Task-irrelevant Stimulus Features Research Articles

Pre-frontal cortex guides dimension-reducing transformations in the occipito-ventral pathway for categorization behaviors

To interpret our surroundings, the brain uses a visual categorization process. Current theories and models suggest that this process comprises a hierarchy of different computations that transforms complex, high-dimensional inputs into lower-dimensional representations (i.e., manifolds) in support of multiple categorization behaviors. Here, we tested this hypothesis by analyzing these transformations reflected in dynamic MEG source activity while individual participants actively categorized the same stimuli according to different tasks: face expression, face gender, pedestrian gender, and vehicle type. Results reveal three transformation stages guided by the pre-frontal cortex. At stage 1 (high-dimensional, 50-120ms), occipital sources represent both task-relevant and task-irrelevant stimulus features; task-relevant features advance into higher ventral/dorsal regions, whereas task-irrelevant features halt at the occipital-temporal junction. At stage 2 (121-150ms), stimulus feature representations reduce to lower-dimensional manifolds, which then transform into the task-relevant features underlying categorization behavior over stage 3 (161-350ms). Our findings shed light on how the brain's network mechanisms transform high-dimensional inputs into specific feature manifolds that support multiple categorization behaviors.

Auditory context-dependent distraction by unexpected visual stimuli.

Research findings indicate that when a task-irrelevant stimulus feature deviates from an otherwise predictable pattern, participants performing a categorization task exhibit slower responses (deviance distraction). This deviance distraction effect reflects the violation of the sensory predictions generated by the cognitive system. In this study, we sought to examine for the first time whether these predictions can be incidentally modulated by the auditory environment. Participants categorized the duration (short vs long) of a colored shape (red square or blue circle) while instructed to disregard the stimulus' visual features and the sound played in the background (two distinct chords played by different instruments). While the two visual stimuli shapes were equiprobable across the task, one was highly likely (p=.882) and the other rare (p=.118) in one auditory context and vice versa in the other context. Our results showed that participants were significantly slower in the duration judgement task whenever the stimulus was unexpected within a given auditory context (context-dependent distraction), and that the reset of their sensory predictions was completed upon the trial following a change of context. We conclude that object features and environmental context are processed in relation to each other and that sensory predictions are produced in relation to the environmental context, evidencing the first demonstration of auditory context-dependent modulation of attention.

Stimulus-triggered task conflict affects task-selection errors in task switching: A Bayesian multinomial processing tree modeling approach.

In the present study, we used a modeling approach for measuring task conflict in task switching, assessing the probability of selecting the correct task via multinomial processing tree (MPT) modeling. With this method, task conflict and response conflict can be independently assessed as the probability of selecting the correct task and the probability of selecting the correct response within a given task, respectively. These probabilities can be estimated on the basis of response accuracy in the different experimental conditions. In two task-switching experiments, we used bivalent stimuli and manipulated irrelevant-task difficulty by varying the saliency of the stimulus feature belonging to the irrelevant task. The more salient the task-irrelevant stimulus feature, the more salient the irrelevant task, leading to more task conflict. Consistent with this assumption, we observed that task conflict, but not response conflict, was larger when the task-irrelevant stimulus feature was made more salient. Furthermore, both task conflict and response conflict were larger when the task switched than when the task was repeated. On a methodological level, the present results demonstrate that MPT modeling is a useful approach for measuring task conflict in task switching and for dissociating it from within-task response conflict. Furthermore, the present results inform theories of task switching by showing that the task-irrelevant feature tends to activate the irrelevant task set rather than being associated with a specific response option via a direct stimulus-response route. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Higher Cardiorespiratory Fitness is Associated with Reduced Functional Brain Connectivity During Performance of the Stroop Task.

Background:Although higher cardiorespiratory fitness (CRF) has been linked to better executive function, the mechanisms by which this occurs remain a matter of speculation. One hypothesis is that higher CRF is associated with elevated top-down control in which brain regions processing task-relevant information are up-regulated and brain regions processing task-irrelevant information are down-regulated.Methods:We tested this top-down hypothesis in 50 young adults (μ age = 25.22 ± 5.17 years) by measuring CRF via a graded maximal exercise test and performing functional Magnetic Resonance Imaging (fMRI) during a color-word Stroop task. We used task-evoked functional connectivity, quantified from a psychophysiological interaction analysis (PPI), to test our hypotheses that (a) higher CRF would be associated with greater connectivity between control centers (i.e., prefrontal and parietal areas) and visual feature centers (i.e., occipital areas) that are involved with processing task-relevant stimulus dimensions (i.e., color), and (b) higher CRF would be associated with lower connectivity between control centers and visual feature centers that are involved with processing task-irrelevant dimensions of the stimuli (i.e., word processing areas).Results:Controlling for sex and BMI, we found, consistent with our second hypothesis, that higher CRF was associated with reduced functional connectivity between parietal and occipital areas involved in the task-irrelevant dimension of the task (i.e., word form areas). There were no associations between CRF and functional connectivity with the prefrontal cortex or evidence of heightened connectivity between attentional control and visual feature centers.Conclusions:These results suggest that CRF associations with executive functioning might be explained by CRF-mediated differences between brain regions involved with attentional control (parietal regions) and the down-regulation of regions involved with processing task-irrelevant stimulus features (occipital regions).

Perceptual learning of task-irrelevant features depends on the sensory context

The brain has evolved to extract behaviourally meaningful information from the environment. For example, it has been shown that visual perceptual learning (VPL) can occur for task-irrelevant stimulus features when those features are consistently paired with internal or external reinforcement signals. It is, however, unclear whether or not task-irrelevant VPL is influenced by stimulus features that are unrelated to reinforcement in a given sensory context. To address this question, we exposed participants to task-irrelevant and subliminal coherent motion stimuli in the background while they performed a central character identification task. A specific motion direction was consistently paired with the task-targets, while two other directions occurred only with distractors and, thus, were unrelated to reinforcement. We found that the magnitude of VPL of the target-paired direction was significantly greater when the distractor-paired directions were close to the target-paired direction, compared to when they were farther. Thus, even very weak signals that are both subliminal and unrelated to reinforcement are processed and exert an influence on VPL. This finding suggests that the outcome of VPL depends on the sensory context in which learning takes place and calls for a refinement of VPL theories to incorporate exposure-based influences on learning.

Causal Evidence for Learning-Dependent Frontal Lobe Contributions to Cognitive Control.

The lateral prefrontal cortex (LPFC) plays a central role in the prioritization of sensory input based on task relevance. Such top-down control of perception is of fundamental importance in goal-directed behavior, but can also be costly when deployed excessively, necessitating a mechanism that regulates control engagement to align it with changing environmental demands. We have recently introduced the "flexible control model" (FCM), which explains this regulation as resulting from a self-adjusting reinforcement-learning mechanism that infers latent statistical structure in dynamic task environments to predict forthcoming states. From this perspective, LPFC-based control is engaged as a function of anticipated cognitive demand, a notion for which we previously obtained correlative neuroimaging evidence. Here, we put this hypothesis to a rigorous, causal test by combining the FCM with a transcranial magnetic stimulation (TMS) intervention that transiently perturbed the LPFC. Human participants (male and female) completed a nonstationary version of the Stroop task with dynamically changing probabilities of conflict between task-relevant and task-irrelevant stimulus features. TMS was given on each trial before stimulus onset either over the LPFC or over a control site. In the control condition, we observed adaptive performance fluctuations consistent with demand predictions that were inferred from recent and remote trial history and effectively captured by our model. Critically, TMS over the LPFC eliminated these fluctuations while leaving basic cognitive and motor functions intact. These results provide causal evidence for a learning-based account of cognitive control and delineate the nature of the signals that regulate top-down biases over stimulus processing.SIGNIFICANCE STATEMENT A core function of the human prefrontal cortex is to control the signal flow in sensory brain regions to prioritize processing of task-relevant information. Abundant work suggests that such control is flexibly recruited to accommodate dynamically changing environmental demands, yet the nature of the signals that serve to engage control remains unknown. Here, we combined computational modeling with noninvasive brain stimulation to show that changes in control engagement are captured by a self-adjusting reinforcement-learning mechanism that tracks changing environmental statistics to predict forthcoming processing demands and that transient perturbation of the prefrontal cortex abolishes these adjustments. These findings delineate the learning signals that underpin adaptive engagement of prefrontal control functions and provide causal evidence for their relevance in behavioral control.

"Should I stop or should I go? The role of associations and expectancies": Correction to Best et al. (2016).

Reports an error in "Should I stop or should I go? The role of associations and expectancies" by Maisy Best, Natalia S. Lawrence, Gordon D. Logan, Ian P. L. McLaren and Frederick Verbruggen (Journal of Experimental Psychology: Human Perception and Performance, 2016[Jan], Vol 42[1], 115-137). In the article, there is an error in Table 3 of the Results and third paragraph of the Results section labeled Test phase. In Experiment 4, the study performed an exploratory post-hoc test of the go reaction times in the training phase, contrasting stop-associated and go-associated items. Control items were excluded. Instead of reporting the results of the full analysis (with all three items types included), the authors incorrectly reported the results of this post-hoc analysis in Table 3 and in the main text. The correct analysis is presented below. Note that all other analyses reported in the tables and main text are correct. The R code shared via Open Research Exeter data repository (http://hdl.handle .net/10871/17735) is also correct. The interaction between image type and block is no longer significant when control items are included (p .094; p .037 for the post-hoc test). (The following abstract of the original article appeared in record 2015-40003-001.) Following exposure to consistent stimulus-stop mappings, response inhibition can become automatized with practice. What is learned is less clear, even though this has important theoretical and practical implications. A recent analysis indicates that stimuli can become associated with a stop signal or with a stop goal. Furthermore, expectancy may play an important role. Previous studies that have used stop or no-go signals to manipulate stimulus-stop learning cannot distinguish between stimulus-signal and stimulus-goal associations, and expectancy has not been measured properly. In the present study, participants performed a task that combined features of the go/no-go task and the stop-signal task in which the stop-signal rule changed at the beginning of each block. The go and stop signals were superimposed over 40 task-irrelevant images. Our results show that participants can learn direct associations between images and the stop goal without mediation via the stop signal. Exposure to the image-stop associations influenced task performance during training, and expectancies measured following task completion or measured within the task. But, despite this, we found an effect of stimulus-stop learning on test performance only when the task increased the task-relevance of the images. This could indicate that the influence of stimulus-stop learning on go performance is strongly influenced by attention to both task-relevant and task-irrelevant stimulus features. More generally, our findings suggest a strong interplay between automatic and controlled processes. (PsycINFO Database Record

Longitudinal alterations in motivational salience processing in ultra-high-risk subjects for psychosis.

Impairments in the attribution of salience are thought to be fundamental to the development of psychotic symptoms and the onset of psychotic disorders. The aim of the present study was to explore longitudinal alterations in salience processing in ultra-high-risk subjects for psychosis. A total of 23 ultra-high-risk subjects and 13 healthy controls underwent functional magnetic resonance imaging at two time points (mean interval of 17 months) while performing the Salience Attribution Test to assess neural responses to task-relevant (adaptive salience) and task-irrelevant (aberrant salience) stimulus features. At presentation, high-risk subjects were less likely than controls to attribute salience to relevant features, and more likely to attribute salience to irrelevant stimulus features. These behavioural differences were no longer evident at follow-up. When attributing salience to relevant cue features, ultra-high-risk subjects showed less activation than controls in the ventral striatum at both baseline and follow-up. Within the high-risk sample, amelioration of abnormal beliefs over the follow-up period was correlated with an increase in right ventral striatum activation during the attribution of salience to relevant cue features. These findings confirm that salience processing is perturbed in ultra-high-risk subjects for psychosis, that this is linked to alterations in ventral striatum function, and that clinical outcomes are related to longitudinal changes in ventral striatum function during salience processing.

Garner-Interference in Skilled Right-Handed Grasping is Possible.

According to the Perception-Action-Model (PAM), the human visual cortex consists of the ventral vision-for-perception and the dorsal vision-for-action streams. Performance decrements with increasing variation of nominally task-irrelevant stimulus features (Garner-Interference) was suggested as an empirical tool for identifying contributions of these streams: vision-for-perception, but not visionfor-action, should suffer from Garner-Interference, but inconsistencies in this argument were revealed by several studies. We here used a new manipulation to induce Garner-Interference in a dorsal task: The stimulus objects did not differ in their lengths but in the side to which they were weighted. In Experiment 1, Garner-Interference was found in a ventral perceptual judgment task. Notably, we did also find Garner-Interference in skilled right-handed grasping in Experiment 2. These findings suggest that the presence or absence of Garner-Interference does not consistently index the contribution of different processing streams for perception and action, but the coprocessing of nominally task-irrelevant stimulus features in general, be it for perception of action.

Intact Rapid Facial Mimicry as well as Generally Reduced Mimic Responses in Stable Schizophrenia Patients.

Spontaneous emotional expressions (rapid facial mimicry) perform both emotional and social functions. In the current study, we sought to test whether there were deficits in automatic mimic responses to emotional facial expressions in patients (15 of them) with stable schizophrenia compared to 15 controls. In a perception-action interference paradigm (the Simon task; first experiment), and in the context of a dual-task paradigm (second experiment), the task-relevant stimulus feature was the gender of a face, which, however, displayed a smiling or frowning expression (task-irrelevant stimulus feature). We measured the electromyographical activity in the corrugator supercilii and zygomaticus major muscle regions in response to either compatible or incompatible stimuli (i.e., when the required response did or did not correspond to the depicted facial expression). The compatibility effect based on interactions between the implicit processing of a task-irrelevant emotional facial expression and the conscious production of an emotional facial expression did not differ between the groups. In stable patients (in spite of a reduced mimic reaction), we observed an intact capacity to respond spontaneously to facial emotional stimuli.

Should I stop or should I go? The role of associations and expectancies.

Following exposure to consistent stimulus–stop mappings, response inhibition can become automatized with practice. What is learned is less clear, even though this has important theoretical and practical implications. A recent analysis indicates that stimuli can become associated with a stop signal or with a stop goal. Furthermore, expectancy may play an important role. Previous studies that have used stop or no-go signals to manipulate stimulus–stop learning cannot distinguish between stimulus-signal and stimulus-goal associations, and expectancy has not been measured properly. In the present study, participants performed a task that combined features of the go/no-go task and the stop-signal task in which the stop-signal rule changed at the beginning of each block. The go and stop signals were superimposed over 40 task-irrelevant images. Our results show that participants can learn direct associations between images and the stop goal without mediation via the stop signal. Exposure to the image-stop associations influenced task performance during training, and expectancies measured following task completion or measured within the task. But, despite this, we found an effect of stimulus–stop learning on test performance only when the task increased the task-relevance of the images. This could indicate that the influence of stimulus–stop learning on go performance is strongly influenced by attention to both task-relevant and task-irrelevant stimulus features. More generally, our findings suggest a strong interplay between automatic and controlled processes.

Auditory selective attention is enhanced by a task-irrelevant temporally coherent visual stimulus in human listeners.

In noisy settings, listening is aided by correlated dynamic visual cues gleaned from a talker's face-an improvement often attributed to visually reinforced linguistic information. In this study, we aimed to test the effect of audio-visual temporal coherence alone on selective listening, free of linguistic confounds. We presented listeners with competing auditory streams whose amplitude varied independently and a visual stimulus with varying radius, while manipulating the cross-modal temporal relationships. Performance improved when the auditory target's timecourse matched that of the visual stimulus. The fact that the coherence was between task-irrelevant stimulus features suggests that the observed improvement stemmed from the integration of auditory and visual streams into cross-modal objects, enabling listeners to better attend the target. These findings suggest that in everyday conditions, where listeners can often see the source of a sound, temporal cues provided by vision can help listeners to select one sound source from a mixture.

Repetition expectancy vs. conflict adaptation: which better explains the congruency sequence effect?

Event Abstract Back to Event Repetition expectancy vs. conflict adaptation: which better explains the congruency sequence effect? Janette L. Smith1* and Christopher Sufani2 1 University of New South Wales, National Drug and Alcohol Research Centre, Australia 2 University of New South Wales, School of Psychology, Australia Aims: Response conflict tasks often involve task-irrelevant stimulus features which are either congruent or incongruent with the relevant target stimulus feature, resulting in interference (increased RT and error rate, larger N2 and P3 amplitude) on incongruent trials. However, this effect is larger if the previous stimulus was a congruent trial: this defines the congruency sequence effect (CSE). In the current study, we examine two competing theories explaining the CSE (namely, that participants expect repetitions, or that they adapt to conflict trial-by-trial) by comparing the effects of longer trial sequences. Method: 35 participants completed an Eriksen flanker task while EEG was recorded. Post-experimentally, trials were sorted according to the identity of not only the current trial, but also the preceding three trials. Results: When trials were sorted according to the sequence of repetitions and alternations, no strong evidence of subjective expectancies was observed. However, when trials were sorted according to the number and recency of congruent trials in the preceding sequence, there were strong effects suggesting conflict adaptation, with error rate, RT, and N2 and P3 amplitude to incongruent trials all showing linear reductions with increasing numbers of incongruent trials in the preceding sequence. Conclusions: The results highlight the utility of considering longer sequences of trials than are traditionally examined. Acknowledgements Dr JL Smith was supported in this work by a Vice-Chancellor's Postdoctoral Research Fellowship and an Australian Rotary Health Royce Abbey Postdoctoral Fellowship. Keywords: congruency sequence effect, conflict adaptation, expectancy, Eriksen Flanker task, Gratton effect Conference: Australasian Society for Psychophysiology, Inc, Coffs Harbour, Australia, 26 Nov - 28 Nov, 2014. Presentation Type: Poster Topic: Psychophysiology Citation: Smith JL and Sufani C (2014). Repetition expectancy vs. conflict adaptation: which better explains the congruency sequence effect?. Conference Abstract: Australasian Society for Psychophysiology, Inc. doi: 10.3389/conf.fnhum.2014.216.00011 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 22 Oct 2014; Published Online: 02 Dec 2014. * Correspondence: Dr. Janette L Smith, University of New South Wales, National Drug and Alcohol Research Centre, Sydney, Australia, janette.smith@unsw.edu.au Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Janette L Smith Christopher Sufani Google Janette L Smith Christopher Sufani Google Scholar Janette L Smith Christopher Sufani PubMed Janette L Smith Christopher Sufani Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Long-Term Cardiovascular Fitness Is Associated with Auditory Attentional Control in Old Adults: Neuro-Behavioral Evidence

It has been shown that healthy aging affects the ability to focus attention on a given task and to ignore distractors. Here, we asked whether long-term physical activity is associated with lower susceptibility to distraction of auditory attention, and how physically active and inactive seniors may differ regarding subcomponents of auditory attention. An auditory duration discrimination task was employed, and involuntary attentional shifts to task-irrelevant rare frequency deviations and subsequent reorientation were studied by analysis of behavioral data and event-related potential measures. The frequency deviations impaired performance more in physically inactive than active seniors. This was accompanied by a stronger frontal positivity (P3a) and increased activation of anterior cingulate cortex, suggesting a stronger involuntary shift of attention towards task-irrelevant stimulus features in inactive compared to active seniors. These results indicate a positive relationship between physical fitness and attentional control in elderly, presumably due to more focused attentional resources and enhanced inhibition of irrelevant stimulus features.

Neural correlates of reward-driven attentional capture in visual search

Event-related potentials (ERPs) were used to investigate whether a physically non-salient and task-irrelevant stimulus feature previously associated with reward can capture attention. In the training phase, participants implicitly associated a certain color with reward. In the subsequent test phase, participants searched for a uniquely shaped singleton among non-target shapes, with color completely irrelevant to the current task demand. Response time was delayed on trials wherein the target was simultaneously presented with an associated distracter, compared with trials without one. In ERPs, a lateralized reward-associated distracter elicited an N2pc component when a concurrent target was presented on the vertical meridian. The control experiment discounted the possibility that this N2pc was caused by familiarity of the reward-associated distracter. Presenting both the target and reward-associated distracter on the opposite side elicited N2pc, with the reward-associated distracter-elicited N2pc preceding the target-elicited N2pc, albeit only in trials with slow responses. These results show that the participants shifted their attention to the target only after noticing the task-irrelevant reward-associated distracter in slow trials. Therefore, task-irrelevant reward-driven salience can capture attention. Distracter positivity was observed in fast distracter-present trials presenting both a lateral distracter and a midline target. Thus, the reward-associated distracter should be actively suppressed to efficiently select the task-relevant target. Lastly, the distracter-elicited N2pc was negatively correlated with individual differences in reward drive score. This correlation may provide insight into reward sensitivity problems.

Conflict Background Triggered Congruency Sequence Effects in Graphic Judgment Task

Congruency sequence effects refer to the reduction of congruency effects when following an incongruent trial than following a congruent trial. The conflict monitoring account, one of the most influential contributions to this effect, assumes that the sequential modulations are evoked by response conflict. The present study aimed at exploring the congruency sequence effects in the absence of response conflict. We found congruency sequence effects occurred in graphic judgment task, in which the conflict stimuli acted as irrelevant information. The findings reveal that processing task-irrelevant conflict stimulus features could also induce sequential modulations of interference. The results do not support the interpretation of conflict monitoring and favor a feature integration account that the congruency sequence effects are attributed to the repetitions of stimulus and response features.

Event-related near-infrared spectroscopy detects conflict in the motor cortex in a Stroop task

The Stroop effect is one of the most popular models of conflict processing in neuroscience and psychology. The response conflict theory of the Stroop effect explains decreased performance in the incongruent condition of Stroop tasks by assuming that the task-relevant and the task-irrelevant stimulus features elicit conflicting response tendencies. However, to date, there is not much explicit neural evidence supporting this theory. Here we used functional near-infrared imaging (fNIRS) to examine whether conflict at the level of the motor cortex can be detected in the incongruent relative to the congruent condition of a Stroop task. Response conflict was determined by comparing the activity of the hemisphere ipsilateral to the response hand in the congruent and incongruent conditions. First, results provided explicit hemodynamic evidence supporting the response conflict theory of the Stroop effect: there was greater motor cortex activation in the hemisphere ipsilateral to the response hand in the incongruent than in the congruent condition during the initial stage of the hemodynamic response. Second, as fNIRS is still a relatively novel technology, it is methodologically significant that our data shows that fNIRS is able to detect a brief and transient increase in hemodynamic activity localized to the motor cortex, which in this study is related to subthreshold motor response activation.

Task-switching abilities in children with autism spectrum disorder

Task-switching performance is often used as a measure of executive control functions. Various task-switching studies in children with autism spectrum disorder (ASD) found, in contrast to expectations, no impairments in cognitive flexibility. Here, we studied whether the role of memory for arbitrary task rules can explain these findings, and how studying rule memory can help to generally better understand executive control. We designed a novel task-switching paradigm to separate cognitive flexibility from demand on memory for arbitrary rules, and we compared 19 children with ASD (9 to 16 years old) with an age- and IQ-matched control group. Children with ASD had increased difficulty with task switching only when memorizing arbitrary rules was required. When no arbitrary rules needed to be memorized, they performed accurately and quickly. Nevertheless, they showed less distraction from task-irrelevant stimulus features, suggesting that they represented tasks differently from the children in the comparison group. We conclude that children with ASD have a weaker capacity of forming rule representations, which only leads to performance impairment when they need to memorize arbitrary rules. Further, executive control impairments in ASD seem more complex than hitherto hypothesized due to mutual interactions between memory demand and task representations.

Maladaptive changes in event related brain activity preceding erroneous behavior

Event Abstract Back to Event Maladaptive changes in event related brain activity preceding erroneous behavior Tom Eichele1* 1 University of Bergen, Norway Recent EEG and fMRI evidence suggests that behavioral errors are foreshadowed by systematic changes in brain activity preceding the outcome by seconds. We have employed independent component analysis of fMRI and EEG data followed by deconvolution to investigate pre-error brain activity on a trial-by-trial basis. In fMRI data from a flanker and a Simon task we found that a coincident decrease of deactivation in default mode regions of the brain, together with a decline of task-related activation in posterior medial frontal and anterior insular regions. In addition to these changes that appear to be related to general maintenance of task effort we found in a further experiment that, prior to errors, activity in perceptual areas was systematically shifted away from the task-relevant features towards task-irrelevant stimulus features. In two additional large-sample EEG studies in which predictability of trial types in a flanker task was varied we observed gradual decrease of N2 amplitudes over multiple trials prior to errors that corroborate the fMRI findings. In sum, brain activity prior to errors reflects a number of parallel adaptive processes that may result in failure when overly active: (1) Increased subjective predictability of events reduces invested effort and performance monitoring activity. (2) Attention may adaptively shift towards irrelevant features of perceptual inputs that transiently predict the required response. (3) Reduced task-related effort allows for increased task-unrelated brain activity reflected in default mode network activity. In sum, this shift of net activity raises the likelihood of future errors. Keywords: EEG, fMRI, N2, neural activity Conference: XI International Conference on Cognitive Neuroscience (ICON XI), Palma, Mallorca, Spain, 25 Sep - 29 Sep, 2011. Presentation Type: Symposium: Oral Presentation Topic: Symposium 8: Preludes to failure: electrophysiological and hemodynamic antecedents of human error Citation: Eichele T (2011). Maladaptive changes in event related brain activity preceding erroneous behavior. Conference Abstract: XI International Conference on Cognitive Neuroscience (ICON XI). doi: 10.3389/conf.fnhum.2011.207.00518 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 09 Nov 2011; Published Online: 28 Nov 2011. * Correspondence: Dr. Tom Eichele, University of Bergen, Bergen, Norway, tom.eichele@gmail.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Tom Eichele Google Tom Eichele Google Scholar Tom Eichele PubMed Tom Eichele Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Role of subthreshold stimuli in task-performance and its underlying mechanism

Considerable evidence exists indicating that a stimulus which is subthreshold and thus consciously invisible, influences brain activity and behavioral performance. However, it is not clear how subthreshold stimuli are processed in the brain. We found that a task-irrelevant subthreshold coherent motion leads to stronger disturbance in task performance than suprathreshold motion. With the subthreshold motion, fMRI activity in the visual cortex was higher, but activity in the dorsolateral prefrontal cortex (DLPFC) was lower, than with suprathreshold motion. The results of the present study demonstrate two important points. First, a weak task-irrelevant stimulus feature which is below but near the perceptual threshold more strongly activates visual area (MT+) which is highly related to the stimulus feature and more greatly disrupts task performance. This contradicts the general view that irrelevant signals that are stronger in stimulus properties more greatly influence the brain and performance and that the influence of a subthreshold stimulus is smaller than that of suprathreshold stimuli. Second, the results may reveal important bidirectional interactions between a cognitive controlling system and the visual system. LPFC, which has been suggested to provide inhibitory control on task-irrelevant signals, may have a higher detection threshold for incoming signals than the visual cortex. Task-irrelevant signals around the threshold level may be sufficiently strong to be processed in the visual system but not strong enough for LPFC to “notice” and, therefore, to provide effective inhibitory control on the signals. In this case, such signals may remain uninhibited, take more resources for a task-irrelevant distractor, and leave fewer resources for a given task, and disrupt task performance more than a suprathreshold signal. On the other hand, suprathreshold coherent motion may be “noticed”, given successful inhibitory control by LPFC, and leave more resources for a task. This mechanism may underlie the present paradoxical finding that subthreshold task-irrelevant stimuli activate the visual area strongly and disrupt task performance more and could also be one of the reasons why subthreshold stimuli tend to lead to relatively robust effects.