Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 98.425
Filtrar
1.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 5232-5235, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33019164

RESUMO

Students, office workers, or other computer and mobile device users can suffer from decrements in alertness or productivity, but many intervention methods on these can be too distracting or even affect daily routines. Using heart rate (HR) to determine a fast and slow target frequency at which to oscillate light brightness stimulation on a laptop, thirty-six participants joined a cognitive task where we hypothesized that fast frequency stimulation would increase alertness and decrease relaxation, while slow frequency stimulation would have the opposite effects. We found that slow frequency stimulation produces a statistically significant delay in response time, users react more slowly (3.8e2 ± 5.5e1 ms), when compared to the no stimulation (3.7e2 ± 4.1e1 ms) (p = 9.0e-3) conditions. The (Slow - No Stimulation) response time (1.7e1 ± 2.7e2 ms) produced a statistically significant delay in response time versus the (Fast - No Stimulation) response time (-0.74 ± 2.4e1 ms) (p = .016). These delays due to slow stimulation occurred without influencing accuracy or subjective sleepiness ratings. We observed that frequency-dependent light stimulation can potentially influence HRV metrics such as the mean normal-to-normal intervals and mean HR. Future work will target breathing rate to determine light stimulation oscillations as we further investigate the potential of using the slow-frequency domain to unobtrusively influence user performance and physiology.


Assuntos
Atenção , Vigília , Frequência Cardíaca , Humanos , Microcomputadores , Tempo de Reação
2.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 5432-5435, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33019209

RESUMO

Early detection of Alzheimer's Disease (AD) is critical in creating better outcomes for patients. Performance in complex tasks such as vehicular driving may be a sensitive tool for early detection of AD and serve as a good indicator of functional status. In this study, we investigate the classification of AD patients and controls using driving simulator data. Our results show that machine learning algorithms, especially random forest classifier, can accurately discriminate AD patients and controls (AUC = 0.96, Sensitivity = 87%, and Specificity = 93%). The model-identified most important features include Pothole Avoidance, Road Signs Recalled, Inattention Measurements, Reaction Time, and Detection Times, among others, all of which closely align with previous studies about cognitive functions that are affected by AD.


Assuntos
Doença de Alzheimer , Condução de Veículo , Doença de Alzheimer/diagnóstico , Cognição , Humanos , Aprendizado de Máquina , Tempo de Reação
3.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 2873-2876, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018606

RESUMO

Recently, rhythmic visual stimulation (RVS) has been demonstrated to affect the brain function by entraining neural oscillations. However, less is known about how RVS influences the functional connectivity across the whole brain. Here, we applied a graph theoretical approach to analyze the electroencephalography (EEG) connections of 60 nodes when subjects deployed their attention on visual task with different background stimulation, i.e. no background flicker, jittered flicker, and RVS of 6, 10, 15 and 40 Hz, respectively. Thirty-three subjects participated in this study. As a result, the 40-Hz rhythm led to the significantly fastest reaction among all conditions. Furthermore, significantly higher clustering coefficient (C) and small worldness (σ) of θ-band brain network were observed for higher-frequency RVS, which were significantly negatively correlated with reaction time (RT) (C-RT: r =-0.917, p =0.010; σ-RT: r =-0.894, p =0.016). In addition, we found an increase in the connections between dorsolateral prefrontal and visual cortices under RVS compared to no flicker. Our results indicate that RVS can improve the efficiency of brain cortical functional network to facilitate attention.


Assuntos
Atenção , Encéfalo , Eletroencefalografia , Humanos , Estimulação Luminosa , Tempo de Reação
4.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 3011-3014, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018639

RESUMO

The estimation of the visual stimulus-based reaction time (RT) using subtle and complex information from the brain signals is still a challenge, as the behavioral response during perceptual decision making varies inordinately across trials. Several investigations have tried to formulate the estimation based on electroencephalogram (EEG) signals. However, these studies are subject-specific and limited to regression-based analysis. In this paper, for the first time to our knowledge, a generalized model is introduced to estimate RT using single-trial EEG features for a simple visual reaction task, considering both regression and classification-based approaches. With the regression-based approach, we could predict RT with a root mean square error of 111.2 ms and a correlation coefficient of 0.74. A binary and a 3-class classifier model were trained, based on the magnitude of RT, for the classification approach. Accuracy of 79% and 72% were achieved for the binary and the 3-class classification, respectively. Limiting our study to only high and low RT groups, the model classified the two groups with an accuracy of 95%. Relevant EEG channels were evaluated to localize the part of the brain significantly responsible for RT estimation, followed by the isolation of important features.Clinical relevance- Electroencephalogram (EEG) signals can be used in Brain-computer interfaces (BCIs), enabling people with neuromuscular disorders like brainstem stroke, amyotrophic lateral sclerosis, and spinal cord injury to communicate with assistive devices. However, advancements regarding EEG signal analysis and interpretation are far from adequate, and this study is a step forward.


Assuntos
Interfaces Cérebro-Computador , Eletroencefalografia , Encéfalo , Humanos , Tempo de Reação , Análise de Regressão
5.
Nat Commun ; 11(1): 4518, 2020 09 09.
Artigo em Inglês | MEDLINE | ID: mdl-32908146

RESUMO

The human brain is specialized for face processing, yet we sometimes perceive illusory faces in objects. It is unknown whether these natural errors of face detection originate from a rapid process based on visual features or from a slower, cognitive re-interpretation. Here we use a multifaceted approach to understand both the spatial distribution and temporal dynamics of illusory face representation in the brain by combining functional magnetic resonance imaging and magnetoencephalography neuroimaging data with model-based analysis. We find that the representation of illusory faces is confined to occipital-temporal face-selective visual cortex. The temporal dynamics reveal a striking evolution in how illusory faces are represented relative to human faces and matched objects. Illusory faces are initially represented more similarly to real faces than matched objects are, but within ~250 ms, the representation transforms, and they become equivalent to ordinary objects. This is consistent with the initial recruitment of a broadly-tuned face detection mechanism which privileges sensitivity over selectivity.


Assuntos
Reconhecimento Facial/fisiologia , Ilusões/fisiologia , Modelos Neurológicos , Lobo Temporal/fisiologia , Córtex Visual/fisiologia , Adolescente , Adulto , Mapeamento Encefálico , Simulação por Computador , Feminino , Humanos , Imagem por Ressonância Magnética , Magnetoencefalografia , Masculino , Neuroimagem , Estimulação Luminosa , Tempo de Reação , Lobo Temporal/diagnóstico por imagem , Córtex Visual/diagnóstico por imagem , Adulto Jovem
6.
PLoS One ; 15(9): e0232808, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32941428

RESUMO

Studies on evoked responses in Parkinson's disease (PD) may be useful for elucidating the etiology and quantitative evaluation of PD. However, in previous studies, the association between evoked responses and detailed motor symptoms or cognitive functions has not been clear. This study investigated the characteristics of the visual (VEF), auditory (AEF), and somatosensory (SEF) evoked magnetic fields in patients with Parkinson's disease (PD), and the correlations between evoked fields and the patient's clinical characteristics, motor symptoms, and cognitive functions. Twenty patients with PD and 10 healthy controls (HCs) were recruited as participants. We recorded VEF, AEF, and SEF, collected clinical characteristics, performed physical examinations, and administered 10 cognitive tests. We investigated differences in the latencies of the evoked fields between patients with PD and HCs. We also evaluated the correlation of the latencies with motor symptoms and cognitive functioning. There were significant differences between the two groups in 6 of the cognitive tests, all of which suggested mild cognitive impairment in patients with PD. The latencies of the VEF N75m, P100m, N145m, AEF P50m, P100m, and SEF P60m components were greater in the patients with PD than in the HCs. The latencies mainly correlated with medication and motor symptoms, less so with cognitive tests, with some elements of the correlations remaining significant after Bonferroni correction. In conclusion, the latencies of the VEF, AEF, and SEF were greater in PD patients than in HCs and were mainly correlated with medication and motor symptoms rather than cognitive functioning. Findings from this study suggest that evoked fields may reflect basal ganglia functioning and are candidates for assessing motor symptoms or the therapeutic effects of medication in patients with PD.


Assuntos
Potenciais Evocados , Campos Magnéticos , Doença de Parkinson/fisiopatologia , Idoso , Cognição , Feminino , Humanos , Magnetoencefalografia , Masculino , Pessoa de Meia-Idade , Movimento , Doença de Parkinson/patologia , Tempo de Reação
7.
PLoS One ; 15(9): e0237663, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32870908

RESUMO

The information available through our senses is noisy, incomplete, and to varying degrees ambiguous. The perceptual system must create stable and reliable percepts out of this restricted information. It solves this perceptual inference problem by integrating memories of previous percepts and making predictions about the perceptual future. Using ambiguous figures and a new experimental approach, we studied whether generating predictions based on regularities in the past affects processing of the present and how this is done. Event-related potentials (ERPs) were measured to investigate whether a highly regular temporal context of either ambiguous or unambiguous stimulus variants differently affects processing of a current stimulus and/or task execution. Further, we tested whether symbolic announcements about the immediate perceptual future can replace the past experience of regularities as a source for making predictions. Both ERP and reaction time varied as a function of stimulus ambiguity in the temporal context of a present stimulus. No such effects were found with symbolic announcements. Our results indicate that predictions about the future automatically alter processing of the present, even if the predictions are irrelevant for the present percept and task. However, direct experiences of past regularities are necessary for predicting the future whereas symbolic information about the future is not sufficient.


Assuntos
Potenciais Evocados Visuais , Memória , Percepção Visual , Adulto , Feminino , Humanos , Masculino , Tempo de Reação , Adulto Jovem
8.
PLoS One ; 15(8): e0238221, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32866181

RESUMO

After perceiving cognitive conflicts or errors, children as well as adults adjust their performance in terms of reaction time slowing on subsequent actions, resulting in the so called post-conflict slowing and post-error slowing, respectively. The development of these phenomena has been studied separately and with different methods yielding inconsistent findings. We aimed to assess the temporal dynamics of these two slowing phenomena within a single behavioral task. To do so, 9-13-year-old children and young adults performed a Simon task in which every fifth trial was incongruent and thus induced cognitive conflict and, frequently, also errors. We compared the reaction times on four trials following a conflict or an error. Both age groups slowed down after conflicts and did so even more strongly after errors. Disproportionally high reaction times on the first post-error trial were followed by a steady flattening of the slowing. Generally, children slowed down more than adults. In addition to highlighting the phenomenal and developmental robustness of post-conflict and post-error slowing these findings strongly suggest increasingly efficient performance adjustment through fine-tuning of cognitive control in the course of development.


Assuntos
Cognição/fisiologia , Desempenho Psicomotor/fisiologia , Adaptação Psicológica/fisiologia , Adolescente , Adulto , Criança , Conflito Psicológico , Eletroencefalografia/métodos , Feminino , Humanos , Masculino , Tempo de Reação/fisiologia , Adulto Jovem
9.
Proc Biol Sci ; 287(1935): 20201884, 2020 09 30.
Artigo em Inglês | MEDLINE | ID: mdl-32962551

RESUMO

Fast saccades are rapid automatic oculomotor responses to salient and ecologically important visual stimuli such as animals and faces. Discriminating the number of friends, foe, or prey may also have an evolutionary advantage. In this study, participants were asked to saccade rapidly towards the more numerous of two arrays. Participants could discriminate numerosities with high accuracy and great speed, as fast as 190 ms. Intermediate numerosities were more likely to elicit fast saccades than very low or very high numerosities. Reaction-times for vocal responses (collected in a separate experiment) were slower, did not depend on numerical range, and correlated only with the slow not the fast saccades, pointing to different systems. The short saccadic reaction-times we observe are surprising given that discrimination using numerosity estimation is thought to require a relatively complex neural circuit, with several relays of information through the parietal and prefrontal cortex. Our results suggest that fast numerosity-driven saccades may be generated on a single feed-forward pass of information recruiting a primitive system that cuts through the cortical hierarchy and rapidly transforms the numerosity information into a saccade command.


Assuntos
Movimentos Sacádicos , Adulto , Animais , Feminino , Humanos , Masculino , Tempo de Reação , Percepção Visual , Adulto Jovem
10.
PLoS One ; 15(9): e0233942, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32937652

RESUMO

Age-related changes in the human brain functioning crucially affect the motor system, causing increased reaction time, low ability to control and execute movements, difficulties in learning new motor skills. The lifestyle and lowered daily activity of elderly adults, along with the deficit of motor and cognitive brain functions, might lead to the developed ambidexterity, i.e., the loss of dominant limb advances. Despite the broad knowledge about the changes in cortical activity directly related to the motor execution, less is known about age-related differences in the motor initiation phase. We hypothesize that the latter strongly influences the behavioral characteristics, such as reaction time, the accuracy of motor performance, etc. Here, we compare the neuronal processes underlying the motor initiation phase preceding fine motor task execution between elderly and young subjects. Based on the results of the whole-scalp sensor-level electroencephalography (EEG) analysis, we demonstrate that the age-related slowing down in the motor initiation before the dominant hand movements is accompanied by the increased theta activation within sensorimotor area and reconfiguration of the theta-band functional connectivity in elderly adults.


Assuntos
Envelhecimento/fisiologia , Cognição/fisiologia , Atividade Motora , Desempenho Psicomotor , Tempo de Reação , Adulto , Idoso , Mapeamento Encefálico , Eletroencefalografia , Feminino , Voluntários Saudáveis , Humanos , Masculino , Pessoa de Meia-Idade , Córtex Sensório-Motor/fisiologia , Ritmo Teta , Adulto Jovem
11.
PLoS One ; 15(9): e0238738, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32915847

RESUMO

The fatigue of truck, bus, and taxi drivers has been a causal trigger for road accidents. However, the relationship between collision risk and the extent of objective fatigue has yet to be confirmed. In this study, we aimed to identify the relationship between autonomic nerve function as an objective parameter of fatigue and the extent of rear-end collision risk, which includes not only objectively risky events but also situations in which truck drivers require safety guidance from safety transport managers. Data of 33 truck driver participants (2 females, 31 males, 46.0 ± 9.1 years old, min-max: 24-65 years old) were analyzed. Drive recorder and automotive sensor data were collected over an eight-month period, and the autonomic nerve function during resting state in drivers was evaluated daily, pre- and post-shift, using pulse waves and electrocardiographic waveform measurement. The rear-end collision risk Index was developed using decision tree analysis of the audiovisual drive recorder data and distance data from the front automotive sensors. The rear-end collision risk index of shift-day was positively correlated with the sympathetic nerve activity index of post-shift condition on the previous day. This suggests that fatigue-related sympathetic nerve overactivity of post-shift condition increases the rear-end collision risk in the following day. Measures, such as actively seeking rest and undertaking fatigue recovery according to the degree of sympathetic nerve activity of post-shift condition, are necessary in order to prevent truck drivers' rear-end collisions.


Assuntos
Acidentes de Trânsito/estatística & dados numéricos , Condução de Veículo/estatística & dados numéricos , Fadiga , Veículos Automotores , Adulto , Idoso , Fadiga/fisiopatologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Tempo de Reação , Risco , Adulto Jovem
12.
PLoS One ; 15(9): e0238292, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32877440

RESUMO

In eyewitness research the frequent use of video playback presented on a computer screen (i.e., 2D videos) in laboratory-based research is problematic due to the low realism of this method when presenting, for example, threatening (and non-threatening) first-person (and third-person) scenarios. However, in contrast to 2D videos, 360-degree videos presented in virtual reality (VR) presents the opportunity of achieving more realistic and immersive scenarios that might be better suited to mimic real-life incidents, as for example, in the case of a threatening first-person robbery. In the present study, we asked 37 participants to watch eight pre-recorded threatening or non-threatening 2D and VR videos, viewed from either a first- or third-person perspective. After each video, participants assessed the observed target's appearance and were then presented with either a target present (TP) or target absent (TA) six-person photograph line-up. We expected that VR would result in higher degrees of accuracy in both TP and TA line-ups compared with 2D and that the differences between manipulations would be more pronounced within VR compared with 2D. We found that TP (but not TA) accuracy was higher in 2D compared with VR videos (91 vs. 66%), that there was no main effect of perspective, and that threatening scenes increased TP (but not TA) accuracy compared to non-threatening scenes (86 vs. 70%). Furthermore, in VR (but not in 2D), threatening scenes increased TP (but not TA) accuracy compared with non-threatening scenes (85 vs. 40%). The results go against the expected increased accuracy in VR (vs. 2D) videos but support the notion that threatening (vs. non-threatening) scenes can increase identification accuracy in VR but not necessarily in 2D.


Assuntos
Emoções/fisiologia , Medo/psicologia , Rememoração Mental/fisiologia , Modelos Psicológicos , Reconhecimento Psicológico , Violência/psicologia , Realidade Virtual , Adulto , Feminino , Humanos , Masculino , Tempo de Reação , Adulto Jovem
13.
PLoS Biol ; 18(8): e3000841, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32833962

RESUMO

The integration of normative and descriptive analyses of decision processes in humans struggles with the fact that measuring preferences by different procedures yields different rankings and that humans appear irrationally impulsive (namely, show maladaptive preference for immediacy). Failure of procedure invariance has led to the widespread hypothesis that preferences are constructed "on the spot" by cognitive evaluations performed at choice time, implying that choices should take extra time in order to perform the necessary comparisons. We examine this issue in experiments with starlings (Sturnus vulgaris) and show that integrating normative and descriptive arguments is possible and may help reinterpreting human decision results. Our main findings are that (1) ranking alternatives through direct rating (response time) accurately predicts preference in choice, overcoming failures of procedure invariance; (2) preference is not constructed at choice time nor does it involve extra time (we show that the opposite is true); and (3) starlings' choices are not irrationally impulsive but are instead directly interpretable in terms of profitability ranking. Like all nonhuman research, our protocols examine decisions by experience rather than by description, and hence support the conjecture that irrationalities that prevail in research with humans may not be observed in decisions by experience protocols.


Assuntos
Comportamento de Escolha/fisiologia , Estorninhos/fisiologia , Animais , Meio Ambiente , Tempo de Reação/fisiologia , Fatores de Tempo
14.
Psychol Aging ; 35(5): 627-638, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32744846

RESUMO

Optimal performance in many tasks requires minimizing the impact of both visual distraction and mind-wandering. Yet, so far, these two types of distraction have been studied in isolation and it remains unclear whether they act in similar or dissociable ways across age groups. Here, we studied the impact of visual distraction and mind-wandering on performance in a go/no-go task in young and older adults. Older adults reported higher task focus than young, which was associated with a specific age-related reduction in mind-wandering, rather than to thoughts triggered by the task. Older adults exhibited fewer no-go errors, higher mean reaction time (RT) and reduced RT variability compared to young adults. In contrast, visual distraction was associated with a disproportionate effect in older versus young adults on go accuracy, mean RT, and RT variability. Decreasing task focus was similarly associated with reduced go- and no-go accuracy and increased RT variability across age groups. In summary, our results suggest that whereas older adults are disproportionately affected by visual distraction compared to young, they exhibit a reduction in mind-wandering frequency. Moreover, the impact of decreasing task focus on task performance is similar across age groups. Our results suggest a dissociation of the impact of visual distraction and mind-wandering as a function of age. (PsycInfo Database Record (c) 2020 APA, all rights reserved).


Assuntos
Atenção/fisiologia , Inibição Psicológica , Análise e Desempenho de Tarefas , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Envelhecimento , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Tempo de Reação , Adulto Jovem
15.
Psychol Aging ; 35(5): 744-764, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32744855

RESUMO

In most attentional-control tasks, incongruent trials (i.e., trials with a conflict between two responses) are intermixed with congruent trials (i.e., trials without conflict). Typically, performance is slower and more error-prone on incongruent trials than on congruent trials. This congruency effect has been found to be smaller after incongruent trials than after congruent trials. This finding-labeled the congruency sequence effect (CSE)-has been assumed to reflect a dynamic adjustment of attentional control, which enables participants to enhance goal-relevant features and to inhibit irrelevant features. Only a few studies have investigated the impact of aging on the CSE, and their results are mixed. Compared to young adults, older adults were found to show a similar CSE, no CSE, a larger CSE, or a smaller CSE. This discrepancy in results has been interpreted as the consequence of using different tasks. To test for this, we conducted new analyses on 9 tasks-the color Stroop, number Stroop, arrow flanker, letter flanker, Simon, global-local, positive compatibility, and negative compatibility task-from our previous study (Rey-Mermet, Gade, & Oberauer, 2018). Both a null-hypothesis significance testing approach and a Bayesian hypothesis testing approach showed a similar CSE in both age groups for most tasks. Only in the Stroop tasks, the CSE was larger for older adults. These results are incompatible with the hypothesis of a general age-related deficit in attentional control. At the same time, they question the construct validity of the CSE. (PsycInfo Database Record (c) 2020 APA, all rights reserved).


Assuntos
Atenção/fisiologia , Tempo de Reação/fisiologia , Adolescente , Adulto , Idoso , Envelhecimento , Feminino , Humanos , Masculino , Adulto Jovem
16.
Proc Biol Sci ; 287(1933): 20201473, 2020 08 26.
Artigo em Inglês | MEDLINE | ID: mdl-32842931

RESUMO

In humans and other mammals, defensive responses to danger vary with threat imminence, but it is unknown how those responses affect decisions to help conspecifics. Here, we manipulated threat imminence to investigate the impact of different defensive states on human helping behaviour. Ninety-eight healthy adult participants made trial-by-trial decisions about whether to help a co-participant avoid an aversive shock, at the risk of receiving a shock themselves. Helping decisions were prompted under imminent or distal threat, based on temporal distance to the moment of shock administration to the co-participant. Results showed that, regardless of how likely participants were to also receive a shock, they helped the co-participant more under imminent than distal threat. Reaction times and cardiac changes during the task supported the efficacy of the threat imminence manipulation in eliciting dissociable defensive states, with faster responses and increased heart rate during imminent compared to distal threats. Individual differences in empathic concern were specifically correlated with helping during imminent threats. These results suggest that defensive states driving active escape from immediate danger may also facilitate decisions to help others, potentially by engaging neurocognitive systems implicated in caregiving across mammals.


Assuntos
Defesa Perceptiva , Ansiedade , Medo , Humanos , Tempo de Reação
17.
Nat Commun ; 11(1): 4007, 2020 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-32782282

RESUMO

Everyday life unfolds continuously, yet we tend to remember past experiences as discrete event sequences or episodes. Although this phenomenon has been well documented, the neuromechanisms that support the transformation of continuous experience into distinct and memorable episodes remain unknown. Here, we show that changes in context, or event boundaries, elicit a burst of autonomic arousal, as indexed by pupil dilation. Event boundaries also lead to the segmentation of adjacent episodes in later memory, evidenced by changes in memory for the temporal duration, order, and perceptual details of recent event sequences. These subjective and objective changes in temporal memory are also related to distinct temporal features of pupil dilations to boundaries as well as to the temporal stability of more prolonged pupil-linked arousal states. Collectively, our findings suggest that pupil measures reflect both stability and change in ongoing mental context representations, which in turn shape the temporal structure of memory.


Assuntos
Nível de Alerta/fisiologia , Memória Episódica , Pupila/fisiologia , Percepção do Tempo/fisiologia , Adulto , Percepção Auditiva/fisiologia , Discriminação Psicológica/fisiologia , Feminino , Humanos , Masculino , Tempo de Reação , Adulto Jovem
18.
Nat Commun ; 11(1): 4014, 2020 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-32782303

RESUMO

Perception reflects not only sensory inputs, but also the endogenous state when these inputs enter the brain. Prior studies show that endogenous neural states influence stimulus processing through non-specific, global mechanisms, such as spontaneous fluctuations of arousal. It is unclear if endogenous activity influences circuit and stimulus-specific processing and behavior as well. Here we use intracranial recordings from 30 pre-surgical epilepsy patients to show that patterns of endogenous activity are related to the strength of trial-by-trial neural tuning in different visual category-selective neural circuits. The same aspects of the endogenous activity that relate to tuning in a particular neural circuit also correlate to behavioral reaction times only for stimuli from the category that circuit is selective for. These results suggest that endogenous activity can modulate neural tuning and influence behavior in a circuit- and stimulus-specific manner, reflecting a potential mechanism by which endogenous neural states facilitate and bias perception.


Assuntos
Rede Nervosa/fisiologia , Córtex Visual/fisiologia , Percepção Visual/fisiologia , Adulto , Eletrocorticografia , Epilepsia/fisiopatologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Modelos Neurológicos , Reconhecimento Visual de Modelos/fisiologia , Estimulação Luminosa , Tempo de Reação/fisiologia
19.
Nat Commun ; 11(1): 4057, 2020 08 13.
Artigo em Inglês | MEDLINE | ID: mdl-32792523

RESUMO

Mammalian cortex has both local and cross-area connections, suggesting vital roles for both local and cross-area neural population dynamics in cortically-dependent tasks, like movement learning. Prior studies of movement learning have focused on how single-area population dynamics change during short-term adaptation. It is unclear how cross-area dynamics contribute to movement learning, particularly long-term learning and skill acquisition. Using simultaneous recordings of rodent motor (M1) and premotor (M2) cortex and computational methods, we show how cross-area activity patterns evolve during reach-to-grasp learning in rats. The emergence of reach-related modulation in cross-area activity correlates with skill acquisition, and single-trial modulation in cross-area activity predicts reaction time and reach duration. Local M2 neural activity precedes local M1 activity, supporting top-down hierarchy between the regions. M2 inactivation preferentially affects cross-area dynamics and behavior, with minimal disruption of local M1 dynamics. Together, these results indicate that cross-area population dynamics are necessary for learned motor skills.


Assuntos
Aprendizagem/fisiologia , Córtex Motor/fisiologia , Animais , Eletrofisiologia , Masculino , Neurofisiologia , Dinâmica Populacional , Ratos , Tempo de Reação/fisiologia
20.
Psychiatr Danub ; 32(2): 210-213, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32796786

RESUMO

The auditory N1 component has been gaining interest as a possible biomarker in schizophrenia (SCZ). N1 to right (RE) and left ear (LE) amplitudes and latencies were assessed using a monoaural auditory oddball paradigm in 12 SCZ subjects and 15 matched healthy controls (M=40.1±8.53 and 39.4±7.73, respectively). T-student test revealed no differences between RE and LE stimulation for N1 amplitude and latency to both groups. However, there were differences in peak-to-peak N1 amplitudes between the two groups for both LE (t=-3.067; ρ=0.003) and RE (t=-2.794; ρ=0.007). These findings strengthen auditory N1 has an electrophysiological biomarker for schizophrenia.


Assuntos
Potenciais Evocados Auditivos , Esquizofrenia , Biomarcadores , Eletroencefalografia , Humanos , Tempo de Reação , Esquizofrenia/diagnóstico
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA