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1.
Nat Commun ; 12(1): 2205, 2021 04 13.
Artigo em Inglês | MEDLINE | ID: mdl-33850154

RESUMO

Parents frequently report behavioral problems among children who snore. Our understanding of the relationship between symptoms of obstructive sleep disordered breathing (oSDB) and childhood behavioral problems associated with brain structural alterations is limited. Here, we examine the associations between oSDB symptoms, behavioral measures such as inattention, and brain morphometry in the Adolescent Brain Cognitive Development (ABCD) study comprising 10,140 preadolescents. We observe that parent-reported symptoms of oSDB are associated with composite and domain-specific problem behaviors measured by parent responses to the Child Behavior Checklist. Alterations of brain structure demonstrating the strongest negative associations with oSDB symptoms are within the frontal lobe. The relationships between oSDB symptoms and behavioral measures are mediated by significantly smaller volumes of multiple frontal lobe regions. These results provide population-level evidence for an association between regional structural alterations in cortical gray matter and problem behaviors reported in children with oSDB.


Assuntos
Comportamento Infantil , Lobo Frontal/fisiologia , Apneia Obstrutiva do Sono , Adolescente , Encéfalo , Criança , Feminino , Substância Cinzenta , Humanos , Masculino , Pais , Apneia Obstrutiva do Sono/diagnóstico , Ronco
2.
Nat Commun ; 12(1): 2000, 2021 03 31.
Artigo em Inglês | MEDLINE | ID: mdl-33790301

RESUMO

A crucial role of cortical networks is the conversion of sensory inputs into perception. In the cortical somatosensory network, neurons of the primary somatosensory cortex (S1) show invariant sensory responses, while frontal lobe neuronal activity correlates with the animal's perceptual behavior. Here, we report that in the secondary somatosensory cortex (S2), neurons with invariant sensory responses coexist with neurons whose responses correlate with perceptual behavior. Importantly, the vast majority of the neurons fall along a continuum of combined sensory and categorical dynamics. Furthermore, during a non-demanding control task, the sensory responses remain unaltered while the sensory information exhibits an increase. However, perceptual responses and the associated categorical information decrease, implicating a task context-dependent processing mechanism. Conclusively, S2 neurons exhibit intriguing dynamics that are intermediate between those of S1 and frontal lobe. Our results contribute relevant evidence about the role that S2 plays in the conversion of touch into perception.


Assuntos
Macaca mulatta/fisiologia , Neurônios/fisiologia , Células Receptoras Sensoriais/fisiologia , Córtex Somatossensorial/fisiologia , Percepção do Tato/fisiologia , Algoritmos , Animais , Lobo Frontal/citologia , Lobo Frontal/fisiologia , Modelos Neurológicos , Estimulação Física/métodos , Córtex Somatossensorial/citologia
3.
Nat Commun ; 12(1): 1757, 2021 03 19.
Artigo em Inglês | MEDLINE | ID: mdl-33741947

RESUMO

Voluntary allocation of visual attention is controlled by top-down signals generated within the Frontal Eye Fields (FEFs) that can change the excitability of lower-level visual areas. However, the mechanism through which this control is achieved remains elusive. Here, we emulated the generation of an attentional signal using single-pulse transcranial magnetic stimulation to activate the FEFs and tracked its consequences over the visual cortex. First, we documented changes to brain oscillations using electroencephalography and found evidence for a phase reset over occipital sites at beta frequency. We then probed for perceptual consequences of this top-down triggered phase reset and assessed its anatomical specificity. We show that FEF activation leads to cyclic modulation of visual perception and extrastriate but not primary visual cortex excitability, again at beta frequency. We conclude that top-down signals originating in FEF causally shape visual cortex activity and perception through mechanisms of oscillatory realignment.


Assuntos
Lobo Frontal/fisiologia , Estimulação Magnética Transcraniana/métodos , Córtex Visual/fisiologia , Campos Visuais/fisiologia , Percepção Visual/fisiologia , Adulto , Algoritmos , Eletroencefalografia/métodos , Feminino , Humanos , Masculino , Modelos Neurológicos , Lobo Occipital/fisiologia , Estimulação Luminosa
4.
Neuron ; 109(7): 1202-1213.e5, 2021 04 07.
Artigo em Inglês | MEDLINE | ID: mdl-33609483

RESUMO

The frontal cortex, especially the anterior cingulate cortex area (ACA), is essential for exerting cognitive control after errors, but the mechanisms that enable modulation of attention to improve performance after errors are poorly understood. Here we demonstrate that during a mouse visual attention task, ACA neurons projecting to the visual cortex (VIS; ACAVIS neurons) are recruited selectively by recent errors. Optogenetic manipulations of this pathway collectively support the model that rhythmic modulation of ACAVIS neurons in anticipation of visual stimuli is crucial for adjusting performance following errors. 30-Hz optogenetic stimulation of ACAVIS neurons in anesthetized mice recapitulates the increased gamma and reduced theta VIS oscillatory changes that are associated with endogenous post-error performance during behavior and subsequently increased visually evoked spiking, a hallmark feature of visual attention. This frontal sensory neural circuit links error monitoring with implementing adjustments of attention to guide behavioral adaptation, pointing to a circuit-based mechanism for promoting cognitive control.


Assuntos
Atenção/fisiologia , Lobo Frontal/fisiologia , Recrutamento Neurofisiológico/fisiologia , Animais , Comportamento Animal , Eletroencefalografia , Fenômenos Eletrofisiológicos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Atividade Motora/fisiologia , Vias Neurais/fisiologia , Neurônios/fisiologia , Optogenética , Estimulação Luminosa , Desempenho Psicomotor/fisiologia , Tempo de Reação/fisiologia , Córtex Somatossensorial/fisiologia , Córtex Visual/fisiologia
5.
Nat Commun ; 12(1): 1103, 2021 02 17.
Artigo em Inglês | MEDLINE | ID: mdl-33597516

RESUMO

Neurons in some sensory areas reflect the content of working memory (WM) in their spiking activity. However, this spiking activity is seldom related to behavioral performance. We studied the responses of inferotemporal (IT) neurons, which exhibit object-selective activity, along with Frontal Eye Field (FEF) neurons, which exhibit spatially selective activity, during the delay period of an object WM task. Unlike the spiking activity and local field potentials (LFPs) within these areas, which were poor predictors of behavioral performance, the phase-locking of IT spikes and LFPs with the beta band of FEF LFPs robustly predicted successful WM maintenance. In addition, IT neurons exhibited greater object-selective persistent activity when their spikes were locked to the phase of FEF LFPs. These results reveal that the coordination between prefrontal and temporal cortex predicts the successful maintenance of visual information during WM.


Assuntos
Macaca mulatta/fisiologia , Memória de Curto Prazo/fisiologia , Neurônios/fisiologia , Córtex Pré-Frontal/fisiologia , Lobo Temporal/fisiologia , Potenciais de Ação/fisiologia , Algoritmos , Animais , Lobo Frontal/citologia , Lobo Frontal/fisiologia , Masculino , Modelos Neurológicos , Estimulação Luminosa , Córtex Pré-Frontal/citologia , Lobo Temporal/citologia
6.
Clin Neurophysiol ; 132(3): 730-736, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33567379

RESUMO

OBJECTIVE: To study if limited frontotemporal electroencephalogram (EEG) can guide sedation changes in highly infectious novel coronavirus disease 2019 (COVID-19) patients receiving neuromuscular blocking agent. METHODS: 98 days of continuous frontotemporal EEG from 11 consecutive patients was evaluated daily by an epileptologist to recommend reduction or maintenance of the sedative level. We evaluated the need to increase sedation in the 6 h following this recommendation. Post-hoc analysis of the quantitative EEG was correlated with the level of sedation using a machine learning algorithm. RESULTS: Eleven patients were studied for a total of ninety-eight sedation days. EEG was consistent with excessive sedation on 57 (58%) and adequate sedation on 41 days (42%). Recommendations were followed by the team on 59% (N = 58; 19 to reduce and 39 to keep the sedation level). In the 6 h following reduction in sedation, increases of sedation were needed in 7 (12%). Automatized classification of EEG sedation levels reached 80% (±17%) accuracy. CONCLUSIONS: Visual inspection of a limited EEG helped sedation depth guidance. In a secondary analysis, our data supported that this determination may be automated using quantitative EEG analysis. SIGNIFICANCE: Our results support the use of frontotemporal EEG for guiding sedation in patients with COVID-19.


Assuntos
/tratamento farmacológico , Eletroencefalografia/métodos , Lobo Frontal/fisiologia , Hipnóticos e Sedativos/administração & dosagem , Aprendizado de Máquina , Lobo Temporal/fisiologia , Idoso , Anestesia/métodos , /fisiopatologia , Estudos de Coortes , Eletroencefalografia/efeitos dos fármacos , Feminino , Humanos , Unidades de Terapia Intensiva , Masculino , Pessoa de Meia-Idade
7.
Nature ; 591(7849): 270-274, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33408410

RESUMO

Neural mechanisms that mediate the ability to make value-guided decisions have received substantial attention in humans and animals1-6. Experiments in animals typically involve long training periods. By contrast, choices in the real world often need to be made between new options spontaneously. It is therefore possible that the neural mechanisms targeted in animal studies differ from those required for new decisions, which are typical of human imaging studies. Here we show that the primate medial frontal cortex (MFC)7 is involved in making new inferential choices when the options have not been previously experienced. Macaques spontaneously inferred the values of new options via similarities with the component parts of previously encountered options. Functional magnetic resonance imaging (fMRI) suggested that this ability was mediated by the MFC, which is rarely investigated in monkeys3; MFC activity reflected different processes of comparison for unfamiliar and familiar options. Multidimensional representations of options in the MFC used a coding scheme resembling that of grid cells, which is well known in spatial navigation8,9, to integrate dimensions in this non-physical space10 during novel decision-making. By contrast, the orbitofrontal cortex held specific object-based value representations1,11. In addition, minimally invasive ultrasonic disruption12 of MFC, but not adjacent tissue, altered the estimation of novel choice values.


Assuntos
Comportamento de Escolha/fisiologia , Lobo Frontal/citologia , Lobo Frontal/fisiologia , Macaca mulatta/fisiologia , Neurônios/fisiologia , Adulto , Animais , Feminino , Células de Grade/fisiologia , Humanos , Imagem por Ressonância Magnética , Masculino , Córtex Pré-Frontal/citologia , Córtex Pré-Frontal/fisiologia , Navegação Espacial/fisiologia , Adulto Jovem
8.
Neuron ; 109(5): 852-868.e8, 2021 03 03.
Artigo em Inglês | MEDLINE | ID: mdl-33482086

RESUMO

Human brain pathways supporting language and declarative memory are thought to have differentiated substantially during evolution. However, cross-species comparisons are missing on site-specific effective connectivity between regions important for cognition. We harnessed functional imaging to visualize the effects of direct electrical brain stimulation in macaque monkeys and human neurosurgery patients. We discovered comparable effective connectivity between caudal auditory cortex and both ventro-lateral prefrontal cortex (VLPFC, including area 44) and parahippocampal cortex in both species. Human-specific differences were clearest in the form of stronger hemispheric lateralization effects. In humans, electrical tractography revealed remarkably rapid evoked potentials in VLPFC following auditory cortex stimulation and speech sounds drove VLPFC, consistent with prior evidence in monkeys of direct auditory cortex projections to homologous vocalization-responsive regions. The results identify a common effective connectivity signature in human and nonhuman primates, which from auditory cortex appears equally direct to VLPFC and indirect to the hippocampus. VIDEO ABSTRACT.


Assuntos
Lobo Frontal/fisiologia , Lobo Temporal/fisiologia , Adolescente , Adulto , Animais , Córtex Auditivo/fisiologia , Mapeamento Encefálico , Estimulação Elétrica , Feminino , Humanos , Macaca mulatta , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Vias Neurais/fisiologia , Giro Para-Hipocampal/fisiologia , Córtex Pré-Frontal/fisiologia , Especificidade da Espécie , Adulto Jovem
9.
Nat Commun ; 12(1): 360, 2021 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-33452252

RESUMO

Endogenous attention is the cognitive function that selects the relevant pieces of sensory information to achieve goals and it is known to be controlled by dorsal fronto-parietal brain areas. Here we expand this notion by identifying a control attention area located in the temporal lobe. By combining a demanding behavioral paradigm with functional neuroimaging and diffusion tractography, we show that like fronto-parietal attentional areas, the human posterior inferotemporal cortex exhibits significant attentional modulatory activity. This area is functionally distinct from surrounding cortical areas, and is directly connected to parietal and frontal attentional regions. These results show that attentional control spans three cortical lobes and overarches large distances through fiber pathways that run orthogonally to the dominant anterior-posterior axes of sensory processing, thus suggesting a different organizing principle for cognitive control.


Assuntos
Atenção/fisiologia , Lobo Frontal/fisiologia , Lobo Parietal/fisiologia , Lobo Temporal/fisiologia , Adulto , Mapeamento Encefálico , Imagem de Tensor de Difusão , Feminino , Lobo Frontal/diagnóstico por imagem , Voluntários Saudáveis , Humanos , Masculino , Percepção de Movimento/fisiologia , Vias Neurais/diagnóstico por imagem , Vias Neurais/fisiologia , Lobo Parietal/diagnóstico por imagem , Estimulação Luminosa/métodos , Lobo Temporal/diagnóstico por imagem , Adulto Jovem
10.
J Neurosci ; 41(7): 1516-1528, 2021 02 17.
Artigo em Inglês | MEDLINE | ID: mdl-33310756

RESUMO

In recent years, several hierarchical extensions of well-known learning algorithms have been proposed. For example, when stimulus-action mappings vary across time or context, the brain may learn two or more stimulus-action mappings in separate modules, and additionally (at a hierarchically higher level) learn to appropriately switch between those modules. However, how the brain mechanistically coordinates neural communication to implement such hierarchical learning remains unknown. Therefore, the current study tests a recent computational model that proposed how midfrontal theta oscillations implement such hierarchical learning via the principle of binding by synchrony (Sync model). More specifically, the Sync model uses bursts at theta frequency to flexibly bind appropriate task modules by synchrony. The 64-channel EEG signal was recorded while 27 human subjects (female: 21, male: 6) performed a probabilistic reversal learning task. In line with the Sync model, postfeedback theta power showed a linear relationship with negative prediction errors, but not with positive prediction errors. This relationship was especially pronounced for subjects with better behavioral fit (measured via Akaike information criterion) of the Sync model. Also consistent with Sync model simulations, theta phase-coupling between midfrontal electrodes and temporoparietal electrodes was stronger after negative feedback. Our data suggest that the brain uses theta power and synchronization for flexibly switching between task rule modules, as is useful, for example, when multiple stimulus-action mappings must be retained and used.SIGNIFICANCE STATEMENT Everyday life requires flexibility in switching between several rules. A key question in understanding this ability is how the brain mechanistically coordinates such switches. The current study tests a recent computational framework (Sync model) that proposed how midfrontal theta oscillations coordinate activity in hierarchically lower task-related areas. In line with predictions of this Sync model, midfrontal theta power was stronger when rule switches were most likely (strong negative prediction error), especially in subjects who obtained a better model fit. Additionally, also theta phase connectivity between midfrontal and task-related areas was increased after negative feedback. Thus, the data provided support for the hypothesis that the brain uses theta power and synchronization for flexibly switching between rules.


Assuntos
Aprendizagem/fisiologia , Ritmo Teta/fisiologia , Adulto , Algoritmos , Cognição/fisiologia , Simulação por Computador , Eletroencefalografia , Retroalimentação Psicológica/fisiologia , Feminino , Lobo Frontal/fisiologia , Humanos , Masculino , Desempenho Psicomotor/fisiologia , Tempo de Reação/fisiologia , Reversão de Aprendizagem/fisiologia , Adulto Jovem
11.
J Neurosci ; 41(7): 1455-1469, 2021 02 17.
Artigo em Inglês | MEDLINE | ID: mdl-33376156

RESUMO

In the macaque brain, projections from distant, interconnected cortical areas converge in specific zones of the striatum. For example, specific zones of the motor putamen are targets of projections from frontal motor, inferior parietal, and ventrolateral prefrontal hand-related areas and thus are integral part of the so-called "lateral grasping network." In the present study, we analyzed the laminar distribution of corticostriatal neurons projecting to different parts of the motor putamen. Retrograde neural tracers were injected in different parts of the putamen in 3 Macaca mulatta (one male) and the laminar distribution of the labeled corticostriatal neurons was analyzed quantitatively. In frontal motor areas and frontal operculum, where most labeled cells were located, almost everywhere the proportion of corticostriatal labeled neurons in layers III and/or VI was comparable or even stronger than in layer V. Furthermore, within these regions, the laminar distribution pattern of corticostriatal labeled neurons largely varied independently from their density and from the projecting area/sector, but likely according to the target striatal zone. Accordingly, the present data show that cortical areas may project in different ways to different striatal zones, which can be targets of specific combinations of signals originating from the various cortical layers of the areas of a given network. These observations extend current models of corticostriatal interactions, suggesting more complex modes of information processing in the basal ganglia for different motor and nonmotor functions and opening new questions on the architecture of the corticostriatal circuitry.SIGNIFICANCE STATEMENT Projections from the ipsilateral cerebral cortex are the major source of input to the striatum. Previous studies have provided evidence for distinct zones of the putamen specified by converging projections from specific sets of interconnected cortical areas. The present study shows that the distribution of corticostriatal neurons in the various layers of the primary motor and premotor areas varies depending on the target striatal zone. Accordingly, different striatal zones collect specific combinations of signals from the various cortical layers of their input areas, possibly differing in terms of coding, timing, and direction of information flow (e.g., feed-forward, or feed-back).


Assuntos
Córtex Cerebral/fisiologia , Corpo Estriado/fisiologia , Vias Neurais/fisiologia , Putamen/fisiologia , Animais , Mapeamento Encefálico , Córtex Cerebral/citologia , Corpo Estriado/citologia , Retroalimentação Fisiológica/fisiologia , Feminino , Lobo Frontal/fisiologia , Macaca mulatta , Masculino , Córtex Motor/fisiologia , Vias Neurais/citologia , Neurônios/fisiologia , Lobo Parietal/fisiologia , Putamen/citologia
12.
Neuron ; 109(5): 882-893.e7, 2021 03 03.
Artigo em Inglês | MEDLINE | ID: mdl-33357412

RESUMO

Our brains at rest spontaneously replay recently acquired information, but how this process is orchestrated to avoid interference with ongoing cognition is an open question. Here we investigated whether replay coincided with spontaneous patterns of whole-brain activity. We found, in two separate datasets, that replay sequences were packaged into transient bursts occurring selectively during activation of the default mode network (DMN) and parietal alpha networks. These networks are believed to support inwardly oriented attention and inhibit bottom-up sensory processing and were characterized by widespread synchronized oscillations coupled to increases in high frequency power, mechanisms thought to coordinate information flow between disparate cortical areas. Our data reveal a tight correspondence between two widely studied phenomena in neural physiology and suggest that the DMN may coordinate replay bursts in a manner that minimizes interference with ongoing cognition.


Assuntos
Ritmo alfa , Encéfalo/fisiologia , /fisiologia , Adulto , Feminino , Lobo Frontal/fisiologia , Humanos , Masculino , Lobo Parietal/fisiologia , Lobo Temporal/fisiologia , Adulto Jovem
13.
Elife ; 92020 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-33319745

RESUMO

Despite the importance of programming to modern society, the cognitive and neural bases of code comprehension are largely unknown. Programming languages might 'recycle' neurocognitive mechanisms originally developed for natural languages. Alternatively, comprehension of code could depend on fronto-parietal networks shared with other culturally-invented symbol systems, such as formal logic and symbolic math such as algebra. Expert programmers (average 11 years of programming experience) performed code comprehension and memory control tasks while undergoing fMRI. The same participants also performed formal logic, symbolic math, executive control, and language localizer tasks. A left-lateralized fronto-parietal network was recruited for code comprehension. Patterns of activity within this network distinguish between 'for' loops and 'if' conditional code functions. In terms of the underlying neural basis, code comprehension overlapped extensively with formal logic and to a lesser degree math. Overlap with executive processes and language was low, but laterality of language and code covaried across individuals. Cultural symbol systems, including code, depend on a distinctive fronto-parietal cortical network.


Assuntos
Cognição , Compreensão , Função Executiva , Lobo Frontal/fisiologia , Lobo Parietal/fisiologia , Software , Adulto , Mapeamento Encefálico , Feminino , Lobo Frontal/diagnóstico por imagem , Lateralidade Funcional , Humanos , Imagem por Ressonância Magnética , Masculino , Vias Neurais/fisiologia , Lobo Parietal/diagnóstico por imagem , Adulto Jovem
14.
PLoS One ; 15(12): e0241578, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33362255

RESUMO

This study investigated consumers' responses to fashion visual merchandising (VM) from a neuroscientific perspective. The brain activations of 20 subjects differently involved in fashion were recorded using functional near-infrared spectroscopy in response to three different fashion VM types. According to the types of fashion VM, significant differences were observed, which were significantly higher for the creative VM. Moreover, highly fashion-involved subjects showed activation of the orbital frontal cortex region in response to the creative VM. Based on these results, it is suggested that marketing strategies should be devised explicitly for the brand's targeted audience and goals.


Assuntos
Comportamento do Consumidor , Marketing/métodos , Estimulação Luminosa/métodos , Percepção Visual/fisiologia , Adulto , Mapeamento Encefálico , Criatividade , Tomada de Decisões , Emoções/fisiologia , Feminino , Lobo Frontal/diagnóstico por imagem , Lobo Frontal/fisiologia , Voluntários Saudáveis , Humanos , Comportamento Impulsivo/fisiologia , Espectroscopia de Luz Próxima ao Infravermelho
15.
Nat Commun ; 11(1): 4856, 2020 09 25.
Artigo em Inglês | MEDLINE | ID: mdl-32978385

RESUMO

In humans and macaque monkeys, socially relevant face processing is accomplished via a distributed functional network that includes specialized patches in frontal cortex. It is unclear whether a similar network exists in New World primates, who diverged ~35 million years from Old World primates. The common marmoset is a New World primate species ideally placed to address this question given their complex social repertoire. Here, we demonstrate the existence of a putative high-level face processing network in marmosets. Like Old World primates, marmosets show differential activation in anterior cingulate and lateral prefrontal cortices while they view socially relevant videos of marmoset faces. We corroborate the locations of these frontal regions by demonstrating functional and structural connectivity between these regions and temporal lobe face patches. Given the evolutionary separation between macaques and marmosets, our results suggest this frontal network specialized for social face processing predates the separation between Platyrrhini and Catarrhini.


Assuntos
Callithrix/fisiologia , Face/fisiologia , Lobo Frontal/fisiologia , Animais , Mapeamento Encefálico , Feminino , Lobo Frontal/diagnóstico por imagem , Giro do Cíngulo , Humanos , Imagem por Ressonância Magnética , Córtex Pré-Frontal/fisiologia , Lobo Temporal
16.
PLoS Comput Biol ; 16(9): e1008198, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32931495

RESUMO

Calcium imaging with fluorescent protein sensors is widely used to record activity in neuronal populations. The transform between neural activity and calcium-related fluorescence involves nonlinearities and low-pass filtering, but the effects of the transformation on analyses of neural populations are not well understood. We compared neuronal spikes and fluorescence in matched neural populations in behaving mice. We report multiple discrepancies between analyses performed on the two types of data, including changes in single-neuron selectivity and population decoding. These were only partially resolved by spike inference algorithms applied to fluorescence. To model the relation between spiking and fluorescence we simultaneously recorded spikes and fluorescence from individual neurons. Using these recordings we developed a model transforming spike trains to synthetic-imaging data. The model recapitulated the differences in analyses. Our analysis highlights challenges in relating electrophysiology and imaging data, and suggests forward modeling as an effective way to understand differences between these data.


Assuntos
Cálcio/metabolismo , Fenômenos Eletrofisiológicos/fisiologia , Modelos Neurológicos , Imagem Molecular/métodos , Neurônios , Potenciais de Ação/fisiologia , Animais , Lobo Frontal/citologia , Lobo Frontal/fisiologia , Camundongos , Neurônios/metabolismo , Neurônios/fisiologia , Imagem Óptica
17.
PLoS Biol ; 18(9): e3000854, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32898172

RESUMO

Working memory is imprecise, and these imprecisions can be explained by the combined influences of random diffusive error and systematic drift toward a set of stable states ("attractors"). However, the neural correlates of diffusion and drift remain unknown. Here, we investigated how delay-period activity in frontal and parietal cortex, which is known to correlate with the decline in behavioral memory precision observed with increasing memory load, might relate to diffusion and drift. We analyzed data from an existing experiment in which subjects performed delayed recall for line orientation, at different loads, during functional magnetic resonance imaging (fMRI) scanning. To quantify the influence of drift and diffusion, we modeled subjects' behavior using a discrete attractor model and calculated within-subject correlation between frontal and parietal delay-period activity and whole-trial estimates of drift and diffusion. We found that although increases in frontal and parietal activity were associated with increases in both diffusion and drift, diffusion explained the most variance in frontal and parietal delay-period activity. In comparison, a subsequent whole-brain regression analysis showed that drift, rather than diffusion, explained the most variance in delay-period activity in lateral occipital cortex. These results are consistent with a model of the differential recruitment of general frontoparietal mechanisms in response to diffusive noise and of stimulus-specific biases in occipital cortex.


Assuntos
Lobo Frontal/fisiologia , Memória de Curto Prazo/fisiologia , Lobo Occipital/fisiologia , Lobo Parietal/fisiologia , Percepção Visual/fisiologia , Adolescente , Adulto , Viés , Mapeamento Encefálico/métodos , Feminino , Lobo Frontal/anatomia & histologia , Lobo Frontal/diagnóstico por imagem , Humanos , Imagem por Ressonância Magnética , Masculino , Rememoração Mental/fisiologia , Lobo Occipital/anatomia & histologia , Lobo Occipital/diagnóstico por imagem , Lobo Parietal/anatomia & histologia , Lobo Parietal/diagnóstico por imagem , Estimulação Luminosa , Razão Sinal-Ruído , Fatores de Tempo , Vias Visuais/anatomia & histologia , Vias Visuais/diagnóstico por imagem , Vias Visuais/fisiologia , Adulto Jovem
18.
Br J Anaesth ; 125(4): 518-528, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32773216

RESUMO

BACKGROUND: Coherent alpha electroencephalogram (EEG) rhythms in the frontal cortex have been correlated with the hypnotic effects of propofol and dexmedetomidine, but less is known about frontal connectivity as a state-specific correlate of unresponsiveness as compared with long-range connectivity. We aimed to distinguish dose- and state-dependent effects of dexmedetomidine and propofol on EEG connectivity. METHODS: Forty-seven healthy males received either dexmedetomidine (n=23) or propofol (n=24) as target-controlled infusion with stepwise increments until loss of responsiveness (LOR). We attempted to arouse participants during constant dosing (return of responsiveness [ROR]), and the target concentration was then increased 50% to achieve presumed loss of consciousness. We collected 64-channel EEG data and prefrontal-frontal and anterior-posterior functional connectivity in the alpha band (8-14 Hz) was measured using coherence and weighted phase lag index (wPLI). Directed connectivity was measured with directed phase lag index (dPLI). RESULTS: Prefrontal-frontal EEG-based connectivity discriminated the states at the different drug concentrations. At ROR, prefrontal-frontal connectivity reversed to the level observed before LOR, indicating that connectivity changes were related to unresponsiveness rather than drug concentration. Unresponsiveness was associated with emergence of frontal-to-prefrontal dominance (dPLI: -0.13 to -0.40) in contrast to baseline (dPLI: 0.01-0.02). Coherence, wPLI, and dPLI had similar capability to discriminate the states that differed in terms of responsiveness and drug concentration. In contrast, anterior-posterior connectivity in the alpha band did not differentiate LOR and ROR. CONCLUSIONS: Local prefrontal-frontal EEG-based connectivity reflects unresponsiveness induced by propofol or dexmedetomidine, suggesting its utility in monitoring the anaesthetised state with these agents. CLINICAL TRIAL REGISTRATION: NCT01889004.


Assuntos
Dexmedetomidina/farmacologia , Eletroencefalografia/efeitos dos fármacos , Propofol/farmacologia , Adulto , Relação Dose-Resposta a Droga , Lobo Frontal/efeitos dos fármacos , Lobo Frontal/fisiologia , Humanos , Masculino , Córtex Pré-Frontal/efeitos dos fármacos , Córtex Pré-Frontal/fisiologia
19.
Proc Natl Acad Sci U S A ; 117(35): 21681-21689, 2020 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-32817555

RESUMO

With the medial frontal cortex (MFC) centrally implicated in several major neuropsychiatric disorders, it is critical to understand the extent to which MFC organization is comparable between humans and animals commonly used in preclinical research (namely rodents and nonhuman primates). Although the cytoarchitectonic structure of the rodent MFC has mostly been conserved in humans, it is a long-standing question whether the structural analogies translate to functional analogies. Here, we probed this question using ultra high field fMRI data to compare rat, marmoset, and human MFC functional connectivity. First, we applied hierarchical clustering to intrinsically define the functional boundaries of the MFC in all three species, independent of cytoarchitectonic definitions. Then, we mapped the functional connectivity "fingerprints" of these regions with a number of different brain areas. Because rats do not share cytoarchitectonically defined regions of the lateral frontal cortex (LFC) with primates, the fingerprinting method also afforded the unique ability to compare the rat MFC and marmoset LFC, which have often been suggested to be functional analogs. The results demonstrated remarkably similar intrinsic functional organization of the MFC across the species, but clear differences between rodent and primate MFC whole-brain connectivity. Rat MFC patterns of connectivity showed greatest similarity with premotor regions in the marmoset, rather than dorsolateral prefrontal regions, which are often suggested to be functionally comparable. These results corroborate the viability of the marmoset as a preclinical model of human MFC dysfunction, and suggest divergence of functional connectivity between rats and primates in both the MFC and LFC.


Assuntos
Vias Neurais/fisiologia , Córtex Pré-Frontal/fisiologia , Animais , Evolução Biológica , Encéfalo/fisiologia , Mapeamento Encefálico/métodos , Callithrix/anatomia & histologia , Conectoma/métodos , Feminino , Lobo Frontal/anatomia & histologia , Lobo Frontal/fisiologia , Substância Cinzenta/fisiologia , Humanos , Imagem por Ressonância Magnética/métodos , Masculino , Vias Neurais/anatomia & histologia , Córtex Pré-Frontal/anatomia & histologia , Ratos , Ratos Wistar
20.
PLoS Comput Biol ; 16(6): e1007862, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32579563

RESUMO

Shared neuronal variability has been shown to modulate cognitive processing. However, the relationship between shared variability and behavioral performance is heterogeneous and complex in frontal areas such as the orbitofrontal cortex (OFC). Mounting evidence shows that single-units in OFC encode a detailed cognitive map of task-space events, but the existence of a robust neuronal ensemble coding for the predictability of choice outcome is less established. Here, we hypothesize that the coding of foreseeable outcomes is potentially unclear from the analysis of units activity and their pairwise correlations. However, this code might be established more conclusively when higher-order neuronal interactions are mapped to the choice outcome. As a case study, we investigated the trial-to-trial shared variability of neuronal ensemble activity during a two-choice interval-discrimination task in rodent OFC, specifically designed such that a lose-switch strategy is optimal by repeating the rewarded stimulus in the upcoming trial. Results show that correlations among triplets are higher during correct choices with respect to incorrect ones, and that this is sustained during the entire trial. This effect is not observed for pairwise nor for higher than third-order correlations. This scenario is compatible with constellations of up to three interacting units assembled during trials in which the task is performed correctly. More interestingly, a state-space spanned by such constellations shows that only correct outcome states that can be successfully predicted are robust over 100 trials of the task, and thus they can be accurately decoded. However, both incorrect and unpredictable outcome representations were unstable and thus non-decodeable, due to spurious negative correlations. Our results suggest that predictability of successful outcomes, and hence the optimal behavioral strategy, can be mapped out in OFC ensemble states reliable over trials of the task, and revealed by sufficiency complex neuronal interactions.


Assuntos
Comportamento de Escolha , Lobo Frontal/fisiologia , Neurônios/fisiologia , Córtex Pré-Frontal/fisiologia , Recompensa , Animais , Teorema de Bayes , Comportamento Animal/fisiologia , Tomada de Decisões , Modelos Lineares , Modelos Estatísticos , Distribuição Normal , Ratos , Ratos Wistar , Reprodutibilidade dos Testes
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