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42
result(s) for
"Task-relevance"
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Gamma band activity and the P3 reflect post-perceptual processes, not visual awareness
by
Martínez, Antígona
,
Hillyard, Steven A.
,
Padwal, Jennifer
in
Adult
,
Attention
,
Attention - physiology
2014
A primary goal in cognitive neuroscience is to identify neural correlates of conscious perception (NCC). By contrasting conditions in which subjects are aware versus unaware of identical visual stimuli, a number of candidate NCCs have emerged; among them are induced gamma band activity in the EEG and the P3 event-related potential. In most previous studies, however, the critical stimuli were always directly relevant to the subjects' task, such that aware versus unaware contrasts may well have included differences in post-perceptual processing in addition to differences in conscious perception per se. Here, in a series of EEG experiments, visual awareness and task relevance were manipulated independently. Induced gamma activity and the P3 were absent for task-irrelevant stimuli regardless of whether subjects were aware of such stimuli. For task-relevant stimuli, gamma and the P3 were robust and dissociable, indicating that each reflects distinct post-perceptual processes necessary for carrying-out the task but not for consciously perceiving the stimuli. Overall, this pattern of results challenges a number of previous proposals linking gamma band activity and the P3 to conscious perception.
•Visual awareness and task-relevance were manipulated in a series of EEG experiments.•Induced gamma activity and the P3 component were measured.•Gamma and P3 were absent for task-irrelevant stimuli regardless of awareness.•Gamma and P3 were robust and dissociable for task-relevant stimuli.•Gamma and P3 reflect distinct post-perceptual processes, not conscious perception.
Journal Article
Dissociating neural correlates of consciousness and task relevance during auditory processing
by
Bruchmann, Maximilian
,
Schlossmacher, Insa
,
Straube, Thomas
in
Adolescent
,
Adult
,
Attention - physiology
2021
•The study of neural correlates of consciousness (NCC) focused mostly on vision, while audition has been largely overlooked.•We conducted an inattentional deafness study addressing the prevalent confound of conscious perception with reporting it.•Auditory awareness is associated with an anterior early negativity, while later effects reflect task relevance of stimuli.
In recent years, several ERP components have been identified as potential neural correlates of consciousness (NCC), including early negativities and late positivities. Based on experiments in the visual modality, it has recently been shown that awareness is often confounded with reporting it, possibly overestimating the NCC. It is unknown whether similar constraints also exist in the auditory modality. In order to address this gap, we presented spoken words in a sustained inattentional deafness paradigm. Electrophysiological responses were obtained in three physically identical experimental conditions that differed only with respect to the participants’ instructions. Participants were either left uninformed or informed about the presence of spoken words while confronted with an auditory distractor task (U/I condition), informed about the words while exposed to the same task as before (I condition), or requested to respond to the now task-relevant speech stimuli (TR condition). After completion of the U/I condition, only informed participants reported awareness of the words. In ERPs, awareness of words in the U/I and I condition was accompanied by an anterior auditory awareness negativity (AAN). Only when stimuli were task-relevant, i.e., during the TR condition, late positivities emerged. Taken together, these results indicate that early negativities but not late positivities index awareness across sensory modalities. Thus, they provide evidence for a recurrent processing framework, which highlights the importance of early sensory processing in conscious perception.
Journal Article
Task relevance effect on number/shape conflict detection in the number-matching task: An ERP study
2020
It is debatable whether the task relevance effect on a conflict occurs in the detection or in the inhibition underlying sequential matching. To explore this issue, three types of number pairs, identical (e.g., 12, 12), conserved (e.g., 12, 十二), and non-conserved (e.g., 12, 15) pairs, were displayed to be judged as perceptually (identical shape condition) or quantitatively (identical value condition) the same. Both error rates and RTs for the three types of number pairs showed different patterns to detect perceptual mismatch in the identical shape condition and number inequivalence in the identical value conditions. The event-related potential (ERP) results showed that increased N200 and N400 as well as decreased P300 were triggered by the conserved and non-conserved pairs in contrast to identical pairs in the identical shape condition and by the non-conserved pairs relative to the conserved and identical pairs in the identical value condition. These results showed that task-relevant mismatches were attended to and detected in both conditions. Therefore, for the task-relevance effect on a conflict, attention is selectively directed to task-relevant features rather than inhibiting task-irrelevant conflict.
Journal Article
Occipital, parietal, and frontal cortices selectively maintain task-relevant features of multi-feature objects in visual working memory
2017
Previous studies have shown that information held in visual working memory is represented in the occipital, parietal, and frontal cortices. However, less is known about whether the mnemonic information of multi-feature objects is modulated by task demand in the parietal and frontal regions. To address this question, we asked participants to remember either color or orientation of one of the two colored gratings for a delay. Using fMRI and an inverted encoding model, we reconstructed population-level, feature-selective responses in the occipital, parietal and frontal cortices during memory maintenance. We found that not only orientation but also color information can be maintained in higher-order parietal and frontal cortices as well as the early visual cortex when it was cued to be remembered. Conversely, neither the task-irrelevant feature of the cued object, nor any feature of the uncued object was maintained in the occipital, parietal, or frontal cortices. These results suggest a highly selective mechanism of visual working memory that maintains task-relevant features only.
•Non-spatial features can be maintained in the parietal and frontal cortices.•Feature-specific representations in visual working memory are highly selective.•Only task-relevant features are maintained during visual working memory.
Journal Article
Context matters: task relevance shapes neural responses to emotional facial expressions
2024
Recent research shows that emotional facial expressions impact behavioral responses only when their valence is relevant to the task. Under such conditions, threatening faces delay attentional disengagement, resulting in slower reaction times and increased omission errors compared to happy faces. To investigate the neural underpinnings of this phenomenon, we used functional magnetic resonance imaging to record the brain activity of 23 healthy participants while they completed two versions of the go/no-go task. In the emotion task (ET), participants responded to emotional expressions (fearful or happy faces) and refrained from responding to neutral faces. In the gender task (GT), the same images were displayed, but participants had to respond based on the posers’ gender. Our results confirmed previous behavioral findings and revealed a network of brain regions (including the angular gyrus, the ventral precuneus, the left posterior cingulate cortex, the right anterior superior frontal gyrus, and two face-responsive regions) displaying distinct activation patterns for the same facial emotional expressions in the ET compared to the GT. We propose that this network integrates internal representations of task rules with sensory characteristics of facial expressions to evaluate emotional stimuli and exert top-down control, guiding goal-directed actions according to the context.
Journal Article
Serial dependence in facial identity perception and visual working memory
Serial dependence (SD) refers to the effect in which a person’s current perceptual judgment is attracted toward recent stimulus history. Perceptual and memory processes, as well as response and decisional biases, are thought to contribute to SD effects. The current study examined the processing stages of SD facial identity effects in the context of task-related decision processes and how such effects may differ from visual working memory (VWM) interactions. In two experiments, participants were shown a series of two sequentially presented face images. In Experiment
1
, the two faces were separated by an interstimulus interval (ISI) of 1, 3, 6, or 10 s, and participants were instructed to reproduce the second face after a varying response delay of 0, 1, 3, 6, or 10 s. Results showed that SD effects occurred most consistently at ISI of 1 s and response delays of 1 and 6 s consistent with early and late stages of processing. In Experiment
2
, the ISI was held constant at 1 s, and to separate SD from VWM interactions participants were post-cued to reproduce either the first or the second face. When the second face was the target, SD effects again occurred at response delays of 1 and 6 s, but not when the first face was the target. Together, the results demonstrates that SD facial identity effects occur independently of task-related processes in a distinct temporal fashion and suggest that SD and VWM interactions may rely on separate underlying mechanisms.
Journal Article
The Timing of Gaze Direction Perception: ERP Decoding and Task Modulation
2024
•We decoded gaze direction (GD) and head orientation (HO) from EEG signal.•In GD task decoding of HO commenced earlier than decoding of GD.•Task context had an impact on decoding accuracy and latency in GD and HO decoding.•Our results suggest a hierarchical visual processing of GD and HO representations.
Distinguishing the direction of another person's eye gaze is extremely important in everyday social interaction, as it provides critical information about people's attention and, therefore, intentions. The temporal dynamics of gaze processing have been investigated using event-related potentials (ERPs) recorded with electroencephalography (EEG). However, the moment at which our brain distinguishes the gaze direction (GD), irrespectively of other facial cues, remains unclear. To solve this question, the present study aimed to investigate the time course of gaze direction processing, using an ERP decoding approach, based on the combination of a support vector machine and error-correcting output codes. We recorded EEG in young healthy subjects, 32 of them performing GD detection and 34 conducting face orientation tasks. Both tasks presented 3D realistic faces with five different head and gaze orientations each: 30°, 15° to the left or right, and 0°. While the classical ERP analyses did not show clear GD effects, ERP decoding analyses revealed that discrimination of GD, irrespective of head orientation, started at 140 ms in the GD task and at 120 ms in the face orientation task. GD decoding accuracy was higher in the GD task than in the face orientation task and was the highest for the direct gaze in both tasks. These findings suggest that the decoding of brain patterns is modified by task relevance, which changes the latency and the accuracy of GD decoding.
Journal Article
Effects of sensory modality and task relevance on omitted stimulus potentials
by
Ishida, Tomomi
,
Nittono, Hiroshi
in
Brain research
,
College students
,
Event-related potentials
2024
Omitted stimulus potentials (OSPs) occur when a sensory stimulus is unexpectedly omitted. They are thought to reflect predictions about upcoming sensory events. The present study examined how OSPs differ across the sensory modalities of predicted stimuli. Twenty-nine university students were asked to press a mouse button at a regular interval of 1–2 s, which was immediately followed by either a visual or auditory stimulus in different blocks. The stimuli were sometimes omitted (p = 0.2), to which event-related potentials (ERPs) were recorded. The results showed that stimulus omissions in both modalities elicited ERP waveforms consisting of three components, oN1, oN2, and oP3. The peak latencies of these components were shorter in the auditory modality than in the visual modality. The amplitudes of OSPs were larger when participants were told that the omission indicated their poor performance (i.e., they pressed a button at an irregular interval) than when it was irrelevant to their performance. These findings suggest that OSPs occur from around 100 ms in a modality-specific manner and increase in amplitude depending on the task relevance of stimulus omissions.
Journal Article
What types of information can and do latent print examiners review? A survey of practicing examiners
by
Kelley, Sharon
,
Neuman, Maddisen
,
Gardner, Brett O.
in
Access to information
,
Accessibility
,
Decision making
2023
Understanding typical work practices is important to understanding the decision-making process underlying latent print comparison and improving the reliability of the discipline. Despite efforts to standardize work practices, a growing literature has demonstrated that contextual effects can influence every aspect of the analytic process. However, very little is known about what types of information are available to latent print examiners, and what types of information latent print examiners routinely review. We surveyed practicing latent print examiners (N = 284) regarding what types of information are accessible during routine casework, and what types of information they routinely review during casework. We also explored whether access and inclination to review different types of information vary according to unit size and examiner role. Results indicated that information describing the physical evidence is accessible by almost all examiners (94.4%), and most examiners have access to offense type (90.5%), method of evidence collection (77.8%), and the names of both suspect (76.1%) and victim (73.9%). However, evidence description (86.3%) and method of evidence collection (68.3%) were the only information types consistently reviewed by most examiners. Findings also indicate that examiners in smaller laboratories have access to more information types and often review more information types than examiners from larger laboratories, but both populations choose to not review information at similar rates. Further, examiners in supervisory positions are more likely to choose to not review information than examiners in non-supervisory positions. Although there is some consensus regarding what types of information examiners routinely review, findings suggest that there is little absolute consensus regarding what information examiners can even access, and highlight two sources of variability in examiner work practices: employment setting and examiner role. This is concerning in light of efforts to maximize the reliability of analytic procedures (and ultimately, conclusions) and represents an important area of future study as the field progresses.
•Latent print examiners vary in the types of information available to review during analysis.•Examiners also vary in the types of information they actually review during analysis.•Only the evidence description and method of collection were reviewed by most examiners.•Examiners in smaller laboratories have access to – and review – more information types.•Examiners in supervisory positions are more likely to not review available information.
Journal Article
The Effect of Task-Irrelevant Emotional Valence on Limited Attentional Resources During Deception: An ERPs Study
by
Liang, Jing
,
Ruan, Qian-Nan
,
Yan, Wen-Jing
in
attentional resources
,
deception
,
emotional valence
2021
Deception is a complex and cognitively draining dyadic process that simultaneously involves cognitive and emotional processes, both of which demand/capture attentional resources. However, few studies have investigated the allocation of attentional resources between cognitive and emotional processes during deception. The current study presented facial expressions of different valences to 36 participants. While an electroencephalogram was recording, they were asked to make either truthful or deceptive gender judgments according to preceding cues. The results showed that deceptive responses induced smaller P300 amplitudes than did truthful responses. Task-irrelevant negative emotional information (TiN) elicited larger P300 amplitudes than did task-irrelevant positive emotional information (TiP). Furthermore, the results showed that TiN elicited larger LPP amplitudes than did TiP in deceptive responses, but not in truthful ones. The results suggested that attentional resources were directed away to deception-related cognitive processes and TiN, but not TiP, was consistently able to compete for and obtain attentional resources during deception. The results indicated that TiN could disrupt with deception and may facilitate deception detection.
Journal Article