Oculomotor control and the maintenance of spatially and temporally distributed events in visuo-spatial working memory

Social prioritisation in scene viewing and the effects of a spatial memory load

When free-viewing scenes, participants tend to preferentially fixate social elements (e.g., people). In the present study, we tested whether this bias would be disrupted by increasing the demands of a secondary dual-task: holding a set of (one or six) spatial locations in memory, presented either simultaneously or sequentially. Following a retention interval, participants judged whether a test location was present in the to-be-remembered stimuli. During the retention interval participants free-viewed scenes containing a social element (a person) and a non-social element (an object) that served as regions of interest. In order to assess the impact of physical salience, the non-social element was presented in both an unaltered baseline version, and in a version where its salience was artificially increased. The results showed that the preference to look at social elements decreased when the demands of the spatial memory task were increased from one to six locations, regardless of presentation mode (simultaneous or sequential). The high-load condition also resulted in more central fixations and reduced exploration of the scene. The results indicate that the social prioritisation effect, and scene viewing more generally, can be affected by a concurrent memory load.

Decoupling of the pupillary light response during internal attention: The modulating effect of luminance intensity

In a world full of sensory stimuli, attention guides us between the external environment and our internal thoughts. While external attention involves processing sensory stimuli, internal attention is devoted to self-generated representations such as planning or spontaneous mind wandering. They both draw from common cognitive resources, thus simultaneous engagement in both often leads to interference between processes. In order to maintain internal focus, an attentional mechanism known as perceptual decoupling takes effect. This mechanism supports internal cognition by decoupling attention from the perception of sensory information. Two previous studies of our lab investigated to what extent perceptual decoupling is evident in voluntary eye movements. Findings showed that the effect is mediated by the internal task modality and workload (visuospatial > arithmetic and high > low, respectively). However, it remains unclear whether it extends to involuntary eye behavior, which may not share cognitive resources with internal activities. Therefore, the present experiment aimed to further elucidate attentional dynamics by examining whether internal attention affects the pupillary light response (PLR). Specifically, we consistently observed that workload and task modality of the internal task reduced the PLR to luminance changes of medium intensity. However, the PLR to strong luminance changes was less or not at all affected by the internal task. These results suggest that perceptual decoupling effects may be less consistent in involuntary eye behavior, particularly in the context of a salient visual stimulus.

Selection within working memory impairs perceptual detection

There is broad consensus supporting the reciprocal influence of working memory (WM) and attention. Top-down mechanisms operate to cope with either environmental or internal demands. In that sense, it is possible to select an item within the contents of WM to endow it with prioritized access. Although evidence supports that maintaining an item in this privileged state does not rely on sustained visual attention, it is unknown whether selection within WM depends on perceptual attention. To answer this question, we recorded electrophysiological neural activity while participants performed a retro-cue task in which we inserted a detection task in the delay period after retro-cue presentation. Critically, the onset of to-be-detected near threshold stimuli was unpredictable, and thus, sustained perceptual spatial attention was needed to accomplish the detection task from the offset of the retro-cue. At a behavioral level, we found decreased visual detection when a WM representation was retro-cued. At a neural level, alpha oscillatory activity confirmed a spatial shift of attention to the retro-cued representation. We interpret the convergence of neural oscillations and behavioral data to point towards the theory that selection within WM could be accomplished through a perceptual attentional mechanism.

Audio-Corsi: a novel system to evaluate audio-spatial memory skills

Spatial memory (SM) is a multimodal representation of the external world, which different sensory inputs can mediate. It is essential in accomplishing everyday activities and strongly correlates with sleep processes. However, despite valuable knowledge of the spatial mechanisms in the visual modality, the multi-sensory aspects of SM have yet to be thoroughly investigated due to a lack of proper technologies.This work presents a novel acoustic system built around 3D audio spatial technology. Our goal was to examine if an afternoon nap can improve memory performance, measured through the acoustic version of the Corsi Block Tapping Task (CBTT), named Audio-Corsi. We tested five adults over two days. During one of the two days (Wake), participants performed the Audio-Corsi before (Pre) and after (Post) a wake resting period; while the other day (Sleep), participants performed the Audio-Corsi before (Pre) and after (Post) a nap. Day orders were randomized. We calculated the memory span for the Pre and Post session in both the Wake and Sleep days. Preliminary results show a significant difference in the memory span between the Wake and Sleep days. Specifically, memory span decreased between the pre-and post-test during the wake day. The opposite trend was found for the sleep day. Results indicate that SM can be improved by sleeping also in the acoustic modality other than the visual one.Clinical Relevance- The technology and procedure we designed and developed could be suitable in clinical and experimental settings to study high-level cognitive skills in the auditory sensory modality and their relationship with sleep, especially when vision is absent or distorted (i.e. blindness).

Hanging on the telephone: Maintaining visuospatial bootstrapping over time in working memory

Visuospatial bootstrapping (VSB) refers to the phenomenon in which performance on a verbal working memory task can be enhanced by presenting the verbal material within a familiar visuospatial configuration. This effect is part of a broader literature concerning how working memory is influenced by use of multimodal codes and contributions from long-term memory. The present study aimed to establish whether the VSB effect extends over a brief (5-s) delay period, and to explore the possible mechanisms operating during retention. The VSB effect, as indicated by a verbal recall advantage for digit sequences presented within a familiar visuospatial configuration (modelled on the T-9 keypad) relative to a single-location display, was observed across four experiments. The presence and size of this effect changed with the type of concurrent task activity applied during the delay. Articulatory suppression (Experiment 1) increased the visuospatial display advantage, while spatial tapping (Experiment 2) and a visuospatial judgment task (Experiment 3) both removed it. Finally, manipulation of the attentional demands placed by a verbal task also reduced (but did not abolish) this effect (Experiment 4). This pattern of findings demonstrates how provision of familiar visuospatial information at encoding can continue to support verbal working memory over time, with varying demands on modality-specific and general processing resources.

Effects of internally directed cognition on smooth pursuit eye movements: A systematic examination of perceptual decoupling

Eye behavior differs between internally and externally directed cognition and thus is indicative of an internal versus external attention focus. Recent work implicated perceptual decoupling (i.e., eye behavior becoming less determined by the sensory environment) as one of the key mechanisms involved in these attention-related eye movement differences. However, it is not yet understood how perceptual decoupling depends on the characteristics of the internal task. Therefore, we systematically examined effects of varying internal task demands on smooth pursuit eye movements. Specifically, we evaluated effects of the internal workload (control vs. low vs. high) and of internal task (arithmetic vs. visuospatial). The results of multilevel modelling showed that effects of perceptual decoupling were stronger for higher workload, and more pronounced for the visuospatial modality. Effects also followed a characteristic time-course relative to internal operations. The findings provide further support of the perceptual decoupling mechanism by showing that it is sensitive to the degree of interference between external and internal information.

Dynamic resource allocation in spatial working memory during full and partial report tasks

Serial position effects are well-documented in working memory literature. Studies of spatial short-term memory that rely on binary response; full report tasks tend to report stronger primacy than recency effects. In contrast, studies that utilize a continuous response, partial report task report stronger recency than primacy effects (Gorgoraptis, Catalao, Bays, & Husain, 2011; Zokaei, Gorgoraptis, Bahrami, Bays, & Husain, 2011). The current study explored the idea that probing spatial working memory using full and partial continuous response tasks would produce different distributions of visuospatial working memory resources across spatial sequences and, therefore, explain the conflicting results in the literature. Experiment 1 demonstrated that primacy effects were observed when memory was probed with a full report task. Experiment 2 confirmed this finding while controlling eye movements. Critically, Experiment 3 demonstrated that switching from a full to a partial report task abolished the primacy effect and produced a recency effect, consistent with the idea that the distribution of resources in visuospatial working memory depends on the type of recall required. It is argued that the primacy effect in the whole report task arose from the accumulation of noise caused by the execution of multiple spatially directed actions during recall, whereas the recency effect in the partial report task reflects the redistribution of preallocated resources when an anticipated item is not presented. These data show that it is possible to reconcile apparently contradictory findings within the resource theory of spatial working memory and the importance of considering how memory is probed when interpreting behavioral data through the lens of resource theories of spatial working memory.

Effects of eye and hand movement on cross-modal memory

In this study, we determined whether information in eye-hand/hand-eye cross-modal memory is maintained by the input modality used for encoding, the output modality used for testing, or both. In experiments, two categories of effect were examined: facilitatory, produced by rehearsal work with eyes or hands corresponding to the movement of the stimulus to be memorized after its presentation, and interference, formed through the performance of a noncorresponding movement. The results indicated that both the eye and hand facilitated the eye-hand cross-modal memory tasks (Experiment 1A), confirming that both serve a rehearsal function. Subsequently, we conducted an interference effect experiment (Experiment 1B) using the same memory task as that used in Experiment 1A and found that neither modality produced interference effects. This result indicates that information was preserved via output-modality-specific representations when the eye-interference task interfered with the information retention of input-modality-specific representations and via input-modality-specific representations when the hand-interference task interfered with the information retention of output-modality-specific representations. We observed the same facilitation and disappearance of interference effects for the hand-eye cross-modal memory task (Experiments 2A and 2B). In the eye-hand/hand-eye cross-modal memory tasks, the effects of eye and hand rehearsals were found to be comparable, which indicated that the two types of representations functioned together during encoding and testing. From the disappearance of interference effects, the possibility that modality-specific representations have functional aspects arises.

Oculomotor rehearsal in visuospatial working memory

The neural and cognitive mechanisms of spatial working memory are tightly coupled with the systems that control eye movements, but the precise nature of this coupling is not well understood. It has been argued that the oculomotor system is selectively involved in rehearsal of spatial but not visual material in visuospatial working memory. However, few studies have directly compared the effect of saccadic interference on visual and spatial memory, and there is little consensus on how the underlying working memory representation is affected by saccadic interference. In this study we aimed to examine how working memory for visual and spatial features is affected by overt and covert attentional interference across two experiments. Participants were shown a memory array, then asked to either maintain fixation or to overtly or covertly shift attention in a detection task during the delay period. Using the continuous report task we directly examined the precision of visual and spatial working memory representations and fit psychophysical functions to investigate the sources of recall error associated with different types of interference. These data were interpreted in terms of embodied theories of attention and memory and provide new insights into the nature of the interactions between cognitive and motor systems.

On the Effect of Bilateral Eye Movements on Memory Retrieval in Ageing and Dementia

It has been reported that performing bilateral eye movements for a short period can lead to an enhancement of memory retrieval and recall (termed the “saccade induced retrieval effect (SIRE)”). The source of this effect has been debated within the literature and the phenomenon has come under scrutiny as the robustness of the effect has recently been questioned. To date investigations of SIRE have largely been restricted to younger adult populations. Here, across two experiments, we assess the robustness and generalisability of the SIRE specifically in relation to disease and ageing. Experiment 1 employed a between subject’s design and presented younger and older participants with 36 words prior to completing one of three eye movement conditions (bilateral, antisaccade or a fixation eye movement). Participants then performed a word recognition task. Experiment 2 assessed the SIRE in individuals diagnosed with Alzheimer’s, Mild cognitive impairment and Parkinson’s by employing an online within subject’s design. Results showed no significant difference between groups in the number of words recognised based on eye movement condition. Neither experiment 1 or 2 replicated the SIRE effect therefore the findings from this study add to the growing number of studies that have failed to replicate the SIRE effect.

Spatial attention and spatial short term memory in PSP and Parkinson's disease

Progressive Supranuclear Palsy (PSP) is a neurodegenerative disorder characterised by deterioration in motor, oculomotor and cognitive function. A key clinical feature of PSP is the progressive paralysis of eye movements, most notably for vertical saccades. These oculomotor signs can be subtle, however, and PSP is often misdiagnosed as Parkinson's disease (PD), in its early stages. Although some of the clinical features of PD and PSP overlap, they are distinct disorders with differing underlying pathological processes, responses to treatment and prognoses. One key difference lies in the effects the diseases have on cognition. The oculomotor system is tightly linked to cognitive processes such as spatial attention and spatial short-term memory (sSTM), and previous studies have suggested that PSP and PD experience different deficits in these domains. We therefore hypothesised that people with PSP (N = 15) would experience problems with attention (assessed with feature and conjunction visual search tasks) and sSTM (assessed with the Corsi blocks task) compared to people with PD (N = 16) and Age Matched Controls (N = 15). As predicted, feature and conjunction search were sgnificantly slower in the PSP group compared to the other groups, and this deficit was significantly worse for feature compared to conjunction search. The PD group did not differ from AMC on feature search but were significantly impaired on the conjunction search. The PSP group also had a pronounced vertical sSTM impairment that was not present in PD or AMC groups. It is argued that PSP is associated with specific impairment of visuospatial cognition which is caused by degeneration of the oculomotor structures that support exogenous spatial attention, consistent with oculomotor theories of spatial attention and memory.

Charting the Diversity of Strategic Processes in Visuospatial Short-Term Memory

Despite the abundant literature on visuospatial short-term memory, researchers have devoted little attention to strategic processes: What procedures do subjects implement to memorize visuospatial material? Evidence for various strategies exists, but it is spread across a variety of fields. This integrative review of the literature brings together scattered evidence to provide an overview of strategic processes in visuospatial memory tasks. The diversity of strategies and their proposed operating mechanisms are reviewed and discussed. The evidence leads to proposing seven broad strategic processes used in visuospatial short-term memory, each with multiple variants. Strategies can vary across individuals, but the same subjects also appear to use multiple strategies depending on the perceptual features of to-be-remembered displays. These results point to a view of visuospatial strategies as a functional library of facilitatory processes on which subjects can draw to support visuospatial short-term memory performance. Implications are discussed for the difference between visual and spatial tasks, for the appropriate measurement of strategic behaviors, and for the interpretation of performance in visuospatial memory tasks.

Bold moves: Inevitable saccadic selection in visual short-term memory

Selection for visual short-term memory (vstm) provides a basis for many cognitive functions. Saccadic eye movements sway this selection in favor of stimuli previously seen at locations congruent with their target. In three experiments, we provide converging evidence that this saccadic selection is implemented as a fundamental, inevitable selection process, rather than a top-down strategy. In particular, benefits for congruent over incongruent items were largely constant across set sizes ranging from two to eight items (Experiment 1), showing that saccadic selection imposes priorities on vstm irrespective of memory load and is effective even when only few representations need to be maintained. Moreover, a decrement in performance for incongruent items occurred reliably, whether the congruent location contained a task-relevant item or an irrelevant noise patch (Experiment 2). Finally, saccadic selection was immune to a strong manipulation of the observer's attentional priorities (Experiment 3). Given the prevalence of saccades in natural vision, our results demonstrate a fundamental and ecologically relevant selection mechanism for vstm: Saccades systematically eliminate information seen at non-target locations, while information at the saccade target remains available to recall. This simple heuristic is effective in the absence of informative cues and may incapacitate voluntary selection mechanisms that are incongruent with ongoing movement plans.

Egocentric metric representations in peripersonal space: A bridge between motor resources and spatial memory

Research on visuospatial memory has shown that egocentric (subject-to-object) and allocentric (object-to-object) reference frames are connected to categorical (non-metric) and coordinate (metric) spatial relations, and that motor resources are recruited especially when processing spatial information in peripersonal (within arm reaching) than extrapersonal (outside arm reaching) space. In order to perform our daily-life activities, these spatial components cooperate along a continuum from recognition-related (e.g., recognizing stimuli) to action-related (e.g., reaching stimuli) purposes. Therefore, it is possible that some types of spatial representations rely more on action/motor processes than others. Here, we explored the role of motor resources in the combinations of these visuospatial memory components. A motor interference paradigm was adopted in which participants had their arms bent behind their back or free during a spatial memory task. This task consisted in memorizing triads of objects and then verbally judging what was the object: (1) closest to/farthest from the participant (egocentric coordinate); (2) to the right/left of the participant (egocentric categorical); (3) closest to/farthest from a target object (allocentric coordinate); and (4) on the right/left of a target object (allocentric categorical). The triads appeared in participants' peripersonal (Experiment 1) or extrapersonal (Experiment 2) space. The results of Experiment 1 showed that motor interference selectively damaged egocentric-coordinate judgements but not the other spatial combinations. The results of Experiment 2 showed that the interference effect disappeared when the objects were in the extrapersonal space. A third follow-up study using a within-subject design confirmed the overall pattern of results. Our findings provide evidence that motor resources play an important role in the combination of coordinate spatial relations and egocentric representations in peripersonal space.

Working memory load does not affect sequential motor planning

Movement planning disrupts the recall performance in a short term memory task, indicating that both processes share common working memory (WM) resources. In the current study, we tested whether this interference was bidirectional. To this end, we combined an easy or a difficult memory task (depleting different amounts of WM resources) with a sequential motor task (opening a column of drawers). The size of the hysteresis effect in the sequential motor task was measured as a proxy for the fraction of motor plan reuse. The different WM loads created by the memory task had no effect on the fractions of motor plan reuse and motor (re-)planning, which supports the idea that motor planning has priority access to WM. A recency effect (better recall of late items) was absent in a verbal memory task but present in a spatial one. Recency is commonly attributed to the episodic buffer, a non-domain-specific storage of the central executive. The domain-specific interference of the motor task with recency indicates that the second assumption needs to be reevaluated.

Executive Functions and Emotion Regulation in Attention-Deficit/Hyperactivity Disorder and Borderline Intellectual Disability

The main objective of this study is to investigate the multiple relations and to determine the differences between executive functions (EFs), emotion regulation, and behavioral and emotional problems in children with attention-deficit/hyperactivity disorder (ADHD), borderline intellectual disability (ID), and typical development (TD). The sample included 85 children aged 6 to 11 years, 42 with typical development (TD), 27 with ADHD, and 16 with borderline ID. The results emphasized a positive correlation between adaptive emotion regulation strategies and EFs, and no significant relations between the maladaptive emotion regulation strategies and EFs. In addition, the executive function of planning correlated negatively with anxiety, ADHD symptoms, and conduct problems. The performance of both clinical groups regarding EFs was significantly lower than that of the TD group, and they differed significantly from each other only on visual attention. The presence of oppositional-defiant and conduct problems was higher in both clinical groups than in the TD group, and more anxiety symptoms were reported in children with ADHD. This study supports the idea that emotion regulation, Efs, and clinical symptoms are interconnected. It also profiles the deficits in cognitive functioning and emotion regulation in two clinical groups, thus helping future intervention programs.

On-item fixations during serial encoding do not affect spatial working memory

Ample evidence suggests that there is overlap between the eye-movement system and spatial working memory. Such overlapping structures or capacities may result in interference on the one hand and beneficial support on the other. We investigated eye-movement control during encoding of verbal or spatial information, keeping the display the same between tasks. Saccades to to-be-encoded items were scarce during spatial encoding in comparison with verbal encoding. However, despite replicating this difference across different tasks (serial, free recall) and presentation modalities (simultaneous, sequential presentation), we found no relation between item fixations and memory performance-that is, no costs or benefits. Inducing a change from covert to overt encoding did not affect spatial memory performance as well. In contrast, regressive fixations on prior items, that were no longer on the screen, were associated with increased spatial memory performance. Regressions occurred mainly at the end of the encoding period and were targeted at the first presented item. Our results suggest a dissociation between two types of fixations that accompany serial spatial memory: On-item fixations are epiphenomenal; regressions indicate rehearsal or output preparation.

Dual Process Coding of Recalled Locations in Human Oscillatory Brain Activity

A mental representation of the location of an object can be constructed using sensory information selected from the environment and information stored internally. Human electrophysiological evidence indicates that behaviorally relevant locations, regardless of the source of sensory information, are represented in alpha-band oscillations suggesting a shared process. Here, we present evidence from human subjects of either sex for two distinct alpha-band-based processes that separately support the representation of location, exploiting sensory evidence sampled either externally or internally.SIGNIFICANCE STATEMENT Our sensory environment and our internal trains of thought are coded in patterns of brain activity and are used to guide coherent behavior. Oscillations in the alpha-frequency band are a predominant feature of human brain activity. This oscillation plays a central role in both selective attention and working memory, suggesting that these important cognitive functions are mediated by a unitary mechanism. We show that the alpha oscillation reflects two distinct processes, one that is supported by continuous sampling of the external sensory environment, and one that is based on sampling from internal representations coded in visual short-term memory. This represents a significant change in our understanding of the nature of alpha oscillations and their relationship to attention and memory.

Updating spatial working memory in a dynamic visual environment

The present review describes recent developments regarding the role of the eye movement system in representing spatial information and keeping track of locations of relevant objects. First, we discuss the active vision perspective and why eye movements are considered crucial for perception and attention. The second part focuses on the question of how the oculomotor system is used to represent spatial attentional priority, and the role of the oculomotor system in maintenance of this spatial information. Lastly, we discuss recent findings demonstrating rapid updating of information across saccadic eye movements. We argue that the eye movement system plays a key role in maintaining and rapidly updating spatial information. Furthermore, we suggest that rapid updating emerges primarily to make sure actions are minimally affected by intervening eye movements, allowing us to efficiently interact with the world around us.

Refixation patterns reveal memory-encoding strategies in free viewing

We investigated visual working memory encoding across saccadic eye movements, focusing our analysis on refixation behavior. Over 10-s periods, participants performed a visual search for three, four, or five targets and remembered their orientations for a subsequent change-detection task. In 50% of the trials, one of the targets had its orientation changed. From the visual search period, we scored three types of refixations and applied measures for quantifying eye-fixation recurrence patterns. Repeated fixations on the same regions as well as repeated fixation patterns increased with memory load. Correct change detection was associated with more refixations on targets and less on distractors, with increased frequency of recurrence, and with longer intervals between refixations. The results are in accordance with the view that patterns of eye movement are an integral part of visual working memory representation.

Memory for positional movements as a component of the visuospatial working memory

Though the Corsi block-tapping task (CBT) is widely used for assessing visuospatial memory, information about what exactly it measures is still debated. We investigated such issue by observing how motor, visual, and spatial secondary tasks affect the performance on three versions of the CBT. Results showed a double dissociation pattern, wherein two motor secondary tasks had larger effects when the CBT was administered by the examiner tapping on the blocks. A spatial secondary task had larger effects when the CBT was administered by automatically illuminating the blocks. Finally, a visual secondary task had larger effects on a two-dimensional, computerized version of the CBT. These findings suggest that memory for movements plays a relevant role in the CBT, and are especially relevant due to their implications for assessment of brain-damaged patients, besides providing further evidence of a fractionation of visuospatial memory into multiple subcomponents.

Overlapping frontoparietal networks in response to oculomotion and traumatic autobiographical memory retrieval: implications for eye movement desensitization and reprocessing

Background: Oculomotor movements have been shown to aid in the retrieval of episodic memories, serving as sensory cues that engage frontoparietal brain regions to reconstruct visuospatial details of a memory. Frontoparietal brain regions not only are involved in oculomotion, but also mediate, in part, the retrieval of autobiographical episodic memories and assist in emotion regulation. Objective: We sought to investigate how oculomotion influences retrieval of traumatic memories by examining patterns of frontoparietal brain activation during autobiographical memory retrieval in post-traumatic stress disorder (PTSD) and in healthy controls. Method: Thirty-nine participants (controls, n = 19; PTSD, n = 20) recollected both neutral and traumatic/stressful autobiographical memories while cued simultaneously by horizontal and vertical oculomotor stimuli. The frontal (FEF) and supplementary (SEF) eye fields were used as seed regions for psychophysiological interaction analyses in SPM12. Results: As compared to controls, upon retrieval of a traumatic/stressful memory while also performing simultaneous horizontal eye movements, PTSD showed: i) increased SEF and FEF connectivity with the right dorsolateral prefrontal cortex, ii) increased SEF connectivity with the right dorsomedial prefrontal cortex, and iii) increased SEF connectivity with the right anterior insula. By contrast, as compared to PTSD, upon retrieval of a traumatic/stressful memory while also performing simultaneous horizontal eye movements, controls showed: i) increased FEF connectivity with the right posterior insula and ii) increased SEF connectivity with the precuneus. Conclusions: These findings provide a neurobiological account for how oculomotion may influence the frontoparietal cortical representation of traumatic memories. Implications for eye movement desensitization and reprocessing are discussed.

Testing the validity of the attention control video: An eye-tracking approach of the ego depletion effect

The attention control video has been frequently applied to test the ego depletion effect. However, its validity has never been tested, a shortcoming we address in this preregistered study. In the first task, self-control strength was temporarily depleted in the depletion condition (n = 56) but remained intact in the control condition (n = 56). The attention control video served as the secondary task, and we assumed that the depletion condition would perform significantly worse compared to the control condition. Attention regulation was measured with an eye-tracking device. The results revealed that the gaze behavior in the two conditions differed statistically significantly; however, the actual difference was small, indicating that the attention control video may not be an optimal measure of self-control.

A novel paradigm to study spatial memory skills in blind individuals through the auditory modality

Spatial memory is a multimodal representation of the environment, which can be mediated by different sensory signals. Here we investigate how the auditory modality influences memorization, contributing to the mental representation of a scene. We designed an audio test inspired by a validated spatial memory test, the Corsi-Block test for blind individuals. The test was carried out in two different conditions, with non-semantic and semantic stimuli, presented in different sessions and displaced on an audio-tactile device. Furthermore, the semantic sounds were spatially displaced in order to reproduce an audio scene, explored by participants during the test. Thus, we verified if semantic rather than non-semantic sounds are better recalled and whether exposure to an auditory scene can enhance memorization skills. Our results show that sighted subjects performed better than blind participants after the exploration of the semantic scene. This suggests that blind participants focus on the perceived sound positions and do not use items’ locations learned during the exploration. We discuss these results in terms of the role of visual experience on spatial memorization skills and the ability to take advantage of semantic information stored in the memory.

The contributions of visual and central attention to visual working memory

We investigated the role of two kinds of attention-visual and central attention-for the maintenance of visual representations in working memory (WM). In Experiment 1 we directed attention to individual items in WM by presenting cues during the retention interval of a continuous delayed-estimation task, and instructing participants to think of the cued items. Attending to items improved recall commensurate with the frequency with which items were attended (0, 1, or 2 times). Experiments 1 and 3 further tested which kind of attention-visual or central-was involved in WM maintenance. We assessed the dual-task costs of two types of distractor tasks, one tapping sustained visual attention and one tapping central attention. Only the central attention task yielded substantial dual-task costs, implying that central attention substantially contributes to maintenance of visual information in WM. Experiment 2 confirmed that the visual-attention distractor task was demanding enough to disrupt performance in a task relying on visual attention. We combined the visual-attention and the central-attention distractor tasks with a multiple object tracking (MOT) task. Distracting visual attention, but not central attention, impaired MOT performance. Jointly, the three experiments provide a double dissociation between visual and central attention, and between visual WM and visual object tracking: Whereas tracking multiple targets across the visual filed depends on visual attention, visual WM depends mostly on central attention.

Effects of environmental support on overt and covert visuospatial rehearsal

People can rehearse to-be-remembered locations either overtly, using eye movements, or covertly, using only shifts of spatial attention. The present study examined whether the effectiveness of these two strategies depends on environmental support for rehearsal. In Experiment 1, when environmental support (i.e., the array of possible locations) was present and participants could engage in overt rehearsal during retention intervals, longer intervals resulted in larger spans, whereas in Experiment 2, when support was present but participants could only engage in covert rehearsal, longer intervals resulted in smaller spans. When environmental support was absent, however, longer retention intervals resulted in smaller memory spans regardless of which rehearsal strategies were available. In Experiment 3, analyses of participants' eye movements revealed that the presence of support increased participants' fixations of to-be-remembered target locations more than fixations of non-targets, and that this was associated with better memory performance. Further, although the total time fixating targets increased, individual target fixations were actually briefer. Taken together, the present findings suggest that in the presence of environmental support, overt rehearsal is more effective than covert rehearsal at maintaining to-be-remembered locations in working memory, and that having more time for overt rehearsal can actually increase visuospatial memory spans.

Short Article: Sequential Tapping Interferes Selectively with Multiple-Object Tracking: Do Finger-Tapping and Tracking Share a Common Resource?

Multiple-object tracking involves simultaneously monitoring positions of a number of target items as they move among distractors. Young adults are capable of tracking only 3–5 items at once. In this study we investigated the origin of this limitation by looking for secondary tasks that interfere with tracking. We compared tracking performance (baseline condition), with performance when participants tapped three fingers in a specific order while tracking (sequential tapping) or articulated three syllables in a specific order while tracking (sequential articulation). The articulation task was used to ensure that the interference produced by sequential tapping was more than would be expected by the executive demands of carrying out any two “attention-demanding” tasks at once. Even though sequential tapping does not require vision or memorizing the positions of external items, it produced significantly more interference than did sequential articulation, as might be expected if tracking and sequential tapping shared a common (limited) resource.

The Impact of Path Crossing on Visuo-Spatial Serial Memory: Encoding or Rehearsal Effect?

The determinants of visuo-spatial serial memory have been the object of little research, despite early evidence that not all sequences are equally remembered. Recently, empirical evidence was reported indicating that the complexity of the path formed by the to-be-remembered locations impacted on recall performance, defined for example by the presence of crossings in the path formed by successive locations (Parmentier, Elford, & Maybery, 2005). In this study, we examined whether this effect reflects rehearsal or encoding processes. We examined the effect of a retention interval and spatial interference on the ordered recall of spatial sequences with and without path crossings. Path crossings decreased recall performance, as did a retention interval. In line with the encoding hypothesis, but in contrast with the rehearsal hypothesis, the effect of crossing was not affected by the retention interval nor by tapping. The possible nature of the impact of path crossing on encoding mechanisms is discussed.

Multiple-Target Tracking: A Role for Working Memory?

In order to identify the cognitive processes associated with target tracking, a dual-task experiment was carried out in which participants undertook a dynamic multiple-object tracking task first alone and then again, concurrently with one of several secondary tasks, in order to investigate the cognitive processes involved. The research suggests that after designated targets within the visual field have attracted preattentive indexes that point to their locations in space, conscious processes, vulnerable to secondary visual and spatial task interference, form deliberate strategies beneficial to the tracking task, before tracking commences. Target tracking itself is realized by central executive processes, which are sensitive to any other cognitive demands. The findings are discussed in the context of integrating dynamic spatial cognition within a working memory framework.

Following instructions in a dual-task paradigm: Evidence for a temporary motor store in working memory

Evidence from dual-task studies suggests that working memory supports the retention and implementation of verbal instructions. One key finding that is not readily accommodated by existing models of working memory is that participants are consistently more accurate at physically performing rather than verbally repeating a sequence of commands. This action advantage has no obvious source within the multi-component model of working memory and has been proposed to be driven by an as yet undetected limited-capacity store dedicated to the temporary maintenance of spatial, motoric, and temporal features of intended movements. To test this hypothesis, we sought to selectively disrupt the action advantage with concurrent motor suppression. In three dual-task experiments, young adults' immediate memory for sequences of spoken instructions was assessed by both action-based and spoken recall. In addition to classic interference tasks known to tax the phonological loop and central executive, motor suppression tasks designed to impair the encoding and retention of motoric representations were included. These required participants to produce repetitive sequences of either fine motor gestures (Experiment 1, N = 16) or more basic ones (Experiments 2, N = 16, and 3, N = 16). The benefit of action-based recall was reduced following the production of basic gestures but remained intact under all other interference conditions. These results suggest that the mnemonic advantage of enacted recall depends on a cognitive system dedicated to the temporary maintenance of motoric representations of planned action sequences.

Does differential visual exploration contribute to visual memory impairments in 22q11.2 microdeletion syndrome?

BACKGROUND

Chromosome 22q11.2 microdeletion syndrome (22q11.2DS) is a genetic syndrome characterised by a unique cognitive profile. Individuals with the syndrome present several non-verbal deficits, including visual memory impairments and atypical exploration of visual information. In this study, we seek to understand how visual attention may contribute to memory difficulties in 22q11.2DS by tracking eye movements during the encoding phase of a visual short-term memory task.

METHOD

Eye movements were recorded during a computerised version of the multiple-choice Benton Visual Retention Test, which consisted of exploring and then recognising complex visual stimuli. Seventy-four participants affected by 22q11.2DS were compared with 70 typically developing participants.

RESULTS

Participants with 22q11.2DS performed less well than healthy controls on the task and spent more time and fixations on the principal (larger central) figures and less time and fixations on the smaller peripheral figures within the stimuli.

CONCLUSIONS

This study is the first to investigate visual attention in 22q11.2DS during a memory task. The results delineate impaired processes during encoding that affect visual memory performance. The findings may be especially useful for informing interventions intended to boost visual learning in patients with 22q11.2DS.

Word Learning Deficits in Children With Dyslexia

PURPOSE

The purpose of this study is to investigate word learning in children with dyslexia to ascertain their strengths and weaknesses during the configuration stage of word learning.

METHOD

Children with typical development (N = 116) and dyslexia (N = 68) participated in computer-based word learning games that assessed word learning in 4 sets of games that manipulated phonological or visuospatial demands. All children were monolingual English-speaking 2nd graders without oral language impairment. The word learning games measured children's ability to link novel names with novel objects, to make decisions about the accuracy of those names and objects, to recognize the semantic features of the objects, and to produce the names of the novel words. Accuracy data were analyzed using analyses of covariance with nonverbal intelligence scores as a covariate.

RESULTS

Word learning deficits were evident for children with dyslexia across every type of manipulation and on 3 of 5 tasks, but not for every combination of task/manipulation. Deficits were more common when task demands taxed phonology. Visuospatial manipulations led to both disadvantages and advantages for children with dyslexia.

CONCLUSION

Children with dyslexia evidence spoken word learning deficits, but their performance is highly dependent on manipulations and task demand, suggesting a processing trade-off between visuospatial and phonological demands.

The effects of task-relevant saccadic eye movements performed during the encoding of a serial sequence on visuospatial memory performance

Visuospatial working memory (VSWM) is a set of cognitive processes used to encode, maintain and manipulate spatial information. One important feature of VSWM is that it has a limited capacity such that only few items can be actively stored and manipulated simultaneously. Given the limited capacity, it is important to determine the conditions that affect memory performance as this will improve our understanding of the architecture and function of VSWM. Previous studies have shown that VSWM is disrupted when task-irrelevant eye movements are performed during the maintenance phase; however, relatively fewer studies examined the role of eye movements performed during the encoding phase. On one hand, performing eye movements during the encoding phase could result in a stronger memory trace because the memory formation is reinforced by the activation of the motor system. On the other hand, performing eye movements to each target could disrupt the configural processing of the spatial array because the spatial representation has to be updated with each movement to maintain perceptual stability. Therefore, this work was conducted to examine whether task-relevant saccadic eye movements performed during the encoding phase of a visuospatial working memory task affect the recall of serially presented targets. Results from two experiments showed that average recall accuracy was significantly higher when the spatial array (set size ≥ 7) was encoded using a covert strategy-that is, while participants fixated on a central target, in comparison to an overt strategy-that is, while participants moved their eyes to fixate on each target. Furthermore, the improvement in accuracy was evident only for targets presented in the first half of the sequence, suggesting that the primacy effect is modulated by the presence of eye movements. We propose that executing saccades during encoding could interfere with the ability to use a chunking strategy or disrupt active visualization of the configuration. In conclusion, this is the first study to show that task-relevant saccadic eye movements performed during encoding may actually reduce the spatial span of VSWM. These results extend the current knowledge about the role of eye movements in VSWM, and have implications for future studies investigating the VSWM.

Working memory training involves learning new skills

We present a new framework characterizing training-induced changes in WM as the acquisition of novel cognitive routines akin to learning a new skill. Predictions were tested in three studies analyzing the transfer between WM tasks following WM training. Study 1 reports a meta-analysis establishing substantial transfer when trained and untrained tasks shared either a serial recall, complex span or backward span paradigm. Transfer was weaker for serial recall of verbal than visuo-spatial material, suggesting that this paradigm is served by an existing verbal STM system and does not require a new routine. Re-analysis of published WM training data in Study 2 showed that transfer was restricted to tasks sharing properties proposed to require new routines. In a re-analysis of data from four studies, Study 3 demonstrated that transfer was greatest for children with higher fluid cognitive abilities. These findings suggest that development of new routines depends on general cognitive resources and that they can only be applied to other similarly-structured tasks.

Cognitive Health Assessment and Establishment of a Virtual Cohort of Dementia Caregivers

Background

Many factors impact caregivers’ cognitive health and, by extension, their ability to provide care. This study examined the relationship between psychosocial factors and cognitive performance among dementia caregivers and established a virtual cohort of caregivers for future research.

Methods

Data on 527 caregivers were collected via a Web-based survey that assessed cognitive performance. Caregiver data were compared to corresponding data from 527 age-, race-, gender-, and education-matched controls from a normative database. Caregiver self-reported sleep, stress, health, and social support were also assessed.

Results

Caregivers performed significantly worse than controls on 3 of 5 cognitive subtests. Stress, sleep, perceived support, self-rated health, years of caregiving, race, and gender were significant predictors of cognitive performance.

Conclusion

In this sample of dementia caregivers, psychosocial factors interacted in complex ways to impact cognitive performance. Further investigation is needed to better understand how these factors affect cognitive performance among caregivers. This could be accomplished by the establishment of a virtual cohort that facilitates the development of digital tools to support the evaluation and management of caregiver needs in a manner that helps them remain effective in their caregiving roles.

Oculomotor selection underlies feature retention in visual working memory

Oculomotor selection, spatial task relevance, and visual working memory (WM) are described as three processes highly intertwined and sustained by similar cortical structures. However, because task-relevant locations always constitute potential saccade targets, no study so far has been able to distinguish between oculomotor selection and spatial task relevance. We designed an experiment that allowed us to dissociate in humans the contribution of task relevance, oculomotor selection, and oculomotor execution to the retention of feature representations in WM. We report that task relevance and oculomotor selection lead to dissociable effects on feature WM maintenance. In a first task, in which an object's location was encoded as a saccade target, its feature representations were successfully maintained in WM, whereas they declined at nonsaccade target locations. Likewise, we observed a similar WM benefit at the target of saccades that were prepared but never executed. In a second task, when an object's location was marked as task relevant but constituted a nonsaccade target (a location to avoid), feature representations maintained at that location did not benefit. Combined, our results demonstrate that oculomotor selection is consistently associated with WM, whereas task relevance is not. This provides evidence for an overlapping circuitry serving saccade target selection and feature-based WM that can be dissociated from processes encoding task-relevant locations.

The effects of environmental support and secondary tasks on visuospatial working memory

In the present experiments, we examined the effects of environmental support on participants' ability to rehearse locations and the role of such support in the effects of secondary tasks on memory span. In Experiment 1, the duration of interitem intervals and the presence of environmental support for visuospatial rehearsal (i.e., the array of possible memory locations) during the interitem intervals were both manipulated across four tasks. When support was provided, memory spans increased as the interitem interval durations increased, consistent with the hypothesis that environmental support facilitates rehearsal. In contrast, when environmental support was not provided, spans decreased as the duration of the interitem intervals increased, consistent with the hypothesis that visuospatial memory representations decay when rehearsal is impeded. In Experiment 2, the ratio of interitem interval duration to intertrial interval duration was kept the same on all four tasks, in order to hold temporal distinctiveness constant, yet forgetting was still observed in the absence of environmental support, consistent with the decay hypothesis. In Experiment 3, the effects of impeding rehearsal were compared to the effects of verbal and visuospatial secondary processing tasks. Forgetting of locations was greater when presentation of to-be-remembered locations alternated with the performance of a secondary task than when rehearsal was impeded by the absence of environmental support. The greatest forgetting occurred when a secondary task required the processing visuospatial information, suggesting that in addition to decay, both domain-specific and domain-general effects contribute to forgetting on visuospatial working memory tasks.

The Role of Eye Movements in EMDR: Conducting Eye Movements While Concentrating on Negative Autobiographical Memories Results in Fewer Intrusions

In dismantling eye movement desensitization and reprocessing (EMDR) therapy, researchers have found that the central executive is likely responsible for the effect of eye movements on negative memories. Arguably, however, researchers have not satisfactorily explained central executive mechanisms responsible. One possible central executive mechanism is that of suppression. The aim of this research was to evaluate the effect of eye movements on vividness, emotionality, and suppression of memories. Thirty-one nonclinical participants in Experiment 1 completed fast- and no-eye-movement conditions. Thirty-three nonclinical participants in Experiment 2 completed fast-, slow-, and no-eye-movement conditions. Number of intrusions during a suppression period and self-ratings of vividness and emotionality were the dependent variables in both experiments. Experiment 2 also included a measure of central executive capacity. Results from both experiments supported the hypotheses and showed that fast eye movements resulted in fewer intrusions than no- and slow-eye-movement conditions. Experiment 2 also found a correlation between number of intrusions after fast eye movements and central executive capacity. Limitations of this research are discussed as well as possibilities for future research and implications for understanding EMDR therapy.

Rewards modulate saccade latency but not exogenous spatial attention

The eye movement system is sensitive to reward. However, whilst the eye movement system is extremely flexible, the extent to which changes to oculomotor behavior induced by reward paradigms persist beyond the training period or transfer to other oculomotor tasks is unclear. To address these issues we examined the effects of presenting feedback that represented small monetary rewards to spatial locations on the latency of saccadic eye movements, the time-course of learning and extinction of the effects of rewarding saccades on exogenous spatial attention and oculomotor inhibition of return. Reward feedback produced a relative facilitation of saccadic latency in a stimulus driven saccade task which persisted for three blocks of extinction trials. However, this hemifield-specific effect failed to transfer to peripheral cueing tasks. We conclude that rewarding specific spatial locations is unlikely to induce long-term, systemic changes to the human oculomotor or attention systems.

Attentional costs and failures in air traffic control notifications

Large display screens are common in supervisory tasks, meaning that alerts are often perceived in peripheral vision. Five air traffic control notification designs were evaluated in their ability to capture attention during an ongoing supervisory task, as well as their impact on the primary task. A range of performance measures, eye-tracking and subjective reports showed that colour, even animated, was less effective than movement, and notifications sometimes went unnoticed. Designs that drew attention to the notified aircraft by a pulsating box, concentric circles or the opacity of the background resulted in faster perception and no missed notifications. However, the latter two designs were intrusive and impaired primary task performance, while the simpler animated box captured attention without an overhead cognitive cost. These results highlight the need for a holistic approach to evaluation, achieving a balance between the benefits for one aspect of performance against the potential costs for another. Practitioner summary: We performed a holistic examination of air traffic control notification designs regarding their ability to capture attention during an ongoing supervisory task. The combination of performance, eye-tracking and subjective measurements demonstrated that the best design achieved a balance between attentional power and the overhead cognitive cost to primary task performance.

eCorsi: implementation and testing of the Corsi block-tapping task for digital tablets

The Corsi block-tapping task is a widely used test to assess visuo-spatial working memory. The test is traditionally administered using nine square blocks positioned on a wooden board, but numerous digital versions have been developed. In this study, we tested one-hundred and seven participants divided into two age groups (18–30 and over 50) in forward, backward and supraspan-forward conditions with eCorsi, a tablet version of the Corsi task. Compared to the traditional physical board, eCorsi has several advantages, including: simple installation, set-up, and use; considerably increased accuracy in presentation timing, automatic measures of span and reaction times, in both the forward and backward response modalities. Results showed that average span and error rates were essentially analogous to the ones obtained in the main standardization studies, which have used the original physical version of the Corsi test. Furthermore, timing results provide new indications about the mechanisms underlying spatial sequence processing, suggesting that the subject's response is not planned during sequence presentation, but between the end of the presentation and the beginning of the response.

Attentional load interferes with target localization across saccades

The retinal positions of objects in the world change with each eye movement, but we seem to have little trouble keeping track of spatial information from one fixation to the next. We examined the role of attention in trans-saccadic localization by asking participants to localize targets while performing an attentionally demanding secondary task. In the first experiment, attentional load decreased localization precision for a remembered target, but only when a saccade intervened between target presentation and report. We then repeated the experiment and included a salient landmark that shifted on half the trials. The shifting landmark had a larger effect on localization under high load, indicating that observers rely more on landmarks to make localization judgments under high than under low attentional load. The results suggest that attention facilitates trans-saccadic localization judgments based on spatial updating of gaze-centered coordinates when visual landmarks are not available. The availability of reliable landmarks (present in most natural circumstances) can compensate for the effects of scarce attentional resources on trans-saccadic localization.

Visual-spatial attention aids the maintenance of object representations in visual working memory

Theories have proposed that the maintenance of object representations in visual working memory is aided by a spatial rehearsal mechanism. In this study, we used two different approaches to test the hypothesis that overt and covert visual-spatial attention mechanisms contribute to the maintenance of object representations in visual working memory. First, we tracked observers' eye movements while they remembered a variable number of objects during change-detection tasks. We observed that during the blank retention interval, participants spontaneously shifted gaze to the locations that the objects had occupied in the memory array. Next, we hypothesized that if attention mechanisms contribute to the maintenance of object representations, then drawing attention away from the object locations during the retention interval should impair object memory during these change-detection tasks. Supporting this prediction, we found that attending to the fixation point in anticipation of a brief probe stimulus during the retention interval reduced change-detection accuracy, even on the trials in which no probe occurred. These findings support models of working memory in which visual-spatial selection mechanisms contribute to the maintenance of object representations.