Stroop interference is affected in inhibition of return

The role of the parietal cortex in inhibitory processing in the vertical meridian: Evidence from elderly brain damaged patients

We explored the effects of parietal damage on inhibitory effects of visuospatial attention, inhibition of return (IOR) and inhibitory tagging (IT), in the vertical meridian. We combined a vertical spatial cue paradigm with a Stroop task employing three different temporal intervals between the spatial cue and the target (700, 1200 and 2000 ms) in two groups of patients, one with damage to the parietal cortex and underlying white matter (the parietal patients group) and the other with damage in other brain areas not including the parietal lobe (the control patient group), and a healthy control group. Healthy controls showed the expected inhibitory effects, IOR at the 700 and 1200 intervals and IT at the 1200 interval (as evidenced in a reduction in the magnitude of Stroop interference at the cued location). On the other hand, only the group of parietal patients showed delayed onset of inhibitory effects, IOR and IT appeared at the 1200 ms and 2000 ms intervals, respectively. These findings provide evidence for a role of the parietal cortex, and the underlying fibre tracts, in inhibitory processing in the vertical meridian, with damage to the parietal cortex altering the time course of attention-dependent inhibition.

An ERP investigation of the working memory stroop effect

This study aimed to explore the neural activity associated with the Working Memory (WM) Stroop effect. Stroop facilitation and interference effects in WM were also investigated by adding a neutral condition to the WM Stroop paradigm. In each trial, participants were first asked to remember a word in WM, then respond to the color of the subsequent rectangle. The word meaning and rectangular color were congruent, incongruent, or irrelevant (neutral). Finally, a probe word appeared and participants judged whether it was the same as the first presented word. For the color decision task, behavioral results showed that 1) RTs were longer for the incongruent than congruent condition, indicating a WM Stroop effect; 2) RTs were shorter for the congruent than neutral condition, indicating a WM Stroop facilitation effect; and 3) RTs were shorter for the incongruent than neutral condition, indicating no Stroop interference effect in WM. ERPs locked to the rectangle revealed that 1) greater N2 and P3 activity was evoked for the incongruent than congruent condition, indicating more intensive conflict detection and conflict resolution processes for the incongruent condition; and 2) enhanced N2 but decreased P3 components were evoked for the neutral than the congruent and incongruent conditions, indicating a more intensive conflict monitoring process but decreased conflict resolution process for the neutral condition. These results demonstrate that when WM content is congruent with the attention task, it can facilitate attention, but WM content may not interfere with attention when they are incongruent.

Time course of the inhibitory tagging effect in ongoing emotional processing. A HD-tDCS study

When a cueing procedure that usually triggers inhibition of return (IOR) effects is combined with tasks that tap semantic processing, or involve response-based conflict, an inhibitory tagging (IT) emerges that disrupts responses to stimuli at inhibited locations. IT seems to involve the executive prefrontal cortex, mainly the left dorsolateral prefrontal cortex (DLPFC), in cognitive conflict tasks. Contrary to other inhibitory effects, IT has been observed with rather short intervals, concretely when the stimulus onset asynchrony (SOA) between the prime presented at the cued location, and the subsequent target is 250 ms. Here we asked whether IT is also applied to ongoing emotional processing, and whether the left DLPFC plays a causal role in IT using HD-tDCS. In two experiments with an emotional conflict task, we observed reduced conflict effects, the signature of IT, when the prime word was presented at the cued location, and once again when the prime-target SOA was just 250 ms. Also, the IT effect was eliminated when cathodal stimulation was applied to the left DLPFC. These findings suggest that the IT effect involves areas of the executive attention network and cooperates with IOR to favor attentional allocation to novel unexplored objects/locations, irrespective of their emotional content.

The Stroop-matching task as a tool to study the correspondence effect using images of graspable and non-graspable objects

The Stroop-matching task is a variation of the Stroop task in which participants have to compare a Stroop stimulus attribute (color or word) to a second stimulus. The Stroop-matching response conflict (SMRC) represents an interference related to the processes involved in selection/execution of manual responses. In the present study, we developed a variation of the Stroop-matching task in which the Stroop stimuli were matched to graspable objects (a cup) with intact or broken handles laterally oriented (Experiment 1) or to colored bars laterally presented (Experiment 2). It allowed testing the presence of the correspondence effect for lateralized handles and bars and its possible influence on SMRC. Two different intervals (100 and 800 ms) were also included to investigate time modulations in behavioral performance (reaction time and accuracy). Fifty-five volunteers participated in the study. In both experiments, significant SMRC was found, but no interaction occurred between SMRC and correspondence effect, supporting that the hypothesis of different and relatively independent psychological mechanisms is at the basis of each effect. Because significant facilitation for ipsilateral motor responses (correspondence effect) occurred for graspable objects but not for lateralized bars, the attentional shift/spatial-coding view was not able to completely explain our data, and therefore, the grasping affordance hypothesis remained as the most plausible explanation. The time course of facilitation observed in the first experiment and by others indicates the importance of further studies to better understand the time dynamic of facilitation/inhibition of motor responses induced by graspable objects.

Sluggish dorsally-driven inhibition of return during orthographic processing in adults with dyslexia

Dyslexia (D) is a neurodevelopmental reading disorder characterized by phonological and orthographic deficits. Before phonological decoding, reading requires a specialized orthographic system for parallel letter processing that assigns letter identities to different spatial locations. The magnocellular-dorsal (MD) stream rapidly process the spatial location of visual stimuli controlling visuo-spatial attention. To investigate the visuo-spatial attention efficiency during orthographic processing, inhibition of return (IOR) was measured in adults with and without D in a lexical decision task. IOR is the delay in responding to stimuli displayed in a cued location after a long cue-target interval. Only adults with D did not showed IOR effect during letter-string recognition, despite the typical left-hemisphere specialization for word identification. A specific deficit in coherent-dot-motion perception confirmed an MD-stream disorder in adults with D. Our results suggest that adults with D might develop an efficient visual word form area, but a dorsal-attentional dysfunction impairs their reading fluency.

The Effects of Martial Arts Training on Attentional Networks in Typical Adults

There is substantial evidence that training in Martial Arts is associated with improvements in cognitive function in children; but little has been studied in healthy adults. Here, we studied the impact of extensive training in Martial Arts on cognitive control in adults. To do so, we used the Attention Network Test (ANT) to test two different groups of participants: with at least 2 years of Martial Arts experience, and with no experience with the sport. Participants were screened from a wider sample of over 500 participants who volunteered to participate. 48 participants were selected: 21 in the Martial Arts group (mean age = 19.68) and 27 in the Non-Martial Arts group (mean age = 19.63). The two groups were matched on a number of demographic variables that included Age and BMI, following the results of a previous pilot study where these factors were found to significantly impact the ANT measures. An effect of Martial Arts experience was found on the Alert network, but not the Orienting or Executive ones. More specifically, Martial Artists showed improved performance when alert had to be sustained endogenously, performing more like the control group when an exogenous cue was provided. This result was further confirmed by a negative correlation between number of years of Martial Arts experience and the costs due to the lack of an exogenous cue suggesting that the longer a person takes part in the sport, the better their endogenous alert is. Results are interpreted in the context of the impact of training a particular attentional state in specific neurocognitive pathways.

The effect of interference in the early processing stages on response inhibition in the stop signal task

In the present study, the relation between interference at the early processing stages and response inhibition was investigated. In previous studies, response stopping appeared to be slowed down when irrelevant distracting information was presented. The purpose of the present study was to further explore the relationship between interference control and response inhibition. In Experiment 1, a stop signal paradigm was combined with a global/local task. The typical global-to-local interference effect is generally attributed to early processing stages, such as stimulus perception and identification. Results of this experiment demonstrated a congruency effect for both reaction time data and stopping performance. In Experiment 2, these results were replicated with a flanker task that used stimulus-incongruent but response-congruent flankers. Results of both experiments suggest that response inhibition and interference at the early processing stages interact.

Behavioral and neural interaction between spatial inhibition of return and the Simon effect

It has been well documented that the anatomically independent attention networks in the human brain interact functionally to achieve goal-directed behaviors. By combining spatial inhibition of return (IOR) which implicates the orienting network with some executive function tasks (e.g., the Stroop and the flanker tasks) which implicate the executive network, researchers consistently found that the interference effects are significantly reduced at cued compared to uncued locations, indicating the functional interaction between the two attention networks. However, a unique, but consistent effect is observed when spatial IOR is combined with the Simon effect: the Simon effect is significantly larger at the cued than uncued locations. To investigate the neural substrates underlying this phenomenon, we orthogonally combined the spatial IOR with the Simon effect in the present event-related fMRI study. Our behavioral data replicated previous results by showing larger Simon effect at the cued location. At the neural level, we found shared spatial representation system between spatial IOR and the Simon effect in bilateral posterior parietal cortex (PPC); spatial IOR specifically activated bilateral superior parietal cortex while the Simon effect specifically activated bilateral middle frontal cortex. Moreover, left precentral gyrus was involved in the neural interaction between spatial IOR and the Simon effect by showing significantly higher neural activity in the "Cued_Congruent" condition. Taken together, our results suggest that due to the shared spatial representation system in the PPC, responses were significantly facilitated when spatial IOR and the Simon effect relied on the same spatial representations, i.e., in the "Cued_Congruent" condition. Correspondingly, the sensorimotor system was significantly involved in the "Cued_Congruent" condition to fasten the responses, which indirectly resulted in the enhanced Simon effect at the cued location.

Attentional orienting and response inhibition: insights from spatial-temporal neuroimaging

Attentional orienting and response inhibition have largely been studied separately. Each has yielded important findings, but controversy remains concerning whether they share any neurocognitive processes. These conflicting findings may originate from two issues: (1) at the cognitive level, attentional orienting and response inhibition are typically studied in isolation; and (2) at the technological level, a single neuroimaging method is typically used to study these processes. This article reviews recent achievements in both spatial and temporal neuroimaging, emphasizing the relationship between attentional orienting and response inhibition. We suggest that coordinated engagement, both top-down and bottom-up, serves as a common neural mechanism underlying these two cognitive processes. In addition, the right ventrolateral prefrontal cortex may play a major role in their harmonious operation.

Biasing the organism for novelty: A pervasive property of the attention system

Although the functional and anatomical independences between the orienting and the executive attention networks have been well established, surprisingly little is known about the potential neural interaction between them. Recent studies point out that spatial inhibition of return (IOR), a mechanism associated with the orienting network, and nonspatial inhibition of return, a mechanism associated with the executive network, might bias the organism for novel locations and objects, respectively. By orthogonally combining the spatial and the nonspatial IOR paradigms in this fMRI study, we demonstrate that the orienting and the executive networks interact and compensate each other in biasing the attention system for novelty. Behaviorally, participants responded slower to the target at the old location only when the color of the target was novel, and participants responded slower to the old color representation only when the target appeared at a novel spatial location. Neurally, the orienting network was involved in slowing down responses to the old location only when the nonspatial IOR mechanism in the executive network was not operative (i.e., when the color of the target was novel); the prefrontal executive network was involved in slowing down responses to the old color representation only when the spatial IOR mechanism in the orienting network was not functioning (i.e., when the target appeared at a novel location).

A repetition-suppression account of between-trial effects in a modified Stroop paradigm

Theories that postulate cognitive inhibition are very common in psychology and cognitive neuroscience [e.g., Hasher, L., Lustig, C., & Zacks, R. T. (2007). Inhibitory mechanisms and the control of attention. In A. Conway, C. Jarrold, M. Kane, A. Miyake, A. Towse, & J. Towse (Eds.), Variation in working memory (pp. 227-249). New York, NY: Oxford, University Press], although they have recently been severely criticized [e.g., MacLeod, C. M., Dodd, M. D., Sheard, E. D., Wilson, D. E., & Bibi, U. (2003). In opposition to inhibition. In H. Ross (Ed.), The psychology of learning and motivation (Vol. 43, pp. 163-214). Elsevier Science]. This paper poses and attempts to answer the question whether a research program with cognitive inhibition as its main theoretical assumption is still worth pursuing. We present a set of empirical data from a modified Stroop paradigm that replicates previously reported findings. These findings refer to between-trial effects previously described in the literature on Stroop, negative priming, and inhibition-of-return. Existing theoretical accounts fail to explain all these effects in an integrated way. A repetition-suppression mechanism is proposed in order to account for these data. This mechanism is instantiated as a computational cognitive model. The theoretical implications of this model are discussed.

The time course of alerting effect over orienting in the attention network test

In the present experiment we used a version of the attention network test (ANT) similar to that of Callejas et al. (Exp Brain Res 167:27-37, 2005) to assess the Posner's attention networks (alerting, orienting and conflict), and their interactions. We observed shorter reaction times with alerting tone than with no alerting tone trials (the alerting effect); with cued than with uncued trials (the orienting effect); and with congruent than with incongruent trials (the conflict effect). These results replicate previous findings with the ANT. We also manipulated cue-target interval at five stimulus onset asynchrony (SOA) values (100, 300, 500, 800, and 1,200 ms) to trace the alerting network influence over the orienting network. The SOA manipulation showed that cuing effects peaked at 300 ms SOA irrespective of whether an alerting tone was present or not, and the alerting tone improved the cuing effect equally for 100-500 SOAs, but it did not at the longest 800-1,200 ms SOAs. These results suggest that alerting improves rather than accelerates orienting effects, a result that agrees with data from neuropsychological rehabilitation of parietal patients with spatial bias.

Inhibitory tagging in inhibition of return: evidence from flanker interference with multiple distractor features

Fuentes, Vivas, and Humphreys (1999) proposed a distinction between inhibition of return (IOR) and inhibitory processing taking place at a location subject to IOR. This latter mechanism, inhibitory tagging (IT), would act at a late level of processing related to response selection. In the present study, we examined whether IT was applied only to the target-relevant properties of the stimuli (e.g., to its color) or whether it was applied to other features of the stimulus as well (e.g., to its shape). Both when the task was to respond to the target's color (Experiment 1) as well as when it was to respond to the target's shape (Experiment 2), there was evidence of IT (reversal of the typical flanker effect at the cued location, relative to the uncued location) only to task-relevant features of the target. These findings suggest that IT is a central process of control constrained by task demands and current goals.

Automatic behaviour: efficient not mindless

Automaticity is a core construct underpinning theoretical accounts of human performance and cognition. In spite of this, its current conceptualisation is plagued by circularity - automaticity is typically defined in terms of the very behaviour it seeks to explain - and a lack of internal consistency-defining features of automaticity do not reliably co-occur. Furthermore, invoking automaticity tends to be post hoc as it is used to explain violations of dominant theories of attention. Prevailing models of automaticity explain automatic processing as merely faster processing than controlled processing. We present an alternative conceptualisation of automaticity as efficient, elegant and economical but not fast. This is supported by functional imaging studies, which reveal a pattern of reduced global activation as well as a shift in activation from cortical to subcortical areas once automaticity has been achieved. Were automaticity to be faster processing, functional imaging would indicate greater activation when an automatic task is performed. We propose possible circuitry of automaticity incorporating the direct pathways of the basal ganglia.

Semantic processing is affected in inhibition of return: evidence from an event-related potentials study

Inhibition of return refers to a slower responding to a target stimulus appearing at previously cued locations. We used the event-related potentials technique to investigate the effects of inhibition of return in semantic processing with the combination of a spatial cueing task and semantic N400 paradigm. The results showed that the N400 component, as an index of semantic processing, was suppressed when the target words were presented in the cued location relative to the uncued location. The results indicated that the semantic processing of the target word presented on the cued location is affected by inhibition of return. Moreover, our findings provided event-related potential evidence for the inhibition of attention theory of inhibition of return.

Distinct Neural Correlates for Resolving Stroop Conflict at Inhibited and Noninhibited Locations in Inhibition of Return

It is well documented that the anterior cingulate cortex (ACC) and the dorsolateral prefrontal cortex (DLPFC) are intensively involved in conflict control. However, it remains unclear how these “executive” brain regions will act when the conflict control process interacts with spatial attentional orienting. In the classical spatial cueing paradigm [Posner, M. I., & Cohen, Y. (1984). Components of visual orienting. In H. Bouma & D. G. Bouwhuis (Eds.), Attention and performance X (pp. 531–556). Hillsdale, NJ: Erlbaum], response to a target is delayed when it appears at the cued location compared with at the uncued location, if the time interval between the cue and the target is greater than 300 msec. This effect of inhibition of return (IOR) can alter the resolution of Stroop conflict such that the Stroop interference effect disappears at the cued (inhibited) location [Vivas, A. B., & Fuentes, L. J. Stroop interference is affected in inhibition of return. Psychonomic Bulletin and Review, 8, 315–323, 2001]. In this event-related functional magnetic resonance study, we investigate the differential neural mechanisms underlying interactions between pre-response interference, response interference, and spatial orienting. Two types of Stroop words [incongruent response-eligible words (IE), incongruent response-ineligible words (II)] and neutral words were presented either at the cued or uncued location. The significant pre-response interference at the uncued location activated the left rostral ACC as compared with at the cued location. Moreover, although the IE words which have conflicts at both pre-response and response levels did not cause significant behavioral interference at the cued location, they activated the left DLPFC as compared with at the uncued location. Furthermore, neutral words showed significant IOR effects behaviorally, and they activated the left frontal eye field (FEF) at the uncued location relative to the cued location. These results suggest that the left rostral ACC is involved in the interaction between pre-response conflict and IOR, whereas the left DLPFC is involved in the interaction between response conflict and IOR. Moreover, the FEF is involved in shifting attentional focus to novel locations during spatial search.

Interaction between location- and frequency-based inhibition of return in human auditory system

Using a cue-target paradigm, this study investigated the interaction between location and frequency information processing in human auditory inhibition of return (IOR). The cue and the target varied in terms of location and frequency and participants were asked to perform a target detection, localization or frequency discrimination task. Results showed that, when neither location nor frequency of auditory stimuli was particularly relevant to the target detection task, there was a location-based IOR only if the cue and the target were identical in frequency and there was a frequency-based IOR only if the cue and the target were presented at the same location. When a particular feature of auditory stimuli, whether location or frequency, was directly relevant to the current task, the IOR effect was evident for this feature only if the cue and the target differed on the task-irrelevant feature, while the IOR effect was eliminated for the task-relevant feature when the cue and the target had the same task-irrelevant feature. Similarly, the IOR effect based on the task-irrelevant feature was evident when the cue and the target differed on the task-relevant feature, and was eliminated or reversed when the cue and the target shared the task-relevant feature. Theoretical implications of these findings for auditory IOR are discussed.

Effects of stimulus-stimulus compatibility and stimulus-response compatibility on response inhibition

Previous studies demonstrated that interference control in stimulus-stimulus compatibility tasks slowed down stopping in the stop signal task (e.g., Kramer, A. F., Humphrey, D. G., Larish, J. F., Logan, G. D., & Strayer, D. L. (1994). Aging and inhibition: beyond a unitary view of inhibitory processing in attention. psychology and aging, 9, 491-512). In the present study, the impact of stimulus-stimulus compatibility and stimulus-response compatibility on response inhibition is further investigated. In Experiment 1, the stop signal task was combined with a traditional horizontal Simon task and with a vertical variant. For both dimensions, stopping responses was prolonged in incompatible trials, but only when the previous trial was compatible. In Experiment 2, the Simon task was combined with a spatial Stroop task in order to compare the effects of stimulus-stimulus and stimulus-response compatibility. The results demonstrated that both types of compatibility influenced stopping in a similar way. These findings are in favor of the hypothesis that response inhibition in the stop signal task and interference control in conflict tasks rely on similar mechanisms.

Differential Age Effects on Attention-Based Inhibition: Inhibitory Tagging and Inhibition of Return

The purpose of this study was to determine whether 2 forms of attentional inhibition, inhibition of return (IOR) and inhibitory tagging, are differentially affected by the aging process. The authors tested 24 younger adults (mean age = 22 years) and 24 older adults (mean age = 69 years) on a combined IOR and Stroop task (Vivas & Fuentes, 2001). As predicted, younger adults' performance was consistent with inhibitory tagging of objects at inhibited locations. Although older adults demonstrated intact IOR, there was no evidence of inhibitory tagging. The results suggest that age deficits in inhibition are selective.

Space-Based Inhibition of Return in Children With Spina Bifida

Inhibition of return (IOR) refers to an increase in time to react to a target in a previously attended location. Children with spina bifida meningomyelocele (SBM) and hydrocephalus have congenital dysmorphology of the midbrain, a brain region associated with the control of covert orienting in general and with IOR in particular. The authors studied exogenously cued covert orienting in 8- to 19-year-old children and adolescents (84 with SBM and 37 age-matched, typically developing controls). The exogenous cue was a luminance change in a peripheral box that was 50% valid for the upcoming target location. Compared with controls, children with SBM showed attenuated IOR in the vertical plane, a deficit that was associated with midbrain dysmorphology in the form of tectal beaking but not with posterior brain volume loss. The data add to the emerging evidence for SBM deficits in attentional orienting to salient information.

Inhibitory processing following damage to the parietal lobe

We investigated inhibitory properties of spatial attention in a group of four patients with lesions involving the posterior parietal lobe. In a first experiment, a double cue inhibition of return (IOR) procedure was employed. The parietal patients showed an IOR effect only when they had to detect targets that appeared on the contralesional side. In a second experiment, we combined an IOR procedure with a Stroop task [Psychon. Bull. Rev. 8 (2001) 315] to explore the neural basis of "inhibitory tagging" as described by Fuentes et al. [Q. J. Exp. Psychol. Hum. Exp. Psychol. 52 (1999) 149]. The results from the control participants replicated the findings of Vivas and Fuentes, Stroop interference was reduced at the cued location, relative to the uncued location. The parietal patients showed a similar result, but only for contralesional targets. These findings suggest that IOR is modulated by the parietal lobe, and that, through this process, the parietal cortex influences the application of inhibitory tagging to stimuli.