Temporal preparation,response inhibition and impulsivity

Temporal preparation and impulsivity involve overlapping neural structures (prefrontal cortex) and cognitive functions (response inhibition and time perception), however, their interrelations had not been investigated. We studied such interrelations by comparing the performance of groups with low vs. high non-clinical trait impulsivity during a temporal preparation go no-go task. This task measured, in less than 10 min, how response inhibition was influenced both by temporal orienting of attention (guided by predictive temporal cues) and by sequential effects (produced by repetition/alternation of the duration of preparatory intervals in consecutive trials). The results showed that sequential effects produced dissociable patterns of temporal preparation as a function of impulsivity. Sequential effects facilitated both response speed (reaction times – RTs – to the go condition) and response inhibition (false alarms to the no-go condition) selectively in the low impulsivity group. In the high impulsivity group, in contrast, sequential effects only improved RTs but not response inhibition. We concluded that both excitatory and inhibitory processing may be enhanced concurrently by sequential effects, which enables the temporal preparation of fast and controlled responses. Impulsivity could hence be related to less efficient temporal preparation of that inhibitory processing.     

The development of attentional orienting during the school‐age years

This study was designed to assess the development of spatial attentional orienting during the school‐age years. To that end, we used a cost‐benefit attentional cueing task with short (100 ms) and long (800 ms) cue‐to‐target intervals to examine attentional processing independent of motor skills and perceptual processing in 200 7–17‐year‐olds and 40 adults. We found that orienting attention, disengaging attention and visual processing in an unattended location, were all progressively more accurate and faster with increasing age. Our data thus suggest that the efficiency of attentional orienting improves in an age‐related manner throughout the school‐age years.     

Time for action versus action in time: time estimation differs between motor preparation and execution

Theories relating to time perception and motor performance predict very different temporal distortions depending on the synchronisation or succession of temporal processing and motor behaviour. However, our knowledge about the temporal difference between motor preparation and execution is still scarce. In order to expand on prior studies, two different time reproduction tasks were utilised to measure motor preparation and motor execution. We found that motor preparation of a planned action allows participants to complete the time reproduction task more accurately and, in short duration trials, less variably than for motor execution. Furthermore, under-reproduction was found in motor preparation compared to motor execution, which may be caused by increased temporal information processing. According to the attentional gate theory, more attention allocated to time processing and reduced motor distraction leads to less temporal distortion in the motor preparation. The findings are also important for designing to study consciousness, temporal and visual processing.     

Independent effects of temporal expectation and stimulus intensity in audition

Temporal orienting—that is, selective attention to instants in time—has been shown to modulate performance in terms of faster responses in a variety of paradigms. Electrophysiological recordings have shown that temporal orienting modulates neural processing at early, probably perceptual, and late, probably decision- or response-related, stages. Recently, it was shown that the effect of temporal orienting on early auditory brain potentials is independent of the effect of the physical sound feature intensity. This indicates that temporal orienting might not affect stimulus processing by increasing the sensory gain of attended stimuli. In the present study, we investigated whether the independence of temporal-orienting and sound-intensity effects could be replicated behaviorally. Sequences were presented that were either rhythmic, most likely creating temporal expectations, or arrhythmic, presumably not creating such expectations. As hypothesized, the main effects of temporal expectation and sound intensity on reaction times were independent (Experiment 1). The exact pattern of results was replicated with a slightly altered paradigm (Experiment 2) and with a different kind of task (Experiment 3). In sum, these results corroborate the notion that the effect of temporal orienting might not rely on the same processes as the effect of sound intensity does.     

Challenging perceptual tasks require more attention: The influence of task difficulty on the N1 effect of temporal orienting

Both filter and resource models of attention suggest an influence of task difficulty on the size of early attention effects. As for temporal orienting, the idea that early effects are modulated by task difficulty has not been tested directly, so far. To fill this empirical gap, the present study used an auditory temporal-orienting task, in which two differently pitched pure tones served as targets. To manipulate perceptual difficulty, the pitch difference between the targets was either small or large. Temporal orienting enhanced the N1 component of the auditory event-related potential. This early, sensory effect tended to be larger in the more difficult condition, particularly over the frontal scalp. Notably, increasing task difficulty affected predominantly the processing of attended stimuli. Hence, temporal orienting may operate by increasing processing resources or gain settings for the attended time point – rather than by withdrawing resources from the unattended time point.     

Knowing when to hear aids what to hear

Temporal preparation often has been assumed to influence motor stages of information processing. Recent studies, however, challenge this notion and provide evidence for a facilitation of visual processing. The present study was designed to investigate whether perceptual processing in the auditory domain also benefits from temporal preparation. To this end, we employed a pitch discrimination task. In Experiment 1, discrimination performance was clearly improved when participants were temporally prepared. This finding was confirmed in Experiment 2, which ruled out possible influences of short-term memory. The results support the notion that temporal preparation enhances perceptual processing not only in the visual, but also in the auditory, modality.     

Knowing when to hear aids what to hear

Temporal preparation often has been assumed to influence motor stages of information processing. Recent studies, however, challenge this notion and provide evidence for a facilitation of visual processing. The present study was designed to investigate whether perceptual processing in the auditory domain also benefits from temporal preparation. To this end, we employed a pitch discrimination task. In Experiment 1, discrimination performance was clearly improved when participants were temporally prepared. This finding was confirmed in Experiment 2, which ruled out possible influences of short-term memory. The results support the notion that temporal preparation enhances perceptual processing not only in the visual, but also in the auditory, modality.     

Responding to emotional scenes: effects of response outcome and picture repetition on reaction times and the late positive potential

Processing the motivational relevance of a visual scene and reacting accordingly is crucial for survival. Previous work suggests the emotional content of naturalistic scenes affects response speed, such that unpleasant content slows responses whereas pleasant content accelerates responses. It is unclear whether these effects reflect motor-cognitive processes, such as attentional orienting, or vary with the function/outcome of the motor response itself. Four experiments manipulated participants’ ability to terminate the picture (offset control) and, thereby, the response’s function and motivational value. Attentive orienting was manipulated via picture repetition, which diminishes orienting. A total of N?=?81 participants completed versions of a go/no-go task, discriminating between distorted versus intact pictures drawn from six content categories varying in positive, negative, or neutral valence. While all participants responded faster with repetition, only participants without offset control exhibited slower responses to unpleasant and accelerated responses to pleasant content. Emotional engagement, measured by the late positive potential, was not modulated by attentional orienting (repetition), suggesting that the interaction between repetition and offset control is not due to altered emotional engagement. Together, results suggest that response time changes as a function of emotional content and sensitivity to attention orienting depends on the motivational function of the motor response.     

The hare and the snail: Dissociating visual orienting from conscious perception

A method for investigating attentional effects of peripheral visual objects, independently of perceptual identification, is described. We report an experiment using this method which shows that visual processing of peripheral objects differs radically, depending on whether participants move attention in response to an object or consciously perceive that object. When luminance contrast was reduced, conscious perceptual discrimination of peripheral letters was massively slower and less accurate—but both low and high contrast letters elicited rapid attentional orienting effects and these rapid orienting effects were equal in magnitude across low and high contrast. This pattern is consistent with known differences in luminance sensitivity between the dorsal and ventral visual processing streams, and with rapid dorsal–ventral interaction mediated via re-entrant feedback. Our findings show that the control system responsible for rapid movements of attention is exquisitely sensitive to visual form information at low levels of contrast, and involves a different neurocognitive pathway to that which gives rise to conscious perception.     

The Mechanisms of Space‐Time Association: Comparing Motor and Perceptual Contributions in Time Reproduction

The spatial‐temporal association indicates that time is represented spatially along a left‐to‐right line. It is unclear whether the spatial‐temporal association is mainly related to a perceptual or a motor component. In addition, the spatial‐temporal association is not consistently found using a time reproduction task. Our rationale for this finding is that, classically, a non‐lateralized button for performing the task has been used. Using two lateralized response buttons, the aim of the study was to find a spatial‐temporal association in a time reproduction task. To account for the perceptual component, reference and target stimuli were presented in different spaces through four experiments. In all experiments, a Spatial‐Temporal Association of Response Codes (STEARC) effect was found and this effect was not modulated by the spatial position of both reference and target stimuli. The results suggested that the spatial‐temporal association was mainly derived from the spatial information provided by response buttons, reflecting a motor but not visuospatial influence.     

The role of mental rotations in primate-inspired robot navigation

Scripts store the temporal order of component events of everyday activities as well as the temporal position of the events within the activity (early or late). When confronted with an activity, predictions are generated about how the component events will unfold. Thereby, an error-detection mechanism continuously monitors whether they unfold as anticipated or not in order to reveal errors in the unfolding activity. We investigated whether the temporal position “early” or “late” influenced the detection of errors using the pupillary response as an index of cognitive resource consumption. An event triplet consisting of three events was presented in a chronological or non-chronological temporal order. Crucially, the triplet focused either on the beginning (temporal position “early”) or the end (temporal position “late”) of an activity. We assumed that these position codes would be used to facilitate error detection when a non-chronological event was presented. Results showed that errors in the temporal order were detected more successfully in early than in late triplets. Results further suggest that strong predictions are formed about how an activity begins. Violations of this prediction must be overcome by zooming into the representation and allocating attention to the temporal position that consumes cognitive resources. Only after zooming in has taken place successfully may the position codes be used to anticipate temporal violations in unfolding event sequences.     

The temporal dynamics of the perceptual consequences of action-effect prediction

An essential aspect of voluntary action control is the ability to predict the perceptual effects of our actions. Although the influence of action-effect prediction on humans’ behavior and perception is unequivocal, it remains unclear when action-effect prediction is generated by the brain. The present study investigates the dynamics of action effect anticipation by tracing the time course of its perceptual consequences. Participants completed an acquisition phase during which specific actions (left and right key-presses) were associated with specific visual effects (upward and downward dots motion). In the test phase they performed a 2 AFC identification task in which they were required to indicate whether the dots moved upward or downward. To isolate any effects of action-effect prediction on perception, participants were presented with congruent and incongruent dot motion in which the association participants learned in the previous acquisition phase was respected and violated, respectively. Crucially, to assess the temporal dynamics of action prediction, congruent and incongruent stimuli were presented at different intervals before or after action execution. We observed higher sensitivity (d′) to motion discrimination in congruent vs. incongruent trials only when stimuli were presented from about 220 ms before the action to 280 ms after the action. The temporal dynamics of our effect suggest that action-effect prediction modulates perception at later stages of motor preparation.     

Great expectations: Temporal expectation modulates perceptual processing speed

In a crowded dynamic world, temporal expectations guide our attention in time. Prior investigations have consistently demonstrated that temporal expectations speed motor behavior. We explore effects of temporal expectation on perceptual speed in three nonspeeded, cued recognition paradigms. Different hazard rate functions for the cue-stimulus foreperiod were used to manipulate temporal expectations. By computational modeling we estimated two distinct components of visual attention: the temporal threshold of conscious perception (t? ms) and the speed of subsequent encoding into visual short-term memory (v items/s). Notably, these components were measured independently of any motor involvement. The threshold t? was unaffected by temporal expectation, but perceptual processing speed v increased with increasing expectation. By employing constant hazard rates to keep expectation constant over time, we further confirmed that the increase in perceptual speed was independent of the cue-stimulus duration. Thus, our results strongly suggest temporal expectations optimize perceptual performance by speeding information processing. (PsycINFO Database Record (c) 2012 APA, all rights reserved).     

Testing whether gaze cues and arrow cues produce reflexive or volitional shifts of attention

It has been suggested that two types of uninformative central cues produce reflexive orienting: gaze and arrow cues. Using the criterion that voluntary shifts of attention facilitate both response speed and perceptual accuracy, whereas reflexive shifts of attention facilitate only response speed (Prinzmetal, McCool, & Park, 2005), we tested whether these cues produce reflexive or volitional shifts of attention. A cued letter discrimination task was used with both gaze (Experiments 1A and 1B) and arrow (Experiments 2A and 2B) cues, in which participants responded to the identity of the target letter. In the response time (respond speed) tasks, participants were asked to respond as quickly as possible to the target; in the accuracy (perceptual quality) tasks, participants were asked to respond as accurately as possible. For both cue types, compatible cues were found to facilitate response speed but not perceptual accuracy, indicating that both gaze and arrow cues generate reflexive shifts in attention.     

Does temporal integration of face parts reflect holistic processing?

We examined whether temporal integration of face parts reflects holistic processing or response interference. Participants learned to name two faces “Fred” and two “Bob.” At test, the top and bottom halves of different faces formed composites and were presented briefly separated in time. Replicating prior findings (Singer & Sheinberg, Vision Research, 46, 1838–1847, 2006), naming of the target half for aligned composites was slowed when the irrelevant half was from a face with a different name rather than from the original face. However, no interference was observed when the irrelevant half had a name identical to the name of the target half but came from a different learned face, arguing against a true holistic effect. Instead, response interference was obtained when the target half briefly preceded the irrelevant half. Experiment 2 confirmed a double dissociation of holistic processing versus response interference for intact faces versus temporally separated face halves, suggesting that simultaneous presentation of facial information is critical for holistic processing.     

Effects of temporal trial-by-trial cuing on early and late stages of auditory processing: Evidence from event-related potentials

Temporal-cuing studies show faster responding to stimuli at an attended versus unattended time point. Whether the mechanisms involved in this temporal orienting of attention are located early or late in the processing stream has not been answered unequivocally. To address this question, we measured event-related potentials in two versions of an auditory temporal cuing task: Stimuli at the uncued time point either required a response (Experiment 1) or did not (Experiment 2). In both tasks, attention was oriented to the cued time point, but attention could be selectively focused on the cued time point only in Experiment 2. In both experiments, temporal orienting was associated with a late positivity in the timerange of the P3. An early enhancement in the timerange of the auditory N1 was observed only in Experiment 2. Thus, temporal attention improves auditory processing at early sensory levels only when it can be focused selectively.     

Temporal preparation decreases perceptual latency: Evidence from a clock paradigm

A clock paradigm was employed to assess whether temporal preparation decreases the time to detect the onset of a stimulus—that is, perceptual latency. In four experiments participants watched a revolving clock hand while listening to soft or loud target tones under high or low temporal preparation. At the end of each trial, participants reported the clock hand position at the onset of the target tone. The deviation of the reported clock hand position from the actual position indexed perceptual latency. As expected, perceptual latency decreased with target tone intensity. Most importantly, however, greater temporal preparation decreased perceptual latency in all four experiments, especially for soft tones, which supports rather directly the idea that temporal preparation diminishes the duration of perceptual processing.     

The time course of temporal attention effects on nonconscious prime processing

We presented a masked prime at various prime–target intervals (PTIs) before a target that required a speeded motor response and investigated the impact of temporal attention on the nonconscious prime processing. The allocation of temporal attention to the target was manipulated by presenting an accessory tone and comparing that condition with a no-tone condition. The results showed that, independently of the visibility of the prime, temporal attention led to an enhanced effect of prime–target congruency on the reaction times, and that the amount of the enhancement increased with increasing PTIs. This effect pattern is consistent with the assumption of increasing influences of temporal attention and of the increasing PTI on nonconscious prime processing; it argues against the hypothesis that temporal attention narrows the time period in which the prime may affect target processing. An accumulator model is proposed assuming that target-related temporal attention increases the accumulation rate for masked primes and, thus, enhances the impact of the prime on the speed of choice decisions.     

Visual search proceeds concurrently during the attentional blink and response selection bottleneck

It is well known that human information processing comprises several distinct subprocesses—namely, the perceptual, central, and motor stage. In each stage, attention plays an important role. Specifically, a type of attention—perceptual attention—operates to detect and identify a sensory input. Following this, another class of attention—central attention—is involved in working memory encoding and response selection at the central stage. While perceptual attention and central attention are known to be separate, distinct processes, some researchers reported findings that loading central attention postponed the deployment of perceptual attention needed to perform a spatial configuration search. We tested whether a similar pattern of results would emerge when a different kind of search task is used. To do so, we had participants perform a visual-search task of searching for a feature conjunction target, taxing perceptual attention while they are engaged in central processes, such as working memory encoding and response selection. The results showed that perceptual processing of conjunction search stimuli could be carried out concurrently with central processes. These results suggest that the nature of the concurrent visual search process is a determinant responsible for the dynamic relationship between perceptual attention deployed for visual search and central attention needed for working memory encoding and response selection.

     

Time processing in children with Tourette’s syndrome

Background

Tourette syndrome (TS) is characterized by dysfunctional connectivity between prefrontal cortex and sub-cortical structures, and altered meso-cortical and/or meso-striatal dopamine release. Since time processing is also regulated by fronto-striatal circuits and modulated by dopaminergic transmission, we hypothesized that time processing is abnormal in TS.

Methods

We compared time processing abilities between nine children with TS-only (i.e. without major psychiatric comorbidities) and 10 age-matched healthy children, employing a time reproduction task in which subjects actively reproduce different temporal intervals, and a time comparison task in which subjects judge whether a test interval is longer or shorter than a reference interval. IQ, sustained and divided attention, and working memory were assessed in both groups using the Leiter International Performance Scale-Revised, and the Digit Span sub-test of the WISC-R.

Results

Children with TS-only reproduced in an overestimated fashion over-second, but not sub-second, time intervals. The precision of over-second intervals reproduction correlated with tic severity, in that the lower the tic severity, the closer the reproduction of over-second time intervals to their real duration. Time reproduction performance did not significantly correlate with IQ, attention and working memory measures in both groups. No differences between groups were documented in the time comparison task.

Conclusions

The improvement of time processing in children with TS-only seems specific for the over-second range of intervals, consistent with an enhancement in the ‘cognitively controlled’ timing system, which mainly processes longer duration intervals, and depends upon dysfunctional connectivity between the basal ganglia and the dorso-lateral prefrontal cortex. The absence of between-group differences on time comparison, moreover, suggests that TS patients manifest a selective improvement of ‘motor’ timing abilities, rather than of perceptual time abilities. Our data also support an enhancement of cognitive control processes in TS children, probably facilitated by effortful tic suppression.