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1.
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
2.
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
3.
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
4.
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
5.
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
6.
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
7.
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
8.
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
9.
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
10.
NeuroRehabilitation ; 48(1): 139-148, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33386819

RESUMEN

BACKGROUND: Action observation describes a concept where the subsequent motor behavior of an individual can be modulated though observing an action. This occurs through the activation of neurons in the action observation network, acting on a variety of motor learning processes. This network has been proven highly useful in the rehabilitation of patients with acquired brain injury, placing "action observation" as one of the most effective techniques for motor recovery in physical neurorehabilitation. OBJECTIVE: The aim of this paper is to define an EEG marker for motor learning, guided through observation. METHODS: Healthy subjects (n = 41) participated voluntarily for this research. They were asked to repeat an unknown motor behavior, immediately after observing a video. During the observation, EEG raw signals where collected with a portable EEG and the results were later compared with success and fail on repeating the motor procedure. The comparison was then analyzed with the Mann-Whitney U test for non-parametrical data, with a confidence interval of 95%. RESULTS: A significant relation between motor performance and neural activity was found for Alpha (p = 0,0149) and Gamma (0,0005) oscillatory patterns. CONCLUSION: Gamma oscillations with frequencies between 41 and 49,75 Hz, seem to be an adequate EEG marker for motor performance guided through the action observation network. The technology used for this paper is easy to use, low-cost and presents valid measurements for the recommended oscillatory frequencies, implying a possible use on rehabilitation, by collecting data in real-time during therapeutic interventions and assessments.


Asunto(s)
Encéfalo/fisiología , Ritmo Gamma/fisiología , Conducta Imitativa/fisiología , Red Nerviosa/fisiología , Estimulación Luminosa/métodos , Desempeño Psicomotor/fisiología , Adulto , Electroencefalografía/métodos , Femenino , Predicción , Humanos , Aprendizaje/fisiología , Masculino , Adulto Joven
11.
Neuroimage ; 229: 117752, 2021 04 01.
Artículo en Inglés | MEDLINE | ID: mdl-33460795

RESUMEN

International spread of the coronavirus SARS-CoV-2 has prompted many MRI scanning facilities to require scan subjects to wear a facial covering ("mask") during scanning as a precaution against transmission of the virus. Because wearing a mask mixes expired air with the subject's inspired air stream, the concentration of inspired carbon dioxide [CO2] is elevated, resulting in mild hypercapnia. Changes in the inspired gas mixture have been demonstrated to alter R2*-weighted Blood Oxygen Dependent (BOLD) contrast. In this study, we investigate a potential for face masking to alter BOLD contrast during a sensory-motor task designed to activate visual, auditory, and sensorimotor cortices in 8 subjects. We utilize a nasal cannula to supply air to the subject wearing a surgical mask in on-off blocks of 90s to displace expired CO2, while the subject performs the sensory-motor task. While only a small fraction (2.5%) of the sensory-motor task activation is related to nasal air modulation, a 30.0% change in gray matter BOLD signal baseline is found due to air modulation. Repeating the scan with mask removed produces a small subject-specific bias in BOLD baseline signal from nasal air supply, which may be due to cognitive influence of airflow or cannula-induced hypoxia. Measurements with capnography demonstrate wearing a mask induces an average increase in ETCO2 of 7.4%. Altogether, these results demonstrate that wearing a face mask during gradient-echo fMRI can alter BOLD baseline signal but minimally affects task activation.


Asunto(s)
Dióxido de Carbono/metabolismo , Neuroimagen Funcional , Sustancia Gris/fisiología , Imagen por Resonancia Magnética , Máscaras , Desempeño Psicomotor/fisiología , Corteza Sensoriomotora/fisiología , Adulto , Sustancia Gris/diagnóstico por imagen , Sustancia Gris/metabolismo , Humanos , Corteza Sensoriomotora/diagnóstico por imagen , Corteza Sensoriomotora/metabolismo , Adulto Joven
12.
PLoS One ; 16(1): e0245049, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33411819

RESUMEN

Most research on power assist suits (PASs) that concerned PAS-human interactions has used human physical reactions as criteria to evaluate the mechanical function, however, with minimal emphasis on human reactions in response to PASs. In this study, we focused on the physiological responses of the upper limbs including muscle activity of the biceps brachii and the triceps brachii, co-activation, force steadiness (CV) and rated perceived exertion (RPE) to various patterns of bilateral assistive force, such as unilateral assistance (L0% & R67% [% = percentage of workload force, L = left arm, R = right arm], L67% & R0%, L0% & R33%, L33% & R0%), symmetrical (L0% & R0%, L33% & R33%, L67% & R67%) and asymmetrical bilateral assistance (L33% & R67%, L67% & R33%), during bilateral isometric force-matching tasks. The results showed a similar muscular response of the two arms to bilateral assistive conditions, and the muscle activity of the arm that was being observed decreased only when the assistive force that applied on itself increased, indicating that both arms may have adopted similar but independent motor control mechanisms to acclimate to the bilateral assistive forces. Comparison between the two unilateral assistances (L0% & R33% and L33% & R0%) and the two asymmetrical bilateral assistances (L33% & R67%, L67% & R33%) showed no significant differences in muscular responses, CV and RPE, indicating that bilateral assistances with bilateral interchanged assistive levels may be equally effective regardless of which arm the higher assistive force is applied to. Comparison between unilateral and symmetrical assistive conditions that have similar overall workloads (L67% & R0%, L33% & R33%, L0% & R67%) showed a lower CV and RPE score at symmetrical assistance compared with unilateral assistance, suggesting that assisting both arms with the same level simultaneously improves task performances compared with applying the assistive force to only one arm.


Asunto(s)
Contracción Isométrica/fisiología , Movimiento/fisiología , Desempeño Psicomotor/fisiología , Dispositivos de Autoayuda , Extremidad Superior/fisiología , Adulto , Electromiografía , Humanos , Masculino , Músculo Esquelético/fisiología
13.
PLoS One ; 16(1): e0245184, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33428665

RESUMEN

Reaching with a visuomotor distortion in a virtual environment leads to reach adaptation in the trained hand, and in the untrained hand. In the current study we asked if reach adaptation in the untrained (right) hand is due to transfer of explicit adaptation (EA; strategic changes in reaches) and/or implicit adaptation (IA; unconscious changes in reaches) from the trained (left) hand, and if this transfer changes depending on instructions provided. We further asked if EA and IA are retained in both the trained and untrained hands. Participants (n = 60) were divided into 3 groups (Instructed (provided with instructions on how to counteract the visuomotor distortion), Non-Instructed (no instructions provided), and Control (EA not assessed)). EA and IA were assessed in both the trained and untrained hands immediately following rotated reach training with a 40° visuomotor distortion, and again 24 hours later by having participants reach in the absence of cursor feedback. Participants were to reach (1) so that the cursor landed on the target (EA + IA), and (2) so that their hand landed on the target (IA). Results revealed that, while initial EA observed in the trained hand was greater for the Instructed versus Non-Instructed group, the full extent of EA transferred between hands for both groups and was retained across days. IA observed in the trained hand was greatest in the Non-Instructed group. However, IA did not significantly transfer between hands for any of the three groups. Limited retention of IA was observed in the trained hand. Together, these results suggest that while initial EA and IA in the trained hand are dependent on instructions provided, transfer and retention of visuomotor adaptation to a large visuomotor distortion are driven almost exclusively by EA.


Asunto(s)
Adaptación Fisiológica , Retroalimentación Sensorial/fisiología , Propiocepción/fisiología , Desempeño Psicomotor/fisiología , Percepción Visual/fisiología , Adulto , Femenino , Humanos , Masculino
14.
Neurosci Lett ; 745: 135630, 2021 02 06.
Artículo en Inglés | MEDLINE | ID: mdl-33440234

RESUMEN

Alcohol use disorder (AUD) is a chronic and progressive disease influenced by genetic, psychosocial, and environmental factors. The consequences of alcohol consumption involve alterations in neural circuits of emotion and cognition, as well as in the motor planning circuit. Furthermore, during the natural aging process, several biochemical and functional alterations are also observed with neurological consequences. Thus, considering the consequences of chronic alcohol consumption on neural systems and natural aging process, we aimed to analyze the degree of motor and functional impairment in elderly with chronic alcohol consumption. Sixty elderly underwent an analysis of alcohol consumption profile (Alcohol Use Disorders Identification Test - AUDIT) that divided them into a control group (CON) and an alcohol group (ALC). The analysis of quality of life was performed using the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36), the analysis of motor function was performed using the Borg Scale, the Six-Minute Walk Test (6MWT) and the Motor Scale for Elderly (MSE). We were able to conclude that the misuse of alcohol by the elderly promotes significant physical limitations. These limitations result in a worsening of functional capacity of walking and various dimensions of motor ability: fine motor skill, global coordination, balance, body scheme, spatial organization, temporal organization, and general motor aptitude. Besides the physical limitations caused by alcohol use, the quality of life in their physical, mental, and social aspects was reduced. Thus, actions are required to help the elderly understand these losses and exercise control over alcohol misuse.


Asunto(s)
Consumo de Bebidas Alcohólicas/fisiopatología , Alcoholismo/fisiopatología , Destreza Motora/fisiología , Equilibrio Postural/fisiología , Desempeño Psicomotor/fisiología , Anciano , Anciano de 80 o más Años , Consumo de Bebidas Alcohólicas/psicología , Alcoholismo/diagnóstico , Alcoholismo/psicología , Femenino , Encuestas Epidemiológicas/métodos , Humanos , Masculino , Persona de Mediana Edad , Prueba de Paso/métodos
15.
Neurosci Lett ; 746: 135653, 2021 02 16.
Artículo en Inglés | MEDLINE | ID: mdl-33482311

RESUMEN

Previous studies have reported that real-time functional magnetic resonance imaging (fMRI) neurofeedback using motor imagery can modulate the activity of several motor-related areas. However, the differences in these modulatory effects on distinct motor-related target regions using the same experimental protocol remain unelucidated. This study aimed to compare neurofeedback effects on the primary motor area (M1) and the ventral premotor cortex (PMv). Of the included participants, 15 received blood oxygenation level-dependent (BOLD) signals from their left M1, and the other 15 received signals from their left PMv. Both groups were instructed to try to increase the neurofeedback score (NF-Score), which reflected the averaged activation level of the target region, by executing or imagining a right-hand clenching movement. The result revealed that during imagery condition, the left M1 was deactivated in the PMv-group but not in the M1-group, whereas the left PMv was activated in the PMv-group but not in the M1-group. Our finding indicates that neurofeedback from distinct motor-related regions has different effects on brain activity regulation.


Asunto(s)
Imaginación/fisiología , Imagen por Resonancia Magnética/métodos , Corteza Motora/diagnóstico por imagen , Corteza Motora/fisiología , Neurorretroalimentación/fisiología , Desempeño Psicomotor/fisiología , Adulto , Mapeo Encefálico/métodos , Femenino , Humanos , Masculino , Neurorretroalimentación/métodos , Distribución Aleatoria , Adulto Joven
16.
Neuron ; 109(5): 869-881.e6, 2021 03 03.
Artículo en Inglés | MEDLINE | ID: mdl-33482087

RESUMEN

The subthalamic nucleus (STN) supports action selection by inhibiting all motor programs except the desired one. Recent evidence suggests that STN can also cancel an already selected action when goals change, a key aspect of cognitive control. However, there is little neurophysiological evidence for dissociation between selecting and cancelling actions in the human STN. We recorded single neurons in the STN of humans performing a stop-signal task. Movement-related neurons suppressed their activity during successful stopping, whereas stop-signal neurons activated at low-latencies near the stop-signal reaction time. In contrast, STN and motor-cortical beta-bursting occurred only later in the stopping process. Task-related neuronal properties varied by recording location from dorsolateral movement to ventromedial stop-signal tuning. Therefore, action selection and cancellation coexist in STN but are anatomically segregated. These results show that human ventromedial STN neurons carry fast stop-related signals suitable for implementing cognitive control.


Asunto(s)
Inhibición Psicológica , Movimiento , Neuronas/fisiología , Desempeño Psicomotor/fisiología , Núcleo Subtalámico/fisiología , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Tiempo de Reacción
17.
Neuron ; 109(5): 839-851.e9, 2021 03 03.
Artículo en Inglés | MEDLINE | ID: mdl-33484641

RESUMEN

Learning new rules and adopting novel behavioral policies is a prominent adaptive behavior of primates. We studied the dynamics of single neurons in the dorsal anterior cingulate cortex and putamen of monkeys while they learned new classification tasks every few days over a fixed set of multi-cue patterns. Representing the rules and the neuronal selectivity as vectors in the space spanned by a set of stimulus features allowed us to characterize neuronal dynamics in geometrical terms. We found that neurons in the cingulate cortex mainly rotated toward the rule, implying a policy search, whereas neurons in the putamen showed a magnitude increase that followed the rotation of cortical neurons, implying strengthening of confidence for the newly acquired rule-based policy. Further, the neural representation at the end of a session predicted next-day behavior, reflecting overnight retention. The novel framework for characterization of neural dynamics suggests complementing roles for the putamen and the anterior cingulate cortex.


Asunto(s)
Toma de Decisiones/fisiología , Giro del Cíngulo/fisiología , Aprendizaje/fisiología , Neuronas/fisiología , Putamen/fisiología , Animales , Conducta Animal , Macaca fascicularis , Masculino , Desempeño Psicomotor/fisiología
18.
Neuron ; 109(4): 700-712.e4, 2021 02 17.
Artículo en Inglés | MEDLINE | ID: mdl-33326754

RESUMEN

Primates excel at categorization, a cognitive process for assigning stimuli into behaviorally relevant groups. Categories are encoded in multiple brain areas and tasks, yet it remains unclear how neural encoding and dynamics support cognitive tasks with different demands. We recorded from parietal cortex during flexible switching between categorization tasks with distinct cognitive and motor demands and also studied recurrent neural networks (RNNs) trained on the same tasks. In the one-interval categorization task (OIC), monkeys rapidly reported their decisions with a saccade. In the delayed match-to-category (DMC) task, monkeys decided whether sequentially presented stimuli were categorical matches. Neuronal category encoding generalized across tasks, but categorical encoding was more binary-like in the DMC task and more graded in the OIC task. Furthermore, analysis of trained RNNs supports the hypothesis that binary-like encoding in DMC arises through compression of graded feature encoding by attractor dynamics underlying stimulus maintenance and/or comparison in working memory.


Asunto(s)
Toma de Decisiones/fisiología , Memoria a Corto Plazo/fisiología , Neuronas/fisiología , Lóbulo Parietal/fisiología , Desempeño Psicomotor/fisiología , Animales , Macaca mulatta , Masculino , Estimulación Luminosa/métodos
19.
Neuron ; 109(4): 724-738.e7, 2021 02 17.
Artículo en Inglés | MEDLINE | ID: mdl-33326755

RESUMEN

Humans possess an exceptional aptitude to efficiently make decisions from high-dimensional sensory observations. However, it is unknown how the brain compactly represents the current state of the environment to guide this process. The deep Q-network (DQN) achieves this by capturing highly nonlinear mappings from multivariate inputs to the values of potential actions. We deployed DQN as a model of brain activity and behavior in participants playing three Atari video games during fMRI. Hidden layers of DQN exhibited a striking resemblance to voxel activity in a distributed sensorimotor network, extending throughout the dorsal visual pathway into posterior parietal cortex. Neural state-space representations emerged from nonlinear transformations of the pixel space bridging perception to action and reward. These transformations reshape axes to reflect relevant high-level features and strip away information about task-irrelevant sensory features. Our findings shed light on the neural encoding of task representations for decision-making in real-world situations.


Asunto(s)
Encéfalo/diagnóstico por imagen , Encéfalo/fisiología , Aprendizaje Profundo , Desempeño Psicomotor/fisiología , Refuerzo en Psicología , Juegos de Video , Adulto , Femenino , Humanos , Imagen por Resonancia Magnética/métodos , Masculino , Adulto Joven
20.
Neuron ; 109(4): 677-689.e4, 2021 02 17.
Artículo en Inglés | MEDLINE | ID: mdl-33357383

RESUMEN

Intentional control over external objects is informed by our sensory experience of them. To study how causal relationships are learned and effected, we devised a brain machine interface (BMI) task using wide-field calcium signals. Mice learned to entrain activity patterns in arbitrary pairs of cortical regions to guide a visual cursor to a target location for reward. Brain areas that were normally correlated could be rapidly reconfigured to exert control over the cursor in a sensory-feedback-dependent manner. Higher visual cortex was more engaged when expert but not naive animals controlled the cursor. Individual neurons in higher visual cortex responded more strongly to the cursor when mice controlled it than when they passively viewed it, with the greatest response boosting as the cursor approached the target location. Thus, representations of causally controlled objects are sensitive to intention and proximity to the subject's goal, potentially strengthening sensory feedback to allow more fluent control.


Asunto(s)
Interfaces Cerebro-Computador , Retroalimentación Sensorial/fisiología , Desempeño Psicomotor/fisiología , Recompensa , Corteza Visual/fisiología , Animales , Prueba de Esfuerzo/métodos , Prueba de Esfuerzo/psicología , Femenino , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos
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