Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 32.688
Filtrar
1.
Nat Commun ; 11(1): 6441, 2020 12 23.
Artigo em Inglês | MEDLINE | ID: mdl-33361766

RESUMO

The learning of motor skills unfolds over multiple timescales, with rapid initial gains in performance followed by a longer period in which the behavior becomes more refined, habitual, and automatized. While recent lesion and inactivation experiments have provided hints about how various brain areas might contribute to such learning, their precise roles and the neural mechanisms underlying them are not well understood. In this work, we propose neural- and circuit-level mechanisms by which motor cortex, thalamus, and striatum support motor learning. In this model, the combination of fast cortical learning and slow subcortical learning gives rise to a covert learning process through which control of behavior is gradually transferred from cortical to subcortical circuits, while protecting learned behaviors that are practiced repeatedly against overwriting by future learning. Together, these results point to a new computational role for thalamus in motor learning and, more broadly, provide a framework for understanding the neural basis of habit formation and the automatization of behavior through practice.


Assuntos
Córtex Cerebral/fisiologia , Aprendizagem , Rememoração Mental/fisiologia , Vias Neurais/fisiologia , Comportamento , Simulação por Computador , Humanos , Modelos Neurológicos , Neurônios/fisiologia , Reforço Psicológico , Análise e Desempenho de Tarefas
2.
PLoS One ; 15(12): e0242738, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33259511

RESUMO

OBJECTIVE: Aerobic fitness may be beneficial for neuroanatomical structure. However, few have investigated this in emerging adults while also accounting for potential sex differences. Here we examine aerobic fitness level, sex, and their interaction in relation to cortical thickness, surface area, and volume. METHOD: Sixty-three young adults between the ages of 16-26 were balanced for sex and demonstrated a wide range of aerobic fitness levels. Exclusion criteria included left-handedness, past-year independent Axis-I disorders, major medical/neurologic disorders, prenatal medical issues, prenatal alcohol/illicit drug exposure, or excessive substance use. Participants completed an MRI scan and a graded exercise test to volitional fatigue (VO2 max). Data analyses were run in Freesurfer and data was corrected for multiple comparisons with Monte Carlo simulations at .05. RESULTS: Males demonstrated higher VO2 values. Higher VO2 values were statistically independently related to thinner lateral occipital, superior parietal, cuneus, precuneus, and inferior parietal regions, smaller lateral occipital volume, and larger inferior parietal surface area. Compared to females, males had larger volume in rostral anterior cingulate, lateral occipital, and superior frontal regions, and greater surface area in fusiform, inferior parietal, rostral and caudal anterior cingulate, and superior parietal regions. VO2*Sex interactions revealed higher-fit females had higher inferior parietal, paracentral, and supramarginal surface area, while lower-fit males showed larger surface area in these same regions. CONCLUSIONS: Individuals with higher aerobic fitness performance had thinner cortices, lower volume, and larger surface area in sensorimotor regions than lower fit individuals, perhaps suggesting earlier neuromaturation in higher fit individuals. Larger surface area was associated with higher-fit females and lower-fit males. Thus both sex and aerobic fitness are important in shaping brain health in emerging adults.


Assuntos
Encéfalo/fisiologia , Teste de Esforço , Exercício Físico/fisiologia , Lobo Frontal/fisiologia , Adolescente , Adulto , Encéfalo/diagnóstico por imagem , Mapeamento Encefálico , Córtex Cerebral/diagnóstico por imagem , Córtex Cerebral/fisiologia , Feminino , Lobo Frontal/diagnóstico por imagem , Giro do Cíngulo/diagnóstico por imagem , Giro do Cíngulo/fisiologia , Humanos , Processamento de Imagem Assistida por Computador , Imagem por Ressonância Magnética , Masculino , Lobo Parietal/diagnóstico por imagem , Lobo Parietal/fisiologia , Caracteres Sexuais , Adulto Jovem
3.
PLoS Biol ; 18(11): e3000882, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-33141817

RESUMO

During active tactile exploration, the dynamic patterns of touch are transduced to electrical signals and transformed by the brain into a mental representation of the object under investigation. This transformation from sensation to perception is thought to be a major function of the mammalian cortex. In primary somatosensory cortex (S1) of mice, layer 5 (L5) pyramidal neurons are major outputs to downstream areas that influence perception, decision-making, and motor control. We investigated self-motion and touch representations in L5 of S1 with juxtacellular loose-seal patch recordings of optogenetically identified excitatory neurons. We found that during rhythmic whisker movement, 54 of 115 active neurons (47%) represented self-motion. This population was significantly more modulated by whisker angle than by phase. Upon active touch, a distinct pattern of activity was evoked across L5, which represented the whisker angle at the time of touch. Object location was decodable with submillimeter precision from the touch-evoked spike counts of a randomly sampled handful of these neurons. These representations of whisker angle during self-motion and touch were independent, both in the selection of which neurons were active and in the angle-tuning preference of coactive neurons. Thus, the output of S1 transiently shifts from a representation of self-motion to an independent representation of explored object location during active touch.


Assuntos
Córtex Somatossensorial/fisiologia , Percepção do Tato/fisiologia , Tato/fisiologia , Potenciais de Ação/fisiologia , Animais , Encéfalo/fisiologia , Córtex Cerebral/fisiologia , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Movimento/fisiologia , Neurônios/fisiologia , Vibrissas/fisiologia
4.
PLoS Biol ; 18(11): e3000979, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-33253185

RESUMO

The vast net of fibres within and underneath the cortex is optimised to support the convergence of different levels of brain organisation. Here, we propose a novel coordinate system of the human cortex based on an advanced model of its connectivity. Our approach is inspired by seminal, but so far largely neglected models of cortico-cortical wiring established by postmortem anatomical studies and capitalises on cutting-edge in vivo neuroimaging and machine learning. The new model expands the currently prevailing diffusion magnetic resonance imaging (MRI) tractography approach by incorporation of additional features of cortical microstructure and cortico-cortical proximity. Studying several datasets and different parcellation schemes, we could show that our coordinate system robustly recapitulates established sensory-limbic and anterior-posterior dimensions of brain organisation. A series of validation experiments showed that the new wiring space reflects cortical microcircuit features (including pyramidal neuron depth and glial expression) and allowed for competitive simulations of functional connectivity and dynamics based on resting-state functional magnetic resonance imaging (rs-fMRI) and human intracranial electroencephalography (EEG) coherence. Our results advance our understanding of how cell-specific neurobiological gradients produce a hierarchical cortical wiring scheme that is concordant with increasing functional sophistication of human brain organisation. Our evaluations demonstrate the cortical wiring space bridges across scales of neural organisation and can be easily translated to single individuals.


Assuntos
Encéfalo/anatomia & histologia , Encéfalo/fisiologia , Conectoma/métodos , Adulto , Encéfalo/diagnóstico por imagem , Córtex Cerebral/anatomia & histologia , Córtex Cerebral/diagnóstico por imagem , Córtex Cerebral/fisiologia , Imagem de Difusão por Ressonância Magnética , Epilepsia Resistente a Medicamentos/diagnóstico por imagem , Epilepsia Resistente a Medicamentos/patologia , Epilepsia Resistente a Medicamentos/fisiopatologia , Eletrocorticografia , Epilepsias Parciais/diagnóstico por imagem , Epilepsias Parciais/patologia , Epilepsias Parciais/fisiopatologia , Feminino , Neuroimagem Funcional , Humanos , Aprendizado de Máquina , Masculino , Modelos Anatômicos , Modelos Neurológicos , Rede Nervosa/anatomia & histologia , Rede Nervosa/diagnóstico por imagem , Rede Nervosa/fisiologia , Adulto Jovem
5.
PLoS One ; 15(10): e0237204, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33075046

RESUMO

The amygdala, a subcortical structure known for social and emotional processing, consists of multiple subnuclei with unique functions and connectivity patterns. Tracer studies in adult macaques have shown that the basolateral subnuclei differentially connect to parts of visual cortex, with stronger connections to anterior regions and weaker connections to posterior regions; infant macaques show robust connectivity even with posterior visual regions. Do these developmental differences also exist in the human amygdala, and are there specific functional regions that undergo the most pronounced developmental changes in their connections with the amygdala? To address these questions, we explored the functional connectivity (from resting-state fMRI data) of the basolateral amygdala to occipitotemporal cortex in human neonates scanned within one week of life and compared the connectivity patterns to those observed in young adults. Specifically, we calculated amygdala connectivity to anterior-posterior gradients of the anatomically-defined occipitotemporal cortex, and also to putative occipitotemporal functional parcels, including primary and high-level visual and auditory cortices (V1, A1, face, scene, object, body, high-level auditory regions). Results showed a decreasing gradient of functional connectivity to the occipitotemporal cortex in adults-similar to the gradient seen in macaque tracer studies-but no such gradient was observed in neonates. Further, adults had stronger connections to high-level functional regions associated with face, body, and object processing, and weaker connections to primary sensory regions (i.e., A1, V1), whereas neonates showed the same amount of connectivity to primary and high-level sensory regions. Overall, these results show that functional connectivity between the amygdala and occipitotemporal cortex is not yet differentiated in neonates, suggesting a role of maturation and experience in shaping these connections later in life.


Assuntos
Tonsila do Cerebelo/fisiologia , Complexo Nuclear Basolateral da Amígdala/fisiologia , Mapeamento Encefálico/métodos , Córtex Cerebral/fisiologia , Conectoma , Vias Neurais/fisiologia , Lobo Occipital/fisiologia , Adulto , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Recém-Nascido , Imagem por Ressonância Magnética , Masculino , Adulto Jovem
6.
Neuron ; 108(2): 259-269, 2020 10 28.
Artigo em Inglês | MEDLINE | ID: mdl-33120022

RESUMO

This Perspective examines the status of large-scale cortical interfaces through the lens of potential applications to active implants for brain-machine interfaces. Examples of research and development in a still embryonic field are discussed from a neuroengineer's perspective, touching on the design of scalable electrophysiological sensors with the ambition to access thousands of cortical points at near-cellular-level resolution. Important issues include microscale geometry of neural probes, design of implantable ultra-low-power electronics, implementation of high-data-rate wireless telemetry, and compatible device packaging-all requiring advanced solutions along a translational path for chronic human use.


Assuntos
Interfaces Cérebro-Computador , Córtex Cerebral/fisiologia , Neurociências/instrumentação , Neurociências/métodos , Animais , Estimulação Elétrica , Eletrodos Implantados , Humanos , Próteses e Implantes , Telemetria
7.
Nat Protoc ; 15(11): 3615-3631, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-33046899

RESUMO

Intracellular neuronal recordings from the brain of awake nonhuman primates have remained difficult to obtain because of several formidable technical challenges, such as poor recording stability and difficulties in maintaining long-term recording conditions. We have developed a technique to record neuronal activity by using a coaxial guide tube and sharp electrode assembly, which allows researchers to repeatedly and reliably perform intracellular recordings in the cortex of awake marmosets. Recordings from individual neurons last from several minutes to more than an hour. A key advantage of this approach is that it does not require dura removal, permitting recordings over weeks and months in a single animal. This protocol describes the step-by-step procedures for construction of a custom-made marmoset chair, head-cap implantation, preparation of the sharp electrode and guide tube, neuronal recording and data analysis. As the technique is practical and easy to adapt, we anticipate that it can also be applied to other mammalian models, including larger-size nonhuman primates.


Assuntos
Callithrix/fisiologia , Córtex Cerebral/fisiologia , Eletrofisiologia/instrumentação , Neurônios/fisiologia , Animais , Córtex Cerebral/citologia , Eletrodos Implantados , Eletrofisiologia/métodos , Desenho de Equipamento , Neurônios/citologia , Vigília
8.
Sci Rep ; 10(1): 16928, 2020 10 09.
Artigo em Inglês | MEDLINE | ID: mdl-33037260

RESUMO

During interpersonal interactions, people perform actions with different forms of vitality, communicating their positive or negative attitude toward others. For example, a handshake can be "soft" or "vigorous", a caress can be 'kind' or 'rushed'. While previous studies have shown that the dorso-central insula is a key area for the processing of human vitality forms, there is no information on the perception of vitality forms generated by a humanoid robot. In this study, two fMRI experiments were conducted in order to investigate whether and how the observation of actions generated by a humanoid robot (iCub) with low and fast velocities (Study 1) or replicating gentle and rude human forms (Study 2) may convey vitality forms eliciting the activation of the dorso-central insula. These studies showed that the observation of robotic actions, generated with low and high velocities, resulted in activation of the parieto-frontal circuit typically involved in the recognition and the execution of human actions but not of the insula (Study 1). Most interestingly, the observation of robotic actions, generated by replicating gentle and rude human vitality forms, produced a BOLD signal increase in the dorso-central insula (Study 2). In conclusion, these data highlight the selective role of dorso-central insula in the processing of vitality forms opening future perspectives on the perception and understanding of actions performed by humanoid robots.


Assuntos
Córtex Cerebral/fisiologia , Adulto , Atitude , Mapeamento Encefálico/métodos , Compreensão/fisiologia , Feminino , Humanos , Imagem por Ressonância Magnética/métodos , Masculino , Fenômenos Fisiológicos do Sistema Nervoso , Reconhecimento Psicológico/fisiologia , Robótica/métodos , Percepção Social
9.
Nat Commun ; 11(1): 5046, 2020 10 07.
Artigo em Inglês | MEDLINE | ID: mdl-33028816

RESUMO

Signal loss in blood oxygen level-dependent (BOLD) functional neuroimaging is common and can lead to misinterpretation of findings. Here, we reconstructed compromised fMRI signal using deep machine learning. We trained a model to learn principles governing BOLD activity in one dataset and reconstruct artificially compromised regions in an independent dataset, frame by frame. Intriguingly, BOLD time series extracted from reconstructed frames are correlated with the original time series, even though the frames do not independently carry any temporal information. Moreover, reconstructed functional connectivity maps exhibit good correspondence with the original connectivity maps, indicating that the model recovers functional relationships among brain regions. We replicated this result in two healthy datasets and in patients whose scans suffered signal loss due to intracortical electrodes. Critically, the reconstructions capture individual-specific information. Deep machine learning thus presents a unique opportunity to reconstruct compromised BOLD signal while capturing features of an individual's own functional brain organization.


Assuntos
Mapeamento Encefálico/métodos , Córtex Cerebral/diagnóstico por imagem , Aprendizado Profundo , Processamento de Imagem Assistida por Computador/métodos , Imagem por Ressonância Magnética/métodos , Adolescente , Adulto , Córtex Cerebral/irrigação sanguínea , Córtex Cerebral/fisiologia , Conjuntos de Dados como Assunto , Estimulação Encefálica Profunda , Feminino , Voluntários Saudáveis , Humanos , Masculino , Modelos Neurológicos , Oxigênio/sangue , Doença de Parkinson/diagnóstico , Doença de Parkinson/fisiopatologia , Doença de Parkinson/terapia , Adulto Jovem
10.
Science ; 370(6514)2020 10 16.
Artigo em Inglês | MEDLINE | ID: mdl-33060328

RESUMO

At the earliest developmental stages, spontaneous activity synchronizes local and large-scale cortical networks. These networks form the functional template for the establishment of global thalamocortical networks and cortical architecture. The earliest connections are established autonomously. However, activity from the sensory periphery reshapes these circuits as soon as afferents reach the cortex. The early-generated, largely transient neurons of the subplate play a key role in integrating spontaneous and sensory-driven activity. Early pathological conditions-such as hypoxia, inflammation, or exposure to pharmacological compounds-alter spontaneous activity patterns, which subsequently induce disturbances in cortical network activity. This cortical dysfunction may lead to local and global miswiring and, at later stages, can be associated with neurological and psychiatric conditions.


Assuntos
Córtex Cerebral/embriologia , Córtex Cerebral/fisiologia , Vias Neurais/embriologia , Vias Neurais/fisiologia , Animais , Apoptose , Claustrum/fisiologia , Humanos , Imagem por Ressonância Magnética , Camundongos , Neurogênese , Plasticidade Neuronal , Esquizofrenia/fisiopatologia , Núcleos Talâmicos/fisiologia
11.
Nat Commun ; 11(1): 5109, 2020 10 09.
Artigo em Inglês | MEDLINE | ID: mdl-33037209

RESUMO

Perceptual decisions entail the accumulation of sensory evidence for a particular choice towards an action plan. An influential framework holds that sensory cortical areas encode the instantaneous sensory evidence and downstream, action-related regions accumulate this evidence. The large-scale distribution of this computation across the cerebral cortex has remained largely elusive. Here, we develop a regionally-specific magnetoencephalography decoding approach to exhaustively map the dynamics of stimulus- and choice-specific signals across the human cortical surface during a visual decision. Comparison with the evidence accumulation dynamics inferred from behavior disentangles stimulus-dependent and endogenous components of choice-predictive activity across the visual cortical hierarchy. We find such an endogenous component in early visual cortex (including V1), which is expressed in a low (<20 Hz) frequency band and tracks, with delay, the build-up of choice-predictive activity in (pre-) motor regions. Our results are consistent with choice- and frequency-specific cortical feedback signaling during decision formation.


Assuntos
Córtex Cerebral/fisiologia , Tomada de Decisões , Magnetoencefalografia/métodos , Percepção Visual/fisiologia , Comportamento de Escolha , Feminino , Humanos , Masculino , Experimentação Humana não Terapêutica , Processamento de Sinais Assistido por Computador , Córtex Visual/fisiologia
12.
Nat Commun ; 11(1): 5363, 2020 10 23.
Artigo em Inglês | MEDLINE | ID: mdl-33097714

RESUMO

Inter-areal synchronization of neuronal oscillations at frequencies below ~100 Hz is a pervasive feature of neuronal activity and is thought to regulate communication in neuronal circuits. In contrast, faster activities and oscillations have been considered to be largely local-circuit-level phenomena without large-scale synchronization between brain regions. We show, using human intracerebral recordings, that 100-400 Hz high-frequency oscillations (HFOs) may be synchronized between widely distributed brain regions. HFO synchronization expresses individual frequency peaks and exhibits reliable connectivity patterns that show stable community structuring. HFO synchronization is also characterized by a laminar profile opposite to that of lower frequencies. Importantly, HFO synchronization is both transiently enhanced and suppressed in separate frequency bands during a response-inhibition task. These findings show that HFO synchronization constitutes a functionally significant form of neuronal spike-timing relationships in brain activity and thus a mesoscopic indication of neuronal communication per se.


Assuntos
Encéfalo/patologia , Córtex Cerebral/fisiologia , Sincronização Cortical/fisiologia , Adulto , Mapeamento Encefálico , Estimulação Elétrica , Eletroencefalografia , Humanos , Masculino , Neurônios/fisiologia , Adulto Jovem
13.
Sci Rep ; 10(1): 16090, 2020 09 30.
Artigo em Inglês | MEDLINE | ID: mdl-32999329

RESUMO

Working memory (WM) consists of short-term storage and executive components. We studied cortical oscillatory correlates of these two components in a large sample of 156 participants to assess separately the contribution of them to individual differences in WM. The participants were presented with WM tasks of above-average complexity. Some of the tasks required only storage in WM, others required storage and mental manipulations. Our data indicate a close relationship between frontal midline theta, central beta activity and the executive components of WM. The oscillatory counterparts of the executive components were associated with individual differences in verbal WM performance. In contrast, alpha activity was not related to the individual differences. The results demonstrate that executive components of WM, rather than short-term storage capacity, play the decisive role in individual WM capacity limits.


Assuntos
Memória de Curto Prazo/fisiologia , Adolescente , Ritmo alfa/fisiologia , Ritmo beta/fisiologia , Córtex Cerebral/fisiologia , Eletroencefalografia , Fenômenos Eletrofisiológicos , Função Executiva/fisiologia , Feminino , Humanos , Masculino , Estimulação Luminosa , Análise e Desempenho de Tarefas , Ritmo Teta/fisiologia , Percepção Visual/fisiologia , Adulto Jovem
14.
Sci Rep ; 10(1): 16394, 2020 10 05.
Artigo em Inglês | MEDLINE | ID: mdl-33020498

RESUMO

The hub role of the right anterior insula (AI) has been emphasized in cognitive neurosciences and been demonstrated to be frequency-dependently organized. However, the functional organization of left AI (LAI) has not been systematically investigated. Here we used 100 unrelated datasets from the Human Connectome Project to study the frequency-dependent organization of LAI along slow 6 to slow 1 bands. The broadband functional connectivity of LAI was similar to previous findings. In slow 6-slow 3 bands, both dorsal and ventral seeds in LAI were correlated to the salience network (SN) and language network (LN) and anti-correlated to the default mode network (DMN). However, these seeds were only correlated to the LAI in slow 2-slow 1 bands. These findings indicate that broadband and narrow band functional connections reflect different functional organizations of the LAI. Furthermore, the dorsal seed had a stronger connection with the LN and anti-correlation with DMN while the ventral seed had a stronger connection within the SN in slow 6-slow 3 bands. In slow 2-slow 1 bands, both seeds had stronger connections with themselves. These observations indicate distinctive functional organizations for the two parts of LAI. Significant frequency effect and frequency by seed interaction were also found, suggesting different frequency characteristics of these two seeds. The functional integration and functional segregation of LDAI and LVAI were further supported by their cognitive associations. The frequency- and seed-dependent functional organizations of LAI may enlighten future clinical and cognitive investigations.


Assuntos
Córtex Cerebral/fisiologia , Rede Nervosa/fisiologia , Vias Neurais/fisiologia , Adulto , Cognição/fisiologia , Conectoma/métodos , Feminino , Humanos , Imagem por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Descanso/fisiologia , Adulto Jovem
15.
Sci Rep ; 10(1): 16336, 2020 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-33004897

RESUMO

The presence of synchronized clusters in neuron networks is a hallmark of information transmission and processing. Common approaches to study cluster synchronization in networks of coupled oscillators ground on simplifying assumptions, which often neglect key biological features of neuron networks. Here we propose a general framework to study presence and stability of synchronous clusters in more realistic models of neuron networks, characterized by the presence of delays, different kinds of neurons and synapses. Application of this framework to two examples with different size and features (the directed network of the macaque cerebral cortex and the swim central pattern generator of a mollusc) provides an interpretation key to explain known functional mechanisms emerging from the combination of anatomy and neuron dynamics. The cluster synchronization analysis is carried out also by changing parameters and studying bifurcations. Despite some modeling simplifications in one of the examples, the obtained results are in good agreement with previously reported biological data.


Assuntos
Relógios Biológicos/fisiologia , Geradores de Padrão Central/fisiologia , Córtex Cerebral/fisiologia , Modelos Neurológicos , Rede Nervosa/fisiologia , Neurônios/fisiologia , Potenciais de Ação/fisiologia , Animais , Simulação por Computador , Macaca , Moluscos , Sinapses/fisiologia
16.
Anesthesiology ; 133(4): 774-786, 2020 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-32930729

RESUMO

BACKGROUND: It is a commonly held view that information flow between widely separated regions of the cerebral cortex is a necessary component in the generation of wakefulness (also termed "connected" consciousness). This study therefore hypothesized that loss of wakefulness caused by propofol anesthesia should be associated with loss of information flow, as estimated by the effective connectivity in the scalp electroencephalogram (EEG) signal. METHODS: Effective connectivity during anesthesia was quantified by applying bivariate Granger to multichannel EEG data recorded from 16 adult subjects undergoing a slow induction of, and emergence from, anesthesia with intravenous propofol. During wakefulness they were conducting various auditory and motor tasks. Functional connectivity using EEG coherence was also estimated. RESULTS: There was an abrupt, substantial, and global decrease in effective connectivity around the point of loss of responsiveness. Recovery of behavioral responsiveness was associated with a comparable recovery in information flow pattern (expressed as normalized values). The median (interquartile range) change was greatest in the delta frequency band: decreasing from 0.15 (0.21) 2 min before loss of behavioral response, to 0.06 (0.04) 2 min after loss of behavioral response (P < 0.001). Regional decreases in information flow were maximal in a posteromedial direction from lateral frontal and prefrontal regions (0.82 [0.24] 2 min before loss of responsiveness, decreasing to 0.17 [0.05] 2 min after), and least for information flow from posterior channels. The widespread decrease in bivariate Granger causality reflects loss of cortical coordination. The relationship between functional connectivity (coherence) and effective connectivity (Granger causality) was inconsistent. CONCLUSIONS: Propofol-induced unresponsiveness is marked by a global decrease in information flow, greatest from the lateral frontal and prefrontal brain regions in a posterior and medial direction. Loss of information flow may be a useful measure of connected consciousness.


Assuntos
Anestésicos Intravenosos/administração & dosagem , Córtex Cerebral/efeitos dos fármacos , Eletroencefalografia/efeitos dos fármacos , Rede Nervosa/efeitos dos fármacos , Propofol/administração & dosagem , Inconsciência/induzido quimicamente , Adulto , Córtex Cerebral/fisiologia , Eletroencefalografia/métodos , Feminino , Humanos , Hipnóticos e Sedativos/administração & dosagem , Masculino , Rede Nervosa/fisiologia , Desempenho Psicomotor/efeitos dos fármacos , Desempenho Psicomotor/fisiologia , Inconsciência/psicologia
17.
Nat Neurosci ; 23(11): 1388-1398, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32989293

RESUMO

In the basal ganglia (BG), anatomically segregated and topographically organized feedforward circuits are thought to modulate multiple behaviors in parallel. Although topographically arranged BG circuits have been described, the extent to which these relationships are maintained across the BG output nuclei and in downstream targets is unclear. Here, using focal trans-synaptic anterograde tracing, we show that the motor-action-related topographical organization of the striatum is preserved in all BG output nuclei. The topography is also maintained downstream of the BG and in multiple parallel closed loops that provide striatal input. Furthermore, focal activation of two distinct striatal regions induces either licking or turning, consistent with their respective anatomical targets of projection outside of the BG. Our results confirm the parallel model of BG function and suggest that the integration and competition of information relating to different behavior occur largely outside of the BG.


Assuntos
Gânglios da Base/citologia , Gânglios da Base/fisiologia , Comportamento Animal/fisiologia , Neurônios/fisiologia , Animais , Córtex Cerebral/fisiologia , Feminino , Núcleos Intralaminares do Tálamo/citologia , Núcleos Intralaminares do Tálamo/fisiologia , Masculino , Camundongos Endogâmicos C57BL , Vias Neurais/citologia , Vias Neurais/fisiologia , Técnicas de Rastreamento Neuroanatômico , Parte Reticular da Substância Negra/citologia , Parte Reticular da Substância Negra/fisiologia , Colículos Superiores/citologia , Colículos Superiores/fisiologia , Núcleos Ventrais do Tálamo/citologia , Núcleos Ventrais do Tálamo/fisiologia
18.
PLoS Biol ; 18(9): e3000584, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32956387

RESUMO

The insular cortex (IC) participates in diverse complex brain functions, including social function, yet their cellular bases remain to be fully understood. Using microendoscopic calcium imaging of the agranular insular cortex (AI) in mice interacting with freely moving and restrained social targets, we identified 2 subsets of AI neurons-a larger fraction of "Social-ON" cells and a smaller fraction of "Social-OFF" cells-that change their activity in opposite directions during social exploration. Social-ON cells included those that represented social investigation independent of location and consisted of multiple subsets, each of which was preferentially active during exploration under a particular behavioral state or with a particular target of physical contact. These results uncover a previously unknown function of AI neurons that may act to monitor the ongoing status of social exploration while an animal interacts with unfamiliar conspecifics.


Assuntos
Comportamento Animal/fisiologia , Córtex Cerebral/fisiologia , Comportamento Social , Animais , Córtex Cerebral/citologia , Masculino , Camundongos
19.
PLoS Comput Biol ; 16(9): e1008192, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32946433

RESUMO

Balanced excitation and inhibition is widely observed in cortex. How does this balance shape neural computations and stimulus representations? This question is often studied using computational models of neuronal networks in a dynamically balanced state. But balanced network models predict a linear relationship between stimuli and population responses. So how do cortical circuits implement nonlinear representations and computations? We show that every balanced network architecture admits stimuli that break the balanced state and these breaks in balance push the network into a "semi-balanced state" characterized by excess inhibition to some neurons, but an absence of excess excitation. The semi-balanced state produces nonlinear stimulus representations and nonlinear computations, is unavoidable in networks driven by multiple stimuli, is consistent with cortical recordings, and has a direct mathematical relationship to artificial neural networks.


Assuntos
Modelos Neurológicos , Rede Nervosa/fisiologia , Neurônios/fisiologia , Dinâmica não Linear , Animais , Córtex Cerebral/fisiologia , Biologia Computacional , Redes Neurais de Computação , Sinapses/fisiologia
20.
Nat Commun ; 11(1): 4819, 2020 09 23.
Artigo em Inglês | MEDLINE | ID: mdl-32968048

RESUMO

In many parts of the nervous system, experience-dependent refinement of neuronal circuits predominantly involves synapse elimination. The role of sleep in this process remains unknown. We investigated the role of sleep in experience-dependent dendritic spine elimination of layer 5 pyramidal neurons in the visual (V1) and frontal association cortex (FrA) of 1-month-old mice. We found that monocular deprivation (MD) or auditory-cued fear conditioning (FC) caused rapid spine elimination in V1 or FrA, respectively. MD- or FC-induced spine elimination was significantly reduced after total sleep or REM sleep deprivation. Total sleep or REM sleep deprivation also prevented MD- and FC-induced reduction of neuronal activity in response to visual or conditioned auditory stimuli. Furthermore, dendritic calcium spikes increased substantially during REM sleep, and the blockade of these calcium spikes prevented MD- and FC-induced spine elimination. These findings reveal an important role of REM sleep in experience-dependent synapse elimination and neuronal activity reduction.


Assuntos
Córtex Cerebral/fisiologia , Espinhas Dendríticas/fisiologia , Sono REM/fisiologia , Animais , Condicionamento Clássico , Medo/fisiologia , Camundongos , Camundongos Transgênicos , Modelos Animais , Plasticidade Neuronal/fisiologia , Neurônios/fisiologia , Células Piramidais/fisiologia , Privação Sensorial/fisiologia , Privação do Sono , Sinapses , Córtex Visual/fisiologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA