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1.
Adv Exp Med Biol ; 1232: 113-119, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31893402

RESUMO

The prefrontal cortex (PFC) is sensitive to the stress exposure and involved in stress coping. And the effects of gum chewing on the stress have been studied using NIRS. However, when measuring NIRS on PFC during gum chewing, blood flows in shallow tissues (scalp, skin, muscle) might be affected. A NIRS used in the present study first, which has a short distance (1 cm) and the usual (3 cm) source-detector (S-D) regression, can allow eliminating shallow tissues effect of gum chewing. The aim of this study was to investigate the hypothesis that gum chewing activates the right prefrontal cortex (PFC) in stress coping against negative sounds (NS) from the International Affective Digitized Sounds-2 (IADS) as a mental stress task. NS showed activation in the right PFC. There was a significant difference between NS, and NS with Gum, where NS with Gum showed an increased PFC activity, increased alpha wave appearance rate, a higher value in heart rate level, and a higher VAS score indicating 'pleasant'. Gum chewing activated right PFC activity while exposed to negative sounds from IADS as a mental stress task.


Assuntos
Goma de Mascar , Mastigação , Som , Estresse Psicológico , Adaptação Psicológica , Adulto , Feminino , Humanos , Masculino , Córtex Pré-Frontal/fisiologia , Córtex Pré-Frontal/efeitos da radiação , Som/efeitos adversos , Estresse Psicológico/terapia , Adulto Jovem
2.
Adv Exp Med Biol ; 1232: 121-127, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31893403

RESUMO

Changes in NIRS signals are related to changes in local cerebral blood flow or oxy-Hb concentration. On the other hand, recent studies have revealed the effect of chewing gum on cognitive performance, stress control etc. which accompanied brain activity in the prefrontal cortex (PFC). However, these relationships are still controversial. To evaluate the chewing effect on PFC, NIRS seems to be a suitable method of imaging such results. When measuring NIRS on PFC, blood volume in superficial tissues (scalp, skin, muscle) might have some affect. The aim of the present study was to clarify the effect of the anterior temporal muscle on NIRS signals during gum chewing. Eight healthy volunteers participated. Two-channel NIRS (HOT-1000, NeU, Japan), which can distinguish total-Hb concentrations in deep tissue and superficial tissue layers, was used. In addition to a conventional optode separation distance of 3.0 cm, Hot 1000 has a short distance of 1.0 cm (NEAR channel) to measure NIRS signals that originate exclusively from surface tissues. NIRS probes were placed at Fp1 and Fp2 in the normal probe setting. The headset was displaced to the left in order to allow the left probe to be placed over the left anterior temporal muscle. In the normal setting, the superficial signal curve shows no notable change; however, the neural (calculated and defined in HOT-1000) and deep curves show an increase during the gum chewing task. At the deviated setting, all three signals show marked changes during the task. Total-Hb concentration in the deviated probe setting is significantly large (p < 0.05) than that of in the normal probe setting. When using gum chewing as a task, it would be better to consider a probe position carefully so that the influence of muscle activity on NIRS signal can be distinguished.


Assuntos
Mastigação , Córtex Pré-Frontal , Espectroscopia de Luz Próxima ao Infravermelho , Adulto , Hemoglobinas/metabolismo , Humanos , Japão , Projetos Piloto , Córtex Pré-Frontal/fisiologia , Adulto Jovem
3.
Brain Lang ; 200: 104712, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31704517

RESUMO

Previous studies investigating the processing of complex sentences have demonstrated the involvement of the left inferior frontal gyrus (LIFG) and left superior temporal gyrus (LSTG), which might subserve ordering and storage of linguistic components, respectively, for sentence comprehension. However, how these brain regions are interconnected, especially during the processing of Chinese sentences, need to be further explored. In this study, the neural network supporting the comprehension of Chinese relative clause was identified. Both the LIFG and LSTG exhibited higher activation in processing subject-extracted relative clauses (SRCs) than object-extracted relative clauses (ORCs). Moreover, a Granger causality analysis revealed that the effective connectivity from the LIFG to LSTG was significant only when participants read Chinese SRCs, which were argued to be more difficult than ORCs. Contrary to the observations of an SRC advantage in most other languages, the present results provide clear neuroimaging evidence for an ORC advantage in Chinese.


Assuntos
Grupo com Ancestrais do Continente Asiático , Mapeamento Encefálico , Compreensão/fisiologia , Linguagem , Imagem por Ressonância Magnética , Adulto , Feminino , Humanos , Linguística , Masculino , Córtex Pré-Frontal/fisiologia , Leitura , Lobo Temporal/fisiologia , Adulto Jovem
4.
Br J Sports Med ; 54(2): 110-115, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31420319

RESUMO

INTRODUCTION: The brain plays a key role in the perceptual regulation of exercise, yet neuroimaging techniques have only demonstrated superficial brain areas responses during exercise, and little is known about the modulation of the deeper brain areas at different intensities. OBJECTIVES/METHODS: Using a specially designed functional MRI (fMRI) cycling ergometer, we have determined the sequence in which the cortical and subcortical brain regions are modulated at low and high ratings perceived exertion (RPE) during an incremental exercise protocol. RESULTS: Additional to the activation of the classical motor control regions (motor, somatosensory, premotor and supplementary motor cortices and cerebellum), we found the activation of the regions associated with autonomic regulation (ie, insular cortex) (ie, positive blood-oxygen-level-dependent (BOLD) signal) during exercise. Also, we showed reduced activation (negative BOLD signal) of cognitive-related areas (prefrontal cortex), an effect that increased during exercise at a higher perceived intensity (RPE 13-17 on Borg Scale). The motor cortex remained active throughout the exercise protocol whereas the cerebellum was activated only at low intensity (RPE 6-12), not at high intensity (RPE 13-17). CONCLUSIONS: These findings describe the sequence in which different brain areas become activated or deactivated during exercise of increasing intensity, including subcortical areas measured with fMRI analysis.


Assuntos
Exercício/fisiologia , Córtex Motor/fisiologia , Adolescente , Adulto , Cerebelo/fisiologia , Córtex Cerebral/fisiologia , Ergometria/métodos , Humanos , Imagem por Ressonância Magnética , Masculino , Percepção/fisiologia , Esforço Físico/fisiologia , Córtex Pré-Frontal/fisiologia , Adulto Jovem
5.
Neural Netw ; 121: 242-258, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31581065

RESUMO

We present a framework based on iterative free-energy optimization with spiking neural networks for modeling the fronto-striatal system (PFC-BG) for the generation and recall of audio memory sequences. In line with neuroimaging studies carried out in the PFC, we propose a genuine coding strategy using the gain-modulation mechanism to represent abstract sequences based solely on the rank and location of items within them. Based on this mechanism, we show that we can construct a repertoire of neurons sensitive to the temporal structure in sequences from which we can represent any novel sequences. Free-energy optimization is then used to explore and to retrieve the missing indices of the items in the correct order for executive control and compositionality. We show that the gain-modulation mechanism permits the network to be robust to variabilities and to have long-term dependencies as it implements a gated recurrent neural network. This model, called Inferno Gate, is an extension of the neural architecture Inferno standing for Iterative Free-Energy Optimization of Recurrent Neural Networks with Gating or Gain-modulation. In experiments performed with an audio database of ten thousand MFCC vectors, Inferno Gate is capable of encoding efficiently and retrieving chunks of fifty items length. We then discuss the potential of our network to model the features of working memory in the PFC-BG loop for structural learning, goal-direction and hierarchical reinforcement learning.


Assuntos
Potenciais de Ação/fisiologia , Aprendizagem/fisiologia , Memória de Curto Prazo/fisiologia , Córtex Pré-Frontal/fisiologia , Humanos , Rememoração Mental/fisiologia , Neurônios/fisiologia
6.
Brain Nerve ; 71(12): 1357-1371, 2019 Dec.
Artigo em Japonês | MEDLINE | ID: mdl-31787625

RESUMO

The prefrontal cortex is greatly developed in primates and is considered to play an important role in cognitive control of behavior. In the visual and motor systems, research into the functional division between cortical areas has advanced. The prefrontal cortex has also been shown to be divided into several areas which have different anatomical connections with other brain sites. However, the functional division among prefrontal cortical areas has been less well studied. Knowledge of the functional division is expected to help in understanding the cognitive control of complex behaviors in terms of more elementary processes.


Assuntos
Comportamento , Cognição , Córtex Pré-Frontal/fisiologia , Animais , Humanos , Neurociências
7.
Nat Neurosci ; 22(12): 2013-2022, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31768051

RESUMO

The prefrontal cortex (PFC) plays an important role in regulating social functions in mammals, and its dysfunction has been linked to social deficits in neurodevelopmental disorders. Yet little is known of how the PFC encodes social information and how social representations may be altered in such disorders. Here, we show that neurons in the medial PFC of freely behaving male mice preferentially respond to socially relevant olfactory cues. Population activity patterns in this region differed between social and nonsocial stimuli and underwent experience-dependent refinement. In mice lacking the autism-associated gene Cntnap2, both the categorization of sensory stimuli and the refinement of social representations were impaired. Noise levels in spontaneous population activity were higher in Cntnap2 knockouts and correlated with the degree to which social representations were disrupted. Our findings elucidate the encoding of social sensory cues in the medial PFC and provide a link between altered prefrontal dynamics and autism-associated social dysfunction.


Assuntos
Proteínas de Membrana/fisiologia , Proteínas do Tecido Nervoso/fisiologia , Percepção Olfatória/fisiologia , Córtex Pré-Frontal/fisiologia , Comportamento Social , Animais , Sinais (Psicologia) , Masculino , Proteínas de Membrana/genética , Camundongos , Camundongos Knockout , Proteínas do Tecido Nervoso/genética , Percepção Olfatória/genética
8.
Nat Commun ; 10(1): 4885, 2019 10 25.
Artigo em Inglês | MEDLINE | ID: mdl-31653852

RESUMO

Economic choice options contain multiple components and constitute vectorial bundles. The question arises how they are represented by single-dimensional, scalar neuronal signals that are suitable for economic decision-making. Revealed Preference Theory provides formalisms for establishing preference relations between such bundles, including convenient graphic indifference curves. During stochastic choice between bundles with the same two juice components, we identified neuronal signals for vectorial, multi-component bundles in the orbitofrontal cortex of monkeys. A scalar signal integrated the values from all bundle components in the structured manner of the Theory; it followed the behavioral indifference curves within their confidence limits, was indistinguishable between differently composed but equally revealed preferred bundles, predicted bundle choice and complied with an optimality axiom. Further, distinct signals in other neurons coded the option components separately but followed indifference curves as a population. These data demonstrate how scalar signals represent vectorial, multi-component choice options.


Assuntos
Comportamento Animal , Comportamento de Escolha/fisiologia , Neurônios/fisiologia , Córtex Pré-Frontal/citologia , Animais , Tomada de Decisões/fisiologia , Macaca mulatta , Modelos Teóricos , Córtex Pré-Frontal/fisiologia , Recompensa , Processos Estocásticos
9.
PLoS Comput Biol ; 15(10): e1006667, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31609973

RESUMO

A fundamental and recurrent question in systems neuroscience is that of assessing what variables are encoded by a given population of neurons. Such assessments are often challenging because neurons in one brain area may encode multiple variables, and because neuronal representations might be categorical or non-categorical. These issues are particularly pertinent to the representation of decision variables in the orbitofrontal cortex (OFC)-an area implicated in economic choices. Here we present a new algorithm to assess whether a neuronal representation is categorical or non-categorical, and to identify the encoded variables if the representation is indeed categorical. The algorithm is based on two clustering procedures, one variable-independent and the other variable-based. The two partitions are then compared through adjusted mutual information. The present algorithm overcomes limitations of previous approaches and is widely applicable. We tested the algorithm on synthetic data and then used it to examine neuronal data recorded in the primate OFC during economic decisions. Confirming previous assessments, we found the neuronal representation in OFC to be categorical in nature. We also found that neurons in this area encode the value of individual offers, the binary choice outcome and the chosen value. In other words, during economic choice, neurons in the primate OFC encode decision variables in a categorical way.


Assuntos
Comportamento de Escolha/fisiologia , Biologia Computacional/métodos , Tomada de Decisões/fisiologia , Algoritmos , Animais , Análise por Conglomerados , Lobo Frontal/fisiologia , Macaca mulatta , Modelos Teóricos , Neurônios/fisiologia , Córtex Pré-Frontal/fisiologia , Recompensa
10.
Handb Clin Neurol ; 163: 179-196, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31590729

RESUMO

With the exception of language, hemispheric asymmetry has not historically been an important issue in the frontal lobe literature. Data generated over the past 20 years is forcing a reconsideration of this position. There is now considerable evidence to suggest that the left prefrontal cortex is an inference engine that automatically makes simple conceptual, logical, and causal connections to fill in missing information and eliminate uncertainty or indeterminacy. This is a fine-tuning of the "left hemisphere interpreter" account from the callosotomy patient literature. What is new is an understanding of the important contributions of the right prefrontal cortex to formal logical inference, conflict detection, and indeterminacy tolerance and maintenance. This chapter articulates these claims and reviews the data on which they are based. The chapter concludes by speculating that the inference capabilities of the left prefrontal cortex are built into the very fabric of language and can be accounted for by the left hemisphere dominance for language. The roles of the right PFC require multiple mechanisms for explanation. Its role in formal inference may be a function of its visual-spatial processing capabilities. Its role in conflict detection may be explained as a system for checking for consistency between existing beliefs and new information coming into the system and inferences drawn from beliefs and/or new information. There are at least three possible mechanisms to account for its role in indeterminacy tolerance. First, it could contain a representational system with properties very different from those of language, and an accompanying inference engine. Second, it could just contain this different representational system, and the information is at some point passed back to the left prefrontal cortex for inference. Third, the role of the right prefrontal cortex may be largely preventative. That is, it doesn't provide alternative representational and inference capabilities but simply prevents the left prefrontal cortex from settling on initial, local inferences. The current data do not allow differentiating between these possibilities. Successful real-world functioning requires the participation of both hemispheres.


Assuntos
Cognição/fisiologia , Lateralidade Funcional/fisiologia , Linguagem , Córtex Pré-Frontal/fisiologia , Tomada de Decisões/fisiologia , Humanos , Testes Neuropsicológicos
11.
Handb Clin Neurol ; 163: 221-235, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31590732

RESUMO

Recent research has demonstrated that the lateral prefrontal cortex is extensively involved in human memory, including working memory processes that support retention of information across short delays, and episodic long-term memory encoding and retrieval processes. This chapter reviews results from neuroimaging studies of memory, from noninvasive brain stimulation studies of memory, and from studies of memory in patients with prefrontal lesions. The available evidence is consistent with the idea that different prefrontal regions implement cognitive or executive control processes that support working memory and episodic long-term memory encoding and retrieval.


Assuntos
Lateralidade Funcional/fisiologia , Memória de Longo Prazo/fisiologia , Córtex Pré-Frontal/fisiologia , Mapeamento Encefálico , Estimulação Elétrica , Humanos , Neuroimagem , Testes Neuropsicológicos
12.
Handb Clin Neurol ; 163: 237-255, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31590733

RESUMO

The prefrontal cortex serves a critical role in the coordination and execution of motor actions via its involvement in goal setting, decision-making, motivation, and cognitive control. Using the macaque connectome, the anatomic pathways from prefrontal cortex to motor circuitry are summarized, revealing a remarkably limited set of direct connections. A highly similar connectivity pattern is inferred from human neuroimaging. The results motivate the prefrontal-premotor connector hub model, which highlights both functional segregation and a limited set of connector hub regions that provide a direct linking of prefrontal cortex to the (pre-)motor network. Moreover, the macaque connectome reveals a set of motor translator regions that provide the most direct projection from premotor to prefrontal areas. The connector hub model leads to important functional implications: Neural activation or disruption in connector hubs should lead to functional deficits that undermine integration between higher cognitive action control and motor performance ranging from response selection and inhibition to perceived agency of actions. Segregation of prefrontal-premotor networks challenges hierarchical models of motor control and underscores the critical role of the indirect pathway from prefrontal to premotor areas via the parietal cortex. The model provides a predictive framework to design neurostimulation paradigms for modulating skill learning or recovery in both healthy subjects and patient cohorts.


Assuntos
Atividade Motora/fisiologia , Córtex Motor/fisiologia , Córtex Pré-Frontal/fisiologia , Desempenho Psicomotor/fisiologia , Mapeamento Encefálico , Humanos , Vias Neurais/fisiologia
13.
Handb Clin Neurol ; 163: 295-315, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31590736

RESUMO

Over the past 150 years, the frontal lobes (FLs) have been implicated in the neural mediation of both normal and abnormal moral conduct and social behavior (MCSB). Despite the remarkable advances that have permeated this period up to the present, a comprehensive account of the neural underpinnings of MCSB has stubbornly defied the best minds of psychology, psychiatry, and neurology. The goal of this chapter is to review a few practical and conceptual achievements that have proved heuristically valuable as an impetus for further advance of knowledge. In virtually all cases in which MCSB was compromised by brain damage, the injuries were located (i) in the prefrontal cortices, (ii) in their connections with the temporal poles and anterior insula, or (iii) in related subcortical structures and pathways, such as the thalamic dorsomedial nucleus or the anterior thalamic radiation. The clinicoanatomic associations among these structures originated the "frontal network systems" concept, which satisfactorily explains the occurrence of classical FL syndromes in patients with lesions outside the prefrontal cortices. Overall, clinicoanatomic observational studies and experimental evidence from patients with acquired sociopathy/psychopathy indicate that abnormalities of MCSB are the final common pathway of single or mixed impairments of subordinate psychologic and neural domains that support MCSB. Independent studies on normal volunteers concur with this view, indicating that MCSB is shaped by the dynamic interplay of subordinate psychologic domains, such as moral sensitivity and judgment, and their neural correlates.


Assuntos
Julgamento/fisiologia , Princípios Morais , Córtex Pré-Frontal/fisiologia , Comportamento Social , Mapeamento Encefálico , Humanos , Testes Neuropsicológicos
14.
Handb Clin Neurol ; 163: 3-15, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31590737

RESUMO

Throughout the nervous system, posterior structures are mainly devoted to receptive functions-sensation and perception-while anterior structures are devoted to motor functions. In the cortex, that dichotomy is unclear because perception and action are intertwined in the perception-action cycle, the biocybernetic cycle that adapts the organism to its environment. All neural systems store information (memory), which they enact in behavior and language. There are no "systems of memory" but the memory of systems. The cortex of the frontal lobe is a hierarchical system: motor cortex at the bottom for coordination of simple movements, and prefrontal cortex at the top for complex goal-directed actions. In the coordination of such actions, the frontal hierarchy engages the posterior (perceptual) cortex in the perception-action cycle. Inputs to the cycle come to prefrontal cortex from sensory-evoked perceptual memory and biologic (phyletic) memory. The first comes from neocortex, the second from limbic structures-through orbitomedial cortex. Outputs flow to pyramidal and diencephalic structures. Feedback inputs for monitoring and correction operate at all levels of the cycle. All prefrontal functions-planning, executive attention, working memory, decision-making, and inhibitory controls-are prospective, i.e., have a future perspective for the cycle to reach its goal. Damage to lateral prefrontal cortex impairs all of them. Orbitofrontal damage impairs the exclusionary aspect of attention and often leads to poor impulse control, excessive risk taking, unstable mood, and antisocial behavior. Medial prefrontal damage leads to poor monitoring of behavioral outcome for prevention of errors.


Assuntos
Tomada de Decisões/fisiologia , Função Executiva/fisiologia , Memória/fisiologia , Córtex Pré-Frontal/fisiologia , Humanos , Vias Neurais/fisiologia , Neurologia
15.
Handb Clin Neurol ; 163: 35-59, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31590740

RESUMO

The prefrontal cortex (PFC) provides the structural basis for complex rule-guided goal-directed behavior. However, the functional mechanisms that underlie cognitive control and flexibility are not as well understood. Over the last decade, novel electrophysiological methods and analysis techniques have begun to elucidate the neural mechanisms underlying higher cognitive functions. Here we review how electrophysiology and, in particular, intracranial recordings in humans and primates enable imaging of cognitive processing with an unprecedented spatiotemporal resolution. Convergent evidence from multiple species and across several spatial scales suggests that cell assemblies and transient synchronized network activity constitute the functional units of PFC implementation of organized behavior. These observations indicate that the functional architecture of cognition is inherently rhythmic and not static. We highlight that prefrontal neurons exhibit a mixed selectivity to various task-relevant aspects and code information in a time-varying dynamic population code and not at the level of individual neurons or in stable coding schemes. We argue that network neuroscience and network neurology are emergent paradigms to understand complex behavior and mental diseases.


Assuntos
Cognição/fisiologia , Rede Nervosa/fisiologia , Neurônios/fisiologia , Córtex Pré-Frontal/fisiologia , Animais , Humanos , Primatas
16.
Nat Neurosci ; 22(11): 1883-1891, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31570859

RESUMO

When making decisions we often face the need to adjudicate between conflicting strategies or courses of action. Our ability to understand the neuronal processes underlying conflict processing is limited on the one hand by the spatiotemporal resolution of functional MRI and, on the other hand, by imperfect cross-species homologies in animal model systems. Here we examine the responses of single neurons and local field potentials in human neurosurgical patients in two prefrontal regions critical to controlled decision-making, the dorsal anterior cingulate cortex (dACC) and dorsolateral prefrontal cortex (dlPFC). While we observe typical modest conflict-related firing rate effects, we find a widespread effect of conflict on spike-phase coupling in the dACC and on driving spike-field coherence in the dlPFC. These results support the hypothesis that a cross-areal rhythmic neuronal coordination is intrinsic to cognitive control in response to conflict, and provide new evidence to support the hypothesis that conflict processing involves modulation of the dlPFC by the dACC.


Assuntos
Cognição/fisiologia , Giro do Cíngulo/fisiologia , Córtex Pré-Frontal/fisiologia , Fatores de Tempo , Feminino , Humanos , Masculino , Potenciais da Membrana/fisiologia , Vias Neurais/fisiologia , Neurônios/fisiologia
17.
Nat Commun ; 10(1): 4835, 2019 10 23.
Artigo em Inglês | MEDLINE | ID: mdl-31645545

RESUMO

Learning the structure of the world can be driven by reinforcement but also occurs incidentally through experience. Reinforcement learning theory has provided insight into how prediction errors drive updates in beliefs but less attention has been paid to the knowledge resulting from such learning. Here we contrast associative structures formed through reinforcement and experience of task statistics. BOLD neuroimaging in human volunteers demonstrates rigid representations of rewarded sequences in temporal pole and posterior orbito-frontal cortex, which are constructed backwards from reward. By contrast, medial prefrontal cortex and a hippocampal-amygdala border region carry reward-related knowledge but also flexible statistical knowledge of the currently relevant task model. Intriguingly, ventral striatum encodes prediction error responses but not the full RL- or statistically derived task knowledge. In summary, representations of task knowledge are derived via multiple learning processes operating at different time scales that are associated with partially overlapping and partially specialized anatomical regions.


Assuntos
Aprendizagem por Associação/fisiologia , Encéfalo/diagnóstico por imagem , Adulto , Tonsila do Cerebelo/diagnóstico por imagem , Tonsila do Cerebelo/fisiologia , Encéfalo/fisiologia , Feminino , Neuroimagem Funcional , Hipocampo/diagnóstico por imagem , Hipocampo/fisiologia , Humanos , Aprendizagem/fisiologia , Imagem por Ressonância Magnética , Masculino , Córtex Pré-Frontal/diagnóstico por imagem , Córtex Pré-Frontal/fisiologia , Lobo Temporal/diagnóstico por imagem , Lobo Temporal/fisiologia , Estriado Ventral/diagnóstico por imagem , Estriado Ventral/fisiologia , Adulto Jovem
18.
Nat Commun ; 10(1): 4745, 2019 10 18.
Artigo em Inglês | MEDLINE | ID: mdl-31628322

RESUMO

Measuring neuronal tuning curves has been instrumental for many discoveries in neuroscience but requires a priori assumptions regarding the identity of the encoded variables. We applied unsupervised learning to large-scale neuronal recordings in behaving mice from circuits involved in spatial cognition and uncovered a highly-organized internal structure of ensemble activity patterns. This emergent structure allowed defining for each neuron an 'internal tuning-curve' that characterizes its activity relative to the network activity, rather than relative to any predefined external variable, revealing place-tuning and head-direction tuning without relying on measurements of place or head-direction. Similar investigation in prefrontal cortex revealed schematic representations of distances and actions, and exposed a previously unknown variable, the 'trajectory-phase'. The internal structure was conserved across mice, allowing using one animal's data to decode another animal's behavior. Thus, the internal structure of neuronal activity itself enables reconstructing internal representations and discovering new behavioral variables hidden within a neural code.


Assuntos
Movimentos da Cabeça/fisiologia , Rede Nervosa/fisiologia , Neurônios/fisiologia , Córtex Pré-Frontal/fisiologia , Percepção Espacial/fisiologia , Potenciais de Ação/fisiologia , Algoritmos , Animais , Cognição/fisiologia , Hipocampo/citologia , Hipocampo/fisiologia , Masculino , Camundongos Endogâmicos C57BL , Modelos Neurológicos , Rede Nervosa/citologia , Orientação/fisiologia , Córtex Pré-Frontal/citologia
19.
F1000Res ; 82019.
Artigo em Inglês | MEDLINE | ID: mdl-31602292

RESUMO

Cognitive control, the ability to regulate one's cognition and actions on the basis of over-riding goals, is impaired in many psychiatric conditions. Although control requires the coordinated function of several prefrontal cortical regions, it has been challenging to determine how they work together, in part because doing so requires simultaneous recordings from multiple regions. Here, we provide a précis of cognitive control and describe the beneficial consequences of recent advances in neurosurgical practice that make large-scale prefrontal cortical network recordings possible in humans. Such recordings implicate inter-regional theta (5-8 Hz) local field potential (LFP) synchrony as a key element in cognitive control. Major open questions include how theta might influence other oscillations within these networks, the precise timing of information flow between these regions, and how perturbations such as brain stimulation might demonstrate the causal role of LFP phenomena. We propose that an increased focus on human electrophysiology is essential for an understanding of the neural basis of cognitive control.


Assuntos
Cognição , Fenômenos Eletrofisiológicos , Córtex Pré-Frontal/fisiologia , Humanos
20.
Nature ; 574(7779): 543-548, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31645720

RESUMO

Multicellular organisms have co-evolved with complex consortia of viruses, bacteria, fungi and parasites, collectively referred to as the microbiota1. In mammals, changes in the composition of the microbiota can influence many physiologic processes (including development, metabolism and immune cell function) and are associated with susceptibility to multiple diseases2. Alterations in the microbiota can also modulate host behaviours-such as social activity, stress, and anxiety-related responses-that are linked to diverse neuropsychiatric disorders3. However, the mechanisms by which the microbiota influence neuronal activity and host behaviour remain poorly defined. Here we show that manipulation of the microbiota in antibiotic-treated or germ-free adult mice results in significant deficits in fear extinction learning. Single-nucleus RNA sequencing of the medial prefrontal cortex of the brain revealed significant alterations in gene expression in excitatory neurons, glia and other cell types. Transcranial two-photon imaging showed that deficits in extinction learning after manipulation of the microbiota in adult mice were associated with defective learning-related remodelling of postsynaptic dendritic spines and reduced activity in cue-encoding neurons in the medial prefrontal cortex. In addition, selective re-establishment of the microbiota revealed a limited neonatal developmental window in which microbiota-derived signals can restore normal extinction learning in adulthood. Finally, unbiased metabolomic analysis identified four metabolites that were significantly downregulated in germ-free mice and have been reported to be related to neuropsychiatric disorders in humans and mouse models, suggesting that microbiota-derived compounds may directly affect brain function and behaviour. Together, these data indicate that fear extinction learning requires microbiota-derived signals both during early postnatal neurodevelopment and in adult mice, with implications for our understanding of how diet, infection, and lifestyle influence brain health and subsequent susceptibility to neuropsychiatric disorders.


Assuntos
Extinção Psicológica/fisiologia , Medo/fisiologia , Metabolômica , Microbiota/fisiologia , Neurônios/fisiologia , Animais , Antibacterianos/farmacologia , Transtorno Autístico/metabolismo , Sangue/metabolismo , Cálcio/metabolismo , Líquido Cefalorraquidiano/química , Líquido Cefalorraquidiano/metabolismo , Sinais (Psicologia) , Espinhas Dendríticas/efeitos dos fármacos , Espinhas Dendríticas/patologia , Espinhas Dendríticas/fisiologia , Extinção Psicológica/efeitos dos fármacos , Medo/efeitos dos fármacos , Fezes/química , Vida Livre de Germes , Indicã/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Microbiota/efeitos dos fármacos , Microbiota/imunologia , Inibição Neural , Neuroglia/patologia , Neuroglia/fisiologia , Neurônios/efeitos dos fármacos , Neurônios/imunologia , Neurônios/patologia , Fenilpropionatos/metabolismo , Córtex Pré-Frontal/citologia , Córtex Pré-Frontal/efeitos dos fármacos , Córtex Pré-Frontal/imunologia , Córtex Pré-Frontal/fisiologia , Esquizofrenia/metabolismo , Transcriptoma , Nervo Vago/fisiologia
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