Dissociating Spatial Attention and Working Memory Storage with Pupillometry.

Temporal attention is not affected by working memory load

P192 Investigating the role of the parietal and prefrontal cortices in spatial working memory using transcranial direct current stimulation

Many theories have proposed that visual working memory plays an important role in visual search. In contrast, by showing that a nonspatial working memory load did not interfere with search efficiency, Woodman, Vogel, and Luck (2001) recently proposed that the role of working memory in visual search is insignificant. However, the visual search process may interfere with spatial working memory. In the present study, a visual search task was performed concurrently with either a spatial working memory task (Experiment 1) or a nonspatial working memory task (Experiment 2). We found that the visual search process interfered with a spatial working memory load, but not with a nonspatial working memory load. These results suggest that there is a distinction between spatial and nonspatial working memory in terms of interactions with visual search tasks. These results imply that the visual search process and spatial working memory storage require the same limited-capacity mechanisms.

Past work reveals a tight relationship between spatial attention and storage in visual working memory. But is spatially attending an item tantamount to working memory encoding? Here, we tracked electroencephalography (EEG) signatures of spatial attention and working memory encoding while independently manipulating the number of memory items and the spatial extent of attention in two studies of adults (N = 39; N = 33). Neural measures of spatial attention tracked the position and size of the attended area independent of the number of individuated items encoded into working memory. At the same time, multivariate decoding of the number of items stored in working memory was insensitive to variations in the breadth and position of spatial attention. Finally, representational similarity analyses provided converging evidence for a pure load signal that is insensitive to the spatial extent of the stored items. Thus, although spatial attention is a persistent partner of visual working memory, it is functionally dissociable from the selection and maintenance of individuated representations in working memory.

Although there is research examining the demographic predictors of self-estimated intelligence (SEI) in young adults, so far SEI in old age is little investigated. This study aims to examine the influence of additional variables such as self-estimated emotional intelligence (SEEQ), physical attractiveness, health, general optimism, religiousness, and working memory (WM) on SEI both in young and older adults. A total of 159 young (90 women, Mage =28.77, SD=8.83) and 152 older adults (93 women, Mage =71.92, SD=6.84) completed a measure of SEI as well as questions regarding the abovementioned variables. Given that WM is considered a very strong predictor of intelligence, neuropsychological assessment included the measurement of WM and phonologically cued semantic retrieval-verbal storage and processing in WM, as assessed by the Digit Span Forward and Verbal Fluency Task. The visual storage in WM was assessed with a variation of the Visual Patterns Test, and the visual storage and processing in WM with the Corsi blocks task (backward). Positive and Negative Affect Schedule (PANAS-X) was also administered as a possible influence on cognitive performance and SEI. Young males rated their intelligence quotient (IQ) and emotional quotient (EQ) higher than young females. This was not confirmed for older adults, for which surprisingly the reversed pattern was found. Older women reported higher IQ and EQ than older men. Correlations showed for all participants that the higher they rated their IQ, the higher their ratings of EQ, physical attractiveness, health, and religiousness. No significant correlations between objective tests regarding WM and SEI were found, supporting SEI overestimations. Age, sex, physical attractiveness, and SEEQ were significant predictors of SEI. For the first time, a reverse sex difference across age groups in SEI is found. Implications for individuals and healthcare professionals involved in assessment are suggested.

A number of studies have provided evidence that the visual system statistically summarizes large amounts of information that would exceed the limitations of attention and working memory (ensemble coding). However the necessity of working memory resources for ensemble coding has not yet been tested directly. In the current study, we used a dual task design to test the effect of object and spatial visual working memory load on size averaging accuracy. In Experiment 1, we tested participants' accuracy in comparing the mean size of two sets under various levels of object visual working memory load. Although the accuracy of average size judgments depended on the difference in mean size between the two sets, we found no effect of working memory load. In Experiment 2, we tested the same average size judgment while participants were under spatial visual working memory load, again finding no effect of load on averaging accuracy. Overall our results reveal that ensemble coding can proceed unimpeded and highly accurately under both object and spatial visual working memory load, providing further evidence that ensemble coding reflects a basic perceptual process distinct from that of individual object processing.

This study examined how spatial working memory and visual (object) working memory interact, focusing on two related questions: First, can these systems function independently from one another? Second, under what conditions do they operate together? In a dual-task paradigm, participants attempted to remember locations in a spatial working memory task and colored objects in a visual working memory task. Memory for the locations and objects was subject to independent working memory storage limits, which indicates that spatial and visual working memory can function independently from one another. However, additional experiments revealed that spatial working memory and visual working memory interact in three memory contexts: when retaining (1) shapes, (2) integrated color-shape objects, and (3) colored objects at specific locations. These results suggest that spatial working memory is needed to bind colors and shapes into integrated object representations in visual working memory. Further, this study reveals a set of conditions in which spatial and visual working memory can be isolated from one another.

Objective To investigate the impact of attention on location,object and location-object working memory. Methods Event-related potentials (ERP) were recorded from 16 healthy subjects while performing tasks of the color-only,the location-only and the color-location binding memory separately. A repeated-measures factorial design was adopted with three levels (tasks:the color,the location,the binding). Results Significant differences of working memory capacity were found among tasks [F(1.95,29.23)=52.72,P =0.00] and listed in a decreasing order as:the location (3.258±0.610),the binding (2.300±0.735) and the color (1.298±0.520). Spatiotemporal patterns of the statistical parametric mapping (SPM) of F-value showed the task effect occurred during two stages:the consolidation stage (400'550 ms) in the frontal-central-parietal network and the maintenance stage (700'1100 ms) in bilateral ventral frontal-parietal regions. Spatiotemporal patterns of SPM(t) showed the significant differences between the color and the binding located at posterior parietal cortex during maintenance stage. Conclusion Spatial attention probably facilitates object working memory during both the consolidation stage by selective encoding and the maintenance stage by attention-based rehearsal mechanism. Key words: Working memory capacity; Spatial attention; Event-related potential (ERP); Statistical parametric mapping (SPM)

Anxiety can be distracting, disruptive, and incapacitating. Despite problems with empirical replication of this phenomenon, one fruitful avenue of study has emerged from working memory (WM) experiments where a translational method of anxiety induction (risk of shock) has been shown to disrupt spatial and verbal WM performance. Performance declines when resources (e.g., spatial attention, executive function) devoted to goal-directed behaviors are consumed by anxiety. Importantly, it has been shown that anxiety-related impairments in verbal WM depend on task difficulty, suggesting that cognitive load may be an important consideration in the interaction between anxiety and cognition. Here we use both spatial and verbal WM paradigms to probe the effect of cognitive load on anxiety-induced WM impairment across task modality. Subjects performed a series of spatial and verbal n-back tasks of increasing difficulty (1, 2, and 3-back) while they were safe or at risk for shock. Startle reflex was used to probe anxiety. Results demonstrate that induced-anxiety differentially impacts verbal and spatial WM, such that low and medium-load verbal WM is more susceptible to anxiety-related disruption relative to high-load, and spatial WM is disrupted regardless of task difficulty. Anxiety impacts both verbal and spatial processes, as described by correlations between anxiety and performance impairment, albeit the effect on spatial WM is consistent across load. Demanding WM tasks may exert top-down control over higher-order cortical resources engaged by anxious apprehension, however high-load spatial WM may continue to experience additional competition from anxiety-related changes in spatial attention, resulting in impaired performance. By describing this disruption across task modalities, these findings inform current theories of emotion–cognition interactions and may facilitate development of clinical interventions that seek to target cognitive impairments associated with anxiety.

Number line estimation under working memory load: Dissociations between working memory subsystems

The current study focuses on the relationship between working memory (WM) and flexibility, which is a dimension of divergent thinking. The research consisted of two experiments in which the participants’ task was to categorize given objects into as many categories as possible. We assumed that manipulation of the visual or relational complexity of a set of figures would respectively affect WM’s ability to maintain and process goal-relevant information. Additionally, the dual-task paradigm was used to observe the relocation of attention resources in the task because WM capacity is limited by attention resources. We hypothesized that both attentional control and the ability to maintain/process goal-relevant information in WM would affect the level of flexibility. The results show that an increased load on WM storage and on processing mechanisms leads to a decline in flexibility scores, which becomes especially apparent when the secondary task, which makes WM capacity more vulnerable, is applied. We conclude that the flexibility of divergent thinking is equally positively associated with the efficiency of WM mechanisms, i.e., storage and processing of current information, and the ability to use controlled attention.

We conducted a comprehensive and systematic assessment of memory functioning in drug-naïve boys with attention deficit hyperactivity disorder (ADHD) and oppositional defiant disorder (ODD). Boys performed verbal and spatial working memory (WM) component (storage and central executive) and verbal and spatial storage load tasks, and the spatial span, spatial executive WM, spatial recognition memory and verbal recognition memory tasks from the Cambridge Neuropsychological Test Automated Battery. Groups comprised: (a) ADHD only (N = 21); (b) ADHD+ODD (N = 27); (c) ODD only (N = 21); and (d) typically developing (TYP) boys (N = 26). Groups were matched for age (M = 9.7 years) and sex (all boys). Confirmatory factor analyses confirmed the presence of five factors: verbal functioning, spatial functioning, WM storage, WM central executive and long-term memory (LTM). All three clinical groups demonstrated impaired memory performance. Boys with ODD and ODD+ADHD but not ADHD alone performed poorly on verbal memory tasks, whilst all three clinical groups showed impaired performance on spatial memory tasks. All three clinical groups performed poorly on the storage and central executive WM factors and the LTM factor. ADHD and ODD are characterised by impaired performance storage and central executive WM tasks and LTM tasks. This is, we believe, the first report of impaired WM and LTM performance in ODD. This study suggests that verbal memory difficulties are more closely associated with ODD than ADHD symptoms and that combined ADHD+ODD represents a true comorbidity. The data also support a small but growing number of suggestions in the literature of impaired LTM in ADHD.

Spatial working memory and spatial attention rely on common neural processes in the intraparietal sulcus

Searching a cluttered visual scene for a specific item of interest can take several seconds to perform if the target item is difficult to discriminate from surrounding items. Whether working memory processes are utilized to guide the path of attentional selection during such searches remains under debate. Previous studies have found evidence to support a role for spatial working memory in inefficient search, but the role of nonspatial working memory remains unclear. Here, we directly compared the role of spatial and nonspatial working memory for both an efficient and inefficient search task. In Experiment 1, we used a dual-task paradigm to investigate the effect of performing visual search within the retention interval of a spatial working memory task. Importantly, by incorporating two working memory loads (low and high) we were able to make comparisons between dual-task conditions, rather than between dual-task and single-task conditions. This design allows any interference effects observed to be attributed to changes in memory load, rather than to nonspecific effects related to "dual-task" performance. We found that the efficiency of the inefficient search task declined as spatial memory load increased, but that the efficient search task remained efficient. These results suggest that spatial memory plays an important role in inefficient but not efficient search. In Experiment 2, participants performed the same visual search tasks within the retention interval of visually matched spatial and verbal working memory tasks. Critically, we found comparable dual-task interference between inefficient search and both the spatial and nonspatial working memory tasks, indicating that inefficient search recruits working memory processes common to both domains.

A bilateral advantage for storage in visual working memory