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1.
Neuron ; 109(7): 1074-1076, 2021 04 07.
Artículo en Inglés | MEDLINE | ID: mdl-33831362

RESUMEN

Errors yield unfavorable outcomes but also elicit adaptive mechanisms optimizing future behavior. Norman et al. demonstrate a previously unknown direct projection from medial frontal performance-monitoring areas in mice that modulate visual cortex network activity and enable post-error attentional adaptation.


Asunto(s)
Desempeño Psicomotor , Corteza Visual , Adaptación Fisiológica , Animales , Atención , Humanos , Ratones , Lóbulo Parietal
2.
Nat Commun ; 12(1): 1985, 2021 03 31.
Artículo en Inglés | MEDLINE | ID: mdl-33790275

RESUMEN

Successful pursuit and evasion require rapid and precise coordination of navigation with adaptive motor control. We hypothesize that the dorsal anterior cingulate cortex (dACC), which communicates bidirectionally with both the hippocampal complex and premotor/motor areas, would serve a mapping role in this process. We recorded responses of dACC ensembles in two macaques performing a joystick-controlled continuous pursuit/evasion task. We find that dACC carries two sets of signals, (1) world-centric variables that together form a representation of the position and velocity of all relevant agents (self, prey, and predator) in the virtual world, and (2) avatar-centric variables, i.e. self-prey distance and angle. Both sets of variables are multiplexed within an overlapping set of neurons. Our results suggest that dACC may contribute to pursuit and evasion by computing and continuously updating a multicentric representation of the unfolding task state, and support the hypothesis that it plays a high-level abstract role in the control of behavior.


Asunto(s)
Cognición/fisiología , Giro del Cíngulo/fisiología , Macaca mulatta/fisiología , Neuronas/fisiología , Conducta Predatoria/fisiología , Algoritmos , Animales , Fijación Ocular/fisiología , Giro del Cíngulo/citología , Hipocampo/fisiología , Humanos , Masculino , Modelos Neurológicos , Corteza Motora/fisiología , Desempeño Psicomotor/fisiología , Recompensa
3.
Percept Mot Skills ; 128(3): 1292-1309, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33928825

RESUMEN

While several empirical studies using dual-task methodology have examined the effect of attentional direction on motor skill execution; few have studied the effect of attentional direction on just the preparation phase of motor practice. In this study, via a keying sequence paradigm, we explored processing stages of preparation for a motor skill and disentangled the effect of attentional direction on various stages across practice. First, participants learned two keying sequences (three versus six keys). Then, they practiced the keying sequences in response to corresponding sequence labels under two block-wise alternating dual-task conditions. To dissect the preparation phase into sequence selection and sequence initiation stages, participants received varying amounts of preparation time (0, 300, 900 ms) before a starting signal instructed them to begin sequence execution. In each trial, a tone was paired with one of the three or six keypresses, and participants indicated either the keypress with which the tone was presented (skill-focused dual task) or the tone's pitch (extraneous dual task) after the sequence execution. We found that attentional direction affected only the sequence selection stage, not the sequence initiation stage. During early practice, compared to drawing attention away from execution, directing attention toward execution led to faster sequence selection. This advantage decreased with practice and vanished during late blocks of trials. Moreover, for the execution phase, relative to directing attention toward execution, drawing attention away from execution led to better performance of keying sequence execution across practice. Thus, attentional direction alone does not fully explain the difference between performance patterns at different skill levels in the dual-task literature; rather, types of motor skills and dual task difficulty levels may also drive performance differences.


Asunto(s)
Atención , Destreza Motora , Humanos , Aprendizaje , Desempeño Psicomotor
4.
Acta Psychol (Amst) ; 216: 103298, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33774503

RESUMEN

The present study asks how behavioral (dual-action) demands in dual tasks are mentally represented and whether changes in representation might govern practice-related dual-task performance improvements. Three different representation accounts were empirically tested based on the idea that dual-action demands required in a dual-task trial might be represented in different ways. According to a compositional (Structuralist) account, component tasks remain structurally intact when combined with another task. In contrast, a holistic (Gestalt) account posits that dual-action requirements in dual tasks are represented holistically and entirely distinct from its component action requirements. Finally, a contextual change account assumes that a change in context (e.g., from single- to dual-action requirement) generally impedes response retrieval, similar to repeating a response while the task context switches. To address this issue, we analyzed trial-by-trial effects in a single/dual switch paradigm (SDS paradigm, involving a randomized mix of single- and dual-task trials within blocks). Specifically, we analyzed performance in an extensive dual-task training setting (involving training sessions across several days) combining an auditory-vocal task and a visual-manual task. The results indicated that, throughout practice, nearly all relevant comparisons of performance between complete switch trials (e.g., between the two single tasks) and partial repetition trials (e.g., from dual to single task) revealed partial repetition benefits, that is, for both the auditory-vocal and the visual-manual task, and for both single- and dual-task performance analyses. Therefore, dual-action requirements in the present dual-task setting are mentally represented in a compositional, Structuralist fashion, probably due to low between-task dimensional overlap.


Asunto(s)
Desempeño Psicomotor , Voz , Humanos , Tiempo de Reacción , Análisis y Desempeño de Tareas
5.
Sensors (Basel) ; 21(4)2021 Feb 22.
Artículo en Inglés | MEDLINE | ID: mdl-33671643

RESUMEN

Many survivors of stroke have persistent somatosensory deficits on the contralesional side of their body. Non-invasive supplemental feedback of limb movement could enhance the accuracy and efficiency of actions involving the upper extremity, potentially improving quality of life after stroke. In this proof-of-concept study, we evaluated the feasibility and the immediate effects of providing supplemental kinesthetic feedback to stroke survivors, performing goal-directed actions with the contralesional arm. Three survivors of stroke in the chronic stage of recovery participated in experimental sessions wherein they performed reaching and stabilization tasks with the contralesional arm under different combinations of visual and vibrotactile feedback, which was induced on the ipsilesional arm. Movement kinematics were encoded by a vibrotactile feedback interface in two ways: state feedback-an optimal combination of hand position and velocity; and error feedback-the difference between the actual hand position and its instantaneous target. In each session we evaluated the feedback encoding scheme's immediate objective utility for improving motor performance as well as its perceived usefulness. All three participants improved their stabilization performance using at least one of the feedback encoding schemes within just one experimental session. Two of the participants also improved reaching performance with one or the other of the encoding schemes. Although the observed beneficial effects were modest in each participant, these preliminary findings show that supplemental vibrotactile kinesthetic feedback can be readily interpreted and exploited to improve reaching and object stabilizing actions performed with the contralesional arm after stroke. These short-term training results motivate a longer multisession training study using personalized vibrotactile feedback as a means to improve the accuracy and efficacy of contralesional arm actions after stroke.


Asunto(s)
Retroalimentación , Rehabilitación de Accidente Cerebrovascular , Accidente Cerebrovascular , Femenino , Objetivos , Humanos , Cinestesia , Masculino , Desempeño Psicomotor , Calidad de Vida
6.
Acta Psychol (Amst) ; 215: 103285, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33676068

RESUMEN

Joint actions are omnipresent, ranging from a handshake between two people to the coordination of groups of people playing in an orchestra. We are highly skilled at coordinating our actions with those of others to reach common goals and rely on this ability throughout our daily lives. What are the social, cognitive and neural processes underlying this ability? How do others around us influence our task representations? How does joint action influence interpersonal interactions? How do language and gesture support joint action? What differentiates joint action from individual action? This article forms an introductory editorial to the field of joint action. It accompanies contributions to the special issue entitled "Current Issues in Joint Action Research". The issue brings together conceptual and empirical approaches on different topics, ranging from lower-level issues such as the link between perception and joint action, to higher-level issues such as language as a form of joint action.


Asunto(s)
Relaciones Interpersonales , Desempeño Psicomotor , Humanos , Lenguaje
7.
Acta Psychol (Amst) ; 215: 103273, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33735788

RESUMEN

The learning process of ball juggling is characterized by considerable individual differences in acquired coordination patterns. Previous research has shown that the coordination patterns observed in novice jugglers can be roughly divided into two classes: the high ratio pattern, in which the ball is held for a relatively long time, and the low ratio pattern, in which the ball is held for a relatively short time. To account for these differences in coordination patterns, we examined the anchoring strategies employed by novice jugglers for controlling the juggling movements. Analyses of the correlation between coordination patterns and selected spatiotemporal variabilities revealed that the coordination patterns with a high dwell ratio had lower temporal variability than patterns with a low dwell ratio, which in turn had lower variability of spatial variables than patterns with a high dwell ratio. These findings indicate that individual differences in the coordination patterns adopted by novice jugglers, and hence their learning paths, result from differences in the control strategies employed.


Asunto(s)
Destreza Motora , Desempeño Psicomotor , Humanos , Individualidad , Aprendizaje , Movimiento
8.
Percept Mot Skills ; 128(3): 1252-1274, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33775176

RESUMEN

Piano performance motor learning research requires more "artful" methodologies if it is to meaningfully address music performance as a corporeal art. To date, research has been sparse and it has typically constrained multiple performance variables in order to isolate specific phenomena. This approach has denied the fundamental ethos of music performance which, for elite performers, is an act of interpretation, not mere reproduction. Piano performances are intentionally manipulated for artistic expression. We documented motor movements in the complex task of performance of the first six measures of Chopin's "Revolutionary" Etude by two anthropometrically different elite pianists. We then discussed their motor strategy selections as influenced by anthropometry and the composer's musical directives. To quantify the joint angles of the trunk, shoulders, elbows, and wrists, we used a VICON 3 D motion capture system and biomechanical modeling. A Kistler force plate (1 N, Swiss) quantified center of gravity (COG) shifts. Changes in COG and trunk angles had considerable influence on the distal segments of the upper limbs. The shorter pianist used an anticipatory strategy, employing larger shifts in COG and trunk angles to produce dynamic stability as compensation for a smaller stature. Both pianists took advantage of low inertial left shoulder internal rotation and adduction to accommodate large leaps in the music. For the right arm, motor strategizing was confounded by rests in the music. These two cases illustrated, in principle, that expert pianists' individualized motor behaviors can be explained as compensatory efforts to accommodate both musical goals and anthropometric constraints. Motor learning among piano students can benefit from systematic attention to motor strategies that consider both of these factors.


Asunto(s)
Música , Humanos , Movimiento , Desempeño Psicomotor
9.
J Vis Exp ; (169)2021 03 11.
Artículo en Inglés | MEDLINE | ID: mdl-33779616

RESUMEN

Eighteen stroke patients were recruited for this study involving the evaluation of cognition and walking ability and multitask gait analysis. Multitask gait analysis consisted of a single walking task (Task 0), a simple motor dual-task (water-holding, Task 1), and a complex motor dual-task (crossing obstacles, Task 2). The task of crossing obstacles was considered to be equivalent to the combination of a simple walking task and a complex motor task as it involved more nervous system, skeletal movement, and cognitive resources. To eliminate heterogeneity in the results of the gait analysis of the stroke patients, the dual-task gait cost values were calculated for various kinematic parameters. The major differences were observed in the proximal joint angles, especially in the angles of the trunk, pelvis, and hip joints, which were significantly larger in the dual motor tasks than in the single walking task. This research protocol aims to provide a basis for the clinical diagnosis of gait function and an in-depth study of motor control in stroke patients with motor control deficits through the analyses of dual-motor walking tasks.


Asunto(s)
Marcha , Destreza Motora/fisiología , Rehabilitación de Accidente Cerebrovascular/métodos , Accidente Cerebrovascular/fisiopatología , Caminata , Adulto , Anciano , Fenómenos Biomecánicos , Cognición , Femenino , Análisis de la Marcha , Humanos , Masculino , Persona de Mediana Edad , Movimiento , Desempeño Psicomotor , Accidente Cerebrovascular/psicología
10.
Medicine (Baltimore) ; 100(9): e24656, 2021 Mar 05.
Artículo en Inglés | MEDLINE | ID: mdl-33655929

RESUMEN

INTRODUCTION: To facilitate the command to the learner, therapist can use verbal cues for guidance: internal focus (own body) and external focus (consequence of movement in the environment). OBJECTIVE: To examine the effects of different attentional focus on upper limb motor performance in post-stroke. METHODS: Randomized controlled trial with 2 groups. Study realized at Integrated Clinic of the Faculty of Health Science at Trairi (Santa Cruz, Rio Grande do Norte, Brazil). Twelve participants allocated into 2 groups. Two motor tasks were used: task 1, reach-point; task 2, reach-grasp-fit, with the paretic extremity, using verbal commands directed by a trained therapist. In the first phase, Group 1 received commands with internal focus, while Group 2 was instructed with commands with external focus. After 1 week, the command type was changed between groups. The variables collected was movement time, velocity and number of peaks velocity. RESULTS: Both attentional focus promoted significant differences in movement time and velocity, however, only Internal Focus provided significant results in both tasks of the same variables. DISCUSSION: The benefits of 1 attentional focus on the other are not fully confirmed. However, not receiving any kind of attention guidance compromises motor performance. The results support the hypothesis that the benefits of the External Focus are accentuated when preceded by the Internal Focus. CLINICAL TRIAL REGISTRATION: Research Ethics Committee of the Faculty of Helth Science at Trairi (Facisa - UFRN)- Number CAAE 2.625.609, approved on April 13, 2018; Brazilian Registry of Clinical Trials - RBR-4995cr approved on July 4, 2019 retrospectively registered (http://www.ensaiosclinicos.gov.br/rg/RBR-4995cr/).


Asunto(s)
Atención , Desempeño Psicomotor/fisiología , Rehabilitación de Accidente Cerebrovascular/métodos , Accidente Cerebrovascular/psicología , Extremidad Superior/fisiopatología , Anciano , Brasil , Femenino , Fuerza de la Mano/fisiología , Humanos , Masculino , Persona de Mediana Edad , Movimiento/fisiología , Proyectos Piloto , Accidente Cerebrovascular/fisiopatología
11.
Biol Psychol ; 160: 108030, 2021 03.
Artículo en Inglés | MEDLINE | ID: mdl-33539965

RESUMEN

Task-switching is one of the most popular paradigms to investigate cognitive control. The main finding of interest is the switch cost: RTs in switch trials are longer than RTs in repetition trials. Despite the massive amount of research in these topics, little is known about the underlying temporal dynamics of the cortical regions involved in these phenomena. Here we used high density EEG to unveil the spatiotemporal neural dynamics associated with both the switch cost and to its modulation over time (time-on-task effect), as two markers of cognitive control reflecting effortful and procedural mechanisms, respectively. We found that, as a function of task practice, the switch cost decreased and both the switch-positivity and the switch-negativity event-related responses increased, although the latter showed a larger modulatory effect. At a source level, this effect was revealed by a progressively higher activation of the left middle and superior frontal gyrus.


Asunto(s)
Electroencefalografía , Corteza Prefrontal , Cognición , Humanos , Desempeño Psicomotor , Tiempo de Reacción
12.
Neuron ; 109(7): 1202-1213.e5, 2021 04 07.
Artículo en Inglés | MEDLINE | ID: mdl-33609483

RESUMEN

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.


Asunto(s)
Atención/fisiología , Lóbulo Frontal/fisiología , Reclutamiento Neurofisiológico/fisiología , Animales , Conducta Animal , Electroencefalografía , Fenómenos Electrofisiológicos , Masculino , Ratones , Ratones Endogámicos C57BL , Actividad Motora/fisiología , Vías Nerviosas/fisiología , Neuronas/fisiología , Optogenética , Estimulación Luminosa , Desempeño Psicomotor/fisiología , Tiempo de Reacción/fisiología , Corteza Somatosensorial/fisiología , Corteza Visual/fisiología
13.
Neuron ; 109(7): 1214-1226.e8, 2021 04 07.
Artículo en Inglés | MEDLINE | ID: mdl-33626322

RESUMEN

A prerequisite for intelligent behavior is to understand how stimuli are related and to generalize this knowledge across contexts. Generalization can be challenging when relational patterns are shared across contexts but exist on different physical scales. Here, we studied neural representations in humans and recurrent neural networks performing a magnitude comparison task, for which it was advantageous to generalize concepts of "more" or "less" between contexts. Using multivariate analysis of human brain signals and of neural network hidden unit activity, we observed that both systems developed parallel neural "number lines" for each context. In both model systems, these number state spaces were aligned in a way that explicitly facilitated generalization of relational concepts (more and less). These findings suggest a previously overlooked role for neural normalization in supporting transfer of a simple form of abstract relational knowledge (magnitude) in humans and machine learning systems.


Asunto(s)
Generalización Psicológica/fisiología , Redes Neurales de la Computación , Adulto , Algoritmos , Encéfalo/fisiología , Electroencefalografía , Femenino , Humanos , Aprendizaje Automático , Masculino , Modelos Neurológicos , Desempeño Psicomotor/fisiología , Percepción del Tamaño , Transferencia de Experiencia en Psicología , Adulto Joven
14.
ABCS health sci ; 46: e021401, 09 fev. 2021. tab
Artículo en Inglés | LILACS | ID: biblio-1152238

RESUMEN

INTRODUCTION: Among the communication impairments found in subjects with Autism Spectrum Disorders (ASD), recently the literature has suggested a comorbid relationship with childhood apraxia of speech (CAS). The aim of the present study was to report the CAS assessment of 3 children diagnosed with ASD. REPORT: The subjects were three children aged 4 to 6 years, with a medical diagnosis of ASD. The language development assessment (LDA) was performed in the subjects, as well as the ABFW vocabulary evaluation and oral praxis (verbal, orofacial, a sequence of movements, and parallel movements) and evaluation of vocal, prosodic, and speech characteristics. All subjects had moderate language delay with better performance in the receptive area. Difficulties in oral praxis tasks were more evident in one of the subjects. Vocal, prosodic and speech features of all the cases were compatible with CAS. CONCLUSION: In the 3 cases reported, CAS signs were identified with impaired oral motor skills, prosody, and oral praxis, as well as inconsistent speech sound production.


INTRODUÇÃO: Dentre as dificuldades de comunicação encontradas em casos de Transtornos do Espectro do Autismo (TEA), recentemente a literatura tem apontado uma relação de comorbidade com a apraxia de fala na infância (AFI). O objetivo do presente estudo foi relatar a avaliação de AFI em 3 crianças com diagnóstico de TEA. RELATO: Os sujeitos foram três crianças com idades entre 4 e 6 anos, com diagnóstico médico de TEA. Os sujeitos foram submetidos à avaliação de linguagem, utilizando o teste avaliação de desenvolvimento da linguagem (ADL) e a prova de vocabulário do teste ABFW, avaliação das praxias orais (sonorizadas, orofaciais, sequência de movimentos e movimentos paralelos) e avaliação de características vocais, prosódicas e de fala. Verificou-se que todos os sujeitos apresentaram atraso moderado de linguagem com melhor desempenho em área receptiva. A dificuldade nas tarefas práxicas orais foram mais evidentes em um dos casos estudados. Já as alterações vocais, prosódicas e de fala compatíveis com AFI apareceram em todos os casos relatados. CONCLUSÃO: Nos três casos relatados, foi possível observar sinais de AFI, com prejuízos em habilidades motoras orais, prosódia e praxias orais, assim como inconsistência na produção dos sons da fala.


Asunto(s)
Humanos , Femenino , Preescolar , Niño , Apraxias/diagnóstico , Habla , Trastornos del Habla/diagnóstico , Salud del Niño , Trastorno del Espectro Autista/complicaciones , Trastornos del Desarrollo del Lenguaje/diagnóstico , Desempeño Psicomotor , Destreza Motora
15.
Nat Neurosci ; 24(3): 412-424, 2021 03.
Artículo en Inglés | MEDLINE | ID: mdl-33619403

RESUMEN

Rapid execution of motor sequences is believed to depend on fusing movement elements into cohesive units that are executed holistically. We sought to determine the contribution of primary motor and dorsal premotor cortex to this ability. Monkeys performed highly practiced two-reach sequences, interleaved with matched reaches performed alone or separated by a delay. We partitioned neural population activity into components pertaining to preparation, initiation and execution. The hypothesis that movement elements fuse makes specific predictions regarding all three forms of activity. We observed none of these predicted effects. Rapid two-reach sequences involved the same set of neural events as individual reaches but with preparation for the second reach occurring as the first was in flight. Thus, at the level of dorsal premotor and primary motor cortex, skillfully executing a rapid sequence depends not on fusing elements, but on the ability to perform two key processes at the same time.


Asunto(s)
Corteza Motora/fisiología , Movimiento/fisiología , Desempeño Psicomotor/fisiología , Tiempo de Reacción/fisiología , Animales , Macaca mulatta , Masculino
16.
Neuron ; 109(4): 597-610.e6, 2021 02 17.
Artículo en Inglés | MEDLINE | ID: mdl-33412101

RESUMEN

Decision-making strategies evolve during training and can continue to vary even in well-trained animals. However, studies of sensory decision-making tend to characterize behavior in terms of a fixed psychometric function that is fit only after training is complete. Here, we present PsyTrack, a flexible method for inferring the trajectory of sensory decision-making strategies from choice data. We apply PsyTrack to training data from mice, rats, and human subjects learning to perform auditory and visual decision-making tasks. We show that it successfully captures trial-to-trial fluctuations in the weighting of sensory stimuli, bias, and task-irrelevant covariates such as choice and stimulus history. This analysis reveals dramatic differences in learning across mice and rapid adaptation to changes in task statistics. PsyTrack scales easily to large datasets and offers a powerful tool for quantifying time-varying behavior in a wide variety of animals and tasks.


Asunto(s)
Percepción Auditiva/fisiología , Toma de Decisiones/fisiología , Desempeño Psicomotor/fisiología , Tiempo de Reacción/fisiología , Percepción Visual/fisiología , Estimulación Acústica/métodos , Adulto , Animales , Femenino , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Estimulación Luminosa/métodos , Ratas , Ratas Long-Evans , Adulto Joven
17.
Neuroimage ; 228: 117691, 2021 03.
Artículo en Inglés | MEDLINE | ID: mdl-33385547

RESUMEN

Research on the development of response inhibition in humans has focused almost exclusively on average stopping performance. The development of intra-individual variability in stopping performance and its underlying neural circuitry has remained largely unstudied, even though understanding variability is of core importance for understanding development. In a total sample of 45 participants (19 children aged 10-12 years and 26 adults aged 18-26 years) of either sex we aimed to identify age-related changes in intra-individual response inhibition performance and its underlying brain signal variability. While there was no difference in average stopping performance between children and adults, stop signal latencies for the children were more variable. Further, brain signal variability during successful stopping was significantly higher in adults compared to children, especially in bilateral thalamus, but also across regions of the inhibition network. Finally, brain signal variability was significantly associated with stopping performance behavioral variability in adults. Together these results indicate that variability in stopping performance decreases, whereas neural variability in the inhibition network increases, from childhood to adulthood. Future work will need to assess whether developmental changes in neural variability drive those in behavioral variability. In sum, both, neural and behavioral variability indices might be a more sensitive measure of developmental differences in response inhibition compared to the standard average-based measurements.


Asunto(s)
Envejecimiento/fisiología , Encéfalo/fisiología , Inhibición Psicológica , Adolescente , Adulto , Mapeo Encefálico/métodos , Niño , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador/métodos , Imagen por Resonancia Magnética/métodos , Masculino , Desempeño Psicomotor/fisiología , Tiempo de Reacción/fisiología , Adulto Joven
18.
Neural Netw ; 136: 1-10, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33401114

RESUMEN

In recent years, deep learning has emerged as a powerful tool for developing Brain-Computer Interface (BCI) systems. However, for deep learning models trained entirely on the data from a specific individual, the performance increase has only been marginal owing to the limited availability of subject-specific data. To overcome this, many transfer-based approaches have been proposed, in which deep networks are trained using pre-existing data from other subjects and evaluated on new target subjects. This mode of transfer learning however faces the challenge of substantial inter-subject variability in brain data. Addressing this, in this paper, we propose 5 schemes for adaptation of a deep convolutional neural network (CNN) based electroencephalography (EEG)-BCI system for decoding hand motor imagery (MI). Each scheme fine-tunes an extensively trained, pre-trained model and adapt it to enhance the evaluation performance on a target subject. We report the highest subject-independent performance with an average (N=54) accuracy of 84.19% (±9.98%) for two-class motor imagery, while the best accuracy on this dataset is 74.15% (±15.83%) in the literature. Further, we obtain a statistically significant improvement (p=0.005) in classification using the proposed adaptation schemes compared to the baseline subject-independent model.


Asunto(s)
Interfaces Cerebro-Computador/clasificación , Encéfalo/fisiología , Electroencefalografía/clasificación , Imaginación/fisiología , Redes Neurales de la Computación , Transferencia de Experiencia en Psicología/fisiología , Adulto , Algoritmos , Electroencefalografía/métodos , Femenino , Mano/fisiología , Humanos , Aprendizaje Automático/clasificación , Masculino , Desempeño Psicomotor/fisiología , Adulto Joven
19.
Neurosci Lett ; 744: 135625, 2021 01 23.
Artículo en Inglés | MEDLINE | ID: mdl-33421488

RESUMEN

Previous studies studies indicate that individuals tend to integrate positive information into their self-concept. However, whether such self-positivity bias would still be observed without an explicit self-related cue is unknown. In the present study, 29 participants were asked to evaluate a series of positive and negative trait adjectives, after the participants were presented with their own name or another name subliminally. During the task, their electroencephalograms were recorded. The results showed participants responded faster to positive traits than to negative traits in the self-name cue conditions. In addition, both the latencies and the amplitudes of the N400 showed significant interaction between name-cue and valence in N400 (240-440 ms) amplitudes. The earlier N400 latencies and smaller N400 amplitudes were associated with positive traits in the self-name cue. These results suggested that the self-positivity bias can also be observed in a subliminally presenting self-cue, indicating the robustness of self-positivity bias.


Asunto(s)
Señales (Psicología) , Potenciales Evocados/fisiología , Optimismo/psicología , Desempeño Psicomotor/fisiología , Autoimagen , Adolescente , Adulto , Electroencefalografía/métodos , Femenino , Humanos , Masculino , Estimulación Luminosa/métodos , Adulto Joven
20.
Proc Biol Sci ; 288(1942): 20202556, 2021 01 13.
Artículo en Inglés | MEDLINE | ID: mdl-33434470

RESUMEN

Anterograde interference emerges when two differing tasks are learned in close temporal proximity, an effect repeatedly attributed to a competition between differing task memories. However, recent development alternatively suggests that initial learning may trigger a refractory period that occludes neuroplasticity and impairs subsequent learning, consequently mediating interference independently of memory competition. Accordingly, this study tested the hypothesis that interference can emerge when the same motor task is being learned twice, that is when competition between memories is prevented. In a first experiment, the inter-session interval (ISI) between two identical motor learning sessions was manipulated to be 2 min, 1 h or 24 h. Results revealed that retention of the second session was impaired as compared to the first one when the ISI was 2 min but not when it was 1 h or 24 h, indicating a time-dependent process. Results from a second experiment replicated those of the first one and revealed that adding a third motor learning session with a 2 min ISI further impaired retention, indicating a dose-dependent process. Results from a third experiment revealed that the retention impairments did not take place when a learning session was preceded by simple rehearsal of the motor task without concurrent learning, thus ruling out fatigue and confirming that retention is impaired specifically when preceded by a learning session. Altogether, the present results suggest that competing memories is not the sole mechanism mediating anterograde interference and introduce the possibility that a time- and dose-dependent refractory period-independent of fatigue-also contributes to its emergence. One possibility is that learning transiently perturbs the homeostasis of learning-related neuronal substrates. Introducing additional learning when homeostasis is still perturbed may not only impair performance improvements, but also memory formation.


Asunto(s)
Adaptación Fisiológica , Desempeño Psicomotor , Aprendizaje , Memoria , Destreza Motora
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