Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 7.691
Filtrar
1.
J Neurosci ; 41(4): 757-765, 2021 01 27.
Artigo em Inglês | MEDLINE | ID: mdl-33380471

RESUMO

Our ability to compare sensory stimuli is a fundamental cognitive function, which is known to be affected by two biases: choice bias, which reflects a preference for a given response, and contraction bias, which reflects a tendency to perceive stimuli as similar to previous ones. To test whether both reflect supervised processes, we designed feedback protocols aimed to modify them and tested them in human participants. Choice bias was readily modifiable. However, contraction bias was not. To compare these results to those predicted from an optimal supervised process, we studied a noise-matched optimal linear discriminator (Perceptron). In this model, both biases were substantially modified, indicating that the "resilience" of contraction bias to feedback does not maximize performance. These results suggest that perceptual discrimination is a hierarchical, two-stage process. In the first, stimulus statistics are learned and integrated with representations in an unsupervised process that is impenetrable to external feedback. In the second, a binary judgment, learned in a supervised way, is applied to the combined percept.SIGNIFICANCE STATEMENT The seemingly effortless process of inferring physical reality from the sensory input is highly influenced by previous knowledge, leading to perceptual biases. Two common ones are contraction bias (the tendency to perceive stimuli as similar to previous ones) and choice bias (the tendency to prefer a specific response). Combining human psychophysical experiments with computational modeling we show that they reflect two different learning processes. Contraction bias reflects unsupervised learning of stimuli statistics, whereas choice bias results from supervised or reinforcement learning. This dissociation reveals a hierarchical, two-stage process. The first, where stimuli statistics are learned and integrated with representations, is unsupervised. The second, where a binary judgment is applied to the combined percept, is learned in a supervised way.


Assuntos
Discriminação Psicológica/fisiologia , Julgamento/fisiologia , Aprendizagem/fisiologia , Percepção/fisiologia , Adulto , Algoritmos , Teorema de Bayes , Comportamento de Escolha/fisiologia , Retroalimentação Psicológica , Feminino , Humanos , Masculino , Redes Neurais de Computação , Desempenho Psicomotor/fisiologia
2.
Nature ; 585(7824): 245-250, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32884146

RESUMO

Adaptive behaviour crucially depends on flexible decision-making, which in mammals relies on the frontal cortex, specifically the orbitofrontal cortex (OFC)1-9. How OFC encodes decision variables and instructs sensory areas to guide adaptive behaviour are key open questions. Here we developed a reversal learning task for head-fixed mice, monitored the activity of neurons of the lateral OFC using two-photon calcium imaging and investigated how OFC dynamically interacts with primary somatosensory cortex (S1). Mice learned to discriminate 'go' from 'no-go' tactile stimuli10,11 and adapt their behaviour upon reversal of stimulus-reward contingency ('rule switch'). Imaging individual neurons longitudinally across all behavioural phases revealed a distinct engagement of S1 and lateral OFC, with S1 neural activity reflecting initial task learning, whereas lateral OFC neurons responded saliently and transiently to the rule switch. We identified direct long-range projections from lateral OFC to S1 that can feed this activity back to S1 as value prediction error. This top-down signal updated sensory representations in S1 by functionally remapping responses in a subpopulation of neurons that was sensitive to reward history. Functional remapping crucially depended on top-down feedback as chemogenetic silencing of lateral OFC neurons disrupted reversal learning, as well as plasticity in S1. The dynamic interaction of lateral OFC with sensory cortex thus implements computations critical for value prediction that are history dependent and error based, providing plasticity essential for flexible decision-making.


Assuntos
Plasticidade Neuronal/fisiologia , Córtex Pré-Frontal/citologia , Córtex Pré-Frontal/fisiologia , Reversão de Aprendizagem/fisiologia , Córtex Somatossensorial/citologia , Córtex Somatossensorial/fisiologia , Percepção do Tato/fisiologia , Adaptação Psicológica , Animais , Mapeamento Encefálico , Sinalização do Cálcio , Tomada de Decisões/fisiologia , Discriminação Psicológica/fisiologia , Masculino , Camundongos , Estimulação Física , Células Receptoras Sensoriais/metabolismo
3.
Nat Commun ; 11(1): 4007, 2020 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-32782282

RESUMO

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


Assuntos
Nível de Alerta/fisiologia , Memória Episódica , Pupila/fisiologia , Percepção do Tempo/fisiologia , Adulto , Percepção Auditiva/fisiologia , Discriminação Psicológica/fisiologia , Feminino , Humanos , Masculino , Tempo de Reação , Adulto Jovem
4.
Nat Commun ; 11(1): 2675, 2020 05 29.
Artigo em Inglês | MEDLINE | ID: mdl-32472088

RESUMO

Abnormal sensory processing has been observed in autism, including superior visual motion discrimination, but the neural basis for these sensory changes remains unknown. Leveraging well-characterized suppressive neural circuits in the visual system, we used behavioral and fMRI tasks to demonstrate a significant reduction in neural suppression in young adults with autism spectrum disorder (ASD) compared to neurotypical controls. MR spectroscopy measurements revealed no group differences in neurotransmitter signals. We show how a computational model that incorporates divisive normalization, as well as narrower top-down gain (that could result, for example, from a narrower window of attention), can explain our observations and divergent previous findings. Thus, weaker neural suppression is reflected in visual task performance and fMRI measures in ASD, and may be attributable to differences in top-down processing.


Assuntos
Transtorno Autístico/patologia , Percepção de Movimento/fisiologia , Acuidade Visual/fisiologia , Adolescente , Adulto , Atenção/fisiologia , Mapeamento Encefálico , Cognição/fisiologia , Simulação por Computador , Discriminação Psicológica/fisiologia , Feminino , Humanos , Imagem por Ressonância Magnética , Masculino , Células Receptoras Sensoriais/fisiologia , Adulto Jovem
5.
Sci Rep ; 10(1): 7872, 2020 05 12.
Artigo em Inglês | MEDLINE | ID: mdl-32398687

RESUMO

The ability to move towards or away from a light source, namely phototaxis, is essential for a number of species to find the right environmental niche and may have driven the appearance of simple visual systems. In this study we ask if the later evolution of more complex visual systems was accompanied by a sophistication of phototactic behaviour. The honey bee is an ideal model organism to tackle this question, as it has an elaborate visual system, demonstrates exquisite abilities for visual learning and performs phototaxis. Our data suggest that in this insect, phototaxis has wavelength specific properties and is a highly dynamical response including multiple decision steps. In addition, we show that previous experience with a light (through exposure or classical aversive conditioning) modulates the phototactic response. This plasticity is dependent on the wavelength used, with blue being more labile than green or ultraviolet. Wavelength, intensity and past experience are integrated into an overall valence for each light that determines phototactic behaviour in honey bees. Thus, our results support the idea that complex visual systems allow sophisticated phototaxis. Future studies could take advantage of these findings to better understand the neuronal circuits underlying this processing of the visual information.


Assuntos
Abelhas/fisiologia , Percepção de Cores/fisiologia , Visão de Cores/fisiologia , Fototaxia/fisiologia , Percepção Visual/fisiologia , Animais , Aprendizagem por Associação/fisiologia , Visão de Cores/efeitos da radiação , Condicionamento Psicológico/fisiologia , Discriminação Psicológica/fisiologia , Discriminação Psicológica/efeitos da radiação , Luz , Estimulação Luminosa , Células Fotorreceptoras de Invertebrados/fisiologia , Fototaxia/efeitos da radiação
6.
J Neurosci ; 40(24): 4750-4760, 2020 06 10.
Artigo em Inglês | MEDLINE | ID: mdl-32381486

RESUMO

Fear is adaptive when the level of the response rapidly scales to degree of threat. Using a discrimination procedure consisting of danger, uncertainty, and safety cues, we have found rapid fear scaling (within 2 s of cue presentation) in male rats. Here, we examined a possible role for the nucleus accumbens core (NAcc) in the acquisition and expression of fear scaling. In experiment 1, male Long-Evans rats received bilateral sham or neurotoxic NAcc lesions, recovered, and underwent fear discrimination. NAcc-lesioned rats were generally impaired in scaling fear to degree of threat, and specifically impaired in rapid uncertainty-safety discrimination. In experiment 2, male Long-Evans rats received NAcc transduction with halorhodopsin (Halo) or a control fluorophore. After fear scaling was established, the NAcc was illuminated during cue or control periods. NAcc-Halo rats receiving cue illumination were specifically impaired in rapid uncertainty-safety discrimination. The results reveal a general role for the NAcc in scaling fear to degree of threat, and a specific role in rapid discrimination of uncertain threat and safety.SIGNIFICANCE STATEMENT Rapidly discriminating cues for threat and safety is essential for survival and impaired threat-safety discrimination is a hallmark of stress and anxiety disorders. In two experiments, we induced nucleus accumbens core (NAcc) dysfunction in rats receiving fear discrimination consisting of cues for danger, uncertainty, and safety. Permanent NAcc dysfunction, via neurotoxic lesion, generally disrupted the ability to scale fear to degree of threat, and specifically impaired one component of scaling: rapid discrimination of uncertain threat and safety. Reversible NAcc dysfunction, via optogenetic inhibition, specifically impaired rapid discrimination of uncertain threat and safety. The results reveal that the NAcc is essential to scale fear to degree of threat, and is a plausible source of dysfunction in stress and anxiety disorders.


Assuntos
Discriminação Psicológica/fisiologia , Medo/fisiologia , Núcleo Accumbens/fisiologia , Animais , Condicionamento Clássico/fisiologia , Masculino , Optogenética , Ratos , Ratos Long-Evans
7.
J Neurosci ; 40(27): 5228-5246, 2020 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-32444386

RESUMO

Humans and animals maintain accurate sound discrimination in the presence of loud sources of background noise. It is commonly assumed that this ability relies on the robustness of auditory cortex responses. However, only a few attempts have been made to characterize neural discrimination of communication sounds masked by noise at each stage of the auditory system and to quantify the noise effects on the neuronal discrimination in terms of alterations in amplitude modulations. Here, we measured neural discrimination between communication sounds masked by a vocalization-shaped stationary noise from multiunit responses recorded in the cochlear nucleus, inferior colliculus, auditory thalamus, and primary and secondary auditory cortex at several signal-to-noise ratios (SNRs) in anesthetized male or female guinea pigs. Masking noise decreased sound discrimination of neuronal populations in each auditory structure, but collicular and thalamic populations showed better performance than cortical populations at each SNR. In contrast, in each auditory structure, discrimination by neuronal populations was slightly decreased when tone-vocoded vocalizations were tested. These results shed new light on the specific contributions of subcortical structures to robust sound encoding, and suggest that the distortion of slow amplitude modulation cues conveyed by communication sounds is one of the factors constraining the neuronal discrimination in subcortical and cortical levels.SIGNIFICANCE STATEMENT Dissecting how auditory neurons discriminate communication sounds in noise is a major goal in auditory neuroscience. Robust sound coding in noise is often viewed as a specific property of cortical networks, although this remains to be demonstrated. Here, we tested the discrimination performance of neuronal populations at five levels of the auditory system in response to conspecific vocalizations masked by noise. In each acoustic condition, subcortical neurons better discriminated target vocalizations than cortical ones and in each structure, the reduction in discrimination performance was related to the reduction in slow amplitude modulation cues.


Assuntos
Comunicação Animal , Percepção Auditiva/fisiologia , Discriminação Psicológica/fisiologia , Ruído , Vocalização Animal/fisiologia , Estimulação Acústica , Algoritmos , Animais , Córtex Auditivo/citologia , Córtex Auditivo/fisiologia , Feminino , Cobaias , Masculino , Mascaramento Perceptivo , Razão Sinal-Ruído , Colículos Superiores/citologia , Colículos Superiores/fisiologia , Tálamo/citologia , Tálamo/fisiologia
8.
Nat Commun ; 11(1): 1687, 2020 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-32245941

RESUMO

Crowding is a profound loss of discriminability of visual features, when a target stimulus is surrounded by distractors. Numerous studies of human perception have characterized how crowding depends on the properties of a visual display. Yet, there is limited understanding of how and where stimulus information is lost in the visual system under crowding. Here, we show that macaque monkeys exhibit perceptual crowding for target orientation that is similar to humans. We then record from neuronal populations in monkey primary visual cortex (V1). These populations show an appreciable loss of information about target orientation in the presence of distractors, due both to divisive and additive modulation of responses to targets by distractors. Our results show that spatial contextual effects in V1 limit the discriminability of visual features and can contribute substantively to crowding.


Assuntos
Aglomeração/psicologia , Discriminação Psicológica/fisiologia , Orientação Espacial/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Córtex Visual/fisiologia , Potenciais de Ação/fisiologia , Adulto , Animais , Eletrodos Implantados , Humanos , Macaca fascicularis , Masculino , Pessoa de Meia-Idade , Estimulação Luminosa , Psicometria , Técnicas Estereotáxicas/instrumentação
9.
Sci Rep ; 10(1): 6572, 2020 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-32313001

RESUMO

Visual perception can be influenced by stimulus context, selective attention, and prior experience. Many previous studies have shown complex interactions among these influencing factors, but it remains unclear whether context-induced illusions could be reduced by perceptual training and whether such a change in perceptual fidelity is linked to improved perceptual discriminability. To address this question, we introduced a context-induced tilt illusion into an orientation discrimination training paradigm. This resulted in parallel and long-term improvements in the discriminability and fidelity of orientation perception. The improved discriminability was specific to the task-relevant target stimulus but nonspecific to the task-irrelevant context. By contrast, the improved perceptual fidelity was specific to the task-irrelevant contextual stimulus that induced the illusion, but not specific to the task-relevant target stimulus or task performed on one of its features. These results indicate two dissociable learning effects associated with the same training procedure. Such a dissociation was further supported by the observation that the sizes of the two learning effects were uncorrelated across the subjects. Our findings suggest two parallel learning processes: a task-dependent process giving rise to enhanced discriminability for the task-relevant stimulus attribute, and a context-dependent process leading to improved perceptual fidelity for the attended stimuli.


Assuntos
Atenção/fisiologia , Orientação Espacial/fisiologia , Comportamento Espacial/fisiologia , Percepção Visual/fisiologia , Discriminação Psicológica/fisiologia , Feminino , Humanos , Ilusões/fisiologia , Aprendizagem , Masculino , Estimulação Luminosa , Visão Ocular/fisiologia
10.
Sci Rep ; 10(1): 6528, 2020 04 16.
Artigo em Inglês | MEDLINE | ID: mdl-32300187

RESUMO

Somatosensory processing can be probed empirically through vibrotactile psychophysical experiments. Psychophysical approaches are valuable for investigating both normal and abnormal tactile function in healthy and clinical populations. To date, the test-retest reliability of vibrotactile detection and discrimination thresholds has yet to be established. This study sought to assess the reproducibility of vibrotactile detection and discrimination thresholds in human adults using an established vibrotactile psychophysical battery. Fifteen healthy adults underwent three repeat sessions of an eleven-task battery that measured a range of vibrotactile measures, including reaction time, detection threshold, amplitude and frequency discrimination, and temporal order judgement. Coefficients of variation and intraclass correlation coefficients (ICCs) were calculated for the measures in each task. Linear mixed-effects models were used to test for length and training effects and differences between tasks within the same domain. Reaction times were shown to be the most reproducible (ICC: ~0.9) followed by detection thresholds (ICC: ~0.7). Frequency discrimination thresholds were the least reproducible (ICC: ~0.3). As reported in prior studies, significant differences in measures between related tasks were also found, demonstrating the reproducibility of task-related effects. These findings show that vibrotactile detection and discrimination thresholds are reliable, further supporting the use of psychophysical experiments to probe tactile function.


Assuntos
Discriminação Psicológica/fisiologia , Córtex Somatossensorial/fisiologia , Percepção do Tato/fisiologia , Tato/fisiologia , Adolescente , Adulto , Feminino , Humanos , Masculino , Estimulação Física , Psicofísica/tendências , Tempo de Reação/fisiologia , Limiar Sensorial/fisiologia , Vibração , Adulto Jovem
11.
J Neurosci ; 40(19): 3751-3767, 2020 05 06.
Artigo em Inglês | MEDLINE | ID: mdl-32273483

RESUMO

Behavior can be guided by neuronal activity in visual, auditory, or somatosensory cerebral cortex, depending on task requirements. In contrast to this flexible access of cortical signals, several observations suggest that behaviors depend more on neurons in later areas of visual cortex than those in earlier areas, although neurons in earlier areas would provide more reliable signals for many tasks. We recorded from neurons in different levels of visual cortex of 2 male rhesus monkeys while the animals did a visual discrimination task and examined trial-to-trial correlations between neuronal and behavioral responses. These correlations became stronger in primary visual cortex as neuronal signals in that area became more reliable relative to the other areas. The results suggest that the mechanisms that read signals from cortex might access any cortical area depending on the relative value of those signals for the task at hand.SIGNIFICANCE STATEMENT Information is encoded by the action potentials of neurons in various cortical areas in a hierarchical manner such that increasingly complex stimulus features are encoded in successive stages. The brain must extract information from the response of appropriate neurons to drive optimal behavior. A widely held view of this decoding process is that the brain relies on the output of later cortical areas to make decisions, although neurons in earlier areas can provide more reliable signals. We examined correlations between perceptual decisions and the responses of neurons in different levels of monkey visual cortex. The results suggest that the brain may access signals in any cortical area depending on the relative value of those signals for the task at hand.


Assuntos
Comportamento Animal/fisiologia , Tomada de Decisões/fisiologia , Discriminação Psicológica/fisiologia , Neurônios/fisiologia , Córtex Visual/fisiologia , Animais , Macaca mulatta , Masculino
12.
J Neurosci ; 40(11): 2200-2214, 2020 03 11.
Artigo em Inglês | MEDLINE | ID: mdl-32047055

RESUMO

The dentate gyrus (DG) in the hippocampus may play key roles in remembering distinct episodes through pattern separation, which may be subserved by the sparse firing properties of granule cells (GCs) in the DG. Low intrinsic excitability is characteristic of mature GCs, but ion channel mechanisms are not fully understood. Here, we investigated ionic channel mechanisms for firing frequency regulation in hippocampal GCs using male and female mice, and identified Kv4.1 as a key player. Immunofluorescence analysis showed that Kv4.1 was preferentially expressed in the DG, and its expression level determined by Western blot analysis was higher at 8-week than 3-week-old mice, suggesting a developmental regulation of Kv4.1 expression. With respect to firing frequency, GCs are categorized into two distinctive groups: low-frequency (LF) and high-frequency (HF) firing GCs. Input resistance (R in) of most LF-GCs is lower than 200 MΩ, suggesting that LF-GCs are fully mature GCs. Kv4.1 channel inhibition by intracellular perfusion of Kv4.1 antibody increased firing rates and gain of the input-output relationship selectively in LF-GCs with no significant effect on resting membrane potential and R in, but had no effect in HF-GCs. Importantly, mature GCs from mice depleted of Kv4.1 transcripts in the DG showed increased firing frequency, and these mice showed an impairment in contextual discrimination task. Our findings suggest that Kv4.1 expression occurring at late stage of GC maturation is essential for low excitability of DG networks and thereby contributes to pattern separation.SIGNIFICANCE STATEMENT The sparse activity of dentate granule cells (GCs), which is essential for pattern separation, is supported by high inhibitory inputs and low intrinsic excitability of GCs. Low excitability of GCs is thought to be attributable to a high K+ conductance at resting membrane potentials, but this study identifies Kv4.1, a depolarization-activated K+ channel, as a key ion channel that regulates firing of GCs without affecting resting membrane potentials. Kv4.1 expression is developmentally regulated and Kv4.1 currents are detected only in mature GCs that show low-frequency firing, but not in less mature high-frequency firing GCs. Furthermore, mice depleted of Kv4.1 transcripts in the dentate gyrus show impaired pattern separation, suggesting that Kv4.1 is crucial for sparse coding and pattern separation.


Assuntos
Aprendizagem da Esquiva/fisiologia , Giro Denteado/citologia , Discriminação Psicológica/fisiologia , Neurônios/fisiologia , Canais de Potássio Shal/fisiologia , Potenciais de Ação , Animais , Região CA1 Hipocampal/citologia , Região CA1 Hipocampal/fisiologia , Condicionamento Clássico , Giro Denteado/fisiologia , Eletrochoque , Feminino , Reação de Congelamento Cataléptica/fisiologia , Regulação da Expressão Gênica no Desenvolvimento , Técnicas de Introdução de Genes , Genes Reporter , Humanos , Masculino , Aprendizagem em Labirinto , Camundongos , Camundongos Endogâmicos C57BL , Neurônios/classificação , Técnicas de Patch-Clamp , Células Piramidais/fisiologia , Interferência de RNA , RNA Mensageiro/antagonistas & inibidores , RNA Mensageiro/genética , RNA Interferente Pequeno/farmacologia , Canais de Potássio Shal/biossíntese , Canais de Potássio Shal/genética , Organismos Livres de Patógenos Específicos
13.
J Neurosci ; 40(11): 2314-2331, 2020 03 11.
Artigo em Inglês | MEDLINE | ID: mdl-32005764

RESUMO

Distinct components of working memory are coordinated by different classes of inhibitory interneurons in the PFC, but the role of cholecystokinin (CCK)-positive interneurons remains enigmatic. In humans, this major population of interneurons shows histological abnormalities in schizophrenia, an illness in which deficient working memory is a core defining symptom and the best predictor of long-term functional outcome. Yet, CCK interneurons as a molecularly distinct class have proved intractable to examination by typical molecular methods due to widespread expression of CCK in the pyramidal neuron population. Using an intersectional approach in mice of both sexes, we have succeeded in labeling, interrogating, and manipulating CCK interneurons in the mPFC. Here, we describe the anatomical distribution, electrophysiological properties, and postsynaptic connectivity of CCK interneurons, and evaluate their role in cognition. We found that CCK interneurons comprise a larger proportion of the mPFC interneurons compared with parvalbumin interneurons, targeting a wide range of neuronal subtypes with a distinct connectivity pattern. Phase-specific optogenetic inhibition revealed that CCK, but not parvalbumin, interneurons play a critical role in the retrieval of working memory. These findings shine new light on the relationship between cortical CCK interneurons and cognition and offer a new set of tools to investigate interneuron dysfunction and cognitive impairments associated with schizophrenia.SIGNIFICANCE STATEMENT Cholecystokinin-expressing interneurons outnumber other interneuron populations in key brain areas involved in cognition and memory, including the mPFC. However, they have proved intractable to examination as experimental techniques have lacked the necessary selectivity. To the best of our knowledge, the present study is the first to report detailed properties of cortical cholecystokinin interneurons, revealing their anatomical organization, electrophysiological properties, postsynaptic connectivity, and behavioral function in working memory.


Assuntos
Colecistocinina/fisiologia , Interneurônios/fisiologia , Memória de Curto Prazo/fisiologia , Rememoração Mental/fisiologia , Córtex Pré-Frontal/fisiologia , Animais , Comportamento Apetitivo/fisiologia , Aprendizagem por Discriminação/fisiologia , Discriminação Psicológica/fisiologia , Feminino , Genes Reporter , Interneurônios/classificação , Masculino , Camundongos , Camundongos Transgênicos , Proteínas do Tecido Nervoso/análise , Odorantes , Optogenética , Parvalbuminas/análise , Técnicas de Patch-Clamp , Recompensa , Esquizofrenia/fisiopatologia , Olfato/fisiologia , Potenciais Sinápticos/fisiologia
14.
J Exp Psychol Hum Percept Perform ; 46(3): 241-251, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32077740

RESUMO

In stimulus identification tasks, stimulus and response, and location and response information, is thought to become integrated into a common event representation following a response. Evidence for this feature integration comes from paradigms requiring keypress responses to pairs of sequentially presented stimuli. In such paradigms, there is a robust cost when a target event only partially matches the preceding event representation. This is known as the partial repetition cost. Notably, however, these experiments rely on discrimination responses. Recent evidence has suggested that changing the responses to localization or detection responses eliminates partial repetition costs. If changing the response type can eliminate partial repetition costs it becomes necessary to question whether partial repetition costs reflect feature integration or some other mechanism. In the current study, we look to answer this question by using a design that as closely as possible matched typical partial repetition cost experiments in overall stimulus processing and response requirements. Unlike typical experiments where participants make a cued response to a first stimulus before making a discrimination response to a second stimulus, here we reversed that sequence such that participants made a discrimination response to the first stimulus before making a cued response to the second. In Experiment 1, this small change eliminated or substantially reduced the typically large partial repetition costs. In Experiment 2 we returned to the typical sequence and restored the large partial repetition costs. Experiment 3 confirmed these findings, which have implications for interpreting partial repetition costs and for feature integration theories in general. (PsycINFO Database Record (c) 2020 APA, all rights reserved).


Assuntos
Atenção/fisiologia , Sinais (Psicologia) , Discriminação Psicológica/fisiologia , Memória Episódica , Rememoração Mental/fisiologia , Desempenho Psicomotor/fisiologia , Percepção Visual/fisiologia , Adolescente , Adulto , Feminino , Humanos , Masculino , Adulto Jovem
15.
Neuron ; 106(2): 316-328.e6, 2020 04 22.
Artigo em Inglês | MEDLINE | ID: mdl-32105611

RESUMO

Cognitive capacities afford contingent associations between sensory information and behavioral responses. We studied this problem using an olfactory delayed match to sample task whereby a sample odor specifies the association between a subsequent test odor and rewarding action. Multi-neuron recordings revealed representations of the sample and test odors in olfactory sensory and association cortex, which were sufficient to identify the test odor as match or non-match. Yet, inactivation of a downstream premotor area (ALM), but not orbitofrontal cortex, confined to the epoch preceding the test odor led to gross impairment. Olfactory decisions that were not context-dependent were unimpaired. Therefore, ALM does not receive the outcome of a match/non-match decision from upstream areas. It receives contextual information-the identity of the sample-to establish the mapping between test odor and action. A novel population of pyramidal neurons in ALM layer 2 may mediate this process.


Assuntos
Tomada de Decisões/fisiologia , Córtex Motor/fisiologia , Animais , Mapeamento Encefálico , Discriminação Psicológica/fisiologia , Camundongos , Odorantes , Córtex Olfatório/fisiologia , Condutos Olfatórios/fisiologia , Optogenética , Córtex Piriforme/fisiologia , Desempenho Psicomotor/fisiologia , Células Piramidais/fisiologia , Recompensa , Olfato/fisiologia
16.
Nat Commun ; 11(1): 1057, 2020 02 26.
Artigo em Inglês | MEDLINE | ID: mdl-32103009

RESUMO

Perceptual decisions are based on sensory information but can also be influenced by expectations built from recent experiences. Can the impact of expectations be flexibly modulated based on the outcome of previous decisions? Here, rats perform an auditory task where the probability to repeat the previous stimulus category is varied in trial-blocks. All rats capitalize on these sequence correlations by exploiting a transition bias: a tendency to repeat or alternate their previous response using an internal estimate of the sequence repeating probability. Surprisingly, this bias is null after error trials. The internal estimate however is not reset and it becomes effective again after the next correct response. This behavior is captured by a generative model, whereby a reward-driven modulatory signal gates the impact of the latent model of the environment on the current decision. These results demonstrate that, based on previous outcomes, rats flexibly modulate how expectations influence their decisions.


Assuntos
Estimulação Acústica , Comportamento Animal/fisiologia , Tomada de Decisões/fisiologia , Discriminação Psicológica/fisiologia , Filtro Sensorial/fisiologia , Animais , Mapeamento Encefálico , Masculino , Motivação , Ratos , Ratos Long-Evans , Tempo de Reação/fisiologia , Recompensa
17.
Atten Percept Psychophys ; 82(2): 715-728, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31974939

RESUMO

Visual and central attention are limited in capacity. In conjunction search, visual attention is required to select the items and to bind their features (e.g., color, form, size), which results in a serial search process. In dual-tasks, central attention is required for response selection, but because central attention is limited in capacity, response selection can only be carried out for one task at a time. Here, we investigated whether visual and central attention rely on a common or on distinct capacity limitations. In two dual-task experiments, participants completed an auditory two-choice discrimination Task 1 and a conjunction search Task 2 that were presented with an experimentally modulated temporal interval between them (stimulus onset asynchrony [SOA]). In Experiment 1, Task 2 was a triple conjunction search task. Each item consisted of a conjunction of three features, so that target and distractors shared two features. In Experiment 2, Task 2 was a plus conjunction search task, in which target and distractors shared the same four features. The hypotheses for conjunction search time were derived from the locus-of-slack method. While plus conjunction search was performed after response selection in Task 1, a small part of triple conjunction search was still performed in parallel to response selection in Task 1. However, the between-experiment comparison was not significant, indicating that both search tasks may require central attention. Taken together, the present study provides evidence that visual and central attention share a common capacity limitation when conjunction search relies strongly on serial item selection.


Assuntos
Atenção/fisiologia , Percepção Auditiva/fisiologia , Discriminação Psicológica/fisiologia , Percepção Visual/fisiologia , Estimulação Acústica , Adolescente , Adulto , Feminino , Humanos , Masculino , Estimulação Luminosa , Tempo de Reação/fisiologia , Análise e Desempenho de Tarefas , Adulto Jovem
18.
Cogn Process ; 21(2): 261-270, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31953644

RESUMO

Previous studies have shown that exogenous attention decreases audiovisual integration (AVI); however, whether the interaction between exogenous attention and AVI is influenced by cue-target onset asynchrony (CTOA) remains unclear. To clarify this matter, twenty participants were recruited to perform an auditory/visual discrimination task, and they were instructed to respond to the target stimuli as rapidly and accurately as possible. The analysis of the mean response times showed an effective cueing effect under all cued conditions and significant response facilitation for all audiovisual stimuli. A further comparison of the differences between the probability of audiovisual cumulative distributive functions (CDFs) and race model CDFs showed that the AVI latency was shortened under the cued condition relative to that under the no-cue condition, and there was a significant break point when the CTOA was 200 ms, with a decrease in the AVI upon going from 100 to 200 ms and an increase upon going from 200 to 400 ms. These results indicated different mechanisms for the interaction between exogenous attention and the AVI under the shorter and longer CTOA conditions and further suggested that there may be a temporal window in which the AVI effect is mainly affected by exogenous attention, but the interaction might be interfered with by endogenous attention when exceeding the temporal window.


Assuntos
Atenção/fisiologia , Percepção Auditiva/fisiologia , Discriminação Psicológica/fisiologia , Percepção Visual/fisiologia , Adulto , Sinais (Psicologia) , Feminino , Humanos , Masculino , Estimulação Luminosa , Tempo de Reação/fisiologia , Adulto Jovem
20.
Mem Cognit ; 48(2): 287-298, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31939041

RESUMO

Subtle metric differences in facial configuration, such as between-person variation in the distances between the eyes, have been used widely in psychology to explain face recognition. However, these studies of configuration have typically utilized unfamiliar faces rather than the familiar faces that the process of recognition ultimately seeks to explain. This study investigates whether face recognition relies on the metric information presumed in configural theory, by manipulating the interocular distance in both unfamiliar and familiar faces. In Experiment 1, observers were asked to detect which face in a pair was presented with its configuration intact. In Experiment 2, this discrimination task was repeated with faces presented individually, and observers were also asked to make familiarity categorizations to the same stimuli. In both experiments, familiarity determined detection of faces in their original configuration, and also enhanced identity categorization in Experiment 2. However, discrimination of configuration was generally low. In turn, recognition accuracy was generally high irrespective of configuration condition. Moreover, observers most sensitive to configuration during discrimination did not appear to rely on this information for recognition of familiar faces. These results demonstrate that configuration theory provides limited explanatory power for the recognition of familiar faces.


Assuntos
Discriminação Psicológica/fisiologia , Reconhecimento Facial/fisiologia , Reconhecimento Psicológico/fisiologia , Percepção Social , Percepção Espacial/fisiologia , Adulto , Feminino , Humanos , Masculino , Adulto Jovem
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...