Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 22.593
Filtrar
1.
Science ; 368(6490): 527-531, 2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-32355031

RESUMO

Retinal ganglion cells (RGCs) drive diverse, light-evoked behaviors that range from conscious visual perception to subconscious, non-image-forming behaviors. It is thought that RGCs primarily drive these functions through the release of the excitatory neurotransmitter glutamate. We identified a subset of melanopsin-expressing intrinsically photosensitive RGCs (ipRGCs) in mice that release the inhibitory neurotransmitter γ-aminobutyric acid (GABA) at non-image-forming brain targets. GABA release from ipRGCs dampened the sensitivity of both the pupillary light reflex and circadian photoentrainment, thereby shifting the dynamic range of these behaviors to higher light levels. Our results identify an inhibitory RGC population in the retina and provide a circuit-level mechanism that contributes to the relative insensitivity of non-image-forming behaviors at low light levels.


Assuntos
Vias Neurais/fisiologia , Células Ganglionares da Retina/fisiologia , Percepção Visual/fisiologia , Animais , Feminino , Neurônios GABAérgicos/fisiologia , Glutamato Descarboxilase/metabolismo , Luz , Masculino , Camundongos , Camundongos Mutantes , Vias Neurais/efeitos dos fármacos , Reflexo Pupilar/fisiologia , Reflexo Pupilar/efeitos da radiação , Células Ganglionares da Retina/efeitos da radiação , Opsinas de Bastonetes/metabolismo , Inconsciente Psicológico , Percepção Visual/efeitos da radiação , Ácido gama-Aminobutírico/metabolismo
2.
Nat Rev Neurosci ; 21(5): 277-295, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32269316

RESUMO

The past decade has witnessed exponentially growing interest in the lateral habenula (LHb) owing to new discoveries relating to its critical role in regulating negatively motivated behaviour and its implication in major depression. The LHb, sometimes referred to as the brain's 'antireward centre', receives inputs from diverse limbic forebrain and basal ganglia structures, and targets essentially all midbrain neuromodulatory systems, including the noradrenergic, serotonergic and dopaminergic systems. Its unique anatomical position enables the LHb to act as a hub that integrates value-based, sensory and experience-dependent information to regulate various motivational, cognitive and motor processes. Dysfunction of the LHb may contribute to the pathophysiology of several psychiatric disorders, especially major depression. Recently, exciting progress has been made in identifying the molecular and cellular mechanisms in the LHb that underlie negative emotional state in animal models of drug withdrawal and major depression. A future challenge is to translate these advances into effective clinical treatments.


Assuntos
Gânglios da Base/fisiologia , Gânglios da Base/fisiopatologia , Habenula/fisiologia , Habenula/fisiopatologia , Sistema Límbico/fisiologia , Sistema Límbico/fisiopatologia , Mesencéfalo/fisiologia , Mesencéfalo/fisiopatologia , Animais , Saúde , Humanos , Transtornos Mentais/fisiopatologia , Vias Neurais/fisiologia , Vias Neurais/fisiopatologia
3.
Science ; 368(6486): 89-94, 2020 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-32241948

RESUMO

Understanding the neurobiological underpinnings of emotion relies on objective readouts of the emotional state of an individual, which remains a major challenge especially in animal models. We found that mice exhibit stereotyped facial expressions in response to emotionally salient events, as well as upon targeted manipulations in emotion-relevant neuronal circuits. Facial expressions were classified into distinct categories using machine learning and reflected the changing intrinsic value of the same sensory stimulus encountered under different homeostatic or affective conditions. Facial expressions revealed emotion features such as intensity, valence, and persistence. Two-photon imaging uncovered insular cortical neuron activity that correlated with specific facial expressions and may encode distinct emotions. Facial expressions thus provide a means to infer emotion states and their neuronal correlates in mice.


Assuntos
Córtex Cerebral/fisiologia , Emoções/fisiologia , Expressão Facial , Vias Neurais/fisiologia , Neurônios/fisiologia , Animais , Córtex Cerebral/citologia , Masculino , Camundongos
4.
Nat Neurosci ; 23(3): 337-350, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32112058

RESUMO

Tissue repair after spinal cord injury requires the mobilization of immune and glial cells to form a protective barrier that seals the wound and facilitates debris clearing, inflammatory containment and matrix compaction. This process involves corralling, wherein phagocytic immune cells become confined to the necrotic core, which is surrounded by an astrocytic border. Here we elucidate a temporally distinct gene signature in injury-activated microglia and macrophages (IAMs) that engages axon guidance pathways. Plexin-B2 is upregulated in IAMs and is required for motor sensory recovery after spinal cord injury. Plexin-B2 deletion in myeloid cells impairs corralling, leading to diffuse tissue damage, inflammatory spillover and hampered axon regeneration. Corralling begins early and requires Plexin-B2 in both microglia and macrophages. Mechanistically, Plexin-B2 promotes microglia motility, steers IAMs away from colliding cells and facilitates matrix compaction. Our data therefore establish Plexin-B2 as an important link that integrates biochemical cues and physical interactions of IAMs with the injury microenvironment during wound healing.


Assuntos
Macrófagos/fisiologia , Microglia/fisiologia , Proteínas do Tecido Nervoso/metabolismo , Traumatismos da Medula Espinal/patologia , Cicatrização/fisiologia , Animais , Axônios/fisiologia , Microambiente Celular , Locomoção/fisiologia , Camundongos , Regeneração Nervosa/genética , Regeneração Nervosa/fisiologia , Vias Neurais/fisiologia , Fagocitose , Recuperação de Função Fisiológica , Sensação/fisiologia , Traumatismos da Medula Espinal/metabolismo
5.
Nat Rev Neurosci ; 21(3): 169-178, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32029928

RESUMO

With advances in connectomics, transcriptome and neurophysiological technologies, the neuroscience of brain-wide neural circuits is poised to take off. A major challenge is to understand how a vast diversity of functions is subserved by parcellated areas of mammalian neocortex composed of repetitions of a canonical local circuit. Areas of the cerebral cortex differ from each other not only in their input-output patterns but also in their biological properties. Recent experimental and theoretical work has revealed that such variations are not random heterogeneities; rather, synaptic excitation and inhibition display systematic macroscopic gradients across the entire cortex, and they are abnormal in mental illness. Quantitative differences along these gradients can lead to qualitatively novel behaviours in non-linear neural dynamical systems, by virtue of a phenomenon mathematically described as bifurcation. The combination of macroscopic gradients and bifurcations, in tandem with biological evolution, development and plasticity, provides a generative mechanism for functional diversity among cortical areas, as a general principle of large-scale cortical organization.


Assuntos
Excitabilidade Cortical/fisiologia , Neocórtex/fisiologia , Inibição Neural/fisiologia , Neurônios/fisiologia , Sinapses/fisiologia , Animais , Conectoma , Humanos , Transtornos Mentais/fisiopatologia , Modelos Neurológicos , Vias Neurais/fisiologia
6.
PLoS Biol ; 18(2): e3000361, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-32078631

RESUMO

Sleep-active neurons depolarize during sleep to suppress wakefulness circuits. Wake-active wake-promoting neurons in turn shut down sleep-active neurons, thus forming a bipartite flip-flop switch. However, how sleep is switched on is unclear because it is not known how wakefulness is translated into sleep-active neuron depolarization when the system is set to sleep. Using optogenetics in Caenorhabditis elegans, we solved the presynaptic circuit for depolarization of the sleep-active RIS neuron during developmentally regulated sleep, also known as lethargus. Surprisingly, we found that RIS activation requires neurons that have known roles in wakefulness and locomotion behavior. The RIM interneurons-which are active during and can induce reverse locomotion-play a complex role and can act as inhibitors of RIS when they are strongly depolarized and as activators of RIS when they are modestly depolarized. The PVC command interneurons, which are known to promote forward locomotion during wakefulness, act as major activators of RIS. The properties of these locomotion neurons are modulated during lethargus. The RIMs become less excitable. The PVCs become resistant to inhibition and have an increased capacity to activate RIS. Separate activation of neither the PVCs nor the RIMs appears to be sufficient for sleep induction; instead, our data suggest that they act in concert to activate RIS. Forward and reverse circuit activity is normally mutually exclusive. Our data suggest that RIS may be activated at the transition between forward and reverse locomotion states, perhaps when both forward (PVC) and reverse (including RIM) circuit activity overlap. While RIS is not strongly activated outside of lethargus, altered activity of the locomotion interneurons during lethargus favors strong RIS activation and thus sleep. The control of sleep-active neurons by locomotion circuits suggests that sleep control may have evolved from locomotion control. The flip-flop sleep switch in C. elegans thus requires an additional component, wake-active sleep-promoting neurons that translate wakefulness into the depolarization of a sleep-active neuron when the worm is sleepy. Wake-active sleep-promoting circuits may also be required for sleep state switching in other animals, including in mammals.


Assuntos
Locomoção/fisiologia , Neurônios/fisiologia , Fases do Sono/fisiologia , Vigília/fisiologia , Animais , Nível de Alerta/fisiologia , Comportamento Animal/fisiologia , Caenorhabditis elegans/fisiologia , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Cálcio/metabolismo , Homeostase , Interneurônios/metabolismo , Interneurônios/fisiologia , Larva/fisiologia , Vias Neurais/fisiologia , Neurônios/metabolismo , Optogenética
7.
Nat Commun ; 11(1): 782, 2020 02 07.
Artigo em Inglês | MEDLINE | ID: mdl-32034128

RESUMO

Food addiction is linked to obesity and eating disorders and is characterized by a loss of behavioral control and compulsive food intake. Here, using a food addiction mouse model, we report that the lack of cannabinoid type-1 receptor in dorsal telencephalic glutamatergic neurons prevents the development of food addiction-like behavior, which is associated with enhanced synaptic excitatory transmission in the medial prefrontal cortex (mPFC) and in the nucleus accumbens (NAc). In contrast, chemogenetic inhibition of neuronal activity in the mPFC-NAc pathway induces compulsive food seeking. Transcriptomic analysis and genetic manipulation identified that increased dopamine D2 receptor expression in the mPFC-NAc pathway promotes the addiction-like phenotype. Our study unravels a new neurobiological mechanism underlying resilience and vulnerability to the development of food addiction, which could pave the way towards novel and efficient interventions for this disorder.


Assuntos
Dependência de Alimentos/fisiopatologia , Núcleo Accumbens/fisiologia , Córtex Pré-Frontal/fisiologia , Receptores de Dopamina D2/genética , Animais , Modelos Animais de Doenças , Comportamento Alimentar/fisiologia , Dependência de Alimentos/genética , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Camundongos Knockout , Vias Neurais/fisiologia , Receptor CB1 de Canabinoide/genética , Transmissão Sináptica , Regulação para Cima
8.
Nat Commun ; 11(1): 960, 2020 02 19.
Artigo em Inglês | MEDLINE | ID: mdl-32075960

RESUMO

The functional organization of the hippocampus is distributed as a gradient along its longitudinal axis that explains its differential interaction with diverse brain systems. We show that the location of human tissue samples extracted along the longitudinal axis of the adult human hippocampus can be predicted within 2mm using the expression pattern of less than 100 genes. Futhermore, this model generalizes to an external set of tissue samples from prenatal human hippocampi. We examine variation in this specific gene expression pattern across the whole brain, finding a distinct anterioventral-posteriodorsal gradient. We find frontal and anterior temporal regions involved in social and motivational behaviors, and more functionally connected to the anterior hippocampus, to be clearly differentiated from posterior parieto-occipital regions involved in visuospatial cognition and more functionally connected to the posterior hippocampus. These findings place the human hippocampus at the interface of two major brain systems defined by a single molecular gradient.


Assuntos
Conectoma , Perfilação da Expressão Gênica , Hipocampo/fisiologia , Rede Nervosa/fisiologia , Encéfalo/metabolismo , Encéfalo/fisiologia , Expressão Gênica , Hipocampo/citologia , Hipocampo/metabolismo , Humanos , Modelos Neurológicos , Rede Nervosa/metabolismo , Vias Neurais/citologia , Vias Neurais/metabolismo , Vias Neurais/fisiologia , Doenças Neurodegenerativas/genética , Doenças Neurodegenerativas/metabolismo , Doenças Neurodegenerativas/patologia , Neurônios/fisiologia , Lobo Temporal/citologia , Lobo Temporal/metabolismo , Lobo Temporal/fisiologia
9.
PLoS One ; 15(2): e0228404, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32053605

RESUMO

The link between anger and bodily states is readily apparent based on the autonomic and behavioral responses elicited. In everyday life angry people react in different ways, from being agitated with an increased heart rate to remaining silent or detached. Neuroimaging evidence supports the role of mid-posterior insula and midcingulate cortex/MCC as key nodes of a sensorimotor network that predominantly responds to salient stimuli, integration of interoceptive and autonomic information, as well as to awareness of bodily movements for coordinated motion. However, there is still a lack of clarity concerning how interindividual variability in bodily states reactions drives the connectivity within these key nodes in the sensorimotor network during anger processing. Therefore, we investigated whether individual differences in body-centered emotional experience, that is an active (inward prone) or inactive (outward prone) emotion-body connection disposition, would differently affect the information flow within these brain regions. Two groups of participants underwent fMRI scanning session watching video clips of actors performing simple actions with angry and joyful facial expressions. The whole-brain group-by-session interaction analysis showed that the bilateral insula and the right MCC were selectively activated by inward group during the angry session, whereas the outward group activated more the precuneus during the joyful session. Accordingly, dynamic causal modeling analyses (DCM) revealed an excitatory modulatory effect exerted by anger all over the insulae-MCC connectivity in the inward group, whereas in the outward group the modulatory effect exerted was inhibitory. Modeling the variability related to individual differences in body-centered emotional experience allowed to better explain to what extent subjective dispositions contributed to the insular activity and its connectivity. In addition, from the perspective of a hierarchical model of neurovisceral integration, these findings add knowledge to the multiple ways which the insula and MCC dynamically integrate affective and bodily aspects of the human experience.


Assuntos
Ira/fisiologia , Encéfalo/fisiologia , Córtex Cerebral/fisiologia , Emoções/fisiologia , Giro do Cíngulo/fisiologia , Vias Neurais/fisiologia , Adulto , Mapeamento Encefálico , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Imagem por Ressonância Magnética , Masculino , Autorrelato , Adulto Jovem
10.
Nature ; 579(7797): 101-105, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32103180

RESUMO

Mating and egg laying are tightly cooordinated events in the reproductive life of all oviparous females. Oviposition is typically rare in virgin females but is initiated after copulation. Here we identify the neural circuitry that links egg laying to mating status in Drosophila melanogaster. Activation of female-specific oviposition descending neurons (oviDNs) is necessary and sufficient for egg laying, and is equally potent in virgin and mated females. After mating, sex peptide-a protein from the male seminal fluid-triggers many behavioural and physiological changes in the female, including the onset of egg laying1. Sex peptide is detected by sensory neurons in the uterus2-4, and silences these neurons and their postsynaptic ascending neurons in the abdominal ganglion5. We show that these abdominal ganglion neurons directly activate the female-specific pC1 neurons. GABAergic (γ-aminobutyric-acid-releasing) oviposition inhibitory neurons (oviINs) mediate feed-forward inhibition from pC1 neurons to both oviDNs and their major excitatory input, the oviposition excitatory neurons (oviENs). By attenuating the abdominal ganglion inputs to pC1 neurons and oviINs, sex peptide disinhibits oviDNs to enable egg laying after mating. This circuitry thus coordinates the two key events in female reproduction: mating and egg laying.


Assuntos
Copulação/fisiologia , Drosophila melanogaster/fisiologia , Vias Neurais/fisiologia , Oviposição/fisiologia , Animais , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/citologia , Feminino , Gânglios Simpáticos/citologia , Masculino , Peptídeos/metabolismo , Células Receptoras Sensoriais/metabolismo , Abstinência Sexual/fisiologia
11.
PLoS One ; 15(1): e0227910, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31990956

RESUMO

In the study of the human connectome, the vertices and the edges of the network of the human brain are analyzed: the vertices of the graphs are the anatomically identified gray matter areas of the subjects; this set is exactly the same for all the subjects. The edges of the graphs correspond to the axonal fibers, connecting these areas. In the biological applications of graph theory, it happens very rarely that scientists examine numerous large graphs on the very same, labeled vertex set. Exactly this is the case in the study of the connectomes. Because of the particularity of these sets of graphs, novel, robust methods need to be developed for their analysis. Here we introduce the new method of the Frequent Network Neighborhood Mapping for the connectome, which serves as a robust identification of the neighborhoods of given vertices of special interest in the graph. We apply the novel method for mapping the neighborhoods of the human hippocampus and discover strong statistical asymmetries between the connectomes of the sexes, computed from the Human Connectome Project. We analyze 413 braingraphs, each with 463 nodes. We show that the hippocampi of men have much more significantly frequent neighbor sets than women; therefore, in a sense, the connections of the hippocampi are more regularly distributed in men and more varied in women. Our results are in contrast to the volumetric studies of the human hippocampus, where it was shown that the relative volume of the hippocampus is the same in men and women.


Assuntos
Axônios/fisiologia , Conectoma , Hipocampo/diagnóstico por imagem , Vias Neurais/fisiologia , Adulto , Mapeamento Encefálico , Feminino , Substância Cinzenta/diagnóstico por imagem , Substância Cinzenta/fisiologia , Hipocampo/fisiologia , Humanos , Masculino , Modelos Neurológicos , Vias Neurais/diagnóstico por imagem , Caracteres Sexuais , Lobo Temporal/diagnóstico por imagem , Lobo Temporal/fisiologia
12.
Nat Commun ; 11(1): 221, 2020 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-31924758

RESUMO

Vocal turn-taking is a fundamental organizing principle of human conversation but the neural circuit mechanisms that structure coordinated vocal interactions are unknown. The ability to exchange vocalizations in an alternating fashion is also exhibited by other species, including zebra finches. With a combination of behavioral testing, electrophysiological recordings, and pharmacological manipulations we demonstrate that activity within a cortical premotor nucleus orchestrates the timing of calls in socially interacting zebra finches. Within this circuit, local inhibition precedes premotor neuron activation associated with calling. Blocking inhibition results in faster vocal responses as well as an impaired ability to flexibly avoid overlapping with a partner. These results support a working model in which premotor inhibition regulates context-dependent timing of vocalizations and enables the precise interleaving of vocal signals during turn-taking.


Assuntos
Tentilhões/fisiologia , Inibição Psicológica , Neurônios/fisiologia , Vocalização Animal/fisiologia , Animais , Comportamento Animal , Feminino , Humanos , Masculino , Rede Nervosa/fisiologia , Vias Neurais/fisiologia , Comportamento Social
13.
Proc Natl Acad Sci U S A ; 117(6): 3220-3231, 2020 02 11.
Artigo em Inglês | MEDLINE | ID: mdl-31988117

RESUMO

The hippocampal formation (HPF) is a focus of intense experimental investigation, particularly because of its roles in conscious memory consolidation, spatial navigation, emotion, and motivated behaviors. However, the HPF has a complex three-dimensional geometry resulting from extreme curvature of its layers, and this presents a challenge for investigators seeking to decipher hippocampal structure and function at cellular and molecular scales (neuronal circuitry, gene expression, and other properties). Previously, this problem was solved qualitatively for the rat by constructing a physical surface model of the HPF based on histological sections, and then deriving from the model a flatmap. Its usefulness is exemplified by previous studies that used it to display topological relationships between different components of intrahippocampal circuitry derived from experimental pathway-tracing experiments. Here the rat HPF flatmap was used as a starting point to construct an analogous flatmap for the mouse, where the great majority of experimental hippocampal research is currently performed. A detailed account of underlying knowledge and principles is provided, including for hippocampal terminology, and development from an embryonic nonfolded sheet into differentiated multiple adjacent cortical areas, giving rise to the adult shape. To demonstrate its utility, the mouse flatmap was used to display the results of pathway-tracing experiments showing the dentate gyrus mossy fiber projection, and its relationship to the intrahippocampal Purkinje cell protein 4 gene-expression pattern. Finally, requirements for constructing a computer graphics quantitative intrahippocampal flatmap, with accompanying intrahippocampal coordinate system, are presented; they should be applicable to all mammals, including human.


Assuntos
Hipocampo , Vias Neurais , Giro Para-Hipocampal , Animais , Hipocampo/anatomia & histologia , Hipocampo/fisiologia , Humanos , Camundongos , Vias Neurais/anatomia & histologia , Vias Neurais/fisiologia , Giro Para-Hipocampal/anatomia & histologia , Giro Para-Hipocampal/fisiologia , Ratos
14.
Nat Commun ; 11(1): 262, 2020 01 14.
Artigo em Inglês | MEDLINE | ID: mdl-31937768

RESUMO

Navigation requires not only the execution of locomotor programs but also high arousal and real-time retrieval of spatial memory that is often associated with hippocampal theta oscillations. However, the neural circuits for coordinately controlling these important processes remain to be fully dissected. Here we show that the activity of the neuromedin B (NMB) neurons in the nucleus incertus (NI) is tightly correlated with mouse locomotor speed, arousal level, and hippocampal theta power. These processes are reversibly suppressed by optogenetic inhibition and rapidly promoted by optogenetic stimulation of NI NMB neurons. These neurons form reciprocal connections with several subcortical areas associated with arousal, theta oscillation, and premotor processing. Their projections to multiple downstream stations regulate locomotion and hippocampal theta, with the projection to the medial septum being particularly important for promoting arousal. Therefore, NI NMB neurons functionally impact the neural circuit for navigation control according to particular brains states.


Assuntos
Nível de Alerta/fisiologia , Hipocampo/fisiologia , Locomoção/fisiologia , Núcleos da Rafe/fisiologia , Animais , Feminino , Masculino , Camundongos , Vias Neurais/fisiologia , Neurocinina B/análogos & derivados , Neurocinina B/metabolismo , Neurônios/metabolismo , Optogenética , Núcleos da Rafe/citologia , Septo do Cérebro/fisiologia , Navegação Espacial/fisiologia , Ritmo Teta
15.
Nat Neurosci ; 23(2): 217-228, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31932767

RESUMO

Unlike the sensory thalamus, studies on the functional organization of the midline and intralaminar nuclei are scarce, and this has hindered the establishment of conceptual models of the function of this brain region. We investigated the functional organization of the paraventricular nucleus of the thalamus (PVT), a midline thalamic structure that is increasingly being recognized as a critical node in the control of diverse processes such as arousal, stress, emotional memory and motivation, in mice. We identify two major classes of PVT neurons-termed type I and type II-that differ in terms of gene expression, anatomy and function. In addition, we demonstrate that type II neurons belong to a previously neglected class of PVT neurons that convey arousal-related information to corticothalamic neurons of the infralimbic cortex. Our results uncover the existence of an arousal-modulated thalamo-corticothalamic loop that links the PVT and the ventromedial prefrontal cortex.


Assuntos
Neurônios/citologia , Neurônios/fisiologia , Núcleo Hipotalâmico Paraventricular/citologia , Núcleo Hipotalâmico Paraventricular/fisiologia , Animais , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Vias Neurais/citologia , Vias Neurais/fisiologia
16.
PLoS Biol ; 18(1): e3000578, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31961854

RESUMO

Internal representations of relationships between events in the external world can be utilized to infer outcomes when direct experience is lacking. This process is thought to involve the orbitofrontal cortex (OFC) and hippocampus (HPC), but there is little evidence regarding the relative role of these areas and their interactions in inference. Here, we used a sensory preconditioning task and pattern-based neuroimaging to study this question. We found that associations among value-neutral cues were acquired in both regions during preconditioning but that value-related information was only represented in the OFC at the time of the probe test. Importantly, inference was accompanied by representations of associated cues and inferred outcomes in the OFC, as well as by increased HPC-OFC connectivity. These findings suggest that the OFC and HPC represent only partially overlapping information and that interactions between the two regions support model-based inference.


Assuntos
Condicionamento Psicológico/fisiologia , Hipocampo/fisiologia , Modelos Psicológicos , Vias Neurais/fisiologia , Córtex Pré-Frontal/fisiologia , Adulto , Sinais (Psicologia) , Feminino , Hipocampo/citologia , Humanos , Masculino , Córtex Pré-Frontal/citologia , Aprendizagem por Probabilidade , Reconhecimento Psicológico/fisiologia , Adulto Jovem
18.
Nat Commun ; 11(1): 325, 2020 01 16.
Artigo em Inglês | MEDLINE | ID: mdl-31949140

RESUMO

Neuroimaging evidence suggests that the default mode network (DMN) exhibits antagonistic activity with dorsal attention (DAN) and salience (SN) networks. Here we use human intracranial electroencephalography to investigate the behavioral relevance of fine-grained dynamics within and between these networks. The three networks show dissociable profiles of task-evoked electrophysiological activity, best captured in the high-frequency broadband (HFB; 70-170 Hz) range. On the order of hundreds of milliseconds, HFB responses peak fastest in the DAN, at intermediate speed in the SN, and slowest in the DMN. Lapses of attention (behavioral errors) are marked by distinguishable patterns of both pre- and post-stimulus HFB activity within each network. Moreover, the magnitude of temporally lagged, negative HFB coupling between the DAN and DMN (but not SN and DMN) is associated with greater sustained attention performance and is reduced during wakeful rest. These findings underscore the behavioral relevance of temporally delayed coordination between antagonistic brain networks.


Assuntos
Atenção/fisiologia , Encéfalo/fisiologia , Córtex Cerebral/fisiologia , Fenômenos Eletrofisiológicos , Vias Neurais/fisiologia , Encéfalo/diagnóstico por imagem , Mapeamento Encefálico , Córtex Cerebral/diagnóstico por imagem , Neurociência Cognitiva , Eletrocorticografia , Humanos , Imageamento Tridimensional , Imagem por Ressonância Magnética , Rede Nervosa/fisiologia , Ondas de Rádio , Descanso , Análise e Desempenho de Tarefas
19.
Elife ; 82019 12 17.
Artigo em Inglês | MEDLINE | ID: mdl-31843053

RESUMO

Social visual engagement difficulties are hallmark early signs of autism (ASD) and are easily quantified using eye tracking methods. However, it is unclear how these difficulties are linked to atypical early functional brain organization in ASD. With resting state fMRI data in a large sample of ASD toddlers and other non-ASD comparison groups, we find ASD-related functional hypoconnnectivity between 'social brain' circuitry such as the default mode network (DMN) and visual and attention networks. An eye tracking-identified ASD subtype with pronounced early social visual engagement difficulties (GeoPref ASD) is characterized by marked DMN-occipito-temporal cortex (OTC) hypoconnectivity. Increased DMN-OTC hypoconnectivity is also related to increased severity of social-communication difficulties, but only in GeoPref ASD. Early and pronounced social-visual circuit hypoconnectivity is a key underlying neurobiological feature describing GeoPref ASD and may be critical for future social-communicative development and represent new treatment targets for early intervention in these individuals.


Assuntos
Transtorno Autístico/fisiopatologia , Movimentos Oculares/fisiologia , Rede Nervosa/fisiopatologia , Vias Neurais/fisiologia , Comportamento Social , Atenção/fisiologia , Transtorno Autístico/classificação , Transtorno Autístico/psicologia , Encéfalo/diagnóstico por imagem , Encéfalo/fisiopatologia , Mapeamento Encefálico/métodos , Pré-Escolar , Deficiências do Desenvolvimento/diagnóstico por imagem , Deficiências do Desenvolvimento/fisiopatologia , Feminino , Humanos , Imagem por Ressonância Magnética , Masculino , Modelos Neurológicos
20.
PLoS Comput Biol ; 15(12): e1007551, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31841504

RESUMO

Dynamic communication and routing play important roles in the human brain in order to facilitate flexibility in task solving and thought processes. Here, we present a network perturbation methodology that allows investigating dynamic switching between different network pathways based on phase offsets between two external oscillatory drivers. We apply this method in a computational model of the human connectome with delay-coupled neural masses. To analyze dynamic switching of pathways, we define four new metrics that measure dynamic network response properties for pairs of stimulated nodes. Evaluating these metrics for all network pathways, we found a broad spectrum of pathways with distinct dynamic properties and switching behaviors. We show that network pathways can have characteristic timescales and thus specific preferences for the phase lag between the regions they connect. Specifically, we identified pairs of network nodes whose connecting paths can either be (1) insensitive to the phase relationship between the node pair, (2) turned on and off via changes in the phase relationship between the node pair, or (3) switched between via changes in the phase relationship between the node pair. Regarding the latter, we found that 33% of node pairs can switch their communication from one pathway to another depending on their phase offsets. This reveals a potential mechanistic role that phase offsets and coupling delays might play for the dynamic information routing via communication pathways in the brain.


Assuntos
Conectoma , Modelos Neurológicos , Rede Nervosa/fisiologia , Encéfalo/anatomia & histologia , Encéfalo/fisiologia , Comunicação , Biologia Computacional , Simulação por Computador , Conectoma/estatística & dados numéricos , Humanos , Rede Nervosa/anatomia & histologia , Redes Neurais de Computação , Vias Neurais/anatomia & histologia , Vias Neurais/fisiologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA