , Humanos , Cognição/fisiologia , Animais , Lobo Frontal/fisiologia , Rede Nervosa/fisiologia , Vias Neurais/fisiologia
16.
Nature ; 633(8030): 624-633, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39232159

RESUMO

Decades of neuroimaging studies have shown modest differences in brain structure and connectivity in depression, hindering mechanistic insights or the identification of risk factors for disease onset1. Furthermore, whereas depression is episodic, few longitudinal neuroimaging studies exist, limiting understanding of mechanisms that drive mood-state transitions. The emerging field of precision functional mapping has used densely sampled longitudinal neuroimaging data to show behaviourally meaningful differences in brain network topography and connectivity between and in healthy individuals2-4, but this approach has not been applied in depression. Here, using precision functional mapping and several samples of deeply sampled individuals, we found that the frontostriatal salience network is expanded nearly twofold in the cortex of most individuals with depression. This effect was replicable in several samples and caused primarily by network border shifts, with three distinct modes of encroachment occurring in different individuals. Salience network expansion was stable over time, unaffected by mood state and detectable in children before the onset of depression later in adolescence. Longitudinal analyses of individuals scanned up to 62 times over 1.5 years identified connectivity changes in frontostriatal circuits that tracked fluctuations in specific symptoms and predicted future anhedonia symptoms. Together, these findings identify a trait-like brain network topology that may confer risk for depression and mood-state-dependent connectivity changes in frontostriatal circuits that predict the emergence and remission of depressive symptoms over time.


Assuntos
Mapeamento Encefálico , Corpo Estriado , Depressão , Lobo Frontal , Rede Nervosa , Vias Neurais , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem , Afeto/fisiologia , Anedonia/fisiologia , Mapeamento Encefálico/métodos , Mapeamento Encefálico/normas , Corpo Estriado/diagnóstico por imagem , Corpo Estriado/patologia , Corpo Estriado/fisiopatologia , Depressão/diagnóstico por imagem , Depressão/patologia , Depressão/fisiopatologia , Lobo Frontal/diagnóstico por imagem , Lobo Frontal/patologia , Lobo Frontal/fisiopatologia , Estudos Longitudinais , Imageamento por Ressonância Magnética , Rede Nervosa/diagnóstico por imagem , Rede Nervosa/patologia , Rede Nervosa/fisiopatologia , Vias Neurais/diagnóstico por imagem , Vias Neurais/patologia , Vias Neurais/fisiopatologia , Reprodutibilidade dos Testes
17.
Neuroimage ; 299: 120840, 2024 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-39241900

RESUMO

Previous studies of operant learning have addressed neuronal activities and network changes in specific brain areas, such as the striatum, sensorimotor cortex, prefrontal/orbitofrontal cortices, and hippocampus. However, how changes in the whole-brain network are caused by cellular-level changes remains unclear. We, therefore, combined resting-state functional magnetic resonance imaging (rsfMRI) and whole-brain immunohistochemical analysis of early growth response 1 (EGR1), a marker of neural plasticity, to elucidate the temporal and spatial changes in functional networks and underlying cellular processes during operant learning. We used an 11.7-Tesla MRI scanner and whole-brain immunohistochemical analysis of EGR1 in mice during the early and late stages of operant learning. In the operant training, mice received a reward when they pressed left and right buttons alternately, and were punished with a bright light when they made a mistake. A group of mice (n = 22) underwent the first rsfMRI acquisition before behavioral sessions, the second acquisition after 3 training-session-days (early stage), and the third after 21 training-session-days (late stage). Another group of mice (n = 40) was subjected to histological analysis 15 min after the early or late stages of behavioral sessions. Functional connectivity increased between the limbic areas and thalamus or auditory cortex after the early stage of training, and between the motor cortex, sensory cortex, and striatum after the late stage of training. The density of EGR1-immunopositive cells in the motor and sensory cortices increased in both the early and late stages of training, whereas the density in the amygdala increased only in the early stage of training. The subcortical networks centered around the limbic areas that emerged in the early stage have been implicated in rewards, pleasures, and fears. The connectivities between the motor cortex, somatosensory cortex, and striatum that consolidated in the late stage have been implicated in motor learning. Our multimodal longitudinal study successfully revealed temporal shifts in brain regions involved in behavioral learning together with the underlying cellular-level plasticity between these regions. Our study represents a first step towards establishing a new experimental paradigm that combines rsfMRI and immunohistochemistry to link macroscopic and microscopic mechanisms involved in learning.


Assuntos
Encéfalo , Condicionamento Operante , Proteína 1 de Resposta de Crescimento Precoce , Imageamento por Ressonância Magnética , Animais , Camundongos , Condicionamento Operante/fisiologia , Proteína 1 de Resposta de Crescimento Precoce/metabolismo , Proteína 1 de Resposta de Crescimento Precoce/genética , Masculino , Encéfalo/diagnóstico por imagem , Encéfalo/fisiologia , Encéfalo/metabolismo , Plasticidade Neuronal/fisiologia , Camundongos Endogâmicos C57BL , Genes Precoces/fisiologia , Rede Nervosa/diagnóstico por imagem , Rede Nervosa/fisiologia , Mapeamento Encefálico/métodos
18.
Phys Rev E ; 110(2-1): 024310, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-39295055

RESUMO

Continuous rate-based neural networks have been widely applied to modeling the dynamics of cortical circuits. However, cortical neurons in the brain exhibit irregular spiking activity with complex correlation structures that cannot be captured by mean firing rate alone. To close this gap, we consider a framework for modeling irregular spiking activity, called the moment neural network, which naturally generalizes rate models to second-order moments and can accurately capture the firing statistics of spiking neural networks. We propose an efficient numerical method that allows for rapid evaluation of moment mappings for neuronal activations without solving the underlying Fokker-Planck equation. This allows simulation of coupled interactions of mean firing rate and firing variability of large-scale neural circuits while retaining the advantage of analytical tractability of continuous rate models. We demonstrate how the moment neural network can explain a range of phenomena including diverse Fano factor in networks with quenched disorder and the emergence of irregular oscillatory dynamics in excitation-inhibition networks with delay.


Assuntos
Potenciais de Ação , Modelos Neurológicos , Rede Nervosa , Neurônios , Rede Nervosa/fisiologia , Neurônios/fisiologia
19.
Elife ; 132024 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-39311855

RESUMO

Computational principles shed light on why movement is preceded by preparatory activity within the neural networks that control muscles.


Assuntos
Movimento , Humanos , Animais , Rede Nervosa/fisiologia , Músculo Esquelético/fisiologia
20.
Sci Rep ; 14(1): 21943, 2024 09 20.
Artigo em Inglês | MEDLINE | ID: mdl-39304732

RESUMO

Visual-vestibular conflicts can induce motion sickness and further postural instability. Visual-vestibular habituation is recommended to reduce the symptoms of motion sickness and improve postural stability with an altered multisensory reweighting progress. However, it is unclear how the human brain reweights multisensory information after repeated exposure to visual-vestibular conflicts. Therefore, we synchronized a rotating platform and a virtual scene to present visual-vestibular congruent (natural visual stimulation) and incongruent (conflicted visual stimulation) conditions and collected EEG and center of pressure (COP) data. We constructed the effective brain connectivity of region of interest (ROI) derived from source-space EEG in theta-band activity, and quantified the postural stability and the inflow and outflow of each ROI. We found repeated exposure to congruent and incongruent conditions both decreased COP path length and increased COP complexity. Besides, we found that repeated exposure to the incongruent environment decreased the inflow into visual cortex, suggesting the brain down-weighted the less reliable visual information for postural stability. In contrast, repeated exposure to the congruent environment increased the inflow into posterior parietal cortex and the outflow from visual cortex and S1, suggesting an increase in efficiency of multisensory integration. We concluded that repeated exposure to congruent and incongruent conditions both improved postural stability with different multisensory reweighting patterns as revealed by different dynamic changes of brain networks.


Assuntos
Eletroencefalografia , Equilíbrio Postural , Vestíbulo do Labirinto , Percepção Visual , Humanos , Masculino , Feminino , Equilíbrio Postural/fisiologia , Vestíbulo do Labirinto/fisiologia , Adulto , Percepção Visual/fisiologia , Adulto Jovem , Estimulação Luminosa , Enjoo devido ao Movimento/fisiopatologia , Córtex Visual/fisiologia , Rede Nervosa/fisiologia
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