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1.
Cereb Cortex ; 33(21): 10877-10900, 2023 10 14.
Artigo em Inglês | MEDLINE | ID: mdl-37724430

RESUMO

Causal perturbations suggest that primate dorsal pulvinar plays a crucial role in target selection and saccade planning, though its basic neuronal properties remain unclear. Some functional aspects of dorsal pulvinar and interconnected frontoparietal areas-e.g. ipsilesional choice bias after inactivation-are similar. But it is unknown if dorsal pulvinar shares oculomotor properties of cortical circuitry, in particular delay and choice-related activity. We investigated such properties in macaque dorsal pulvinar during instructed and free-choice memory saccades. Most recorded units showed visual (12%), saccade-related (30%), or both types of responses (22%). Visual responses were primarily contralateral; diverse saccade-related responses were predominantly post-saccadic with a weak contralateral bias. Memory delay and pre-saccadic enhancement was infrequent (11-9%)-instead, activity was often suppressed during saccade planning (25%) and further during execution (15%). Surprisingly, only few units exhibited classical visuomotor patterns combining cue and continuous delay activity or pre-saccadic ramping; moreover, most spatially-selective neurons did not encode the upcoming decision during free-choice delay. Thus, in absence of a visible goal, the dorsal pulvinar has a limited role in prospective saccade planning, with patterns partially complementing its frontoparietal partners. Conversely, prevalent visual and post-saccadic responses imply its participation in integrating spatial goals with processing across saccades.


Assuntos
Pulvinar , Movimentos Sacádicos , Animais , Pulvinar/fisiologia , Estudos Prospectivos , Macaca mulatta , Movimentos Oculares
2.
Neuroimage ; 240: 118283, 2021 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-34147628

RESUMO

The thalamic pulvinar and the lateral intraparietal area (LIP) share reciprocal anatomical connections and are part of an extensive cortical and subcortical network involved in spatial attention and oculomotor processing. The goal of this study was to compare the effective connectivity of dorsal pulvinar (dPul) and LIP and to probe the dependency of microstimulation effects on task demands and spatial tuning properties of a given brain region. To this end, we applied unilateral electrical microstimulation in the dPul (mainly medial pulvinar) and LIP in combination with event-related BOLD fMRI in monkeys performing fixation and memory-guided saccade tasks. Microstimulation in both dPul and LIP enhanced task-related activity in monosynaptically-connected fronto-parietal cortex and along the superior temporal sulcus (STS) including putative face patch locations, as well as in extrastriate cortex. LIP microstimulation elicited strong activity in the opposite homotopic LIP while no homotopic activation was found with dPul stimulation. Both dPul and LIP stimulation also elicited activity in several heterotopic cortical areas in the opposite hemisphere, implying polysynaptic propagation of excitation. Despite extensive activation along the intraparietal sulcus evoked by LIP stimulation, there was a difference in frontal and occipital connectivity elicited by posterior and anterior LIP stimulation sites. Comparison of dPul stimulation with the adjacent but functionally dissimilar ventral pulvinar also showed distinct connectivity. On the level of single trial timecourses within each region of interest (ROI), most ROIs did not show task-dependence of stimulation-elicited response modulation. Across ROIs, however, there was an interaction between task and stimulation, and task-specific correlations between the initial spatial selectivity and the magnitude of stimulation effect were observed. Consequently, stimulation-elicited modulation of task-related activity was best fitted by an additive model scaled down by the initial response amplitude. In summary, we identified overlapping and distinct patterns of thalamocortical and corticocortical connectivity of pulvinar and LIP, highlighting the dorsal bank and fundus of STS as a prominent node of shared circuitry. Spatial task-specific and partly polysynaptic modulations of cue and saccade planning delay period activity in both hemispheres exerted by unilateral pulvinar and parietal stimulation provide insight into the distributed interhemispheric processing underlying spatial behavior.


Assuntos
Imageamento por Ressonância Magnética/métodos , Rede Nervosa/fisiologia , Lobo Parietal/fisiologia , Pulvinar/fisiologia , Movimentos Sacádicos/fisiologia , Comportamento Espacial/fisiologia , Animais , Estimulação Elétrica/métodos , Macaca mulatta , Masculino , Microeletrodos , Rede Nervosa/diagnóstico por imagem , Lobo Parietal/diagnóstico por imagem , Pulvinar/diagnóstico por imagem
3.
Neuroimage ; 235: 118017, 2021 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-33794355

RESUMO

Brain perturbation studies allow detailed causal inferences of behavioral and neural processes. Because the combination of brain perturbation methods and neural measurement techniques is inherently challenging, research in humans has predominantly focused on non-invasive, indirect brain perturbations, or neurological lesion studies. Non-human primates have been indispensable as a neurobiological system that is highly similar to humans while simultaneously being more experimentally tractable, allowing visualization of the functional and structural impact of systematic brain perturbation. This review considers the state of the art in non-human primate brain perturbation with a focus on approaches that can be combined with neuroimaging. We consider both non-reversible (lesions) and reversible or temporary perturbations such as electrical, pharmacological, optical, optogenetic, chemogenetic, pathway-selective, and ultrasound based interference methods. Method-specific considerations from the research and development community are offered to facilitate research in this field and support further innovations. We conclude by identifying novel avenues for further research and innovation and by highlighting the clinical translational potential of the methods.


Assuntos
Encéfalo/diagnóstico por imagem , Encéfalo/fisiologia , Neuroimagem/métodos , Animais , Humanos , Optogenética , Primatas
4.
PLoS Comput Biol ; 16(1): e1007588, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31917809

RESUMO

Real-world agents, humans as well as animals, observe each other during interactions and choose their own actions taking the partners' ongoing behaviour into account. Yet, classical game theory assumes that players act either strictly sequentially or strictly simultaneously without knowing each other's current choices. To account for action visibility and provide a more realistic model of interactions under time constraints, we introduce a new game-theoretic setting called transparent games, where each player has a certain probability of observing the partner's choice before deciding on its own action. By means of evolutionary simulations, we demonstrate that even a small probability of seeing the partner's choice before one's own decision substantially changes the evolutionary successful strategies. Action visibility enhances cooperation in an iterated coordination game, but reduces cooperation in a more competitive iterated Prisoner's Dilemma. In both games, "Win-stay, lose-shift" and "Tit-for-tat" strategies are predominant for moderate transparency, while a "Leader-Follower" strategy emerges for high transparency. Our results have implications for studies of human and animal social behaviour, especially for the analysis of dyadic and group interactions.


Assuntos
Tomada de Decisões/fisiologia , Teoria dos Jogos , Relações Interpessoais , Modelos Biológicos , Animais , Comportamento Animal , Biologia Computacional , Comportamento Cooperativo , Humanos
5.
J Neurophysiol ; 123(1): 367-391, 2020 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-31747331

RESUMO

Sensorimotor cortical areas contain eye position information thought to ensure perceptual stability across saccades and underlie spatial transformations supporting goal-directed actions. One pathway by which eye position signals could be relayed to and across cortical areas is via the dorsal pulvinar. Several studies have demonstrated saccade-related activity in the dorsal pulvinar, and we have recently shown that many neurons exhibit postsaccadic spatial preference. In addition, dorsal pulvinar lesions lead to gaze-holding deficits expressed as nystagmus or ipsilesional gaze bias, prompting us to investigate the effects of eye position. We tested three starting eye positions (-15°, 0°, 15°) in monkeys performing a visually cued memory saccade task. We found two main types of gaze dependence. First, ~50% of neurons showed dependence on static gaze direction during initial and postsaccadic fixation, and might be signaling the position of the eyes in the orbit or coding foveal targets in a head/body/world-centered reference frame. The population-derived eye position signal lagged behind the saccade. Second, many neurons showed a combination of eye-centered and gaze-dependent modulation of visual, memory, and saccadic responses to a peripheral target. A small subset showed effects consistent with eye position-dependent gain modulation. Analysis of reference frames across task epochs from visual cue to postsaccadic fixation indicated a transition from predominantly eye-centered encoding to representation of final gaze or foveated locations in nonretinocentric coordinates. These results show that dorsal pulvinar neurons carry information about eye position, which could contribute to steady gaze during postural changes and to reference frame transformations for visually guided eye and limb movements.NEW & NOTEWORTHY Work on the pulvinar focused on eye-centered visuospatial representations, but position of the eyes in the orbit is also an important factor that needs to be taken into account during spatial orienting and goal-directed reaching. We show that dorsal pulvinar neurons are influenced by eye position. Gaze direction modulated ongoing firing during stable fixation, as well as visual and saccade responses to peripheral targets, suggesting involvement of the dorsal pulvinar in spatial coordinate transformations.


Assuntos
Comportamento Animal/fisiologia , Fixação Ocular/fisiologia , Pulvinar/fisiologia , Movimentos Sacádicos/fisiologia , Percepção Visual/fisiologia , Animais , Sinais (Psicologia) , Objetivos , Macaca mulatta , Masculino , Memória/fisiologia
6.
J Neurosci ; 37(8): 2234-2257, 2017 02 22.
Artigo em Inglês | MEDLINE | ID: mdl-28119401

RESUMO

The pulvinar complex is interconnected extensively with brain regions involved in spatial processing and eye movement control. Recent inactivation studies have shown that the dorsal pulvinar (dPul) plays a role in saccade target selection; however, it remains unknown whether it exerts effects on visual processing or at planning/execution stages. We used electrical microstimulation of the dPul while monkeys performed saccade tasks toward instructed and freely chosen targets. Timing of stimulation was varied, starting before, at, or after onset of target(s). Stimulation affected saccade properties and target selection in a time-dependent manner. Stimulation starting before but overlapping with target onset shortened saccadic reaction times (RTs) for ipsiversive (to the stimulation site) target locations, whereas stimulation starting at and after target onset caused systematic delays for both ipsiversive and contraversive locations. Similarly, stimulation starting before the onset of bilateral targets increased ipsiversive target choices, whereas stimulation after target onset increased contraversive choices. Properties of dPul neurons and stimulation effects were consistent with an overall contraversive drive, with varying outcomes contingent upon behavioral demands. RT and choice effects were largely congruent in the visually-guided task, but stimulation during memory-guided saccades, while influencing RTs and errors, did not affect choice behavior. Together, these results show that the dPul plays a primary role in action planning as opposed to visual processing, that it exerts its strongest influence on spatial choices when decision and action are temporally close, and that this choice effect can be dissociated from motor effects on saccade initiation and execution.SIGNIFICANCE STATEMENT Despite a recent surge of interest, the core function of the pulvinar, the largest thalamic complex in primates, remains elusive. This understanding is crucial given the central role of the pulvinar in current theories of integrative brain functions supporting cognition and goal-directed behaviors, but electrophysiological and causal interference studies of dorsal pulvinar (dPul) are rare. Building on our previous studies that pharmacologically suppressed dPul activity for several hours, here we used transient electrical microstimulation at different periods while monkeys performed instructed and choice eye movement tasks, to determine time-specific contributions of pulvinar to saccade generation and decision making. We show that stimulation effects depend on timing and behavioral state and that effects on choices can be dissociated from motor effects.


Assuntos
Tomada de Decisões/fisiologia , Estimulação Elétrica , Movimentos Oculares/fisiologia , Pulvinar/fisiologia , Tempo de Reação/fisiologia , Percepção do Tempo/fisiologia , Animais , Macaca mulatta , Imageamento por Ressonância Magnética , Masculino , Memória , Estimulação Luminosa , Pulvinar/diagnóstico por imagem , Viés de Seleção , Estatísticas não Paramétricas , Fatores de Tempo , Campos Visuais/fisiologia
7.
Neuroimage ; 179: 557-569, 2018 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-29940283

RESUMO

The present study aimed at investigating whether associated motivational salience causes preferential processing of inherently neutral faces similar to emotional expressions by means of event-related brain potentials (ERPs) and changes of the pupil size. To this aim, neutral faces were implicitly associated with monetary outcome, while participants (N = 44) performed a face-matching task with masked primes that ensured performance around chance level and thus an equal proportion of gain, loss, and zero outcomes. During learning, motivational context strongly impacted the processing of the fixation, prime and mask stimuli prior to the target face, indicated by enhanced amplitudes of subsequent ERP components and increased pupil size. In a separate test session, previously associated faces as well as novel faces with emotional expressions were presented within the same task but without motivational context and performance feedback. Most importantly, previously gain-associated faces amplified the LPC, although the individually contingent face-outcome assignments were not made explicit during the learning session. Emotional expressions impacted the N170 and EPN components. Modulations of the pupil size were absent in both motivationally-associated and emotional conditions. Our findings demonstrate that neural representations of neutral stimuli can acquire increased salience via implicit learning, with an advantage for gain over loss associations.


Assuntos
Aprendizagem por Associação/fisiologia , Atenção/fisiologia , Encéfalo/fisiologia , Reconhecimento Facial/fisiologia , Motivação/fisiologia , Adolescente , Adulto , Nível de Alerta/fisiologia , Eletroencefalografia , Potenciais Evocados/fisiologia , Expressão Facial , Feminino , Humanos , Masculino , Estimulação Luminosa , Reflexo Pupilar/fisiologia , Recompensa , Adulto Jovem
8.
J Neurosci ; 35(33): 11719-28, 2015 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-26290248

RESUMO

The posterior parietal cortex (PPC) has traditionally been considered important for awareness, spatial perception, and attention. However, recent findings provide evidence that the PPC also encodes information important for making decisions. These findings have initiated a running argument of whether the PPC is critically involved in decision making. To examine this issue, we reversibly inactivated the parietal reach region (PRR), the area of the PPC that is specialized for reaching movements, while two monkeys performed a memory-guided reaching or saccade task. The task included choices between two equally rewarded targets presented simultaneously in opposite visual fields. Free-choice trials were interleaved with instructed trials, in which a single cue presented in the peripheral visual field defined the reach and saccade target unequivocally. We found that PRR inactivation led to a strong reduction of contralesional choices, but only for reaches. On the other hand, saccade choices were not affected by PRR inactivation. Importantly, reaching and saccade movements to single instructed targets remained largely intact. These results cannot be explained as an effector-nonspecific deficit in spatial attention or awareness, since the temporary "lesion" had an impact only on reach choices. Hence, the PPR is a part of a network for reach decisions and not just reach planning. SIGNIFICANCE STATEMENT: There has been an ongoing debate on whether the posterior parietal cortex (PPC) represents only spatial awareness, perception, and attention or whether it is also involved in decision making for actions. In this study we explore whether the parietal reach region (PRR), the region of the PPC that is specialized for reaches, is involved in the decision process. We inactivated the PRR while two monkeys performed reach and saccade choices between two targets presented simultaneously in both hemifields. We found that inactivation affected only the reach choices, while leaving saccade choices intact. These results cannot be explained as a deficit in attention, since the temporary lesion affected only the reach choices. Thus, PRR is a part of a network for making reach decisions.


Assuntos
Tomada de Decisões/fisiologia , Movimento/fisiologia , Inibição Neural/fisiologia , Lobo Parietal/fisiologia , Movimentos Sacádicos/fisiologia , Percepção Espacial/fisiologia , Animais , Macaca mulatta , Masculino , Recompensa , Campos Visuais/fisiologia
10.
Proc Natl Acad Sci U S A ; 109(21): 8274-9, 2012 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-22562793

RESUMO

Impairments of spatial awareness and decision making occur frequently as a consequence of parietal lesions. Here we used event-related functional MRI (fMRI) in monkeys to investigate rapid reorganization of spatial networks during reversible pharmacological inactivation of the lateral intraparietal area (LIP), which plays a role in the selection of eye movement targets. We measured fMRI activity in control and inactivation sessions while monkeys performed memory saccades to either instructed or autonomously chosen spatial locations. Inactivation caused a reduction of contralesional choices. Inactivation effects on fMRI activity were anatomically and functionally specific and mainly consisted of: (i) activity reduction in the upper bank of the superior temporal sulcus (temporal parietal occipital area) for single contralesional targets, especially in the inactivated hemisphere; and (ii) activity increase accompanying contralesional choices between bilateral targets in several frontal and parieto-temporal areas in both hemispheres. There was no overactivation for ipsilesional targets or choices in the intact hemisphere. Task-specific effects of LIP inactivation on blood oxygen level-dependent activity in the temporal parietal occipital area underline the importance of the superior temporal sulcus for spatial processing. Furthermore, our results agree only partially with the influential interhemispheric competition model of spatial neglect and suggest an additional component of interhemispheric cooperation in the compensation of neglect deficits.


Assuntos
Extinção Psicológica/fisiologia , Memória/fisiologia , Plasticidade Neuronal/fisiologia , Lobo Occipital/fisiologia , Lobo Parietal/fisiologia , Transtornos da Percepção/fisiopatologia , Animais , Modelos Animais de Doenças , Lateralidade Funcional/fisiologia , Agonistas de Receptores de GABA-A/farmacologia , Macaca mulatta , Imageamento por Ressonância Magnética , Masculino , Muscimol/farmacologia , Transtornos da Percepção/induzido quimicamente , Movimentos Sacádicos/fisiologia , Percepção Espacial/fisiologia
11.
Front Psychol ; 15: 1304372, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38638515

RESUMO

When comparing themselves with others, people often evaluate their own behaviors more favorably. This egocentric tendency is often categorized as a bias of attribution, with favorable self-evaluation resulting from differing explanations of one's own behavior and that of others. However, studies on information availability in social contexts offer an alternative explanation, ascribing egocentric biases to the inherent informational asymmetries between performing an action and merely observing it. Since biases of attribution and availability often co-exist and interact with each other, it is not known whether they are both necessary for the egocentric biases to emerge. In this study, we used a design that allowed us to directly compare the contribution of these two distinct sources of bias to judgements about the difficulty of an effortful task. Participants exhibited no attribution bias as judgements made for themselves did not differ from those made for others. Importantly, however, participants perceived the tasks they actively performed to be harder than the tasks they observed, and this bias was magnified as the overall task difficulty increased. These findings suggest that information asymmetries inherent to the difference between actively performing a task and observing it can drive egocentric biases in effort evaluations on their own and without a contribution from biases of attribution.

12.
Sci Rep ; 14(1): 12852, 2024 06 04.
Artigo em Inglês | MEDLINE | ID: mdl-38834578

RESUMO

The dorsal pulvinar has been implicated in visuospatial attentional and perceptual confidence processing. Pulvinar lesions in humans and monkeys lead to spatial neglect symptoms, including an overt spatial saccade bias during free choices. However, it remains unclear whether disrupting the dorsal pulvinar during target selection that relies on a perceptual decision leads to a perceptual impairment or a more general spatial orienting and choice deficit. To address this question, we reversibly inactivated the unilateral dorsal pulvinar by injecting GABA-A agonist THIP while two macaque monkeys performed a color discrimination saccade task with varying perceptual difficulty. We used Signal Detection Theory and simulations to dissociate perceptual sensitivity (d-prime) and spatial selection bias (response criterion) effects. We expected a decrease in d-prime if dorsal pulvinar affects perceptual discrimination and a shift in response criterion if dorsal pulvinar is mainly involved in spatial orienting. After the inactivation, we observed response criterion shifts away from contralesional stimuli, especially when two competing stimuli in opposite hemifields were present. Notably, the d-prime and overall accuracy remained largely unaffected. Our results underline the critical contribution of the dorsal pulvinar to spatial orienting and action selection while showing it to be less important for visual perceptual discrimination.


Assuntos
Pulvinar , Movimentos Sacádicos , Animais , Pulvinar/fisiologia , Movimentos Sacádicos/fisiologia , Masculino , Percepção Espacial/fisiologia , Percepção Visual/fisiologia , Estimulação Luminosa , Macaca mulatta , Atenção/fisiologia
13.
Sci Rep ; 14(1): 5644, 2024 03 07.
Artigo em Inglês | MEDLINE | ID: mdl-38453977

RESUMO

Visual perceptual learning is traditionally thought to arise in visual cortex. However, typical perceptual learning tasks also involve systematic mapping of visual information onto motor actions. Because the motor system contains both effector-specific and effector-unspecific representations, the question arises whether visual perceptual learning is effector-specific itself, or not. Here, we study this question in an orientation discrimination task. Subjects learn to indicate their choices either with joystick movements or with manual reaches. After training, we challenge them to perform the same task with eye movements. We dissect the decision-making process using the drift diffusion model. We find that learning effects on the rate of evidence accumulation depend on effectors, albeit not fully. This suggests that during perceptual learning, visual information is mapped onto effector-specific integrators. Overlap of the populations of neurons encoding motor plans for these effectors may explain partial generalization. Taken together, visual perceptual learning is not limited to visual cortex, but also affects sensorimotor mapping at the interface of visual processing and decision making.


Assuntos
Córtex Visual , Percepção Visual , Humanos , Percepção Visual/fisiologia , Movimentos Oculares , Córtex Visual/fisiologia , Aprendizagem Espacial , Generalização Psicológica
14.
PLoS One ; 19(5): e0301849, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38805512

RESUMO

Spatial accuracy in electrophysiological investigations is paramount, as precise localization and reliable access to specific brain regions help the advancement of our understanding of the brain's complex neural activity. Here, we introduce a novel, multi camera-based, frameless neuronavigation technique for precise, 3-dimensional electrode positioning in awake monkeys. The investigation of neural functions in awake primates often requires stable access to the brain with thin and delicate recording electrodes. This is usually realized by implanting a chronic recording chamber onto the skull of the animal that allows direct access to the dura. Most recording and positioning techniques utilize this implanted recording chamber as a holder of the microdrive or to hold a grid. This in turn reduces the degrees of freedom in positioning. To solve this problem, we require innovative, flexible, but precise tools for neuronal recordings. We instead mount the electrode microdrive above the animal on an arch, equipped with a series of translational and rotational micromanipulators, allowing movements in all axes. Here, the positioning is controlled by infrared cameras tracking the location of the microdrive and the monkey, allowing precise and flexible trajectories. To verify the accuracy of this technique, we created iron deposits in the tissue that could be detected by MRI. Our results demonstrate a remarkable precision with the confirmed physical location of these deposits averaging less than 0.5 mm from their planned position. Pilot electrophysiological recordings additionally demonstrate the accuracy and flexibility of this method. Our innovative approach could significantly enhance the accuracy and flexibility of neural recordings, potentially catalyzing further advancements in neuroscientific research.


Assuntos
Encéfalo , Eletrodos Implantados , Animais , Encéfalo/fisiologia , Neuronavegação/métodos , Neuronavegação/instrumentação , Macaca mulatta , Imageamento Tridimensional/métodos , Imageamento Tridimensional/instrumentação , Masculino , Vigília/fisiologia , Macaca
15.
J Cogn Neurosci ; 25(8): 1270-83, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23574581

RESUMO

The ability to selectively process visual inputs and to decide between multiple movement options in an adaptive manner is critical for survival. Such decisions are known to be influenced by factors such as reward expectation and visual saliency. The dorsal pulvinar connects to a multitude of cortical areas that are involved in visuospatial memory and integrate information about upcoming eye movements with expected reward values. However, it is unclear whether the dorsal pulvinar is critically involved in spatial memory and reward-based oculomotor decision behavior. To examine this, we reversibly inactivated the dorsal portion of the pulvinar while monkeys performed a delayed memory saccade task that included choices between equally or unequally rewarded options. Pulvinar inactivation resulted in a delay of saccade initiation toward memorized contralesional targets but did not affect spatial memory. Furthermore, pulvinar inactivation caused a pronounced choice bias toward the ipsilesional hemifield when the reward value in the two hemifields was equal. However, this choice bias could be alleviated by placing a high reward target into the contralesional hemifield. The bias was less affected by the manipulation of relative visual saliency between the two competing targets. These results suggest that the dorsal pulvinar is involved in determining the behavioral desirability of movement goals while being less critical for spatial memory and reward processing.


Assuntos
Tomada de Decisões/fisiologia , Lateralidade Funcional/fisiologia , Recompensa , Percepção Espacial/fisiologia , Córtex Visual/fisiologia , Analgésicos/farmacologia , Animais , Viés , Sensibilidades de Contraste/efeitos dos fármacos , Sensibilidades de Contraste/fisiologia , Tomada de Decisões/efeitos dos fármacos , Lateralidade Funcional/efeitos dos fármacos , Isoxazóis/farmacologia , Macaca mulatta , Imageamento por Ressonância Magnética , Masculino , Memória/efeitos dos fármacos , Memória/fisiologia , Movimento/efeitos dos fármacos , Vias Neurais/efeitos dos fármacos , Vias Neurais/fisiologia , Tempo de Reação/efeitos dos fármacos , Tempo de Reação/fisiologia , Movimentos Sacádicos/efeitos dos fármacos , Córtex Visual/efeitos dos fármacos
16.
PLoS Biol ; 8(8): e1000444, 2010 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-20689802

RESUMO

For optimal response selection, the consequences associated with behavioral success or failure must be appraised. To determine how monetary consequences influence the neural representations of motor preparation, human brain activity was scanned with fMRI while subjects performed a complex spatial visuomotor task. At the beginning of each trial, reward context cues indicated the potential gain and loss imposed for correct or incorrect trial completion. FMRI-activity in canonical reward structures reflected the expected value related to the context. In contrast, motor preparatory activity in posterior parietal and premotor cortex peaked in high "absolute value" (high gain or loss) conditions: being highest for large gains in subjects who believed they performed well while being highest for large losses in those who believed they performed poorly. These results suggest that the neural activity preceding goal-directed actions incorporates the absolute value of that action, predicated upon subjective, rather than objective, estimates of one's performance.


Assuntos
Atividade Motora/fisiologia , Lobo Parietal/fisiologia , Desempenho Psicomotor/fisiologia , Recompensa , Humanos , Imageamento por Ressonância Magnética , Córtex Motor/fisiologia , Tempo de Reação
17.
Proc Natl Acad Sci U S A ; 107(17): 7933-8, 2010 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-20385808

RESUMO

Contralateral hemispheric representation of sensory inputs (the right visual hemifield in the left hemisphere and vice versa) is a fundamental feature of primate sensorimotor organization, in particular the visuomotor system. However, many higher-order cognitive functions in humans show an asymmetric hemispheric lateralization--e.g., right brain specialization for spatial processing--necessitating a convergence of information from both hemifields. Electrophysiological studies in monkeys and functional imaging in humans have investigated space and action representations at different stages of visuospatial processing, but the transition from contralateral to unified global spatial encoding and the relationship between these encoding schemes and functional lateralization are not fully understood. Moreover, the integration of data across monkeys and humans and elucidation of interspecies homologies is hindered, because divergent findings may reflect actual species differences or arise from discrepancies in techniques and measured signals (electrophysiology vs. imaging). Here, we directly compared spatial cue and memory representations for action planning in monkeys and humans using event-related functional MRI during a working-memory oculomotor task. In monkeys, cue and memory-delay period activity in the frontal, parietal, and temporal regions was strongly contralateral. In putative human functional homologs, the contralaterality was significantly weaker, and the asymmetry between the hemispheres was stronger. These results suggest an inverse relationship between contralaterality and lateralization and elucidate similarities and differences in human and macaque cortical circuits subserving spatial awareness and oculomotor goal-directed actions.


Assuntos
Encéfalo/fisiologia , Lateralidade Funcional/fisiologia , Macaca/fisiologia , Memória/fisiologia , Movimentos Sacádicos/fisiologia , Percepção Espacial/fisiologia , Animais , Sinais (Psicologia) , Imagem Ecoplanar , Humanos , Imageamento por Ressonância Magnética , Oxigênio/sangue , Especificidade da Espécie
18.
Curr Biol ; 33(8): R303-R305, 2023 04 24.
Artigo em Inglês | MEDLINE | ID: mdl-37098332

RESUMO

While we fixate an object, our eyes are never stationary but constantly drifting, with miniature movements traditionally thought to be random and involuntary. A new study shows that the orientation of such drift in humans is actually not random but is influenced by the task demands to improve performance.


Assuntos
Movimento , Visão Ocular , Humanos
19.
Elife ; 122023 01 12.
Artigo em Inglês | MEDLINE | ID: mdl-36633125

RESUMO

Many real-world decisions in social contexts are made while observing a partner's actions. To study dynamic interactions during such decisions, we developed a setup where two agents seated face-to-face to engage in game-theoretical tasks on a shared transparent touchscreen display ('transparent games'). We compared human and macaque pairs in a transparent version of the coordination game 'Bach-or-Stravinsky', which entails a conflict about which of two individually-preferred opposing options to choose to achieve coordination. Most human pairs developed coordinated behavior and adopted dynamic turn-taking to equalize the payoffs. All macaque pairs converged on simpler, static coordination. Remarkably, two animals learned to coordinate dynamically after training with a human confederate. This pair selected the faster agent's preferred option, exhibiting turn-taking behavior that was captured by modeling the visibility of the partner's action before one's own movement. Such competitive turn-taking was unlike the prosocial turn-taking in humans, who equally often initiated switches to and from their preferred option. Thus, the dynamic coordination is not restricted to humans but can occur on the background of different social attitudes and cognitive capacities in rhesus monkeys. Overall, our results illustrate how action visibility promotes the emergence and maintenance of coordination when agents can observe and time their mutual actions.


To live with others is to make concessions. You may want to go to the movies tonight, but your partner may prefer the theatre: reaching a mutually desirable goal ­ that is, spending time together ­ requires adjusting your preferences to theirs. Many other social species also make such decisions, in particular monkeys that live in large groups. Conceptually, these interactions are known as coordination games. In such scenarios, two players must coordinate their actions to attain a coveted reward, but they must also resolve a conflict about who gets the larger share. This makes the joint strategy non-trivial, and different pairs of players might resort to different strategies. In the laboratory, coordination games are often tested in settings which do not allow participants to monitor each other's behaviors as they make these complex choices. In real life, however, individuals making a joint decision can often observe each other and receive immediate feedback. In response, Moeller et al. developed a new way to test coordination games that allows more realistic social interactions. In their setup, two participants face each other and use a shared see-through touchscreen to perform a task. This new design was used to test how humans and macaque monkeys solved a simplified version of the 'Bach or Stravinsky' coordination game, which involves choosing between a red and blue target on the screen. Players in a pair had been trained to 'prefer' opposite colors. In this game, collaboration is beneficial (both individuals get a better prize if they choose the same color) but also creates unfairness (the reward is higher for the participant whose 'favorite' color is selected). When paired up, both humans and monkeys learned to collaborate and to go for the same color (or, in some monkey pairs, the same side of the screen). However, only humans took turns selecting red or blue so that players could alternate getting the highest reward. Monkeys usually settled on one color throughout the game, unless they had learned the 'turn-taking' strategy from a human partner; in that case, the color chosen in each trial was typically determined by the monkey who was the faster to move. These experiments show how monkeys and humans use visual information about their partner's actions to coordinate their choices, paving the way for further decision-making studies that accurately reflect how interactions unfold in real life. Moeller et al. expect that this will help to understand how cooperation and competition emerge in these two species, including how direct face-to-face contact, or lack thereof in some aspects of our modern world, shapes our social behavior.


Assuntos
Comportamento Cooperativo , Comportamento Social , Animais , Humanos , Meio Social , Macaca mulatta , Aprendizagem
20.
J Neurosci ; 30(35): 11715-25, 2010 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-20810892

RESUMO

In this time-resolved functional magnetic resonance imaging (fMRI) study, we aimed to trace the neuronal correlates of covert planning processes that precede visually guided motor behavior. Specifically, we asked whether human posterior parietal cortex has prospective planning activity that can be distinguished from activity related to retrospective visual memory and attention. Although various electrophysiological studies in monkeys have demonstrated such motor planning at the level of parietal neurons, comparatively little support is provided by recent human imaging experiments. Rather, a majority of experiments highlights a role of human posterior parietal cortex in visual working memory and attention. We thus sought to establish a clear separation of visual memory and attention from processes related to the planning of goal-directed motor behaviors. To this end, we compared delayed-response tasks with identical mnemonic and attentional demands but varying degrees of motor planning. Subjects memorized multiple target locations, and in a random subset of trials targets additionally instructed (1) desired goals or (2) undesired goals for upcoming finger reaches. Compared with the memory/attention-only conditions, both latter situations led to a specific increase of preparatory fMRI activity in posterior parietal and dorsal premotor cortex. Thus, posterior parietal cortex has prospective plans for upcoming behaviors while considering both types of targets relevant for action: those to be acquired and those to be avoided.


Assuntos
Atenção/fisiologia , Aprendizagem da Esquiva/fisiologia , Movimento/fisiologia , Lobo Parietal/fisiologia , Desempenho Psicomotor/fisiologia , Tempo de Reação/fisiologia , Feminino , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Estimulação Luminosa/métodos
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