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1.
Nat Commun ; 12(1): 4237, 2021 07 09.
Artigo em Inglês | MEDLINE | ID: mdl-34244483

RESUMO

Brain network hubs are both highly connected and highly inter-connected, forming a critical communication backbone for coherent neural dynamics. The mechanisms driving this organization are poorly understood. Using diffusion-weighted magnetic resonance imaging in twins, we identify a major role for genes, showing that they preferentially influence connectivity strength between network hubs of the human connectome. Using transcriptomic atlas data, we show that connected hubs demonstrate tight coupling of transcriptional activity related to metabolic and cytoarchitectonic similarity. Finally, comparing over thirteen generative models of network growth, we show that purely stochastic processes cannot explain the precise wiring patterns of hubs, and that model performance can be improved by incorporating genetic constraints. Our findings indicate that genes play a strong and preferential role in shaping the functionally valuable, metabolically costly connections between connectome hubs.


Assuntos
Encéfalo/fisiologia , Conectoma , Redes Reguladoras de Genes , Rede Nervosa/fisiologia , Adulto , Encéfalo/diagnóstico por imagem , Conjuntos de Dados como Assunto , Imagem de Difusão por Ressonância Magnética , Feminino , Perfilação da Expressão Gênica , Humanos , Masculino , Modelos Genéticos , Gêmeos
2.
Nat Commun ; 12(1): 3374, 2021 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-34099735

RESUMO

Numerosity, the set size of a group of items, helps guide behaviour and decisions. Non-symbolic numerosities are represented by the approximate number system. However, distinct behavioural performance suggests that small numerosities, i.e. subitizing range, are implemented differently in the brain than larger numerosities. Prior work has shown that neural populations selectively responding (i.e. hemodynamic responses) to small numerosities are organized into a network of topographical maps. Here, we investigate how neural populations respond to large numerosities, well into the ANS. Using 7 T fMRI and biologically-inspired analyses, we found a network of neural populations tuned to both small and large numerosities organized within the same topographic maps. These results demonstrate a continuum of numerosity preferences that progressively cover both the subitizing range and beyond within the same numerosity map, suggesting a single neural mechanism. We hypothesize that differences in map properties, such as cortical magnification and tuning width, underlie known differences in behaviour.


Assuntos
Mapeamento Encefálico/métodos , Encéfalo/fisiologia , Rede Nervosa/fisiologia , Percepção Visual/fisiologia , Adulto , Encéfalo/diagnóstico por imagem , Feminino , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Rede Nervosa/diagnóstico por imagem , Estimulação Luminosa/métodos , Reprodutibilidade dos Testes
3.
Nat Commun ; 12(1): 3314, 2021 06 29.
Artigo em Inglês | MEDLINE | ID: mdl-34188024

RESUMO

Control processes associated with working memory play a central role in human cognition, but their underlying dynamic brain circuit mechanisms are poorly understood. Here we use system identification, network science, stability analysis, and control theory to probe functional circuit dynamics during working memory task performance. Our results show that dynamic signaling between distributed brain areas encompassing the salience (SN), fronto-parietal (FPN), and default mode networks can distinguish between working memory load and predict performance. Network analysis of directed causal influences suggests the anterior insula node of the SN and dorsolateral prefrontal cortex node of the FPN are causal outflow and inflow hubs, respectively. Network controllability decreases with working memory load and SN nodes show the highest functional controllability. Our findings reveal dissociable roles of the SN and FPN in systems control and provide novel insights into dynamic circuit mechanisms by which cognitive control circuits operate asymmetrically during cognition.


Assuntos
Encéfalo/fisiologia , Função Executiva/fisiologia , Memória de Curto Prazo/fisiologia , Rede Nervosa/fisiologia , Adulto , Mapeamento Encefálico , Córtex Cerebral/fisiologia , Feminino , Giro do Cíngulo/fisiologia , Humanos , Masculino , Modelos Neurológicos , Vias Neurais , Córtex Pré-Frontal/fisiologia , Reprodutibilidade dos Testes , Adulto Jovem
4.
Cell Mol Life Sci ; 78(14): 5647-5663, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34128077

RESUMO

Inhibitory control is essential for the regulation of neuronal network activity, where excitatory and inhibitory synapses can act synergistically, reciprocally, and antagonistically. Sustained excitation-inhibition (E-I) balance, therefore, relies on the orchestrated adjustment of excitatory and inhibitory synaptic strength. While growing evidence indicates that the brain's extracellular matrix (ECM) is a crucial regulator of excitatory synapse plasticity, it remains unclear whether and how the ECM contributes to inhibitory control in neuronal networks. Here we studied the simultaneous changes in excitatory and inhibitory connectivity after ECM depletion. We demonstrate that the ECM supports the maintenance of E-I balance by retaining inhibitory connectivity. Quantification of synapses and super-resolution microscopy showed that depletion of the ECM in mature neuronal networks preferentially decreases the density of inhibitory synapses and the size of individual inhibitory postsynaptic scaffolds. The reduction of inhibitory synapse density is partially compensated by the homeostatically increasing synaptic strength via the reduction of presynaptic GABAB receptors, as indicated by patch-clamp measurements and GABAB receptor expression quantifications. However, both spiking and bursting activity in neuronal networks is increased after ECM depletion, as indicated by multi-electrode recordings. With computational modelling, we determined that ECM depletion reduces the inhibitory connectivity to an extent that the inhibitory synapse scaling does not fully compensate for the reduced inhibitory synapse density. Our results indicate that the brain's ECM preserves the balanced state of neuronal networks by supporting inhibitory control via inhibitory synapse stabilization, which expands the current understanding of brain activity regulation.


Assuntos
Potenciais Pós-Sinápticos Excitadores , Matriz Extracelular/fisiologia , Rede Nervosa/fisiologia , Plasticidade Neuronal , Neurônios/fisiologia , Sinapses/fisiologia , Transmissão Sináptica , Animais , Astrócitos/citologia , Astrócitos/fisiologia , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Neurônios/citologia , Receptores de GABA/metabolismo
5.
Int J Mol Sci ; 22(11)2021 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-34070424

RESUMO

BACKGROUND: The extracellular matrix of the PNS/CNS is unusual in that it is dominated by glycosaminoglycans, especially hyaluronan, whose space filling and hydrating properties make essential contributions to the functional properties of this tissue. Hyaluronan has a relatively simple structure but its space-filling properties ensure micro-compartments are maintained in the brain ultrastructure, ensuring ionic niches and gradients are maintained for optimal cellular function. Hyaluronan has cell-instructive, anti-inflammatory properties and forms macro-molecular aggregates with the lectican CS-proteoglycans, forming dense protective perineuronal net structures that provide neural and synaptic plasticity and support cognitive learning. AIMS: To highlight the central nervous system/peripheral nervous system (CNS/PNS) and its diverse extracellular and cell-associated proteoglycans that have cell-instructive properties regulating neural repair processes and functional recovery through interactions with cell adhesive molecules, receptors and neuroregulatory proteins. Despite a general lack of stabilising fibrillar collagenous and elastic structures in the CNS/PNS, a sophisticated dynamic extracellular matrix is nevertheless important in tissue form and function. CONCLUSIONS: This review provides examples of the sophistication of the CNS/PNS extracellular matrix, showing how it maintains homeostasis and regulates neural repair and regeneration.


Assuntos
Sistema Nervoso Central/metabolismo , Matriz Extracelular/metabolismo , Rede Nervosa/metabolismo , Neurônios/metabolismo , Sistema Nervoso Periférico/metabolismo , Animais , Sistema Nervoso Central/enzimologia , Sistema Nervoso Central/fisiologia , Humanos , Ácido Hialurônico/metabolismo , Rede Nervosa/enzimologia , Rede Nervosa/fisiologia , Neurogênese/genética , Neurogênese/fisiologia , Sistema Nervoso Periférico/enzimologia , Sistema Nervoso Periférico/fisiologia , Proteoglicanas/metabolismo , Transdução de Sinais/genética , Transdução de Sinais/fisiologia
6.
Nat Commun ; 12(1): 3478, 2021 06 09.
Artigo em Inglês | MEDLINE | ID: mdl-34108456

RESUMO

Dynamical brain state transitions are critical for flexible working memory but the network mechanisms are incompletely understood. Here, we show that working memory performance entails brain-wide switching between activity states using a combination of functional magnetic resonance imaging in healthy controls and individuals with schizophrenia, pharmacological fMRI, genetic analyses and network control theory. The stability of states relates to dopamine D1 receptor gene expression while state transitions are influenced by D2 receptor expression and pharmacological modulation. Individuals with schizophrenia show altered network control properties, including a more diverse energy landscape and decreased stability of working memory representations. Our results demonstrate the relevance of dopamine signaling for the steering of whole-brain network dynamics during working memory and link these processes to schizophrenia pathophysiology.


Assuntos
Encéfalo/fisiologia , Memória de Curto Prazo/fisiologia , Rede Nervosa/fisiologia , Esquizofrenia/fisiopatologia , Adulto , Encéfalo/diagnóstico por imagem , Encéfalo/efeitos dos fármacos , Antagonistas dos Receptores de Dopamina D2/farmacologia , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Memória de Curto Prazo/efeitos dos fármacos , Pessoa de Meia-Idade , Rede Nervosa/diagnóstico por imagem , Rede Nervosa/efeitos dos fármacos , Córtex Pré-Frontal/diagnóstico por imagem , Córtex Pré-Frontal/efeitos dos fármacos , Córtex Pré-Frontal/metabolismo , Córtex Pré-Frontal/fisiologia , Receptores de Dopamina D1/genética , Receptores de Dopamina D1/metabolismo , Receptores de Dopamina D2/genética , Receptores de Dopamina D2/metabolismo , Esquizofrenia/diagnóstico por imagem , Esquizofrenia/genética , Esquizofrenia/metabolismo , Adulto Jovem
7.
Nat Commun ; 12(1): 3151, 2021 05 25.
Artigo em Inglês | MEDLINE | ID: mdl-34035240

RESUMO

Computational modeling and human studies suggest that transcranial alternating current stimulation (tACS) modulates alpha oscillations by entrainment. Yet, a direct examination of how tACS interacts with neuronal spiking activity that gives rise to the alpha oscillation in the thalamo-cortical system has been lacking. Here, we demonstrate how tACS entrains endogenous alpha oscillations in head-fixed awake ferrets. We first show that endogenous alpha oscillations in the posterior parietal cortex drive the primary visual cortex and the higher-order visual thalamus. Spike-field coherence is largest for the alpha frequency band, and presumed fast-spiking inhibitory interneurons exhibit strongest coupling to this oscillation. We then apply alpha-tACS that results in a field strength comparable to what is commonly used in humans (<0.5 mV/mm). Both in these ferret experiments and in a computational model of the thalamo-cortical system, tACS entrains alpha oscillations by following the theoretically predicted Arnold tongue. Intriguingly, the fast-spiking inhibitory interneurons exhibit a stronger entrainment response to tACS in both the ferret experiments and the computational model, likely due to their stronger endogenous coupling to the alpha oscillation. Our findings demonstrate the in vivo mechanism of action for the modulation of the alpha oscillation by tACS.


Assuntos
Ritmo alfa/fisiologia , Tálamo/fisiologia , Estimulação Transcraniana por Corrente Contínua/métodos , Córtex Visual/fisiologia , Animais , Simulação por Computador , Eletrodos Implantados , Eletroencefalografia , Feminino , Furões , Interneurônios/fisiologia , Imageamento por Ressonância Magnética , Masculino , Microeletrodos , Modelos Animais , Modelos Neurológicos , Rede Nervosa/fisiologia , Optogenética , Tálamo/citologia , Tálamo/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Estimulação Transcraniana por Corrente Contínua/instrumentação , Córtex Visual/citologia , Córtex Visual/diagnóstico por imagem
8.
Nat Commun ; 12(1): 2859, 2021 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-34001873

RESUMO

The basolateral amygdalar complex (BLA) is implicated in behaviors ranging from fear acquisition to addiction. Optogenetic methods have enabled the association of circuit-specific functions to uniquely connected BLA cell types. Thus, a systematic and detailed connectivity profile of BLA projection neurons to inform granular, cell type-specific interrogations is warranted. Here, we apply machine-learning based computational and informatics analysis techniques to the results of circuit-tracing experiments to create a foundational, comprehensive BLA connectivity map. The analyses identify three distinct domains within the anterior BLA (BLAa) that house target-specific projection neurons with distinguishable morphological features. We identify brain-wide targets of projection neurons in the three BLAa domains, as well as in the posterior BLA, ventral BLA, posterior basomedial, and lateral amygdalar nuclei. Inputs to each nucleus also are identified via retrograde tracing. The data suggests that connectionally unique, domain-specific BLAa neurons are associated with distinct behavior networks.


Assuntos
Potenciais de Ação/fisiologia , Complexo Nuclear Basolateral da Amígdala/fisiologia , Medo/fisiologia , Rede Nervosa/fisiologia , Neurônios/fisiologia , Algoritmos , Animais , Complexo Nuclear Basolateral da Amígdala/citologia , Medo/psicologia , Feminino , Masculino , Camundongos Endogâmicos C57BL , Modelos Neurológicos , Rede Nervosa/citologia , Optogenética/métodos
9.
Nat Commun ; 12(1): 2632, 2021 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-33976141

RESUMO

The neural systems supporting scene-perception and spatial-memory systems of the human brain are well-described. But how do these neural systems interact? Here, using fine-grained individual-subject fMRI, we report three cortical areas of the human brain, each lying immediately anterior to a region of the scene perception network in posterior cerebral cortex, that selectively activate when recalling familiar real-world locations. Despite their close proximity to the scene-perception areas, network analyses show that these regions constitute a distinct functional network that interfaces with spatial memory systems during naturalistic scene understanding. These "place-memory areas" offer a new framework for understanding how the brain implements memory-guided visual behaviors, including navigation.


Assuntos
Córtex Cerebral/fisiologia , Rememoração Mental/fisiologia , Memória Espacial/fisiologia , Navegação Espacial/fisiologia , Percepção Visual/fisiologia , Adulto , Córtex Cerebral/diagnóstico por imagem , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Rede Nervosa/diagnóstico por imagem , Rede Nervosa/fisiologia , Adulto Jovem
10.
Nat Commun ; 12(1): 2930, 2021 05 18.
Artigo em Inglês | MEDLINE | ID: mdl-34006884

RESUMO

The neural mechanisms underlying conscious recognition remain unclear, particularly the roles played by the prefrontal cortex, deactivated brain areas and subcortical regions. We investigated neural activity during conscious object recognition using 7 Tesla fMRI while human participants viewed object images presented at liminal contrasts. Here, we show both recognized and unrecognized images recruit widely distributed cortical and subcortical regions; however, recognized images elicit enhanced activation of visual, frontoparietal, and subcortical networks and stronger deactivation of the default-mode network. For recognized images, object category information can be decoded from all of the involved cortical networks but not from subcortical regions. Phase-scrambled images trigger strong involvement of inferior frontal junction, anterior cingulate cortex and default-mode network, implicating these regions in inferential processing under increased uncertainty. Our results indicate that content-specific activity in both activated and deactivated cortical networks and non-content-specific subcortical activity support conscious recognition.


Assuntos
Encéfalo/fisiologia , Córtex Cerebral/fisiologia , Estado de Consciência/fisiologia , Reconhecimento Psicológico/fisiologia , Córtex Visual/fisiologia , Adulto , Encéfalo/diagnóstico por imagem , Mapeamento Encefálico , Córtex Cerebral/diagnóstico por imagem , Feminino , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Rede Nervosa/diagnóstico por imagem , Rede Nervosa/fisiologia , Estimulação Luminosa/métodos , Córtex Visual/diagnóstico por imagem , Adulto Jovem
11.
Nat Commun ; 12(1): 3095, 2021 05 25.
Artigo em Inglês | MEDLINE | ID: mdl-34035249

RESUMO

The analysis of biomedical signals for clinical studies and therapeutic applications can benefit from embedded devices that can process these signals locally and in real-time. An example is the analysis of intracranial EEG (iEEG) from epilepsy patients for the detection of High Frequency Oscillations (HFO), which are a biomarker for epileptogenic brain tissue. Mixed-signal neuromorphic circuits offer the possibility of building compact and low-power neural network processing systems that can analyze data on-line in real-time. Here we present a neuromorphic system that combines a neural recording headstage with a spiking neural network (SNN) processing core on the same die for processing iEEG, and show how it can reliably detect HFO, thereby achieving state-of-the-art accuracy, sensitivity, and specificity. This is a first feasibility study towards identifying relevant features in iEEG in real-time using mixed-signal neuromorphic computing technologies.


Assuntos
Encéfalo/fisiologia , Eletrocorticografia/métodos , Rede Nervosa/fisiologia , Neurônios/fisiologia , Potenciais de Ação/fisiologia , Algoritmos , Encéfalo/citologia , Eletrocorticografia/instrumentação , Humanos , Modelos Neurológicos , Convulsões/fisiopatologia , Lobo Temporal/fisiopatologia
12.
Science ; 372(6545)2021 05 28.
Artigo em Inglês | MEDLINE | ID: mdl-34045327

RESUMO

Hippocampal place cells encode the animal's location. Place cells were traditionally studied in small environments, and nothing is known about large ethologically relevant spatial scales. We wirelessly recorded from hippocampal dorsal CA1 neurons of wild-born bats flying in a long tunnel (200 meters). The size of place fields ranged from 0.6 to 32 meters. Individual place cells exhibited multiple fields and a multiscale representation: Place fields of the same neuron differed up to 20-fold in size. This multiscale coding was observed from the first day of exposure to the environment, and also in laboratory-born bats that never experienced large environments. Theoretical decoding analysis showed that the multiscale code allows representation of very large environments with much higher precision than that of other codes. Together, by increasing the spatial scale, we discovered a neural code that is radically different from classical place codes.


Assuntos
Região CA1 Hipocampal/fisiologia , Quirópteros/fisiologia , Voo Animal , Células de Lugar/fisiologia , Células Piramidais/fisiologia , Navegação Espacial , Animais , Região CA3 Hipocampal/fisiologia , Córtex Entorrinal/fisiologia , Rede Nervosa/fisiologia , Redes Neurais de Computação , Neurônios/fisiologia
14.
Nat Commun ; 12(1): 2643, 2021 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-33976118

RESUMO

Prediction of future sensory input based on past sensory information is essential for organisms to effectively adapt their behavior in dynamic environments. Humans successfully predict future stimuli in various natural settings. Yet, it remains elusive how the brain achieves effective prediction despite enormous variations in sensory input rate, which directly affect how fast sensory information can accumulate. We presented participants with acoustic sequences capturing temporal statistical regularities prevalent in nature and investigated neural mechanisms underlying predictive computation using MEG. By parametrically manipulating sequence presentation speed, we tested two hypotheses: neural prediction relies on integrating past sensory information over fixed time periods or fixed amounts of information. We demonstrate that across halved and doubled presentation speeds, predictive information in neural activity stems from integration over fixed amounts of information. Our findings reveal the neural mechanisms enabling humans to robustly predict dynamic stimuli in natural environments despite large sensory input rate variations.


Assuntos
Adaptação Fisiológica/fisiologia , Algoritmos , Encéfalo/fisiologia , Modelos Neurológicos , Rede Nervosa/fisiologia , Sensação/fisiologia , Estimulação Acústica , Adulto , Encéfalo/citologia , Feminino , Humanos , Magnetoencefalografia/métodos , Masculino , Neurônios/fisiologia , Desempenho Psicomotor/fisiologia , Adulto Jovem
15.
Nat Commun ; 12(1): 2943, 2021 05 19.
Artigo em Inglês | MEDLINE | ID: mdl-34011945

RESUMO

Typical patterned movements in animals are achieved through combinations of contraction and delayed relaxation of groups of muscles. However, how intersegmentally coordinated patterns of muscular relaxation are regulated by the neural circuits remains poorly understood. Here, we identify Canon, a class of higher-order premotor interneurons, that regulates muscular relaxation during backward locomotion of Drosophila larvae. Canon neurons are cholinergic interneurons present in each abdominal neuromere and show wave-like activity during fictive backward locomotion. Optogenetic activation of Canon neurons induces relaxation of body wall muscles, whereas inhibition of these neurons disrupts timely muscle relaxation. Canon neurons provide excitatory outputs to inhibitory premotor interneurons. Canon neurons also connect with each other to form an intersegmental circuit and regulate their own wave-like activities. Thus, our results demonstrate how coordinated muscle relaxation can be realized by an intersegmental circuit that regulates its own patterned activity and sequentially terminates motor activities along the anterior-posterior axis.


Assuntos
Drosophila melanogaster/fisiologia , Interneurônios/fisiologia , Relaxamento Muscular/fisiologia , Animais , Animais Geneticamente Modificados , Neurônios Colinérgicos/citologia , Neurônios Colinérgicos/fisiologia , Drosophila melanogaster/anatomia & histologia , Interneurônios/citologia , Larva/anatomia & histologia , Larva/fisiologia , Locomoção/fisiologia , Modelos Neurológicos , Neurônios Motores/citologia , Neurônios Motores/fisiologia , Rede Nervosa/anatomia & histologia , Rede Nervosa/fisiologia , Optogenética
16.
Nat Commun ; 12(1): 2517, 2021 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-33947849

RESUMO

Survival depends on a balance between seeking rewards and avoiding potential threats, but the neural circuits that regulate this motivational conflict remain largely unknown. Using an approach-food vs. avoid-predator threat conflict test in rats, we identified a subpopulation of neurons in the anterior portion of the paraventricular thalamic nucleus (aPVT) which express corticotrophin-releasing factor (CRF) and are preferentially recruited during conflict. Inactivation of aPVTCRF neurons during conflict biases animal's response toward food, whereas activation of these cells recapitulates the food-seeking suppression observed during conflict. aPVTCRF neurons project densely to the nucleus accumbens (NAc), and activity in this pathway reduces food seeking and increases avoidance. In addition, we identified the ventromedial hypothalamus (VMH) as a critical input to aPVTCRF neurons, and demonstrated that VMH-aPVT neurons mediate defensive behaviors exclusively during conflict. Together, our findings describe a hypothalamic-thalamostriatal circuit that suppresses reward-seeking behavior under the competing demands of avoiding threats.


Assuntos
Aprendizagem da Esquiva/fisiologia , Hormônio Liberador da Corticotropina/metabolismo , Hipotálamo/fisiologia , Núcleos da Linha Média do Tálamo/metabolismo , Rede Nervosa/fisiologia , Neurônios/metabolismo , Núcleo Hipotalâmico Ventromedial/fisiologia , Animais , Escala de Avaliação Comportamental , Conflito Psicológico , Feminino , Hipotálamo/metabolismo , Masculino , Núcleos da Linha Média do Tálamo/citologia , Núcleos da Linha Média do Tálamo/efeitos dos fármacos , Núcleos da Linha Média do Tálamo/efeitos da radiação , Neurônios/efeitos dos fármacos , Núcleo Accumbens/metabolismo , Núcleo Accumbens/fisiologia , Núcleo Accumbens/efeitos da radiação , Optogenética , Proteínas Proto-Oncogênicas c-fos/metabolismo , Ratos , Recompensa , Núcleo Hipotalâmico Ventromedial/citologia
18.
J Clin Neurosci ; 87: 97-102, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33863544

RESUMO

Long-term unilateral hearing loss could reorganize the functional network association between the bilateral auditory cortices, while alterations of other functional networks need to be further explored. We attempted to investigate the pattern of the reorganization of functional network associations between the auditory and visual cortex caused by long-term postlingual unilateral hearing loss (UHI) and its relationship with clinical characteristics. Therefore, 48 patients with hearing loss caused by unilateral acoustic tumors and 52 matched healthy controls were enrolled, and their high-resolution structural MRI and resting-state functional MRI data were also collected to depict the brain network. Degree centrality (DC) was employed to evaluate the functional network association of the auditory-visual network interaction. Group comparisons were performed to investigate the network reorganization, and its correlations with clinical data were calculated. Compared with the healthy control group, patients with UHI showed significantly increased DC between the auditory network (superior temporal gyrus and the medial geniculate body) and the visual network. Meanwhile, this difference was positively correlated with the extent of hearing impairment, and the correlation was more significant with the ipsilateral superior temporal gyrus in cases of acoustic neuroma. These results suggest that long-term unilateral hearing impairment may lead to enhancement of the visual-auditory network interactions and that the degree of reorganization is positively correlated with the pure tone average (PTA) and is more significant for the ipsilateral superior temporal gyrus, which provides clinical evidence regarding cross-modal plasticity in the UHI and its lateralization.


Assuntos
Córtex Auditivo/diagnóstico por imagem , Perda Auditiva/diagnóstico por imagem , Rede Nervosa/diagnóstico por imagem , Neuroma Acústico/diagnóstico por imagem , Córtex Visual/diagnóstico por imagem , Adulto , Córtex Auditivo/fisiologia , Mapeamento Encefálico/métodos , Feminino , Perda Auditiva/fisiopatologia , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Rede Nervosa/fisiologia , Neuroma Acústico/fisiopatologia , Córtex Visual/fisiologia
19.
Nat Commun ; 12(1): 2430, 2021 04 23.
Artigo em Inglês | MEDLINE | ID: mdl-33893294

RESUMO

Knowledge about the relevance of environmental features can guide stimulus processing. However, it remains unclear how processing is adjusted when feature relevance is uncertain. We hypothesized that (a) heightened uncertainty would shift cortical networks from a rhythmic, selective processing-oriented state toward an asynchronous ("excited") state that boosts sensitivity to all stimulus features, and that (b) the thalamus provides a subcortical nexus for such uncertainty-related shifts. Here, we had young adults attend to varying numbers of task-relevant features during EEG and fMRI acquisition to test these hypotheses. Behavioral modeling and electrophysiological signatures revealed that greater uncertainty lowered the rate of evidence accumulation for individual stimulus features, shifted the cortex from a rhythmic to an asynchronous/excited regime, and heightened neuromodulatory arousal. Crucially, this unified constellation of within-person effects was dominantly reflected in the uncertainty-driven upregulation of thalamic activity. We argue that neuromodulatory processes involving the thalamus play a central role in how the brain modulates neural excitability in the face of momentary uncertainty.


Assuntos
Córtex Cerebral/fisiologia , Percepção/fisiologia , Tálamo/fisiologia , Incerteza , Adolescente , Adulto , Algoritmos , Córtex Cerebral/diagnóstico por imagem , Eletroencefalografia , Feminino , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Modelos Neurológicos , Rede Nervosa/diagnóstico por imagem , Rede Nervosa/fisiologia , Tálamo/diagnóstico por imagem , Adulto Jovem
20.
Phys Rev Lett ; 126(15): 158102, 2021 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-33929245

RESUMO

A network of propagating nonlinear oscillatory modes (waves) in the human brain is shown to generate collectively synchronized spiking activity (hypersynchronous spiking) when both amplitude and phase coupling between modes are taken into account. The nonlinear behavior of the modes participating in the network are the result of the nonresonant dynamics of weakly evanescent cortical waves that, as shown recently, adhere to an inverse frequency-wave number dispersion relation when propagating through an inhomogeneous anisotropic media characteristic of the brain cortex. This description provides a missing link between simplistic models of synchronization in networks of small amplitude phase coupled oscillators and in networks built with various empirically fitted models of pulse or amplitude coupled spiking neurons. Overall the phase-amplitude coupling mechanism presented in the Letter shows significantly more efficient synchronization compared to current standard approaches and demonstrates an emergence of collective synchronized spiking from subthreshold oscillations that neither phase nor amplitude coupling alone are capable of explaining.


Assuntos
Encéfalo/fisiologia , Modelos Neurológicos , Potenciais de Ação , Humanos , Rede Nervosa/fisiologia , Neurônios/fisiologia , Dinâmica não Linear
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