The speeding of voluntary reaction by a warning signal

Alerting effects require the absence of surprise

Ongoing actions are interrupted for a brief period of time whenever salient and expectancy-discrepant stimuli (surprise stimuli) interfere with the present task set. By contrast, salient stimuli (alerting cues) preceding targets can facilitate behaviour by reducing time to initiate actions. Both phenomena seem to be at odds with each other as actions are either impaired or facilitated. Therefore, in the present study, we asked how surprise and alerting effects interact. In two experiments, participants performed choice reaction tasks without any prior knowledge of the impending alerting cue. After a baseline period of trials without an alerting cue, the alerting cue was presented for the first time. It was found that the initial presentation of the alerting cue significantly slowed down reaction times. However, after just a single trial this impairment went away. This reveals that the beneficial effects of alerting for action presuppose that alerting cues are expected and represented in the top-down task set. As such, the present findings challenge the standard view of phasic alerting as a bottom-up and entirely stimulus-driven phenomenon.

A neuroergonomics approach to driver's cooperation with Lane Departure Warning Systems

Lane Departure Warning Systems (LDWS) are automation that warn drivers in case of immediate lane departure. While LDWS are associated with increased road safety, little is known about the neural aspects of the cooperation between an LDWS and the driver behind the wheel. The present study addresses this issue by combining fMRI and driving simulation for experienced and novice drivers. The results reveal brain areas activated immediately after warning: it involves areas linked to the alertness network (midbrain, thalamus, anterior cingulate cortex), to motor actions and planning (motor and premotor cortexes; BA4/6 -cerebellum) and to attentional redirection (superior frontal cortex; BA10). There were no differences between experienced and novice drivers in this network of cerebral areas. However, prior driving experience mediates the number of lane departures. The results allow for refining a model of cooperation proposed earlier in the literature, by adding a cerebral dimension.

Vision rivals audition in alerting humans for fast action

Successful behaviour requires that humans act promptly upon the ubiquitous rapid changes in the environment. Prompt actions are supported by phasic alertness, the increased readiness for perception and action elicited by warning stimuli (alerting cues). Audition is assumed to induce phasic alertness for action faster and more strongly than other senses. Here, we show that vision can be equally effective as audition. We investigated the temporal evolution and the effectiveness of visual and auditory alerting for action in a speeded choice task, while controlling for basic sensitivity differences between the modalities that are unrelated to action control (by matching auditory and visual stimuli according to reaction times in a prior simple detection task). Results revealed that alerting sped up responses, but this happened equally fast and equally strong for visual and auditory alerting cues. Thus, these findings argue that vision rivals audition in phasic alerting for prompt actions, and suggest that the underlying mechanisms work across both modalities.

Warning signals only support the first action in a sequence

Acting upon target stimuli from the environment becomes faster when the targets are preceded by a warning (alerting) cue. Accordingly, alerting is often used to support action in safety-critical contexts (e.g., honking to alert others of a traffic situation). Crucially, however, the benefits of alerting for action have been established using laboratory tasks assessing only simple choice reactions. Real-world actions are considerably more complex and mainly consist of sensorimotor sequences of several sub-actions. Therefore, it is still unknown if the benefits of alerting for action transfer from simple choice reactions to such sensorimotor sequences. Here, we investigated how alerting affected performance in a sequential action task derived from the Trail-Making-Test, a well-established neuropsychological test of cognitive action control (Experiment 1). In addition to this task, participants performed a classic alerting paradigm including a simple choice reaction task (Experiment 2). Results showed that alerting sped up responding in both tasks, but in the sequential action task, this benefit was restricted to the first action of a sequence. This was the case, even when multiple actions were performed within a short time (Experiment 3), ruling out that the restriction of alerting to the first action was due to its short-lived nature. Taken together, these findings reveal the existence of an interface between phasic alertness and action control that supports the next action.

On the relationship of arousal and attentional distraction by emotional novel sounds

Unexpected and task-irrelevant sounds can impair performance in a task. It has been shown that highly arousing emotional distractor sounds impaired performance less compared to moderately arousing neutral distractor sounds. The present study tests whether these differential emotion-related distraction effects are directly related to an enhancement of arousal evoked by processing of emotional distractor sounds. We disentangled costs of orienting of attention and benefits of increased arousal levels during the presentation of highly arousing emotional and moderately arousing neutral novel sounds that were embedded in a sequence of repeated standard sounds. We used sound-related pupil dilation responses as a marker of arousal and RTs as a marker of distraction in a visual categorization task in 57 healthy young adults. Multilevel analyses revealed increased RT and increased pupil dilation in response to novel vs. standard sounds. Emotional novel sounds reduced distraction effects on the behavioral level and increased pupil dilation responses compared to neutral novel sounds. Bayes Factors revealed strong evidence against an inverse proportional relationship between behavioral distraction effects and sound-related pupil dilation responses for emotional sounds. Given that the activity of the locus coeruleus has been linked to both changes in pupil diameter and arousal, it may embody an indirect relationship as a common antecedent by the release of norepinephrine into brain networks involved in attention control and control of the pupil. The present study provides new insights into the relation of changes in arousal and attentional distraction during the processing of emotional task-irrelevant novel sounds.

Attentional control in middle childhood is highly dynamic-Strong initial distraction is followed by advanced attention control

The ability to shield against distraction while focusing on a task requires the operation of executive functions and is essential for successful learning. We investigated the short-term dynamics of distraction control in a data set of 269 children aged 4-10 years and 51 adults pooled from three studies using multilevel models. Participants performed a visual categorization task while a task-irrelevant sequence of sounds was presented which consisted of frequently repeated standard sounds and rarely interspersed novel sounds. On average, participants responded slower in the categorization task after novel sounds. This distraction effect was more pronounced in children. Throughout the experiment, the initially strong distraction effects declined to the level of adults in the groups of 6- to 10-year-olds. Such a decline was neither observed in the groups of the 4- and 5-year-olds, who consistently showed a high level of distraction, nor in adults, who showed a constantly low level of distraction throughout the experimental session. Results indicate that distraction control is a highly dynamic process that qualitatively and quantitatively differs between age groups. We conclude that the analysis of short-term dynamics provides valuable insights into the development of attention control and might explain inconsistent findings regarding distraction control in middle childhood. In addition, models of attention control need to be refined to account for age-dependent rapid learning mechanisms. Our findings have implications for the design of learning situations and provide an additional source of information for the diagnosis and treatment of children with attention deficit disorders.

Distraction by violation of sensory predictions: Functional distinction between deviant sounds and unexpected silences

It has been established that participants performing a continuous categorization task respond significantly slower following the presentation of unexpected, task-irrelevant, auditory stimuli, compared to a repetitive (standard) sound. Evidence indicates that such distraction emerges because of the violation of sensory predictions. This has typically been studied by measuring the impact of replacing the repeated sound by a different sound on rare and unpredictable trials. Here, we examine the impact of a different type of violation: the mere omission of the standard sound. Capitalizing upon the recent finding that deviant sounds exert distinct effects on response times as a function of whether participants produced or withheld a response on the previous trial, we present the results of an experiment seeking to disentangle two potential effects of sound omission: deviance distraction and the removal of an unspecific warning signal. The results indicate that deviant sound and the unexpected omission of the standard sound impact response times through, at least partially, distinct mechanisms. Deviant sounds affect performance by triggering the orienting of attention towards a new sensory input. Sound omissions, in contrast, appear to affect performance in part because responses no longer benefit from an unspecific warning signal to prepare for action.

Phasic Alertness is Unaffected by the Attentional Set for Orienting

Warning stimuli preceding target stimuli for behaviour improve behavioural performance, which is referred to as phasic alerting. Similar benefits occur due to preceding orienting cues that draw spatial attention to the targets. It has long been assumed that alerting and orienting effects arise from separate attention systems, but recent views call this into question. As it stands, it remains unclear if the two systems are interdependent, or if they function independently. Here, we investigated whether the current attentional set for orienting modulates the effectiveness of alerting. In three experiments, participants classified visual stimuli in a speeded fashion. These target stimuli were preceded by orienting cues that could predict the target’s location, by alerting cues that were neutral regarding the target’s location, or by no cues. Alerting cues and orienting cues consisted of the same visual stimuli, linking alerting cues with the attentional set for orienting. The attentional set for orienting was manipulated in blocks, in which orienting cues were either informative or uninformative about the target’s location. Results showed that while alerting generally enhanced performance, alerting was unaffected by the informativeness of the orienting cues. These findings show that alerting does not depend on the attentional set that controls orienting based on the informational value of orienting cues. As such, the findings provide a simple dissociation of mechanisms underlying phasic alertness and spatial attentional orienting.

A Functional Coupling of Brain and Behavior During Social Categorization of Faces

Considerable research has focused on how people derive information about others' social category memberships from their faces. Theoretical models posit that early extraction of task-relevant information from a face should determine the efficiency with which that face is categorized, but evidence supporting this idea has been elusive. Here, we used a novel trial-level data analytic approach to examine the relationship between two event-related potential components-the P2, indexing early attention to category-relevant information, and the P3, indexing stimulus evaluation-and the speed of overt categorization judgments. As predicted, a larger face-elicited P2 on a particular trial was associated with faster overt race or gender categorization of that face. Moreover, this association was mediated by P3 latency, indicating that extraction of more category-relevant information early in processing facilitated stimulus evaluation. These findings support continuous flow models of information processing and the long-theorized functional significance of face-elicited neurophysiological responses for social categorization.

Effects of a neutral warning signal on spatial two-choice reactions

Posner et al. reported that, at short fixed foreperiods, a neutral warning tone reduced reaction times (RTs) in a visual two-choice task while increasing error rates for both spatially compatible and incompatible stimulus-response mappings. Consequently, they concluded that alertness induced by the warning does not affect the efficiency of information processing but the setting of a response criterion. We conducted two experiments to determine the conditions under which the trade-off occurs. In Experiment 1, participants performed the same two-choice task as in Posner et al.'s study without RT feedback. Results showed that the warning tone speeded responses with no evidence of speed/accuracy trade-off. In Experiment 2, RT feedback was provided after each response, and a speed/accuracy trade-off was found for the 50-ms foreperiod. However, better information-processing efficiency was evident for the 200-ms foreperiod. We conclude that the foreperiod effect of a 50-ms foreperiod is a result of response criterion adjustment and that providing trial-level RT feedback is critical for replicating this pattern. However, fixed foreperiods of 200 ms or longer benefit both speed and accuracy, implying a more controlled preparation component that improves response efficiency.

Rhythmic and non-rhythmic auditory precues: Multiple mechanisms mediating movement performance

Rhythmic auditory stimuli presented before a goal-directed movement have been found to improve temporal and spatial movement outcomes. However, little is known about the mechanisms mediating these benefits. The present experiment used three types of auditory stimuli to probe how improved scaling of movement parameters, temporal preparation and an external focus of attention may contribute to changes in movement performance. Three types of auditory stimuli were presented for 1200 ms before movement initiation; three metronome beats (RAS), a tone that stayed the same (tone-same), a tone that increased in pitch (tone-change) and a no sound control, were presented with and without visual feedback for a total of eight experimental conditions. The sound was presented before a visual go-signal, and participants were instructed to reach quickly and accurately to one of two targets randomly identified in left and right hemispace. Twenty-two young adults completed 24 trials per blocked condition in a counterbalanced order. Movements were captured with an Optotrak 3D Investigator, and a 4(sound) by 2(vision) repeated measures ANOVA was used to analyze dependant variables. All auditory conditions had shorter reaction times than no sound. Tone-same and tone-change conditions had shorter movement times and higher peak velocities, with no change in trajectory variability or endpoint error. Therefore, rhythmic and non-rhythmic auditory stimuli impacted movement performance differently. Based on the pattern of results we propose multiple mechanisms impact movement planning processes when rhythmic auditory stimuli are present.

Brain Activity Associated With Expected Task Difficulty

Previous research shows that people can use a cue to mentally prepare for a cognitive challenge. The response to a cue has been defined as phasic alertness which is reflected in faster responses and increased activity in frontal, parietal, thalamic, and visual brain regions. We examine if and how phasic alertness can be tuned to the expected difficulty of an upcoming challenge. If people in general are able to tune their level of alertness, then an inability to tune may be linked to disease. Twenty-two healthy volunteers performed a cued visual perception task with two levels of task difficulty. Performance and brain activity were compared between these two levels. Performance was lower for difficult stimuli than for easy stimuli. For both cue types, participants showed activation in a network associated with central executive function and deactivation in regions of the default mode network (DMN) and visual cortex. Deactivation was significantly stronger for cues signaling difficult stimuli than for cues signaling easy stimuli. This effect was most prominent in medial prefrontal gyrus, visual, and temporal cortices. Activation did not differ between the cues. Our study shows that phasic alertness is represented by activated as well as deactivated brain regions. However only deactivated brain regions tuned their level of activity to the expected task difficulty. These results suggest that people, in general, are able to tune their level of alertness to an upcoming task. Cognition may be facilitated by a brain-state coupled to expectations about an upcoming cognitive challenge. Unique identifier = 842003004¹.

Neural correlates of anticipatory cardiac deceleration and its association with the speed of perceptual decision-making, in young and older adults

Warning stimuli in sensorimotor tasks induce a state of preparedness characterized by increased alertness, focused attention and immobility. This state of attentive anticipation is associated with heart rate deceleration. Ageing affects the amplitude of the anticipatory cardiac deceleration responses; yet, the impact of this physiological change on cognitive performance is still to be elucidated. In fact, how cardiac deceleration relates to brain function and cognitive performance in the context of perceptual decision-making and different levels of decision complexity remains unknown. Here, we aimed to investigate the relationship between cardiac deceleration, brain function, and performance in perceptual decision tasks and how these associate with age-related changes. We measured simultaneously the electrocardiogram, the pupilogram, and the electroencephalogram in 36 young and 39 older adults, while they were engaged in two auditory cued reaction time tasks: a detection task and a go/no-go task requiring inhibitory control. We observed robust cardiac deceleration responses that increased with increasing task complexity. Notably, stronger modulation of the cardiac response across tasks was associated with the ability to maintain response speed as decision complexity increased suggesting a link between cardiac deceleration and facilitation of perceptual decisions. Additionally, cardiac deceleration appears to have a cortical origin as it correlated with frontocentral event-related potentials. In contrast, beta oscillations at baseline and task-related beta suppression were not predictive of cardiac deceleration suggesting a dissociation between sensorimotor oscillatory activity and this cardiac response. Importantly, we found age-related changes in anticipatory cardiac deceleration associated with deficits in perceptual decision-making.

Context Dependence Signature, Stimulus Properties and Stimulus Probability as Predictors of ERP Amplitude Variability

Typically, in an oddball paradigm with two experimental conditions, the longer the time between novels the greater P3a amplitude. Here the research question is: Does an oddball paradigm maintain the greater P3a amplitude under several experimental conditions? An EEG study was carried out with an oddball number parity decision task having four conditions in control and schizophrenic participants. Contrary to previous findings (Gonsalvez and Polich, 2002; Polich, 2007) in control participants, non-correlation was found between the time of a novel (N) stimulus condition to the next novel condition and P3a amplitude. Moreover, with an innovative method for stimulus properties extraction features and EEG analysis, single trial across-subject averaging of participants' data revealed significant correlations (r > 0.3) of stimulus properties (such as probability, frequency, amplitude, and duration) on P300, and even r > 0.5 was found when N was an environmental sound in schizophrenic patients. Therefore, stimulus properties are strong markers of some of the features in the P3a wave. Finally, a context analysis of ERP waves across electrodes revealed a consistent modulation in novel appearance for MisMatch Negativity in schizophrenia. A supplementary analysis running linear modeling (LIMO) in EEG was also provided (see Supplementary Material). Therefore, in a multiple condition task: stimulus properties and their temporal properties are strong markers of some of the features in the P300 wave. An interpretation was done based on differences between controls and schizophrenics relate to differences in the operation of implicit memory for stimulus properties and stronger correlations were observed within groups related contextual and episodic processes.

Fronto-central P3a to distracting sounds: An index of their arousing properties

The P3a observed after novel events is an event-related potential comprising an early fronto-central phase and a late fronto-parietal phase. It has classically been considered to reflect the attention processing of distracting stimuli. However, novel sounds can lead to behavioral facilitation as much as behavioral distraction. This illustrates the duality of the orienting response which includes both an attentional and an arousal component. Using a paradigm with visual or auditory targets to detect and irrelevant unexpected distracting sounds to ignore, we showed that the facilitation effect by distracting sounds is independent of the target modality and endures more than 1500 ms. These results confirm that the behavioral facilitation observed after distracting sounds is related to an increase in unspecific phasic arousal on top of the attentional capture. Moreover, the amplitude of the early phase of the P3a to distracting sounds positively correlated with subjective arousal ratings, contrary to other event-related potentials. We propose that the fronto-central early phase of the P3a would index the arousing properties of distracting sounds and would be linked to the arousal component of the orienting response. Finally, we discuss the relevance of the P3a as a marker of distraction.

Behavioral and Brain Measures of Phasic Alerting Effects on Visual Attention

In the present study, we investigated effects of phasic alerting on visual attention in a partial report task, in which half of the displays were preceded by an auditory warning cue. Based on the computational Theory of Visual Attention (TVA), we estimated parameters of spatial and non-spatial aspects of visual attention and measured event-related lateralizations (ERLs) over visual processing areas. We found that the TVA parameter sensory effectiveness a, which is thought to reflect visual processing capacity, significantly increased with phasic alerting. By contrast, the distribution of visual processing resources according to task relevance and spatial position, as quantified in parameters top-down control α and spatial bias w_index, was not modulated by phasic alerting. On the electrophysiological level, the latencies of ERLs in response to the task displays were reduced following the warning cue. These results suggest that phasic alerting facilitates visual processing in a general, unselective manner and that this effect originates in early stages of visual information processing.

Distractor-Induced Blindness: A Special Case of Contingent Attentional Capture?

The detection of a salient visual target embedded in a rapid serial visual presentation (RSVP) can be severely affected if target-like distractors are presented previously. This phenomenon, known as distractor-induced blindness (DIB), shares the prerequisites of contingent attentional capture (Folk, Remington, & Johnston, 1992). In both, target processing is transiently impaired by the presentation of distractors defined by similar features. In the present study, we investigated whether the speeded response to a target in the DIB paradigm can be described in terms of a contingent attentional capture process. In the first experiments, multiple distractors were embedded in the RSVP stream. Distractors either shared the target's visual features (Experiment 1A) or differed from them (Experiment 1B). Congruent with hypotheses drawn from contingent attentional capture theory, response times (RTs) were exclusively impaired in conditions with target-like distractors. However, RTs were not impaired if only one single target-like distractor was presented (Experiment 2). If attentional capture directly contributed to DIB, the single distractor should be sufficient to impair target processing. In conclusion, DIB is not due to contingent attentional capture, but may rely on a central suppression process triggered by multiple distractors.

Neurophysiological Correlates of Visual Dominance: A Lateralized Readiness Potential Investigation

When multisensory information concurrently arrives at our receptors, visual information often receives preferential processing and eventually dominates awareness and behavior. Previous research suggested that the visual dominance effect implicated the prioritizing of visual information into the motor system. In order to further reveal the underpinning neurophysiological mechanism of how visual information is prioritized into the motor system when vision dominates audition, the present study examined the time course of a particular motor activation ERP component, the lateralized readiness potential (LRP), during multisensory competition. The onsets of both stimulus-locked LRP (S-LRP) and response-locked LRP (R-LRP) were measured. Results showed that, the R-LRP onset to the auditory target was delayed about 91 ms when it was paired with a simultaneous presented visual target, compared to that when it was presented by itself. For the visual target, however, the R-LRP onset was comparable irrespective of whether it was paired with an auditory target or not. No significant difference was obtained for the onset of S-LRP. Taken together, the time courses of LRPs indicated that visual information was preferentially processed within the motor system, which coincides with the previous finding that the dorsal visual stream prioritizes the flow of visual information into the motor system.

Prepulse inhibition and facilitation of the postauricular reflex, a vestigial remnant of pinna startle

If the postauricular reflex (PAR) is to be used effectively in studies of emotion and attention, its sensitivity to basic modulatory effects such as prepulse inhibition and facilitation must be determined. Two experiments were carried out with healthy young adults to assess the effects of transient and sustained visual prestimuli on the pinna-flexion response to trains of startle probes. In the first experiment, participants passively viewed a small white square. It was displayed from 1,000 ms prior to onset of a train of noise bursts until the end of that train. Relative to no-prepulse control trials, PAR amplitude was inhibited, possibly due to the withdrawal of attentional resources from the auditory modality. In the second experiment, participants performed a visual oddball task in which irrelevant trains of startle probes followed most briefly displayed task stimuli (checkerboards). Prepulse inhibition was observed when a transient stimulus preceded the first probe at a lead time of 100 ms. Amplitude facilitation was observed at longer lead times. In addition to documenting the existence of prepulse inhibition and facilitation, the data suggest that the PAR is not elicited by visual stimuli, that temporal expectancy does not influence its amplitude or latency, and that this vestigial microreflex is resistant to habituation. Results are interpreted in light of a recent theory that the human PAR is a highly degraded pinna startle, in which the reflex arc no longer includes the startle center (nucleus reticularis pontis caudalis).

Arousal facilitates involuntary eye movements

Attention plays a critical role in action selection. However, the role of attention in eye movements is complicated as these movements can be either voluntary or involuntary, with, in some circumstances (antisaccades), these two actions competing with each other for execution. But attending to the location of an impending eye movement is only one facet of attention that may play a role in eye movement selection. In two experiments, we investigated the effect of arousal on voluntary eye movements (antisaccades) and involuntary eye movements (prosaccadic errors) in an antisaccade task. Arousal, as caused by brief loud sounds and indexed by changes in pupil diameter, had a facilitation effect on involuntary eye movements. Involuntary eye movements were both significantly more likely to be executed and significantly faster under arousal conditions (Experiments 1 and 2), and the influence of arousal had a specific time course (Experiment 2). Arousal, one form of attention, can produce significant costs for human movement selection as potent but unplanned actions are benefited more than planned ones.

Temporal cues derived from statistical patterns can overcome resource limitations in the attentional blink

Previous studies have shown that humans are sensitive to statistical patterns indicating the likely locations, identities, and timings of visual targets. Here we tested whether participants can also use this kind of information to ameliorate the attentional blink (AB)—a reduction in accuracy for the second of two targets (T1, T2) presented at brief intertarget intervals (lags). In particular, we asked whether participants can use patterns arising from differential distributions of intertarget lags across trials to predict the arrival of T2. We tested this by comparing the ABs in an aging versus a nonaging distribution of trials, where aging refers to the increased likelihood of T2, given that it has not yet occurred, when lags occur with equal frequencies. Experiments 1 and 2 showed that the aging condition yielded greater T2 accuracy at longer lags than did the nonaging condition. In Experiment 3, we used a more sensitive response time measure to show faster T2 discrimination at shorter lags in the nonaging condition. These results demonstrate that participants can predict the likely onset of T2 by using statistical patterns present in the AB task, and that they can use this ability to more effectively direct limited processing resources.

Subcortical evoked activity and motor enhancement in Parkinson's disease

Enhancements in motor performance have been demonstrated in response to intense stimuli both in healthy subjects and in the form of 'paradoxical kinesis' in patients with Parkinson's disease. Here we identify a mid-latency evoked potential in local field potential recordings from the region of the subthalamic nucleus, which scales in amplitude with both the intensity of the stimulus delivered and corresponding enhancements in biomechanical measures of maximal handgrips, independent of the dopaminergic state of our subjects with Parkinson's disease. Recordings of a similar evoked potential in the related pedunculopontine nucleus - a key component of the reticular activating system - provide support for this neural signature in the subthalmic nucleus being a novel correlate of ascending arousal, propagated from the reticular activating system to exert an 'energizing' influence on motor circuitry. Future manipulation of this system linking arousal and motor performance may provide a novel approach for the non-dopaminergic enhancement of motor performance in patients with hypokinetic disorders such as Parkinson's disease.

Touch automatically upregulates motor readiness in humans

Goal-directed movements require effective integration of tactile input with ongoing movement. Here we investigated the functional consequences of such integration in healthy humans by probing the influence of spatially congruent and incongruent tactile stimuli on performance in a speeded button-press task. In addition, using magnetoencephalography (MEG), we evaluated whether the modulation of somato-motor beta (13-30 Hz) oscillations following tactile input-which has been shown to propagate to motor areas-could underlie this influence. We demonstrate that congruent tactile stimuli, despite being irrelevant to the motor task, lead to both faster and more accurate responses. We further show that this automatic upregulation of lateralized motor readiness 1) is specific to tactile input, 2) is independent of the spatial separation of the hands in peripersonal space, and 3) lasts (and remains facilitatory) for up to a second after the tactile input. This pattern of behavioral results is in line with recent physiological investigations showing that somatosensory and motor areas directly influence each other's processing capacity through joint changes in brain state. At the same time, however, the tactile-induced modulation of beta oscillations (one particular index of such a somato-motor state change) could not account for the observed movement facilitation, because it had a different time course.

Common and distinct neural correlates of inhibitory dysregulation: stroop fMRI study of cocaine addiction and intermittent explosive disorder

Despite the high prevalence and consequences associated with externalizing psychopathologies, little is known about their underlying neurobiological mechanisms. Studying multiple externalizing disorders, each characterized by compromised inhibition, could reveal both common and distinct mechanisms of impairment. The present study therefore compared individuals with intermittent explosive disorder (IED) (N = 11), individuals with cocaine use disorder (CUD) (N = 21), and healthy controls (N = 17) on task performance and functional magnetic resonance imaging (fMRI) activity during an event-related color-word Stroop task; self-reported trait anger expression was also collected in all participants. Results revealed higher error-related activity in the two externalizing psychopathologies as compared with controls in two subregions of the dorsolateral prefrontal cortex (DLPFC) (a region known to be involved in exerting cognitive control during this task), suggesting a neural signature of inhibitory-related error processing common to these psychopathologies. Interestingly, in one DLPFC subregion, error-related activity was especially high in IED, possibly indicating a specific neural correlate of clinically high anger expression. Supporting this interpretation, error-related DLPFC activity in this same subregion positively correlated with trait anger expression across all participants. These collective results help to illuminate common and distinct neural signatures of impaired self-control, and could suggest novel therapeutic targets for increasing self-control in clinical aggression specifically and/or in various externalizing psychopathologies more generally.

Support for the interruption and protection hypotheses of prepulse inhibition of startle: evidence from a modified Attention Network Test

The startle response may interrupt information processing (interruption hypothesis), and prepulse inhibition of startle (PPI) may protect that processing from interruption (protection hypothesis). These hypotheses were tested by measuring startle eyeblinks during an Attention Network Test (ANT), a combined flanker and cue reaction time (RT) task that measures the efficiency of multiple attentional networks. ANT trials with and without startle stimuli presented in the interval between the visual cue (prepulse) and target were compared. Results showed that the startle stimulus served as an alerting stimulus, speeding RT in the ANT. However, this reaction time speeding was most pronounced on trials with no startle response (100% PPI). This suggests that the alerting effect of the startle stimulus was attenuated by the startle response, and that PPI decreased the degree of this interference, in support of the interruption and protection hypotheses.

Outlines of a multiple trace theory of temporal preparation

We outline a new multiple trace theory of temporal preparation (MTP), which accounts for behavior in reaction time (RT) tasks in which the participant is presented with a warning stimulus (S1) followed by a target stimulus (S2) that requires a speeded response. The theory assumes that during the foreperiod (FP; the S1–S2 interval) inhibition is applied to prevent premature response, while a wave of activation occurs upon the presentation of S2. On each trial, these actions are stored in a separate memory trace, which, jointly with earlier formed memory traces, starts contributing to preparation on subsequent trials. We show that MTP accounts for classic effects in temporal preparation, including mean RT–FP functions observed under a variety of FP distributions and asymmetric sequential effects. We discuss the advantages of MTP over other accounts of these effects (trace-conditioning and hazard-based explanations) and suggest a critical experiment to empirically distinguish among them.

Auditory attentional capture: implicit and explicit approaches

The extent to which distracting items capture attention despite being irrelevant to the task at hand can be measured either implicitly or explicitly (e.g., Simons, Trends Cogn Sci 4:147-155, 2000). Implicit approaches include the standard attentional capture paradigm in which distraction is measured in terms of reaction time and/or accuracy costs within a focal task in the presence (vs. absence) of a task-irrelevant distractor. Explicit measures include the inattention paradigm in which people are asked directly about their noticing of an unexpected task-irrelevant item. Although the processes of attentional capture have been studied extensively using both approaches in the visual domain, there is much less research on similar processes as they may operate within audition, and the research that does exist in the auditory domain has tended to focus exclusively on either an explicit or an implicit approach. This paper provides an overview of recent research on auditory attentional capture, integrating the key conclusions that may be drawn from both methodological approaches.

Time- and task-dependent non-neural effects of real and sham TMS

Transcranial magnetic stimulation (TMS) is widely used in experimental brain research to manipulate brain activity in humans. Next to the intended neural effects, every TMS pulse produces a distinct clicking sound and sensation on the head which can also influence task performance. This necessitates careful consideration of control conditions in order to ensure that behavioral effects of interest can be attributed to the neural consequences of TMS and not to non-neural effects of a TMS pulse. Surprisingly, even though these non-neural effects of TMS are largely unknown, they are often assumed to be unspecific, i.e. not dependent on TMS parameters. This assumption is inherent to many control strategies in TMS research but has recently been challenged on empirical grounds. Here, we further develop the empirical basis of control strategies in TMS research. We investigated the time-dependence and task-dependence of the non-neural effects of TMS and compared real and sham TMS over vertex. Critically, we show that non-neural TMS effects depend on a complex interplay of these factors. Although TMS had no direct neural effects, both pre- and post-stimulus TMS time windows modulated task performance on both a sensory detection task and a cognitive angle judgment task. For the most part, these effects were quantitatively similar across tasks but effect sizes were clearly different. Moreover, the effects of real and sham TMS were almost identical with interesting exceptions that shed light on the relative contribution of auditory and somato-sensory aspects of a TMS pulse. Knowledge of such effects is of critical importance for the interpretation of TMS experiments and helps deciding what constitutes an appropriate control condition. Our results broaden the empirical basis of control strategies in TMS research and point at potential pitfalls that should be avoided.

The effect of psychological stress and expectation on auditory perception: A signal detection analysis

Both psychological stress and predictive signals relating to expected sensory input are believed to influence perception, an influence which, when disrupted, may contribute to the generation of auditory hallucinations. The effect of stress and semantic expectation on auditory perception was therefore examined in healthy participants using an auditory signal detection task requiring the detection of speech from within white noise. Trait anxiety was found to predict the extent to which stress influenced response bias, resulting in more anxious participants adopting a more liberal criterion, and therefore experiencing more false positives, when under stress. While semantic expectation was found to increase sensitivity, its presence also generated a shift in response bias towards reporting a signal, suggesting that the erroneous perception of speech became more likely. These findings provide a potential cognitive mechanism that may explain the impact of stress on hallucination-proneness, by suggesting that stress has the tendency to alter response bias in highly anxious individuals. These results also provide support for the idea that top-down processes such as those relating to semantic expectation may contribute to the generation of auditory hallucinations.

The dissociation between the P3a event-related potential and behavioral distraction

Unexpected novel sounds can capture our attention and impair performance. Recent behavioral research revealed that only novel sounds that provided target-related (but not task-related) information impaired performance. This poses the question of the automaticity of novelty processing and its expression at the behavioral level. In an auditory-visual oddball paradigm, the informational content of sounds regarding the time and probability of target occurrence was varied. Independent from the informational content, novel, and deviant sounds elicited the P3a, an ERP-component related to novelty processing. In contrast, impaired performance was only observed if target-related information was provided. Results indicate that distractor sounds are automatically evaluated as potentially significant, but that the consequences for behavior depend on further processes such as the processing of the given information.

Behavioral Distraction by Auditory Deviance Is Mediated by the Sound’s Informational Value *Li and Parmentier share the first authorship of this study

Sounds deviating from an otherwise repetitive background in some task-irrelevant respect (deviant sounds among standard sounds) capture attention in an obligatory fashion and result in behavioral distraction in an ongoing task. Traditionally, such distraction has been considered as the ineluctable consequence of the deviant sound’s low probability of occurrence relative to that of the standard. Recent evidence from a cross-modal oddball task challenged this idea by showing that deviant sounds only yield distraction in a visual task when auditory distractors (standards and deviants) announce with certainty the imminent presentation of a target stimulus (event information), regardless of whether they predict the target’s temporal onset (temporal information). The present study sought to test for the first time whether this finding may be generalized to a purely auditory oddball task in which distractor and target information form part of the same perceptual stimulus. Participants were asked to judge whether a sound starting from a central location moved left or right while ignoring rare and unpredictable changes in the sound’s identity. By manipulating the temporal and probabilistic relationship between sound onset and movement onset, we disentangled the roles of event and temporal information and found that, as in the auditory-visual oddball task, deviance distraction is mediated by the extent to which distractor information harbingers the presentation of the target information (event information). This finding suggests that the provision of event information by auditory distractors is a fundamental prerequisite of behavioral deviance distraction.

Pre-stimulus sham TMS facilitates target detection

Transcranial magnetic stimulation (TMS) allows non-invasive manipulation of brain activity during active task performance. Because every TMS pulse is accompanied by non-neural effects such as a clicking sound and somato-sensation on the head, control conditions are required to ensure that changes in task behavior are indeed due to the induced neural effects. However, the non-neural effects of TMS in the context of a given task performance are largely unknown and, consequently, it is unclear what constitutes a valid control condition. We explored the non-neural effects of TMS on visual target detection. Participants received single pulse sham TMS to each hemisphere at different time points prior to target appearance during a visual target detection task. It was hypothesized that the clicking sound of a sham TMS pulse differentially affects performance depending on the location of the coil and the timing of the pulse.Our results show that, first, sham TMS caused a facilitation of reaction times when preceding the target stimulus by 150, 200, and 250 ms, whereas earlier and later time windows were not effective. Second, positioning the TMS coil ipsilateral instead of contralateral relative to the target stimulus improved reaction times. Third, infrequent noTMS trials that were interleaved with sham TMS trials had oddball-like properties resulting in increased reaction times during noTMS. The clicking sound produced by sham TMS influences task performance in multiple ways. These non-neural effects of TMS need to be controlled for in TMS research and the present findings provide an empirical basis for deciding what constitutes a valid control condition.

The temporal dynamics of early visual cortex involvement in behavioral priming

Transcranial magnetic stimulation (TMS) allows for non-invasive interference with ongoing neural processing. Applied in a chronometric design over early visual cortex (EVC), TMS has proved valuable in indicating at which particular time point EVC must remain unperturbed for (conscious) vision to be established. In the current study, we set out to examine the effect of EVC TMS across a broad range of time points, both before (pre-stimulus) and after (post-stimulus) the onset of symbolic visual stimuli. Behavioral priming studies have shown that the behavioral impact of a visual stimulus can be independent from its conscious perception, suggesting two independent neural signatures. To assess whether TMS-induced suppression of visual awareness can be dissociated from behavioral priming in the temporal domain, we thus implemented three different measures of visual processing, namely performance on a standard visual discrimination task, a subjective rating of stimulus visibility, and a visual priming task. To control for non-neural TMS effects, we performed electrooculographical recordings, placebo TMS (sham), and control site TMS (vertex). Our results suggest that, when considering the appropriate control data, the temporal pattern of EVC TMS disruption on visual discrimination, subjective awareness and behavioral priming are not dissociable. Instead, TMS to EVC disrupts visual perception holistically, both when applied before and after the onset of a visual stimulus. The current findings are discussed in light of their implications on models of visual awareness and (subliminal) priming.

Lying and executive control: an experimental investigation using ego depletion and goal neglect

This study investigated whether lying requires executive control using a reaction-time based lie test. We hypothesized that (1) goal neglect induced by a long response-stimulus interval (RSI; 5-8s) would make lying harder relative to a short RSI (.2 s) that promoted attentional focus, and (2) participants whose executive control resources were depleted by an initial executive control task would experience more difficulty to lie than control participants who performed a task that required little executive control. Across two experiments, the ego depletion manipulation did not reliably affect lying. Both experiments revealed that the cognitive cost associated with lying was larger for the long compared to the short RSI. This finding supports the idea that lying requires more executive control than truth telling. The manipulation of RSI may provide a simple, yet effective means to improve lie detection accuracy.

Decomposition of warning effects in Parkinson's disease

Neutral warning signals speed voluntary reactions by reducing temporal uncertainty and by triggering a brief burst of arousal. We attempted to isolate the phasic arousal mechanism in people with Parkinson's disease (PD) using a clock display to minimize temporal uncertainty. In this condition, the speeding of responses in a color-discrimination task by an accessory stimulus was the fully equivalent to the effect in age-matched control subjects. This indicates preserved phasic arousal in PD. Temporal preparation based on warning cues also appeared to be normal. By contrast, in a condition with high temporal uncertainty, the accessory stimulus (an air puff to the foot) impaired accuracy for the patients but not the neurologically normal subjects. The data are consistent with the view that PD disrupts internal but not external control of alertness.

Does temporal preparation increase the rate of sensory information accumulation?

Recent studies showed that temporal preparation, i.e., the ability to prepare for an upcoming stimulus, improves perceptual processing. The mechanisms underlying this benefit are still controversial. Based upon the theoretical framework of accumulation models, it has been proposed that the accumulation of sensory stimulus information begins earlier when participants are temporally prepared than when they are unprepared. Alternatively, however, temporal preparation might also affect the accumulation rate of sensory information. In the present study, we examined these possibilities. Specifically, in three experiments, we manipulated participants' decision criterion. This manipulation should interact with any experimental manipulation affecting the rate of information processing, but produce additive effects with any manipulation affecting the onset of information accumulation rather than its rate. We obtained additive effects on RT, irrespective of whether the decision criterion was manipulated by increasing catch trial proportion or nogo trial proportion. These results suggest that temporal preparation improves perceptual processing by operating on the onset of sensory information accumulation rather than the rate of sensory information accumulation.