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The problem of how the mind can retain sequentially organized information has a long research tradition that remains unresolved. While various computational models propose a mechanism of binding serial order information to position markers, the representational nature and processes that operate on these position markers are not clear. Recent behavioral work suggests that space is used to mark positions in serial order and that this process is governed by spatial attention. Based on the assumption that brain areas controlling spatial attention are also involved in saccadic planning, we continuously tracked the eye-movements as a direct measure of the spatial attention during retrieval from a verbal WM sequence. Participants memorized a sequence of auditory numbers. During retention, they heard a number-cue that did or did not belong to the memorized set. After this number-cue, a target-beep could be presented to which they had to respond if the number-cue belonged to the memorized sequence. In Experiment 1, the target-beep was either presented to the left or right ear, and in Experiment 2 bilaterally (removing any spatial aspect). We tested the hypothesis that systematic eye-movements are made when people retrieve items of sequences of auditory words and found that the retrieval of begin items resulted in leftward eye-movements and the retrieval of end items in rightward eye-movements. These observations indicate that the oculomotor system is also involved in the serial order processes in verbal WM thereby providing a promising novel approach to get insight into abstract cognitive processes.

The ability to memorize arbitrary sequences contributes to cognitive faculties like language and mathematics. Research suggests that in literate adults, serial order in verbal working memory (WM) is grounded in spatial attention and is mentally organized according to our reading habits, that is, from left-to-right in Western cultures. Currently, it is unknown whether spatialization is a consequence of literacy, or whether the ability already exists early in life but is shaped by literacy in "calibrating" the initial individual differences in the orientation of spatial coding. Here, we investigated the spatial coding of serial order in WM in 5-year-old children who did not yet enter formal literacy education. At the group level, no systematic spatial coding was observed. To investigate whether this absence was due to subjects with reliable but opposing effects, we determined the prevalence of spatial coding at the individual level. This analysis revealed that 36% of the children systematically associated serial order to space, with approximately half of them coding from left-to-right and the rest from right-to-left. These results indicate that a subgroup of preliterate children associate serial order with space and suggest that reading and writing experience calibrates the orientation of spatial coding with reading habits.

Working memory (WM) is one of the most important cognitive functions that may play a role in the relation between math anxiety (MA) and math performance. The processing efficiency theory proposes that the rumination and worrisome thoughts (induced by MA) result in less available WM resources (which are needed to solve math problems). At the same time, high MA individuals have lower verbal and spatial WM capacity in general. Extending these findings, we found that MA is also linked to the spatial coding of serial order in verbal WM: Subjects who organize sequences from left-to-right in verbal WM show lower levels of MA compared to those who do not spatialize. Furthermore, these spatial coders have higher verbal WM capacity, better numerical order judgement abilities and higher math scores. These findings suggest that that spatially structuring the verbal mind is a promising cognitive correlate of the MA and opens new avenues for exploring causal links between elementary cognitive processes and the MA.

Individual differences in arithmetic have been explained by differences in cognitive processes and by arithmetic strategy use and selection. In the present study, we investigated the involvement of reactive and proactive control processes. We explored how variation in proactive and reactive control was related to individual differences in strategy selection. We correlated proactive and reactive measures obtained from the AX-CPT and an adjusted N-back task with a measure of strategy adaptiveness during a numerosity judgment task. The results showed that both measures of reactive control (of the AX-CPT and N-back task) correlated positively with strategy adaptiveness, while proactive control was not. This suggests that both cognitive control modes might have a different effect on adaptive strategy selection, where adaptive strategy selection seems to benefit from a transient (late) control mode, reactive control. We discuss these results in the light of the Dual Mechanisms Framework.

Background: Working memory (WM) problems are commonly observed in Alzheimer's disease (AD), but the affected mechanisms leading to impaired WM are still insufficiently understood. The ability to efficiently process serial order in WM has been demonstrated to be fundamental to fluent daily life functioning. The decreased capability to mentally process serial position in WM has been put forward as the underlying explanation for generally compromised WM performance. Objective: Determine which mechanisms, such as order processing, are responsible for deficient WM functioning in AD. Method: A group of AD patients (n = 32) and their partners (n = 25), assigned to the control group, were submitted to an extensive battery of neuropsychological and experimental tasks, assessing general cognitive state and functioning of several aspects related to serial order WM. Results: The results revealed an impaired ability to bind item information to serial position within WM in AD patients compared to controls. It was additionally observed that AD patients experienced specific difficulties with directing spatial attention when searching for item information stored in WM. Conclusion: The processing of serial order and the allocation of attentional resources are both disrupted, explaining the generally reduced WM functioning in AD patients. Further studies should now clarify whether this observation could explain disease-related problems for other cognitive functions such as verbal expression, auditory comprehension, or planning.

In contrast to a substantial body of research on the neural basis of cognitive performance in several academic domains, less is known about how the brain generates metacognitive (MC) awareness of such performance. The existing work on the neurobiological underpinnings of metacognition has almost exclusively been done in adults and has largely focused on lower level cognitive processing domains, such as perceptual decision‐making. Extending this body of evidence, we investigated MC monitoring by asking children to solve arithmetic problems, an educationally relevant higher‐order process, while providing concurrent MC reports during fMRI acquisition. Results are reported on 50 primary school children aged 9–10 years old. The current study is the first to demonstrate that brain activity during MC monitoring, relative to the control task, increased in the left inferior frontal gyrus in children. This brain activity further correlated with children's arithmetic development over a 3‐year time period. These data are in line with the frequently suggested, yet never empirically tested, hypothesis that activity in the prefrontal cortex during arithmetic is related to the higher‐order process of MC monitoring., The current study is the first to demonstrate that brain activity during metacognitive (MC) monitoring, relative to the control task, increased in the left inferior frontal gyrus in 9‐ to 10‐ year‐old children (n = 50). This brain activity further correlated with children's arithmetic development over a 3‐year time period. These data are in line with the frequently suggested, yet never empirically tested, hypothesis that activity in the prefrontal cortex during arithmetic is related to the higher‐order process of MC monitoring.

Arithmetic is a major building block for children’s development of more complex mathematical abilities. Knowing which cognitive factors underlie individual differences in arithmetic is key to gain further insight into children’s mathematical development. The current study investigated the role of executive functions and metacognition (domain-general cognitive factors) as well as symbolic numerical magnitude processing (domain-specific cognitive factor) in arithmetic, enabling the investigation of their unique contribution in addition to each other. Participants were 127 typically developing second graders (7- to 8-year-olds). Our within-subject design took into account different components of executive functions (i.e., inhibition, shifting and updating), different aspects of metacognitive skills (i.e., task-specific and general metacognition), and different levels of experience in arithmetic, namely addition – in which second graders had extensive experience-, and multiplication – for which second graders were still in the learning phase. This study reveals that both updating and metacognitive monitoring are important unique predictors of arithmetic, in addition to each other and in addition to symbolic numerical magnitude processing. Our results point to a strong and unique role of task-specific metacognitive monitoring skills. These individual differences in noticing your own errors might help you to learn from your mistakes. ispartof: Journal of Experimental Child Psychology vol:182 pages:38-60 ispartof: location:United States status: published

Most general theories on serial order working memory (WM) assume the existence of position markers that are bound to the to-be-remembered items to keep track of the serial order. So far, the exact cognitive/neural characteristics of these markers have remained largely underspecified, while direct empirical evidence for their existence is mostly lacking. In the current study we demonstrate that retrieval from verbal serial order WM can be facilitated or hindered by spatial cuing: begin elements of a verbal WM sequence are retrieved faster after cuing the left side of space, while end elements are retrieved faster after cuing the right side of space. In direct complement to our previous work--where we showed the reversed impact of WM retrieval on spatial processing--we argue that the current findings provide us with a crucial piece of evidence suggesting a direct and functional involvement of space in verbal serial order WM. We outline the idea that serial order in verbal WM is coded within a spatial coordinate system with spatial attention being involved when searching through WM, and we discuss how this account can explain several hallmark observations related to serial order WM.

The temporary storage of serial order information in working memory (WM) has been demonstrated to be crucial to higher order cognition. The previous studies have shown that the maintenance of serial order can be a consequence of the construction of position markers to which to-be-remembered information will be bound. However, the nature of these position markers remains unclear. In this study, we demonstrate the crucial involvement of time in the construction of these markers by establishing a bidirectional relationship. First, results of the first experiment show that the initial items in WM result in faster responding after shorter time presentations, while we observe the opposite for items stored further in WM. Second, in the next experiment, we observe an effect of temporal cueing on WM retrieval; longer time cues facilitate responding to later WM items compared with items stored at the beginning of WM. These findings are discussed in the context of position marker theories, reviewing the functional involvement of time in the construction of these markers and its association with space.

Metacognitive monitoring is a critical predictor of arithmetic in primary school. One outstanding question is whether this metacognitive monitoring is domain-specific or whether it reflects a more general performance monitoring process. To answer this conundrum, we investigated metacognitive monitoring in two related, yet distinct academic domains: arithmetic and spelling. This allowed us to investigate whether monitoring in one domain correlated with monitoring in the other domain, and whether monitoring in one domain was predictive of performance in the other, and vice versa. Participants were 147 typically developing 8-9-year-old children (Study 1) and 77 typically developing 7-8-year-old children (Study 2), who were in the middle of an important developmental period for both metacognitive monitoring and academic skills. Pre-registered analyses revealed that within-domain metacognitive monitoring was an important predictor of arithmetic and spelling at both ages. In 8-9-year-olds the metacognitive monitoring measures in different academic domains were predictive of each other, even after taking into account academic performance in these domains. Monitoring in arithmetic was an important predictor of spelling performance, even when arithmetic performance was controlled for. Likewise, monitoring in spelling was an important predictor of arithmetic performance, even when spelling performance was controlled for. In 7-8-year-olds metacognitive monitoring was domain-specific, with neither correlations between the monitoring measures, nor correlations between monitoring in one domain and performance in the other. Taken together, these findings indicate that more domain-general metacognitive monitoring processes emerge over the ages from 7 to 9. ispartof: Plos One vol:15 issue:3 pages:1-19 ispartof: location:United States status: published

Not all researchers interested in human behavior remain convinced that modern neuroimaging techniques have much to contribute to distinguishing between competing cognitive models for explaining human behavior, especially if one removes reverse inference from the table. Here, we took up this challenge in an attempt to distinguish between two competing accounts of the problem size effect (PSE), a robust finding in investigations of mathematical cognition. The PSE occurs when people solve arithmetic problems and indicates that numerically large problems are solved more slowly and erroneously than small problems. Neurocognitive explanations for the PSE can be categorized into representation-based and process-based views. Behavioral and traditional univariate neural measures have struggled to distinguish between these accounts. By contrast, a representational similarity analysis (RSA) approach with fMRI data provides competing hypotheses that can distinguish between accounts without recourse to reverse inference. To that end, our RSA (but not univariate) results provided clear evidence in favor of the representation-based over the process-based account of the PSE in multiplication; for addition, the results were less clear. Post-hoc similarity analysis distinguished still further between competing representation-based theoretical accounts. Namely, data favored the notion that individual multiplication problems are stored as individual memory traces sensitive to input frequency over a strictly magnitude-based account of memory encoding. Together, these results provide an example of how human neuroimaging evidence can directly inform cognitive-level explanations of a common behavioral phenomenon, the problem size effect. More broadly, these data may expand our understanding of calculation and memory systems in general. ispartof: NEUROPSYCHOLOGIA vol:132 ispartof: location:England status: published

Spatial attention allows us to selectively process information within a certain location in space. Despite the vast literature on spatial attention, the effect of cognitive load on spatial processing is still not fully understood. In this study we added cognitive load to a spatial processing task, so as to see whether it would differentially impact upon the processing of visual information in the left versus the right hemispace. The main paradigm consisted of a detection task that was performed during the maintenance interval of a verbal working memory task. We found that increasing cognitive working memory load had a more negative impact on detecting targets presented on the left side compared to those on the right side. The strength of the load effect correlated with the strength of the interaction on an individual level. The implications of an asymmetric attentional bias with a relative disadvantage for the left (vs the right) hemispace under high verbal working memory (WM) load are discussed.

Inhibiting actions when they are no longer appropriate is essential for adaptive goal-directed behavior. In this study, we used high-density EEG and a standard flanker task to explore the spatiotemporal dynamics of cognitive control and inhibitory mechanisms aimed to prevent the commission of errors. By recording hand-related electromyographic activity, we could disentangle successful from unsuccessful inhibition attempts. Our results confirm that (a) the latency of the error-related negativity (ERN; or Ne) component is too late to be associated with these online inhibitory mechanisms, and (b) instead, a frontal slow negative component with an earlier time course was associated with the implementation of online inhibition. These findings are consistent with single-cell recordings in monkeys showing that the supplementary motor area provides cognitive control signals to the primary motor cortex to exert online inhibition and in turn rectify the course of erroneous actions.

Cognitive theories on consciousness propose a strong link between consciousness and working memory (WM). This link is also present at the neural level: Both consciousness and WM have been implicated in a prefrontal parietal network. However, the link remains empirically unexplored. The present study investigates the relation between consciousness and WM by studying the impact of WM load on one aspect of consciousness, the threshold for subjective visibility. At the same time, we investigated how WM affects cognitive control, a function that has been implicated to consciousness. Results showed an increase in the threshold of subjective visibility when WM load increased. Furthermore, the impact of a prime stimulus on the response to the target was also modulated by WM load. We propose that the observed interference is caused by the functional and neural overlap of these functions.

In recent years, there has been substantial growth in neuroimaging studies investigating neural correlates of symbolic (e.g. Arabic numerals) and non-symbolic (e.g. dot arrays) number processing. At present it remains contested whether number is represented abstractly, or if number representations in the brain are format-dependent. In order to quantitatively evaluate the available neuroimaging evidence, we used activation likelihood estimation (ALE) to conduct quantitative meta-analyses of the results reported in 57 neuroimaging papers. Consistent with the existence of an abstract representation of number in the brain, conjunction analyses revealed overlapping activation for symbolic and nonsymbolic numbers in frontal and parietal lobes. Consistent with the notion of format-dependent activation, contrast analyses demonstrated anatomically distinct fronto-parietal activation for symbolic and non-symbolic processing. Therefore, symbolic and non-symbolic numbers are subserved by format-dependent and abstract neural systems. Moreover, the present results suggest that regions across the parietal cortex, not just the intraparietal sulcus, are engaged in both symbolic and non-symbolic number processing, challenging the notion that the intraparietal sulcus is the key region for number processing. Additionally, our analyses indicate that regions in the frontal cortex subserve magnitude representations rather than non-numerical cognitive processes associated with number tasks, thereby highlighting the importance of considering both frontal and parietal regions as important for number processing.

Contains fulltext : 103141.pdf (Publisher’s version ) (Open Access) In the last decade, research on error and conflict processing has become one of the most influential research areas in the domain of cognitive control. There is now converging evidence that a specific part of the posterior frontomedian cortex (pFMC), the rostral cingulate zone (RCZ), is crucially involved in the processing of errors and conflict. However, error-related research has focused primarily on a specific error type, namely, response errors. The aim of the present study was to investigate whether errors on the task level rely on the same neural and functional mechanisms. Here we report a dissociation of both error types in the pFMC: whereas response errors activate the RCZ, task errors activate the dorsal frontomedian cortex. Although this last region shows an overlap in activation for task and response errors on the group level, a closer inspection of the single-subject data is more in accordance with a functional anatomical dissociation. When investigating brain areas related to conflict on the task and response levels, a clear dissociation was perceived between areas associated with response conflict and with task conflict. Overall, our data support a dissociation between response and task levels of processing in the pFMC. In addition, we provide additional evidence for a dissociation between conflict and errors both at the response level and at the task level. 9 p.

In the literature on aversive conditioning there is still debate on the role of awareness. According to some authors, affective learning can occur with or without contingency learning (dual-process model), whereas others argue that a single process produces both affective responses and contingency knowledge. Although many studies have investigated these models, the results to date are inconclusive. Based on a review of the literature, a new series of experiments was designed to examine aversive conditioning in the absence of contingency awareness. In the present study we examined the effects of subliminal aversive conditioning on a spatial cueing task. Awareness was stringently tested after conditioning. Three kinds of awareness were distinguished: contingency awareness (awareness of the CS−US contingencies, where CS is the conditioned stimulus, and US is the unconditioned stimulus), perceptual awareness (awareness of the perceptual differences between the CSs), and US expectancy (awareness of a threat feeling when confronted with the CS+, but not when confronted with the CS−). The results of three experiments demonstrated that responses on the spatial cueing task were modulated by subliminal aversive conditioning. Importantly, none of the participants was contingency aware or able to perceptually discriminate between the conditioned stimuli. However, in Experiment 3, only those participants showing some level of postconditioning expectancy awareness exhibited conditioning effects. These experiments suggest that subliminal aversive conditioning produces small but significant effects, which may be modulated by expectancy awareness.

A tight correspondence has been postulated between the representations of number and space. The spatial numerical association of response codes (SNARC) effect, which reflects the observation that people respond faster with the left-hand side to small numbers and with the right-hand side to large numbers, is regarded as strong evidence for this correspondence. The dominant explanation of the SNARC effect is that it results from visuospatial coding of magnitude (e.g. the mental number line hypothesis). In a series of experiments, we demonstrated that this is only part of the story and that verbal-spatial coding influences processes and representations that have been believed to be purely visuospatial. Additionally, when both accounts were directly contrasted, verbal-spatial coding was observed in absence of visuospatial coding. Relations to other number-space interactions and implications for other tasks are discussed., Journal Article, Research Support, Non-U.S. Gov't, SCOPUS: ar.j, info:eu-repo/semantics/published

It is generally assumed that slowing after errors is a cognitive control effect reflecting more careful response strategies after errors. However, clinical data are not compatible with this explanation. We therefore consider two alternative explanations, one referring to the possibility of a persisting underlying problem and one on the basis of the low frequency of errors (orienting account). This latter hypothesis argues that infrequent events orient attention away from the task. Support for the orienting account was obtained in two experiments. Using a new experimental procedure, Experiment 1 demonstrated post-error slowing after infrequent errors and post-correct slowing after infrequent correct trials. In Experiment 2, slowing was observed following infrequent irrelevant tones replacing the feedback signals.

The search for the cognitive determinants of mathematical skill has a long history. For some time it has been thought that mathematical proficiency is not determined by a single unique underlying cognitive factor but by multiple cognitive components such as memory, spatial processing, or executive function. Yet it remains unclear exactly what these cognitive components are and how it is that they have an impact on mathematical skills. I argue that specific neurocognitive explanatory models of cognitive components promise to increase our understanding of how these components play a role in numerical and mathematical tasks and determine performance. I outline how recent advances in the understanding of the neurocognitive mechanisms of sensory processing, working memory, and executive functions lead to meaningful hypotheses about their functional involvement in mathematical performance. I also touch upon how this might shed light on dyscalculia and its comorbidity with other learning deficits.

Number processing is characterized by the distance and the size effect, but symbolic numbers exhibit smaller effects than non-symbolic numerosities. The difference between symbolic and non-symbolic processing can either be explained by a different kind of underlying representation or by parametric differences within the same type of underlying representation. We performed a primed naming study to investigate this issue. Prime and target format were manipulated (digits or collections of dots) as well as the numerical distance between prime and target value. Qualitatively different priming patterns were observed for the two formats, showing that the underlying representations differed in kind: Digits activated mental number representations of the place coding type, while collections of dots activated number representations of the summation coding type.

The anterior intraparietal sulcus, and more specifically its horizontal segment (hIPS), is known to play a crucial role in the cognitive representation of numerical quantity. Whether the involvement of hIPS is restricted to the processing of numerical information or generalizes to non-numerical ordinal dimensions remains an open question. Using functional magnetic resonance imaging during comparison tasks, we demonstrate that the hIPS is equally responsive to numbers and letters, indicating that hIPS is also involved in the representation and processing of non-numerical ordinal series. This extends the numerical processing function of IPS into the realm of abstract knowledge processing.

Human actions are driven by the pursuit of goals, especially when achieving these goals entails a reward. Accordingly, recent work showed that anticipating a reward in a motor task influences the motor system, boosting motor excitability and increasing overall readiness. Attaining a reward typically requires some mental or physical effort. Recent neuroimaging evidence suggested that both reward expectation and effort requirements are encoded by a partially overlapping brain network. Moreover, reward and effort information are combined in an integrative value signal. However, whether and how mental effort is integrated with reward at the motor level during task preparation remains unclear. To address these issues, we implemented a mental effort task where reward expectation and effort requirements were manipulated. During task preparation, TMS was delivered on the motor cortex and motor-evoked potentials (MEPs) were recorded on the right hand muscles to probe motor excitability. The results showed an interaction of effort and reward in modulating the motor system, reflecting an unsigned value prediction-error signal. Crucially, this was observed in the motor system in absence of a value-based decision or value-driven action selection. This suggests a high-level cognitive factor such as unsigned value prediction-error can modulate the motor system. Interestingly, effort-related motor excitability was also modulated by individual differences in tendency to engage in (and enjoy) mental effort, as measured by the Need for Cognition questionnaire, underlining a role of subjective effort experience in value-driven preparation for action.

In this study we investigated the development of basic effects that have been found in single-digit multiplication arithmetic: the problem size, five and tie effects. Participants (9-, 10- and 11-year-old children and adults) performed a production task on simple multiplication. The procedure replicated Campbell and Graham’s (1985) study, but the results show that the gradual decrease of the problem size effect ends in sixth grade. We report analyses on raw latencies and state trace analyses, which take into account reaction time scaling as a function of age (Verhaeghen & Cerella, 2002). The results show that 11-year-old children do not differ significantly from adults, on either of the three effects. Before the age of 11, interesting developmental changes occur. ispartof: Journal of Experimental Child Psychology vol:94 issue:1 pages:43-56 ispartof: location:United States status: published

We have been invited by Max Coltheart to play a game. At first sight the game looks easy and the rules are quite clear. First, we have to identify a conflict between two competing psychological theories and second, we have to find at least one neuroimaging experiment that allows selecting one of the two theories as the good one. The game is not about neuroimaging per se since the use of neuroimaging for localisation is, explicitly, not discussed. Rather, the question pertains to the relevance of neuroimaging for cognitive theories. Curiously, Coltheart indicates that his question is not a theoretical one and he emphasizes that he is not interested in the “in-principle question” but in an “in-practice so-far” question. However, this restriction seems mainly rhetorical, since Coltheart underlines that “given the enormous volume of published recent empirical work in this area, if it turns out that none of this work can be used to distinguish between competing psychological theories, the in-principle question of whether cognitive neuroimaging data can ever serve this function will deserve much more attention than it has so far been given”. In other words, what Coltheart suggests is that if after so much work the in-practice question will result in a negative answer then one has to come back to the in-principle question to examine whether this failure isn’t due to some intrinsic theoretical obstacle.

For most adults, retrieval is the most common way to solve a single-digit multiplication problem (Campbell & Xue, 2001). Many theories have been proposed to describe the underlying mechanism of arithmetical fact retrieval. Testing their validity hinges on evaluating how well they account for the basic findings in mental arithmetic. The most important findings are the problem size effect (small multiplication problems are easier than larger ones; cf. 3 × 2 and 7 × 8), the five effect (problems with 5 are easier than can be accounted for by their size), and the tie effect (problems with identical operands are easier than other problems; cf. 8 × 8 and 8 × 7). We show that all existing theories have difficulties in accounting for one or more of these phenomena. A new theory is presented that avoids these difficulties. The basic assumption is that candidate answers to a particular problem are in cooperative/competitive interactions and these interactions favor small, five, and tie problems. The theory is implemented as a connectionist model, and simulation data are described that are in good accord with empirical data.

In the domain of numbers the existence of spatial components in the representation of numerical magnitude has been convincingly demonstrated by an association between number magnitude and response preference with faster left- than right-hand responses for small numbers and faster right- than left-hand responses for large numbers (Dehaene, S., Bossini, S., & Giraux, P. (1993) The mental representation of parity and number magnitude. Journal of Experimental Psychology: General, 122, 371-396). Because numbers convey not only real or integer meaning but also ordinal meaning, the question of whether non-numerical ordinal information is spatially coded naturally follows. While previous research failed to show an association between ordinal position and spatial response preference, we present two experiments involving months (Experiment 1) and letters (Experiment 2) in which spatial coding is demonstrated. Furthermore, the response-side effect was obtained with two different stimulus-response mappings. The association occurred both when ordinal information was relevant and when it was irrelevant to the task, showing that the spatial component of the ordinal representation can be automatically activated.

Most general theories on serial order working memory (WM) assume the existence of position markers that are bound to the to-be-remembered items to keep track of the serial order. So far, the exact cognitive/neural characteristics of these markers have remained largely underspecified, while direct empirical evidence for their existence is mostly lacking. In the current study we demonstrate that retrieval from verbal serial order WM can be facilitated or hindered by spatial cuing: begin elements of a verbal WM sequence are retrieved faster after cuing the left side of space, while end elements are retrieved faster after cuing the right side of space. In direct complement to our previous work - where we showed the reversed impact of WM retrieval on spatial processing - we argue that the current findings provide us with a crucial piece of evidence suggesting a direct and functional involvement of space in verbal serial order WM. We outline the idea that serial order in verbal WM is coded within a spatial coordinate system with spatial attention being involved when searching through WM, and we discuss how this account can explain several hallmark observations related to serial order WM.

Various prominent models on serial order coding in working memory (WM) build on the notion that serial order is achieved by binding the various items to-be-maintained to fixed position markers. Despite being relatively successful in accounting for empirical observations and some recent neuro-imaging support, these models were largely formulated on theoretical grounds and few specifications have been provided with respect to the cognitive and/or neural nature of these position markers. Here we outline a hypothesis on a novel candidate mechanism to substantiate the notion of serial position markers. Specifically, we propose that serial order WM is grounded in the spatial attention system: (I) The position markers that provide multi-item WM with a serial context should be understood as coordinates within an internal, spatially defined system; (II) internal spatial attention is involved in searching through the resulting serial order representation; and (III) retrieval corresponds to selection by spatial attention. We sketch the available empirical support and discuss how the hypothesis may provide a parsimonious framework from which to understand a broad range of observations across behavioral, neural and neuropsychological domains. Finally, we pinpoint what we believe are major questions for future research inspired by the hypothesis.

Feature-based attention was investigated by examining the effect of irrelevant information on the processing of relevant information. In all experiments, irrelevant information consisted of digits whose semantic information is known to be processed in parietal areas. Between experiments we varied the degree of parietal involvement in the processing of the relevant feature. The influence of the irrelevant digit on the binary manual response task on the relevant feature was measured by the SNARC effect, a spatial numerical association of response codes demonstrating faster left than right hand responses for small numbers and faster right than left hand responses for large numbers. When processing of the relevant feature depended on parietal cortex, as is the case for orientation processing (exps. 1 and 4), there was an effect of the digit's semantic value on response times. Conversely, there was no effect of the irrelevant digit on the processing of color (exps. 2 and 3) or shape (exp. 5), which rely only minimally on parietal resources. After ruling out alternative explanations we conclude that the efficiency of feature-based attention is determined by the degree of neural overlap of structures dedicated to process relevant and irrelevant information.

The default mode network (DMN) is the core brain system supporting internally oriented cognition. The ability to attenuate the DMN when switching to externally oriented processing is a prerequisite for effective performance and adaptive self-regulation. Right anterior insula (rAI), a core hub of the salience network (SN), has been proposed to control the switching from DMN to task-relevant brain networks. Little is currently known about the extent of anticipatory processes subserved by DMN and SN during switching. We investigated anticipatory DMN and SN modulation using a novel cued-switching task of between-state (rest-to-task/task-to-rest) and within-state (task-to-task) transitions. Twenty healthy adults performed the task implemented in an event-related functional magnetic resonance imaging (fMRI) design. Increases in activity were observed in the DMN regions in response to cues signalling upcoming rest. DMN attenuation was observed for rest-to-task switch cues. Obversely, DMN was up-regulated by task-to-rest cues. The strongest rAI response was observed to rest-to-task switch cues. Task-to-task switch cues elicited smaller rAI activation, whereas no significant rAI activation occurred for task-to-rest switches. Our data provide the first evidence that DMN modulation occurs rapidly and can be elicited by short duration cues signalling rest- and task-related state switches. The role of rAI appears to be limited to certain switch types — those implicating transition from a resting state and to tasks involving active cognitive engagement.

The representation and maintenance of serial order information is one of the main functions of verbal short-term memory (STM) but its neural correlates remain poorly understood. We show here that the neural substrates allowing for coding of order information in STM are shared with those supporting ordinal processing in the numerical and alphabetical domains. We designed an fMRI experiment determining the neural substrates sensitive to ordinal distance effects in numerical judgment, alphabetical judgment and serial order STM tasks. Null conjunction analyses for parametric ordinal distance effects showed a common involvement of the horizontal segment of the left intraparietal sulcus over the three tasks; in addition, right intraparietal sulcus involvement was also observed for ordinal distance effects in the STM and numerical judgment tasks. These findings demonstrate that shared neural correlates in the intraparietal cortex support processing of order information in verbal STM, number and alphabetical domains, and suggest the existence of domain general, potentially ordinal, comparison processes supported by the left intraparietal sulcus.

A central controversy in cognitive science concerns the roles of rules versus similarity. To gain some leverage on this problem, we propose that rule- versus similarity-based processes can be characterized as extremes in a multidimensional space that is composed of at least two dimensions: the number of features (Pothos, 2005) and the physical presence of features. The transition of similarity- to rule-based processing is conceptualized as a transition in this space. To illustrate this, we show how a neural network model uses input features (and in this sense produces similarity-based responses) when it has a low learning rate or in the early phases of training, but it switches to using self-generated, more abstract features (and in this sense produces rule-based responses) when it has a higher learning rate or is in the later phases of training. Relations with categorization and the psychology of learning are pointed out.

Several psychophysical and neuropsychological investigations have suggested that the mental representation of numbers takes the form of a number line along which magnitude is positioned in ascending order according to our reading habits. A longstanding debate is whether this spatial frame is triggered automatically as intrinsic part of the number semantics or whether it constitutes a short-term representation constructed during task execution. Although several observations clearly favor the working memory account, its causal involvement has not yet been demonstrated. In two experiments we show that information stored in working memory get spatially coded in function of its ordinal position in the sequence and that the spatial-numerical associations typically observed in number categorization tasks draw upon this mechanism.

Neuroimaging studies of numerical cognition have pointed to the horizontal segment of the intraparietal sulcus (hIPS) as the neural correlate of numerical representations in humans. However, the specificity of hIPS for numbers remains controversial. For example, its activation during numerical comparison cannot be distinguished from activation during ordinal judgments on non-numerical sequences such as letters (Fias et al., 2007, J. Neuroscience). Based on the hypothesis that the fine-grained distinction between representations of numerical vs. letter order in hIPS might simply be invisible to conventional fMRI data analysis, we used support vector machines (SVM) to reanalyse the data of Fias et al. (2007). We show that classifiers trained on hIPS voxels can discriminate between number comparison and letter comparison, even though the two tasks produce the same metric of behaviour. Voxels discriminating between the two conditions were consistent across subjects and contribution analysis revealed maps of distinct sets of voxels implicated in the processing of numerical vs. alphabetical order in bilateral hIPS. These results reconcile the neuroimaging data with the neuropsychological evidence suggesting dissociations between numbers and other non-numerical ordered sequences, and demonstrate that multivariate analyses are fundamental to address fine-grained theoretical issues with fMRI studies.

A considerable number of studies have recently used event-related potentials (ERPs) to investigate the mechanisms underlying error processing. Nevertheless, how these mechanisms are associated with behavioral adjustments following errors remains unclear. In the present study, we investigated how posterror slowing is linked to outcome expectations and error feedback. We used an adaptive four-choice reaction time task to manipulate outcome expectancy. Behaviorally, the results show posterror slowing when errors are unexpected and post-correct slowing when correct responses are unexpected, indicating that outcome expectancy is crucial for post-error slowing. ERP analyses revealed that the error-related negativity and the feedback-related negativity were not correlated with the behavioral reaction time pattern, whereas the P3 was. The results support the hypothesis that posterror slowing is caused by attentional orienting to unexpected events.

Objective This work investigates the influence of the static magnetic field of the MR-scanner on ERPs extracted from simultaneous EEG–fMRI recordings. The quality of the ERPs after BallistoCardioGraphic (BCG) artifact removal, as well as the reproducibility of the waveforms in different environments is investigated. Methods We consider a Detection, a Go–Nogo and a Motor task, eliciting peaks that differ in amplitude, latency and scalp topography, repeated in two situations: outside the scanner room (0 T) and inside the MR-scanner but without gradients (3 T). The BCG artifact is removed by means of three techniques: the Average Artifact Subtraction (AAS) method, the Optimal Basis Set (OBS) method and the Canonical Correlation Analysis (CCA) approach. Results The performance of the three methods depends on the amount of averaged trials. Moreover, differences are found on both amplitude and latency of ERP components recorded in two environments (0 T vs 3 T). Conclusions We showed that, while ERPs can be extracted from simultaneous EEG–fMRI data at 3 T, the static magnetic field might affect the physiological processes under investigation. Significance The reproducibility of the ERPs in different recording environments (0 T vs 3 T) is a relevant issue that deserves further investigation to clarify the equivalence of cognitive processes in both behavioral and imaging studies.

Color-grapheme synesthetes automatically perceive achromatic numbers as colored (e.g. 7 is turquoise). Up until recently, synesthesia was believed to be unidirectional. For instance, the number 7 gives rise to the percept of turquoise but the perception of turquoise does not trigger the number 7. However, some recent studies argue for bidirectional connections (Cohen Kadosh et al. 2005; Johnson et al. 2007; Knoch et al. 2005). In this study, a multiplication verification task (e.g. 7 x 2 = 14, true/false?) was used to test bidirectionality. In agreement with previous studies we observed that the presentation of colors evokes numerical magnitudes. The current findings add two important notions to previous studies: (a) The influence of color on the processing of numerical information can be extended to multiplication verification tasks and (b) The perception of color can both facilitate and interfere with the processing of digit-related information., JOURNAL ARTICLE, info:eu-repo/semantics/published

The authors investigated the performance on simple multiplication and division problems of 8-year-old children longitudinally to determine the developmental trajectories of both operations. Twice a year, during 2 consecutive school years, children performed a multiplication and division verification task and a number-matching task. All effects that were observed in multiplication performance (problem size, 5, and tie effect and Tie x Size interaction) were also observed in division performance. The developmental trajectories of these effects are described. The authors observed strong developmental parallels between both operations. These results are in line with strongly interconnected memory networks for multiplication and division facts, at least in young children. The results of the number-matching task showed that the interference effect developed differently for multiplication and division, indicating that automatic activation spreading from division operands to division answers is not at work in children of that age.

In this study, we examined the nature of the spatial-numerical associations underlying the SNARC-effect by imposing a verbal or spatial working memory load during a parity judgment and a magnitude comparison task. The results showed a double dissociation between the type of working memory load and type of task. The SNARC-effect disappeared under verbal load in parity judgment and under spatial load in magnitude comparison. These findings provide the first direct empirical evidence against the view that all behavioral signatures of spatial-numerical associations have their origin in a common spatial code. Instead they show that numbers are associated with different spatial codes which, depending on the task, have a visuospatial or verbally mediated nature.

An important question in research about bilingualism is whether translation from a second language (L2) to the native language (L1) is semantically mediated or whether it occurs through word associations at the lexical level. Recent research has shown that both L1 and L2 number word translation imply semantic access, suggesting strong L2 lexicosemantic mappings for number words (Duyck & Brysbaert, 2004). In the present study, this assumption was further explored by means of a cross-lingual number distance priming paradigm with Dutch–English–French trilinguals. We found that number word translation from L1 to the third language (L3), and vice versa, was facilitated by L2 number masked word primes that represented the same magnitude as the target (translation equivalents), relative to primes that are numerically less close. This confirms the existence of strong L2 lexicosemantic mappings for number words and generalizes previous semantic effects in L1–L2 translation to translation processes between L1 and L3.

This study investigated the notion that children with developmental coordination disorder (DCD) show a reduced capacity of internally simulating movements of their own body or motor imagery. Using a mental rotation paradigm the contribution of hand posture to laterality/mirror judgments of bodily and alphanumeric stimuli was studied in 13 children with DCD and 13 matched typically developing (TD) children. Children were asked to judge whether the stimulus on display, rotated over -90 degrees , -30 degrees , +30 degrees , or +90 degrees , was a right or left hand or a canonical or mirror-reversed letter. Analysis of accuracy (ACC) and response times (RTs) demonstrated that children with DCD were generally slower and made more errors. RTs to letter stimuli were faster than those to hand stimuli in both DCD and TD children. For both groups RTs profiles were influenced by the orientation of the stimulus, showing longer response times for larger rotations. Clockwise rotations of right hands resulted in slower judgments than did counterclockwise rotations, whereas the reverse was true for left hands. Moreover, the results also indicate a contribution of hand posture to the laterality judgments of hands, with longer RTs when the posture of the participants' hands was opposite to the posture of the hands on display. Importantly, these effects that suggest an imagery strategy engaging motor processes were present in both groups. Apparently, the children with DCD of the present study did rely on motor imagery to solve the mental rotation task; however, their judgments seem to be compromised by a less well-defined internal model.

This paper focuses on automatic number processing as instantiated in the size congruity effect. It was recently argued that long-term "associations between individual digits and the attributes 'small' and 'large' create the size congruity effect" (Choplin and Logan 2003, abstract, p. 17). Moreover, these authors proposed the additional assumption that the relevant connections are acquired over a lifetime of experience with numbers. We show that at least one of these assumptions is not true: either the size congruity effect derives from an (online) comparison effect between two numbers at the time of stimulus presentation (violating the first assumption) or the relevant connections flexibly change (offline) between trials during the course of one experimental session (violating the second assumption).

Selective attention has been studied extensively using the negative priming (NP) paradigm. An important issue regards the representational level at which NP occurs. We investigated this issue by using numbers as stimuli. Because numbers have a well-defined semantic organization, which can be clearly measured by means of the distance effect, they are very suitable for testing the assumption that NP is situated at a central semantic level. Four experiments are presented in which the numerical distance between prime distractor and probe target was manipulated. The task was magnitude comparison. Target and distractor were defined on the basis of colour. In Experiment 1, all numbers were presented in Arabic format; NP was observed only with identical prime distractor and probe target, and no distance-related NP was observed. This could not be explained by a decay of inhibition since in Experiment 2 similar results were obtained with a shortened response-to-stimulus interval. Experiment 3 showed that these observations also hold for numbers presented verbally. Nevertheless, a cross-notational experiment with Arabic prime and verbal probe (Experiment 4) revealed no NP whatsoever and excluded the possibility that the absence of distance-related negative priming was the result of a fine-tuned inhibitory mechanism operating at the semantic level. The results are considered in the light of current theories of negative priming.

Clinical Trial, Journal Article, Research Support, Non-U.S. Gov't, info:eu-repo/semantics/published

The close behavioral parallels between the processing of quantitative information conveyed by symbolic and non-symbolic stimuli led to the hypothesis that there exists a common cerebral representation of quantity (Dehaene, Dehaene-Lambertz, & Cohen, 1998). The neural basis underlying the encoding of number magnitude has been localized to regions in and around the intraparietal sulcus (IPS) by brain-imaging studies. However, it has never been demonstrated that these same regions are also involved in the quantitative processing of nonsymbolic stimuli. Using functional brain imaging, we explicitly tested the hypothesis of a common substrate. Angles, lines, and two-digit numbers were presented pairwise, one to the left and one to the right of the fixation point. In the three comparison tasks, participants (n = 18) pressed the key on the side of the largest quantity. In the three control tasks, they indicated the side on which dimming occurred. A conjunction analysis between the three subtractions (comparison task-control task) revealed a site in left IPS that is specifically responsive when two stimuli have to be compared quantitatively, irrespective of stimulus format. The results confirm the hypothesis that quantity is represented by a common mechanism for both symbolic and nonsymbolic stimuli in IPS. In addition, the interaction between task and type of stimulus identified a region anterior to the conjunction site, not specific for quantitative processing, but reflecting general processes loaded by number processing.

Anticipating a potential benefit and how difficult it will be to obtain it are valuable skills in a constantly changing environment. In the human brain, the anticipation of reward is encoded by the Anterior Cingulate Cortex (ACC) and Striatum. Naturally, potential rewards have an incentive quality, resulting in a motivational effect improving performance. Recently it has been proposed that an upcoming task requiring effort induces a similar anticipation mechanism as reward, relying on the same cortico-limbic network. However, this overlapping anticipatory activity for reward and effort has only been investigated in a perceptual task. Whether this generalizes to high-level cognitive tasks remains to be investigated. To this end, an fMRI experiment was designed to investigate anticipation of reward and effort in cognitive tasks. A mental arithmetic task was implemented, manipulating effort (difficulty), reward, and delay in reward delivery to control for temporal confounds. The goal was to test for the motivational effect induced by the expectation of bigger reward and higher effort. The results showed that the activation elicited by an upcoming difficult task overlapped with higher reward prospect in the ACC and in the striatum, thus highlighting a pivotal role of this circuit in sustaining motivated behavior.

In experimental research on the psychology of reasoning one mostly uses the nature and frequency of conclusions to reasoning problems as a measure of the cognitive processes involved in reasoning. Less often, researchers use problem solving latencies as an additional measure. We aimed to add more fine-grained measures to the field of reasoning research: namely those obtained by registering eye-movements. At the same time we ventured that those measures might also be obtained without the use of eye-movement registration equipment. By displaying the constituent clauses of reasoning problems contingent upon the movements of a mouse-cursor, we expected to obtain results equally sensitive to the difficulty of making particular inferences. In order to tackle these questions we conducted some studies in which the negations paradigm was applied to the conditional inferences task. Jargon being what it is, we will first explicate what conditional reasoning is about, how conditional reasoning can be investigated with the conditional inferences task and how the negations paradigm is applied to the conditional inferences task. Only then are we in the position to elaborate the hypothesized difficulties in drawing inferences about conditionals with negative constituent clauses; difficulties which were expected to be reflected in eye-movement measures if these are to provide a sensible measures to reasoning processes.