RESUMO
Spatial processing by receptive fields is a core property of the visual system. However, it is unknown how spatial processing in high-level regions contributes to recognition behavior. As face inversion is thought to disrupt typical holistic processing of information in faces, we mapped population receptive fields (pRFs) with upright and inverted faces in the human visual system. Here we show that in face-selective regions, but not primary visual cortex, pRFs and overall visual field coverage are smaller and shifted downward in response to face inversion. From these measurements, we successfully predict the relative behavioral detriment of face inversion at different positions in the visual field. This correspondence between neural measurements and behavior demonstrates how spatial processing in face-selective regions may enable holistic perception. These results not only show that spatial processing in high-level visual regions is dynamically used towards recognition, but also suggest a powerful approach for bridging neural computations by receptive fields to behavior.
Assuntos
Face/fisiologia , Reconhecimento Facial/fisiologia , Orientação/fisiologia , Processamento Espacial/fisiologia , Adulto , Comportamento , Encéfalo , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Reconhecimento Visual de Modelos/fisiologia , Reconhecimento Psicológico/fisiologia , Córtex Visual/fisiologia , Campos Visuais/fisiologia , Adulto JovemRESUMO
OBJECTIVE: The purpose of this study was to determine better- ear listening effect on spatial separation with the N1-P2 complex. METHODS: Twenty individuals with normal hearing participated in this study. The speech stimulus /ba/ was presented in front of the participant (0°). Continuous Speech Noise (5 dB signal-to-noise ratio) was presented either in front of the participant (0°), left-side (-90°), or right-side (+90°). N1- P2 complex has been recorded in quiet and three noisy conditions. RESULTS: There was a remarkable effect of noise direction on N1, P2 latencies. When the noise was separated from the stimulus, N1 and P2 latency increased in terms of when noise was co-located with the stimulus. There was no statistically significant difference in N1-P2 amplitudes between the stimulus-only and co-located condition. N1-P2 amplitude was increased when the noise came from the sides, according to the stimulus-only and co-located conditions. CONCLUSION: These findings demonstrate that the latency shifts on N1-P2 complex explain cortical mechanisms of spatial separation in better-ear listening.
Assuntos
Estimulação Acústica , Audição/fisiologia , Processamento Espacial , Percepção da Fala , Adulto , Audiometria de Tons Puros , Eletroencefalografia , Potenciais Evocados Auditivos , Feminino , Voluntários Saudáveis , Humanos , Masculino , Pessoa de Meia-Idade , Ruído , Razão Sinal-Ruído , Processamento Espacial/fisiologia , Acústica da Fala , Percepção da Fala/fisiologiaRESUMO
Observations abound about the power of visual imagery in human intelligence, from how Nobel prize-winning physicists make their discoveries to how children understand bedtime stories. These observations raise an important question for cognitive science, which is, what are the computations taking place in someone's mind when they use visual imagery? Answering this question is not easy and will require much continued research across the multiple disciplines of cognitive science. Here, we focus on a related and more circumscribed question from the perspective of artificial intelligence (AI): If you have an intelligent agent that uses visual imagery-based knowledge representations and reasoning operations, then what kinds of problem solving might be possible, and how would such problem solving work? We highlight recent progress in AI toward answering these questions in the domain of visuospatial reasoning, looking at a case study of how imagery-based artificial agents can solve visuospatial intelligence tests. In particular, we first examine several variations of imagery-based knowledge representations and problem-solving strategies that are sufficient for solving problems from the Raven's Progressive Matrices intelligence test. We then look at how artificial agents, instead of being designed manually by AI researchers, might learn portions of their own knowledge and reasoning procedures from experience, including learning visuospatial domain knowledge, learning and generalizing problem-solving strategies, and learning the actual definition of the task in the first place.
Assuntos
Imaginação/fisiologia , Testes de Inteligência , Aprendizado de Máquina , Resolução de Problemas/fisiologia , Humanos , Modelos Psicológicos , Redes Neurais de Computação , Processamento Espacial/fisiologia , Percepção Visual/fisiologiaRESUMO
We performed experiments using magnetoencephalography to clarify the relationship between three-dimensional visuospatial abilities and spontaneous visual thinking characteristics. Subjects were divided into two groups based on the rate of correct answers to mental rotation tasks: those with good performances (Group G) and those with bad performances (Group B). We found the followings: (1) in the mental rotation tasks, the 25-35 Hz lower γ band activities in the superior parietal lobule/intraparietal sulcus regions and in the occipitotemporal region were significantly larger in Group G than in Group B and (2) in the spontaneous mental imagery tasks, the 20-Hz band activity in the left premotor cortex and the 35-Hz band activity in the supplementary motor area were significantly larger in Group G.
Assuntos
Encéfalo/fisiologia , Navegação Espacial/fisiologia , Processamento Espacial/fisiologia , Feminino , Humanos , Imaginação , Magnetoencefalografia , Masculino , Córtex Motor/fisiologia , Lobo Occipital/fisiologia , Lobo Parietal/fisiologia , Rotação , Lobo Temporal/fisiologia , Adulto JovemRESUMO
Cognitive decline is a symptom of healthy ageing and Alzheimer's disease. We examined the effect of real-time fMRI based neurofeedback training on visuo-spatial memory and its associated neuronal response. Twelve healthy subjects and nine patients of prodromal Alzheimer's disease were included. The examination spanned five days (T1-T5): T1 contained a neuropsychological pre-test, the encoding of an itinerary and a fMRI-based task related that itinerary. T2-T4 hosted the real-time fMRI neurofeedback training of the parahippocampal gyrus and on T5 a post-test session including encoding of another itinerary and a subsequent fMRI-based task were done. Scores from neuropsychological tests, brain activation and task performance during the fMRI-paradigm were compared between pre and post-test as well as between healthy controls and patients. Behavioural performance in the fMRI-task remained unchanged, while cognitive testing showed improvements in visuo-spatial memory performance. Both groups displayed task-relevant brain activation, which decreased in the right precentral gyrus and left occipital lobe from pre to post-test in controls, but increased in the right occipital lobe, middle frontal gyrus and left frontal lobe in the patient group. While results suggest that the training has affected brain activation differently between controls and patients, there are no pointers towards a behavioural manifestation of these changes. Future research is required on the effects that can be induced using real-time fMRI based neurofeedback training and the required training duration to elicit broad and lasting effects.
Assuntos
Doença de Alzheimer/diagnóstico por imagem , Envelhecimento Cognitivo/fisiologia , Neurorretroalimentação/métodos , Giro Para-Hipocampal/diagnóstico por imagem , Memória Espacial/fisiologia , Navegação Espacial/fisiologia , Idoso , Doença de Alzheimer/fisiopatologia , Doença de Alzheimer/reabilitação , Encéfalo/diagnóstico por imagem , Encéfalo/fisiopatologia , Disfunção Cognitiva/diagnóstico por imagem , Disfunção Cognitiva/fisiopatologia , Feminino , Neuroimagem Funcional , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Giro Para-Hipocampal/fisiopatologia , Processamento Espacial/fisiologiaRESUMO
Spatial attention may be used to select target speech in one location while suppressing irrelevant speech in another. However, if perceptual resolution of spatial cues is weak, spatially focused attention may work poorly, leading to difficulty communicating in noisy settings. In electroencephalography (EEG), the distribution of alpha (8-14 Hz) power over parietal sensors reflects the spatial focus of attention [Banerjee, Snyder, Molholm, and Foxe (2011). J. Neurosci. 31, 9923-9932; Foxe and Snyder (2011). Front. Psychol. 2, 154.] If spatial attention is degraded, however, alpha may not be modulated across parietal sensors. A previously published behavioral and EEG study found that, compared to normal-hearing (NH) listeners, hearing-impaired (HI) listeners often had higher interaural time difference thresholds, worse performance when asked to report the content of an acoustic stream from a particular location, and weaker attentional modulation of neural responses evoked by sounds in a mixture [Dai, Best, and Shinn-Cunningham (2018). Proc. Natl. Acad. Sci. U. S. A. 115, E3286]. This study explored whether these same HI listeners also showed weaker alpha lateralization during the previously reported task. In NH listeners, hemispheric parietal alpha power was greater when the ipsilateral location was attended; this lateralization was stronger when competing melodies were separated by a larger spatial difference. In HI listeners, however, alpha was not lateralized across parietal sensors, consistent with a degraded ability to use spatial features to selectively attend.
Assuntos
Ritmo alfa , Atenção/fisiologia , Percepção Auditiva/fisiologia , Encéfalo/fisiopatologia , Perda Auditiva Neurossensorial/fisiopatologia , Processamento Espacial/fisiologia , Estimulação Acústica , Adulto , Sinais (Psicologia) , Feminino , Lateralidade Funcional , Humanos , Masculino , Pessoa de Meia-Idade , Lobo Parietal/fisiopatologia , Pessoas com Deficiência Auditiva , Adulto JovemRESUMO
Research has found auditory spatial processing deficits in patients with schizophrenia (SCZ), but no study has examined SCZ patients' auditory spatial processing at both pre-attentional and attentional stages. To address this gap, we investigated schizophrenics' brain responses to sounds originating from different locations (right, left, and bilateral sources). The event-related potentials (ERPs) of 25 chronic schizophrenic patients and 25 healthy subjects were compared. Mismatch negativity (MMN) in response to frequency and duration deviants was assessed. Two P3 components (P3a and P3b) were elicited via a frequency discrimination task, and MMN and P3 were recorded through separate monaural and dichotic stimulation paradigms. Our results corroborated the previously published finding that MMN, P3a, and P3b amplitudes are reduced in SCZ patients, but they showed no significant effect of stimulus location on either MMN or P3. These results indicated similarity between the SCZ patients and healthy individuals as regards patterns of ERP responses to stimuli that come from different directions. No evidence of auditory hemispatial bias in the SCZ patients was found, supporting the existence of non-lateralized spatial processing deficits in such patients and suggesting compensatory changes in the hemispheric laterality of patients' brains.
Assuntos
Encéfalo/fisiopatologia , Variação Contingente Negativa/fisiologia , Fenômenos Eletrofisiológicos , Potenciais Evocados Auditivos/fisiologia , Lateralidade Funcional/fisiologia , Esquizofrenia/fisiopatologia , Processamento Espacial/fisiologia , Estimulação Acústica , Percepção Auditiva , Estudos de Casos e Controles , Eletroencefalografia , Potenciais Evocados , Feminino , Humanos , Masculino , Processamento de Sinais Assistido por ComputadorRESUMO
Previous results suggest that directional information from the head direction cell circuit may inform hippocampal place cell firing when an animal is confronted with visually identical environments. To investigate whether such information might also be essential for spatial behavior, we tested adult, male Lister Hooded rats that had received either bilateral lateral mammillary nuclei (LMN) lesions or sham lesions on a four-way, conditional odor-location discrimination in compartments arranged at 60° to one another. We found that significantly fewer rats in the LMN lesion group were able to learn the task compared to the Sham group. We also found that the extent of the behavioral impairment was highly correlated with the degree of tissue loss in the LMN resulting from the lesion. Animals with LMN lesions were also impaired in a nonmatching-to-sample task in a T maze, and the extent of impairment likewise depended on the extent of the lesion. Performance in the odor-location and T-maze tasks was not affected by tissue loss in the medial mammillary nuclei. Together, these results indicate that the LMN, a key node in the head direction circuit, is critical for solving a spatial task that requires a directional discrimination. (PsycINFO Database Record (c) 2019 APA, all rights reserved).
Assuntos
Comportamento Espacial/fisiologia , Processamento Espacial/fisiologia , Potenciais de Ação , Animais , Cabeça/fisiologia , Masculino , Corpos Mamilares/lesões , Corpos Mamilares/fisiopatologia , Vias Neurais/fisiologia , Neurônios/metabolismo , Neurônios/fisiologia , Ratos , Ratos Endogâmicos , Tálamo/lesõesRESUMO
OBJECTIVE: The ultimate goal of many brain-computer interface (BCI) research efforts is to provide individuals with severe motor impairments with a communication channel that they can control at will. To achieve this goal, an important system requirement is asynchronous control, whereby users can initiate intentional brain activation in a self-paced rather than system-cued manner. However, to date, asynchronous BCIs have been explored in a minority of BCI studies and their performance is generally below that of system-paced alternatives. In this paper, we present an asynchronous electroencephalography (EEG) BCI that detects a non-motor imagery cognitive task and investigated the possibility of improving its performance using error-related potentials (ErrP). APPROACH: Ten able-bodied adults attended two sessions of data collection each, one for training and one for testing the BCI. The visual interface consisted of a centrally located cartoon icon. For each participant, an asynchronous BCI differentiated among the idle state and a personally selected cognitive task (mental arithmetic, word generation or figure rotation). The BCI continuously analyzed the EEG data stream and displayed real-time feedback (i.e. icon fell over) upon detection of brain activity indicative of a cognitive task. The BCI also monitored the EEG signals for the presence of error-related potentials following the presentation of feedback. An ErrP classifier was invoked to automatically alter the task classifier outcome when an error-related potential was detected. MAIN RESULTS: The average post-error correction trial success rate across participants, 85% [Formula: see text] 12%, was significantly higher (pâ < 0.05) than that pre-error correction (78% [Formula: see text] 11%). SIGNIFICANCE: Our findings support the addition of ErrP-correction to maximize the performance of asynchronous BCIs..
Assuntos
Interfaces Cérebro-Computador , Encéfalo/fisiologia , Potenciais Evocados P300/fisiologia , Conceitos Matemáticos , Processos Mentais/fisiologia , Processamento Espacial/fisiologia , Adulto , Eletroencefalografia/métodos , Feminino , Humanos , MasculinoRESUMO
Purpose Working memory capacity and language ability modulate speech reception; however, the respective roles of peripheral and cognitive processing are unclear. The contribution of individual differences in these abilities to utilization of spatial cues when separating speech from informational and energetic masking backgrounds in children has not yet been determined. Therefore, this study explored whether speech reception in children is modulated by environmental factors, such as the type of background noise and spatial configuration of target and noise sources, and individual differences in the cognitive and linguistic abilities of listeners. Method Speech reception thresholds were assessed in 39 children aged 5-7 years in simulated school listening environments. Speech reception thresholds of target sentences spoken by an adult male consisting of number and color combinations were measured using an adaptive procedure, with speech-shaped white noise and single-talker backgrounds that were either collocated (target and back-ground at 0°) or spatially separated (target at 0°, background noise at 90° to the right). Spatial release from masking was assessed alongside memory span and expressive language. Results and Conclusion Significant main effect results showed that speech reception thresholds were highest for informational maskers and collocated conditions. Significant interactions indicated that individual differences in memory span and language ability were related to spatial release from masking advantages. Specifically, individual differences in memory span and language were related to the utilization of spatial cues in separated conditions. Language differences were related to auditory stream segregation abilities in collocated conditions that lack helpful spatial cues, pointing to the utilization of language processes to make up for losses in spatial information.
Assuntos
Individualidade , Memória de Curto Prazo/fisiologia , Mascaramento Perceptivo/fisiologia , Processamento Espacial/fisiologia , Percepção da Fala/fisiologia , Estimulação Acústica , Limiar Auditivo , Criança , Linguagem Infantil , Pré-Escolar , Sinais (Psicologia) , Feminino , Humanos , Linguística , Masculino , Ruído , África do Sul , Teste do Limiar de Recepção da FalaRESUMO
In recent years, advances in cortical-subcortical mapping, intraoperative neurophysiology, and neuropsychology have increased the ability to remove intrinsic brain tumors, expanding indications and maximizing the extent of resection. This has provided a significant improvement in progression-free survival, time of malignant transformation (in low-grade gliomas), and overall survival. Although current techniques enable preservation of language and motor functions during surgery, the maintenance of a complex set of functions defined with the term cognition is not always achievable. Cognition is defined as every neural process underlying a high human function and includes motor haptic and visuospatial functions, memory, social interactions, empathy, and emotions. In this regard, an extensive preoperative and postoperative neuropsychological evaluation is strongly suggested to assess cognitive impairment due to tumor growth, to assess surgical result, and to plan cognitive rehabilitation. This article discusses the main recent innovations introduced for cognitive mapping with the aim to preserve cognitive functions, which are essential to maintain a high quality of life.
Assuntos
Mapeamento Encefálico/métodos , Neoplasias Encefálicas/terapia , Transtornos Cognitivos/prevenção & controle , Terapia por Estimulação Elétrica/métodos , Glioma/terapia , Procedimentos Neurocirúrgicos/métodos , Neoplasias Encefálicas/psicologia , Função Executiva/fisiologia , Glioma/psicologia , Humanos , Margens de Excisão , Testes Neuropsicológicos , Tratamentos com Preservação do Órgão/métodos , Complicações Pós-Operatórias/prevenção & controle , Semântica , Processamento Espacial/fisiologiaRESUMO
Spatial selective attention enables listeners to process a signal of interest in natural settings. However, most past studies on auditory spatial attention used impoverished spatial cues: presenting competing sounds to different ears, using only interaural differences in time (ITDs) and/or intensity (IIDs), or using non-individualized head-related transfer functions (HRTFs). Here we tested the hypothesis that impoverished spatial cues impair spatial auditory attention by only weakly engaging relevant cortical networks. Eighteen normal-hearing listeners reported the content of one of two competing syllable streams simulated at roughly +30° and -30° azimuth. The competing streams consisted of syllables from two different-sex talkers. Spatialization was based on natural spatial cues (individualized HRTFs), individualized IIDs, or generic ITDs. We measured behavioral performance as well as electroencephalographic markers of selective attention. Behaviorally, subjects recalled target streams most accurately with natural cues. Neurally, spatial attention significantly modulated early evoked sensory response magnitudes only for natural cues, not in conditions using only ITDs or IIDs. Consistent with this, parietal oscillatory power in the alpha band (8-14 âHz; associated with filtering out distracting events from unattended directions) showed significantly less attentional modulation with isolated spatial cues than with natural cues. Our findings support the hypothesis that spatial selective attention networks are only partially engaged by impoverished spatial auditory cues. These results not only suggest that studies using unnatural spatial cues underestimate the neural effects of spatial auditory attention, they also illustrate the importance of preserving natural spatial cues in assistive listening devices to support robust attentional control.
Assuntos
Atenção/fisiologia , Percepção Auditiva/fisiologia , Encéfalo/fisiologia , Sinais (Psicologia) , Processamento Espacial/fisiologia , Estimulação Acústica , Adolescente , Adulto , Eletroencefalografia , Feminino , Humanos , Masculino , Vias Neurais/fisiologia , Percepção da Fala/fisiologia , Adulto JovemRESUMO
Purpose This study was carried out to understand the neural intricacies of auditory spatial processing in listeners with sensorineural hearing impairment (SNHI) and compare it with normal hearing (NH) listeners using both local and global measures of waveform analyses. Method A standard group comparison research design was adopted in this study. Participants were assigned to 2 groups. Group I consisted of 13 participants with mild-moderate flat or sloping SNHI, while Group II consisted of 13 participants with NH sensitivity. Electroencephalographic data using virtual acoustic stimuli (spatially loaded stimuli played in center, right, and left hemifields) were recorded from 64 electrode sites in passive oddball paradigm. Both local (electrode-wise waveform analysis) and global (dissimilarity index, electric field strength, and topographic pattern analyses) measures were performed on the electroencephalographic data. Results Results of local waveform analyses marked the appearance of mismatch negativity in an earlier time window, relative to those reported conventionally in both the groups. The global measures of electric field strength and topographic modulations (dissimilarity index) revealed differences between the 2 groups in different time periods, indicating multiphases (integration and consolidation) of spatial processing. Further, the topographic pattern analysis showed the emergence of different scalp maps for SNHI and NH in the time window corresponding to mismatch negativity (78-150 ms), suggestive of differential spatial processing between the groups at the cortical level. Conclusions The findings of this study highlights the differential allotment of neural generators, denoting variations in spatial processing between SNHI and NH individuals.
Assuntos
Encéfalo/fisiopatologia , Potenciais Evocados Auditivos/fisiologia , Perda Auditiva Neurossensorial/fisiopatologia , Processamento Espacial/fisiologia , Estimulação Acústica , Adulto , Idoso , Atenção , Estudos de Casos e Controles , Eletroencefalografia , Feminino , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
In discrete aiming movements the task criteria of time-minimization to a spatial target (e.g., Fitts, 1954) and time-matching to a spatial-temporal goal (e.g., Schmidt et al., 1979) tend to produce different functions of the speed-accuracy trade-off. Here we examined whether the task-related movement speed-accuracy characteristics were due to differential space-time trade-offs in time-matching, velocity-matching and time-minimizing task goals. Twenty participants performed 100 aiming trials for each of 15 combinations of task-type (3) and space-time condition (5). The prevalence of the primary types of sub-movement (none, pre-peak, post-peak, undershooting and overshooting) was determined from the kinematics of the movement trajectory. There were comparable distributions of trajectory sub-movement profiles and space-time movement outcomes across the three tasks at the short movement duration that became increasingly dissimilar over decreasing movement velocity and increasing movement time conditions. Movement time was the most influential variable in mediating sub-movement characteristics and the spatial/temporal outcome accuracy and variability of discrete aiming tasks - a role that was magnified in the explicit task demands of time-matching. The time-matching and time-minimization task goals in discrete aiming induce qualitatively different control processes that progressively contribute beyond the minimal time conditions to task-specific space-time accuracy and variability characteristics of the respective movement speed-accuracy functions.
Assuntos
Desempenho Psicomotor/fisiologia , Adulto , Análise de Variância , Biorretroalimentação Psicológica/fisiologia , Fenômenos Biomecânicos , Feminino , Voluntários Saudáveis , Humanos , Masculino , Movimento/fisiologia , Processamento Espacial/fisiologia , Fatores de Tempo , Adulto JovemRESUMO
Spatial attention (i.e., task-relevance) and expectation (i.e., signal probability) are two critical top-down mechanisms guiding perceptual inference. Spatial attention prioritizes processing of information at task-relevant locations. Spatial expectations encode the statistical structure of the environment. An unresolved question is how the brain allocates attention and forms expectations in a multisensory environment, where task-relevance and signal probability over space can differ across sensory modalities. We used functional magnetic resonance imaging in human participants (female and male) to investigate whether the brain encodes task-relevance and signal probability over space separately or interactively across sensory modalities. In a novel multisensory paradigm, we manipulated spatial attention and expectation selectively in audition and assessed their effects on behavioral and neural responses to auditory and visual stimuli. Our results show that both auditory and visual stimuli increased activations in a right-lateralized frontoparietal system, when they were presented at locations that were task-irrelevant in audition. Yet, only auditory stimuli increased activations in the medial prefrontal cortex when presented at expected locations and in audiovisual and frontoparietal cortices signaling a prediction error when presented at unexpected locations. This dissociation in multisensory generalization for attention and expectation effects shows that the brain controls attentional resources interactively across the senses but encodes the statistical structure of the environment as spatial expectations independently for each sensory system. Our results demonstrate that spatial attention and expectation engage partly overlapping neural systems via distinct mechanisms to guide perceptual inference in a multisensory world.SIGNIFICANCE STATEMENT In our natural environment the brain is exposed to a constant influx of signals through all our senses. How does the brain allocate attention and form spatial expectations in this multisensory environment? Because observers need to respond to stimuli regardless of their sensory modality, they may allocate attentional resources and encode the probability of events jointly across the senses. This psychophysics and neuroimaging study shows that the brain controls attentional resources interactively across the senses via a frontoparietal system but encodes the statistical structure of the environment independently for each sense in sensory and frontoparietal areas. Thus, spatial attention and expectation engage partly overlapping neural systems via distinct mechanisms to guide perceptual inference in a multisensory world.
Assuntos
Atenção/fisiologia , Percepção Auditiva/fisiologia , Processamento Espacial/fisiologia , Percepção Visual/fisiologia , Estimulação Acústica , Adolescente , Adulto , Mapeamento Encefálico , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Estimulação Luminosa , Psicofísica , Adulto JovemRESUMO
The perceptual separation between a signal speech and a competing speech (masker), induced by the precedence effect, plays an important role in releasing the signal speech from the masker, especially in a reverberant environment. The perceptual-separation-induced unmasking effect has been suggested to involve multiple cognitive processes, such as selective attention. However, whether listeners' spatial attention modulate the perceptual-separation-induced unmasking effect is not clear. The present study investigated how perceptual separation and auditory spatial attention interact with each other to facilitate speech perception under a simulated noisy and reverberant environment by analyzing the cortical auditory evoked potentials to the signal speech. The results showed that the N1 wave was significantly enhanced by perceptual separation between the signal and masker regardless of whether the participants' spatial attention was directed to the signal or not. However, the P2 wave was significantly enhanced by perceptual separation only when the participants attended to the signal speech. The results indicate that the perceptual-separation-induced facilitation of P2 needs more attentional resource than that of N1. The results also showed that the signal speech caused an enhanced N1 in the contralateral hemisphere regardless of whether participants' attention was directed to the signal or not. In contrast, the signal speech caused an enhanced P2 in the contralateral hemisphere only when the participant attended to the signal. The results indicate that the hemispheric distribution of N1 is mainly affected by the perceptual features of the acoustic stimuli, while that of P2 is affected by the listeners' attentional status.
Assuntos
Atenção/fisiologia , Mascaramento Perceptivo/fisiologia , Processamento Espacial/fisiologia , Percepção da Fala/fisiologia , Estimulação Acústica , Adolescente , Adulto , Eletroencefalografia , Potenciais Evocados Auditivos , Feminino , Humanos , Masculino , Ruído , Adulto JovemRESUMO
Attention control is a core element of cognitive aging, but the specific mechanisms that differ with age are unclear. Here we used a novel auditory spatial attention task to evaluate stimulus processing at the level of early attention capture, later response selection, and the lingering effects of attention capture across trials in young and older adults. We found that the shapes of spatial attention capture gradients were remarkably similar in young and older adults, but only the older group had lingering effects of attention capture on the next trial. Response selection for stimulus-response incompatibilities took longer in older subjects, but primarily when attending to the midline location. The results suggest that the likelihood and spatial tuning of attention capture is comparable among groups, but once attention is captured, older subjects take longer to disengage. Age differences in response selection were supported, but may not be a general feature of cognitive aging.
Assuntos
Estimulação Acústica/métodos , Envelhecimento/fisiologia , Atenção/fisiologia , Tempo de Reação/fisiologia , Processamento Espacial/fisiologia , Adolescente , Idoso , Envelhecimento/psicologia , Percepção Auditiva/fisiologia , Envelhecimento Cognitivo/fisiologia , Envelhecimento Cognitivo/psicologia , Feminino , Humanos , Masculino , Distribuição Aleatória , Adulto JovemRESUMO
Musical melodies have "peaks" and "valleys". Although the vertical component of pitch and music is well-known, the mechanisms underlying its mental representation still remain elusive. We show evidence regarding the importance of previous experience with melodies for crossmodal interactions to emerge. The impact of these crossmodal interactions on other perceptual and attentional processes was also studied. Melodies including two tones with different frequency (e.g., E4 and D3) were repeatedly presented during the study. These melodies could either generate strong predictions (e.g., E4-D3-E4-D3-E4-[D3]) or not (e.g., E4-D3-E4-E4-D3-[?]). After the presentation of each melody, the participants had to judge the colour of a visual stimulus that appeared in a position that was, according to the traditional vertical connotations of pitch, either congruent (e.g., high-low-high-low-[up]), incongruent (high-low-high-low-[down]) or unpredicted with respect to the melody. Behavioural and electroencephalographic responses to the visual stimuli were obtained. Congruent visual stimuli elicited faster responses at the end of the experiment than at the beginning. Additionally, incongruent visual stimuli that broke the spatial prediction generated by the melody elicited larger P3b amplitudes (reflecting 'surprise' responses). Our results suggest that the passive (but repeated) exposure to melodies elicits spatial predictions that modulate the processing of other sensory events.
Assuntos
Percepção Auditiva/fisiologia , Potenciais Evocados/fisiologia , Música , Percepção da Altura Sonora/fisiologia , Processamento Espacial/fisiologia , Estimulação Acústica , Adulto , Análise de Variância , Mapeamento Encefálico , Eletroencefalografia , Feminino , Humanos , Masculino , Estimulação Luminosa , Tempo de Reação/fisiologia , Adulto JovemRESUMO
Converging evidence suggests that the perception of auditory pitch exhibits a characteristic spatial organization. This pitch-space association can be demonstrated experimentally by the Spatial Musical Association of Response Codes (SMARC) effect. This is characterized by faster response times when a low-positioned key is pressed in response to a low-pitched tone, and a high-positioned key is pressed in response to a high-pitched tone. To investigate whether the development of this pitch-space association is mediated by normal visual experience, we tested a group of early blind individuals on a task that required them to discriminate the timbre of different instrument sounds with varying pitch. Results revealed a comparable pattern in the SMARC effect in both blind participants and sighted controls, suggesting that the lack of prior visual experience does not prevent the development of an association between pitch height and vertical space.
Assuntos
Aprendizagem por Associação/fisiologia , Cegueira/psicologia , Música/psicologia , Percepção da Altura Sonora/fisiologia , Processamento Espacial/fisiologia , Estimulação Acústica/métodos , Adolescente , Adulto , Idoso , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Tempo de Reação , Som , Adulto JovemRESUMO
In order to obtain a coherent representation of the outside world, auditory and visual information are integrated during human information processing. There is remarkable variance among observers in the capability to integrate auditory and visual information. Here, we propose that visuo-perceptual capabilities predict detection performance for audiovisually coinciding transients in multi-element displays due to severe capacity limitations in audiovisual integration. In the reported experiment, we employed an individual differences approach in order to investigate this hypothesis. Therefore, we measured performance in a useful-field-of-view task that captures detection performance for briefly presented stimuli across a large perceptual field. Furthermore, we measured sensitivity for visual direction changes that coincide with tones within the same participants. Our results show that individual differences in visuo-perceptual capabilities predicted sensitivity for the presence of audiovisually synchronous events among competing visual stimuli. To ensure that this correlation does not stem from superordinate factors, we also tested performance in an unrelated working memory task. Performance in this task was independent of sensitivity for the presence of audiovisually synchronous events. Our findings strengthen the proposed link between visuo-perceptual capabilities and audiovisual integration. The results also suggest that basic visuo-perceptual capabilities provide the basis for the subsequent integration of auditory and visual information.