Perceptual Process

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Ryousuke Kato - One of the best experts on this subject based on the ideXlab platform.

  • Perceptual Process for the early detection of humans remains intact even under a heavy attentional load an erp study
    International Journal of Psychophysiology, 2020
    Co-Authors: Ryousuke Kato, Takemasa Yokoyama, Yuji Takeda
    Abstract:

    Abstract It has been proposed that human beings have an enhanced ability to detect other people in visual scenes. We examined the ability of humans to detect other humans under situations when human images were presented as task-irrelevant stimuli. We measured the anterior N2 elicited by the onset of photographs with and without human images as an indicator of early Processing for the detection of humans. We also manipulated attentional loads (low and high loads in Experiments 1 and 2, respectively) when viewing the images to examine the effects of attention. The results indicated that the anterior N2 elicited by images that included humans was larger than that elicited by images that did not include humans, even when the attentional load was high. This finding suggests that the cognitive Processing for the detection of humans is prioritized even under high attentional loads.

Yuji Takeda - One of the best experts on this subject based on the ideXlab platform.

  • Perceptual Process for the early detection of humans remains intact even under a heavy attentional load an erp study
    International Journal of Psychophysiology, 2020
    Co-Authors: Ryousuke Kato, Takemasa Yokoyama, Yuji Takeda
    Abstract:

    Abstract It has been proposed that human beings have an enhanced ability to detect other people in visual scenes. We examined the ability of humans to detect other humans under situations when human images were presented as task-irrelevant stimuli. We measured the anterior N2 elicited by the onset of photographs with and without human images as an indicator of early Processing for the detection of humans. We also manipulated attentional loads (low and high loads in Experiments 1 and 2, respectively) when viewing the images to examine the effects of attention. The results indicated that the anterior N2 elicited by images that included humans was larger than that elicited by images that did not include humans, even when the attentional load was high. This finding suggests that the cognitive Processing for the detection of humans is prioritized even under high attentional loads.

Stephan A. Brandt - One of the best experts on this subject based on the ideXlab platform.

Peter Kok - One of the best experts on this subject based on the ideXlab platform.

  • prior expectations of motion direction modulate early sensory Processing
    The Journal of Neuroscience, 2020
    Co-Authors: Fraser Aitken, Georgia Turner, Peter Kok
    Abstract:

    Perception is a Process of inference, integrating sensory inputs with prior expectations. However, little is known regarding the temporal dynamics of this integration. It has been proposed that expectation plays a role early in the Perceptual Process, biasing sensory Processing. Alternatively, others suggest that expectations are integrated only at later, post-Perceptual decision-making stages. The current study aimed to dissociate between these hypotheses. We exposed human participants (male and female) to auditory cues predicting the likely direction of upcoming moving dot patterns, while recording neural activity using magnetoencephalography (MEG). Participants’ reports of the moving dot directions were biased towards the direction predicted by the cues. To investigate when expectations affected sensory representations, we used inverted encoding models to decode the direction represented in early sensory signals. Strikingly, the cues modulated the direction represented in the MEG signal as early as 150 ms after visual stimulus onset. While this may not reflect a modulation of the initial feedforward sweep, it does reveal a modulation of early sensory representations. Exploratory analyses showed that the neural modulation was related to Perceptual expectation effects: participants with a stronger Perceptual bias towards the predicted direction also revealed a stronger reflection of the predicted direction in the MEG signal. For participants with this Perceptual bias, a correlation between decoded and perceived direction already emerged prior to visual stimulus onset, suggesting that the pre-stimulus state of the visual cortex influences sensory Processing. Together, these results suggest that expectations play an integral role in the neural computations underlying perception. Significance StatementPerception can be thought of as an inferential Process in which our brains integrate sensory inputs with prior expectations to make sense of the world. This study investigated whether this integration occurs early or late in the Process of perception. We exposed human participants to auditory cues which predicted the likely direction of visual moving dots, while recording neural activity with millisecond resolution using magnetoencephalography (MEG). Participants’ Perceptual reports of the direction of the moving dots were biased towards the predicted direction. Additionally, the predicted direction modulated the neural representation of the moving dots just 150 ms after they appeared. This suggests that prior expectations affected sensory Processing at early stages, playing an integral role in the Perceptual Process.

  • prior expectations of motion direction modulate early sensory Processing
    bioRxiv, 2020
    Co-Authors: Fraser Aitken, Georgia Turner, Peter Kok
    Abstract:

    Abstract Perception is a Process of inference, integrating sensory inputs with prior expectations. However, little is known regarding the temporal dynamics of this integration. It has been proposed that expectation plays a role early in the Perceptual Process, by biasing early sensory Processing. Alternatively, others suggest that expectations are integrated only at later, post-Perceptual decision-making stages. The current study aimed to dissociate between these hypotheses. We exposed male and female human participants (N=24) to auditory cues predicting the likely direction of upcoming noisy moving dot patterns, while recording millisecond-resolved neural activity using magnetoencephalography (MEG). First, we found that participants’ reports of the moving dot directions were biased towards the direction predicted by the auditory cues. To investigate when expectations affected sensory representations, we used inverted encoding models to decode the direction represented in early sensory signals. Strikingly, the auditory cues modulated the direction represented in the MEG signal as early as 150ms after visual stimulus onset. This early neural modulation was related to Perceptual effects of expectation: participants with a stronger Perceptual bias towards the predicted direction also revealed a stronger reflection of the predicted direction in the MEG signal. For participants with this Perceptual bias, a trial-by-trial correlation between decoded and perceived direction already emerged prior to visual stimulus onset (∼-150ms), suggesting that the pre-stimulus state of the visual cortex influences sensory Processing. Together, these results suggest that prior expectations can influence perception by biasing early sensory Processing, making expectation a fundamental component of the neural computations underlying perception. Significance statement Perception can be thought of as an inferential Process in which our brains integrate sensory inputs with prior expectations to make sense of the world. This study investigated whether this integration occurs early or late in the Process of perception. We exposed human participants to auditory cues which predicted the likely direction of visual moving dots, while recording neural activity with millisecond resolution using magnetoencephalography (MEG). Participants’ Perceptual reports of the direction of the moving dots were biased towards the predicted direction. Additionally, the predicted direction modulated the neural representation of the moving dots just 150 ms after they appeared. This suggests that prior expectations affected sensory Processing at very early stages, playing an integral role in the Perceptual Process.

Alan M. Wing - One of the best experts on this subject based on the ideXlab platform.

  • Contribution of the motor system to the perception of reachable space: an fMRI study.
    The European journal of neuroscience, 2014
    Co-Authors: Angela Bartolo, Martin G. Edwards, Martin Edwards, Samuel Delepoulle, Satoshi Endo, Yann Coello, Alan M. Wing
    Abstract:

    The present functional magnetic resonance imaging (fMRI) study investigates the neural correlates of reachability judgements. In a block design experiment, 14 healthy participants judged whether a visual target presented at different distances in a virtual environment display was reachable or not with the right hand. In two control tasks, they judged the colour or the relative position of the visual target according to flankers. Contrasting the activations registered in the reachability judgement task and in the control tasks, we found activations in the frontal structures, and in the bilateral inferior and superior parietal lobe, including the precuneus, and the bilateral cerebellum. This fronto-parietal network including the cerebellum overlaps with the brain network usually activated during actual motor production and motor imagery. In a following event-related design experiment, we contrasted brain activations when targets were rated as 'reachable' with those when they were rated as 'unreachable'. We found activations in the left premotor cortex, the bilateral frontal structures, and the left middle temporal gyrus. At a lower threshold, we also found activations in the left motor cortex, and in the bilateral cerebellum. Given that reaction time increased with target distance in reachable space, we performed a subsequent parametric analysis that revealed a related increase of activity in the fronto-parietal network including the cerebellum. Unreachable targets did not show similar activation, and particularly in regions associated to motor production and motor imagery. Taken together, these results suggest that dynamical motor representations used to determine what is reachable are also part of the Perceptual Process leading to the distinct representation of peripersonal and extrapersonal spaces.