scholarly journals Hemispheric asymmetries in posterior alpha power reflect the selection and inhibition of spatial context information in working memory

2019 ◽  
Author(s):  
Marlene Roesner ◽  
Stefan Arnau ◽  
Isabel Skiba ◽  
Edmund Wascher ◽  
Daniel Schneider
Keyword(s):  
Working Memory ◽  
Memory Task ◽  
Relevant Information ◽  
Spatial Context ◽  
Alpha Power ◽  
Hemispheric Asymmetries ◽  
Distractor Processing ◽  
Oscillatory Power ◽  
Memory Content ◽  
The Impact

There is an ongoing debate on the contribution of target enhancement and distractor inhibition processes to selective attention. In a working memory task, we presented to-be-memorized information in a way that posterior hemispheric asymmetries in oscillatory power could be unambiguously linked to lateral target vs. distractor processing. Alpha power asymmetries (8-14 Hz) were insensitive to the number of cued or non-cued items, supporting their relation to spatial attention. Furthermore, we found an increase in alpha power contralateral to non-cued working memory content and an alpha power suppression contralateral to relevant information. These oscillatory patterns relative to the positions of cued and non-cued items were related to the participants' ability to control for the impact of irrelevant information on working memory retrieval. Based on these results, we propose that spatially specific modulations of posterior alpha power are related to accessing vs. inhibiting the spatial context of information stored in working memory.

scholarly journals Perturbing Neural Representations of Working Memory with Task-irrelevant Interruption

2020 ◽  
Vol 32 (3) ◽  
pp. 558-569 ◽  
Author(s):  
Nicole Hakim ◽  
Tobias Feldmann-Wüstefeld ◽  
Edward Awh ◽  
Edward K. Vogel
Keyword(s):  
Working Memory ◽  
Memory Task ◽  
Relevant Information ◽  
Alpha Power ◽  
Neural Signals ◽  
Neural Representations ◽  
Contralateral Delay Activity ◽  
The Face ◽  
Task Irrelevant ◽  
The Impact

Working memory maintains information so that it can be used in complex cognitive tasks. A key challenge for this system is to maintain relevant information in the face of task-irrelevant perturbations. Across two experiments, we investigated the impact of task-irrelevant interruptions on neural representations of working memory. We recorded EEG activity in humans while they performed a working memory task. On a subset of trials, we interrupted participants with salient but task-irrelevant objects. To track the impact of these task-irrelevant interruptions on neural representations of working memory, we measured two well-characterized, temporally sensitive EEG markers that reflect active, prioritized working memory representations: the contralateral delay activity and lateralized alpha power (8–12 Hz). After interruption, we found that contralateral delay activity amplitude momentarily sustained but was gone by the end of the trial. Lateralized alpha power was immediately influenced by the interrupters but recovered by the end of the trial. This suggests that dissociable neural processes contribute to the maintenance of working memory information and that brief irrelevant onsets disrupt two distinct online aspects of working memory. In addition, we found that task expectancy modulated the timing and magnitude of how these two neural signals responded to task-irrelevant interruptions, suggesting that the brain's response to task-irrelevant interruption is shaped by task context.

scholarly journals Perturbing neural representations of working memory with task-irrelevant interruption

2019 ◽  
Author(s):  
Nicole Hakim ◽  
Tobias Feldmann-Wüstefeld ◽  
Edward Awh ◽  
Edward K. Vogel
Keyword(s):  
Working Memory ◽  
Memory Task ◽  
Relevant Information ◽  
Cognitive Tasks ◽  
Alpha Power ◽  
Task Context ◽  
Neural Representations ◽  
Task Irrelevant ◽  
The Impact ◽  
Neural Signatures

AbstractWorking memory maintains information so that it can be used in complex cognitive tasks. A key challenge for this system is to maintain relevant information in the face of task-irrelevant perturbations. In this series of experiments, we investigated the impact of task-irrelevant interruptions on neural representations of working memory. We recorded electroencephalogram (EEG) activity in humans while they performed a working memory task. On a subset of trials, we interrupted participants with salient, but task-irrelevant objects. To track the impact of these task-irrelevant interruptions on neural representations of working memory, we measured two well-characterized, temporally sensitive EEG markers that reflect active, prioritized working memory representations: the contralateral delay activity (CDA) and lateralized alpha power (8-12hz). Following interruption, we found that CDA momentarily sustained, but was gone by the end of the trial. Lateralized alpha power was immediately influenced by the interrupters, but recovered by the end of the trial. This suggests that dissociable neural processes contribute to the maintenance of working memory information. Additionally, we found that task expectancy modulated the timing and magnitude of how these two neural signals responded to task-irrelevant interruptions, suggesting that the brain’s response to task-irrelevant interruption is shaped by task context. The distinct time courses of and influence of task context on these two neural signatures of working memory have many interesting theoretical implications about how information is actively maintained in working memory.Significance statementWorking memory plays a central role in intelligent behaviors because it actively maintains relevant information that is easily accessible and manipulatable. In everyday life, we are often interrupted while performing such complex cognitive tasks. Therefore, understanding how working memory responds to and overcomes momentary task-irrelevant interruptions is critical for us to understand how complex cognition works. Here, we unveil how two distinct neural signatures of working memory respond to task-irrelevant interruptions by recording electroencephalogram activity in humans. Our findings raise long-standing theoretical questions about how different neural and cognitive processes contribute to the maintenance of information in working memory.

scholarly journals Aging impairs primary task resumption and attentional control processes following interruptions

2021 ◽  
Author(s):  
Marlene Roesner ◽  
Bianca Zickerick ◽  
Melinda Sabo ◽  
Daniel Schneider
Keyword(s):  
Older Adults ◽  
Working Memory ◽  
Age Groups ◽  
Memory Task ◽  
Attentional Selection ◽  
Primary Task ◽  
Alpha Power ◽  
Age Related ◽  
Memory Content ◽  
Task Resumption

Attentional selection of working memory content is impaired after an interruption. This effect was shown to increase with age. Here we investigate how electrophysiological mechanisms underlying attentional selection within working memory differ during primary task resumption between younger and older adults. Participants performed a working memory task, while be-ing frequently interrupted with either a cognitively low- or high-demanding arithmetic task. Afterwards, a retrospective cue (retro-cue) indicated the working memory content required for later report. The detrimental effect of the interruption was evident in both age groups, but while younger adults were more strongly affected by a high- than by a low-demanding inter-ruption, the performance deficit appeared independently of the cognitive requirements of the interruption task in older adults. A similar pattern was found regarding frontal-posterior con-nectivity in the theta frequency range, suggesting that aging decreases the ability to selectively maintain relevant information within working memory. The power of mid-frontal theta oscilla-tions (4-7 Hz) featured a comparable effect of interruptions in both age groups. However, pos-terior alpha power (8-14 Hz) following the retro-cue was more diminished by a preceding in-terruption in older adults. These results suggest an age-related deficit in the attentional selec-tion and maintenance of primary task information following an interruption that appeared in-dependent from the cognitive requirements of the interrupting task.

scholarly journals Fronto-medial theta coordinates posterior maintenance of working memory content

2021 ◽  
Author(s):  
Oliver Ratcliffe ◽  
Kimron Shapiro ◽  
Bernhard P. Staresina
Keyword(s):  
Working Memory ◽  
Computational Models ◽  
Medial Cortex ◽  
Duty Cycles ◽  
Machine Learning Approach ◽  
Theta Frequency ◽  
Oscillatory Power ◽  
Posterior Parietal ◽  
Memory Content ◽  
Memory Contents

AbstractHow does the human brain manage multiple bits of information to guide goal-directed behaviour? Successful working memory (WM) functioning has consistently been linked to oscillatory power in the theta frequency band (4-8 Hz) over fronto-medial cortex (fronto-medial theta, FMT). Specifically, FMT is thought to reflect the mechanism of an executive sub-system that coordinates maintenance of memory contents in posterior regions. However, direct evidence for the role of FMT in controlling specific WM content is lacking. Here we collected high-density Electroencephalography (EEG) data whilst participants engaged in load-varying WM tasks and then used multivariate decoding methods to examine WM content during the maintenance period. Higher WM load elicited a focal increase in FMT. Importantly, decoding of WM content was driven by posterior/parietal sites, which in turn showed load-induced functional theta coupling with fronto-medial cortex. Finally, we observed a significant slowing of FMT frequency with increasing WM load, consistent with the hypothesised broadening of a theta ‘duty cycle’ to accommodate additional WM items. Together these findings demonstrate that frontal theta orchestrates posterior maintenance of WM content. Moreover, the observed frequency slowing elucidates the function of FMT oscillations by specifically supporting phase-coding accounts of WM.Significance StatementHow does the brain juggle the maintenance of multiple items in working memory (WM)? Here we show that increased WM demands increase theta power (4-8 Hz) in fronto-medial cortex. Interestingly, using a machine learning approach, we found that the content held in WM could be read out not from frontal, but from posterior areas. These areas were in turn functionally coupled with fronto-medial cortex, consistent with the idea that frontal cortex orchestrates WM representations in posterior regions. Finally, we observed that holding an additional item in WM leads to significant slowing of the frontal theta rhythm, supporting computational models that postulate longer ‘duty cycles’ to accommodate additional WM demands.

scholarly journals Contralateral Delay Activity Tracks Fluctuations in Working Memory Performance

2018 ◽  
Vol 30 (9) ◽  
pp. 1229-1240 ◽  
Author(s):  
Kirsten C. S. Adam ◽  
Matthew K. Robison ◽  
Edward K. Vogel
Keyword(s):  
Working Memory ◽  
Individual Differences ◽  
Memory Load ◽  
Memory Performance ◽  
Memory Task ◽  
Memory Storage ◽  
Alpha Power ◽  
Working Memory Load ◽  
Contralateral Delay Activity ◽  
Trial Performance

Neural measures of working memory storage, such as the contralateral delay activity (CDA), are powerful tools in working memory research. CDA amplitude is sensitive to working memory load, reaches an asymptote at known behavioral limits, and predicts individual differences in capacity. An open question, however, is whether neural measures of load also track trial-by-trial fluctuations in performance. Here, we used a whole-report working memory task to test the relationship between CDA amplitude and working memory performance. If working memory failures are due to decision-based errors and retrieval failures, CDA amplitude would not differentiate good and poor performance trials when load is held constant. If failures arise during storage, then CDA amplitude should track both working memory load and trial-by-trial performance. As expected, CDA amplitude tracked load (Experiment 1), reaching an asymptote at three items. In Experiment 2, we tracked fluctuations in trial-by-trial performance. CDA amplitude was larger (more negative) for high-performance trials compared with low-performance trials, suggesting that fluctuations in performance were related to the successful storage of items. During working memory failures, participants oriented their attention to the correct side of the screen (lateralized P1) and maintained covert attention to the correct side during the delay period (lateralized alpha power suppression). Despite the preservation of attentional orienting, we found impairments consistent with an executive attention theory of individual differences in working memory capacity; fluctuations in executive control (indexed by pretrial frontal theta power) may be to blame for storage failures.

scholarly journals Tracking stimulus representation across a 2-back visual working memory task

2020 ◽  
Vol 7 (8) ◽  
pp. 190228 ◽  
Author(s):  
Quan Wan ◽  
Ying Cai ◽  
Jason Samaha ◽  
Bradley R. Postle
Keyword(s):  
Working Memory ◽  
Visual Working Memory ◽  
Memory Task ◽  
Memory Item ◽  
Neural Representation ◽  
Stimulus Representation ◽  
Representational Format ◽  
The Status ◽  
Memory Content ◽  
Default Assumption

How does the neural representation of visual working memory content vary with behavioural priority? To address this, we recorded electroencephalography (EEG) while subjects performed a continuous-performance 2-back working memory task with oriented-grating stimuli. We tracked the transition of the neural representation of an item ( n ) from its initial encoding, to the status of ‘unprioritized memory item' (UMI), and back to ‘prioritized memory item', with multivariate inverted encoding modelling. Results showed that the representational format was remapped from its initially encoded format into a distinctive ‘opposite' representational format when it became a UMI and then mapped back into its initial format when subsequently prioritized in anticipation of its comparison with item n + 2. Thus, contrary to the default assumption that the activity representing an item in working memory might simply get weaker when it is deprioritized, it may be that a process of priority-based remapping helps to protect remembered information when it is not in the focus of attention.

scholarly journals Shielding working-memory representations from temporally predictable external interference

2021 ◽  
Author(s):  
Daniela Gresch ◽  
Sage Boettcher ◽  
Freek van Ede ◽  
Anna C. Nobre
Keyword(s):  
Working Memory ◽  
Memory Performance ◽  
Memory Task ◽  
Memory Retention ◽  
Protective Effects ◽  
External Interference ◽  
Irrelevant Distractors ◽  
Temporal Predictability ◽  
Memory Representations ◽  
Memory Content

Protecting working-memory content from distracting external sensory inputs and intervening tasks is a ubiquitous demand in daily life. Here, we ask whether and how temporal expectations about external events can help mitigate effects of such interference during working-memory retention. We manipulated the temporal predictability of interfering items that occurred during the retention period of a visual working-memory task and report that temporal expectations reduce the detrimental influence of external interference on subsequent memory performance. Moreover, to determine if the protective effects of temporal expectations rely mainly on distractor suppression or also involve shielding of internal representations, we compared effects after irrelevant distractors that could be ignored vs. interrupters that required a response. Whereas distractor suppression may be sufficient to confer protection from predictable distractors, any benefits after interruption are likely to involve memory shielding. We found similar benefits of temporal expectations after both types of interference. We conclude that temporal expectations may play an important role in safeguarding behaviour based on working memory – acting, at least partly, through mechanisms that include the shielding of internal content from external interference.

scholarly journals Neural markers of category-based selective working memory in aging

2018 ◽  
Author(s):  
Robert M Mok ◽  
M. Clare O'Donoghue ◽  
Nicholas E Myers ◽  
Erin H.S. Drazich ◽  
Anna Christina Nobre
Keyword(s):  
Older Adults ◽  
Working Memory ◽  
Selective Attention ◽  
Memory Task ◽  
Relevant Information ◽  
Anterior Cingulate ◽  
Memory Processing ◽  
Normal Cognitive Function ◽  
Psychophysiological Interaction ◽  
Relevant Category

Working memory (WM) is essential for normal cognitive function, but shows marked decline in aging. Studies have shown that the ability to attend selectively to relevant information amongst competing distractors is related to WM capacity. The extent to which WM deficits in aging are related to impairments in selective attention is unclear. To investigate the neural mechanisms supporting selective attention in WM in aging, we tested a large group of older adults using functional magnetic resonance imaging whilst they performed a category-based (faces/houses) selective-WM task. Older adults were able to use attention to encode targets and suppress distractors to reach high levels of task performance. A subsequent, surprise recognition-memory task showed strong consequences of selective attention. Attended items in the relevant category were recognised significantly better than items in the ignored category. Neural measures also showed reliable markers of selective attention during WM. Purported control regions including the dorsolateral and inferior prefrontal and anterior cingulate cortex were reliably recruited for attention to both categories. Activation levels in category-sensitive visual cortex showed reliable modulation according to attentional demands, and positively correlated with subsequent memory measures of attention and WM span. Psychophysiological interaction analyses showed that activity in category-sensitive areas were coupled with non-sensory cortex known to be involved in cognitive control and memory processing, including regions in the PFC and hippocampus. In summary, we found that brain mechanisms of attention for selective WM are relatively preserved in aging, and individual differences in these abilities corresponded to the degree of attention-related modulation in the brain.

scholarly journals The impact of retro-cue validity on working memory representation: Evidence from electroencephalograms

2020 ◽  
Author(s):  
Xueying Fu ◽  
Chaoxiong Ye ◽  
huzhonghua ◽  
Tengfei Liang ◽  
Ziyuan Li ◽  
...  
Keyword(s):  
Working Memory ◽  
Spatial Attention ◽  
Memory Storage ◽  
Time Interval ◽  
Memory Representation ◽  
Attention And Memory ◽  
Alpha Power ◽  
Cue Validity ◽  
Validity Condition ◽  
The Impact

Memory performance can be improved by retrospectively cueing an item maintained in visual working memory (VWM). Different hypotheses have been proposed to explain the mechanisms behind retro-cueing and VWM. Previous behavioral studies suggest that different retro-cue validities may lead individuals to implement retro-cues in different ways to obtain a retro-cue effect. However, there is still no clear electroencephalogram (EEG) evidence to support that the retro-cue effect under different validity conditions is triggered by different mechanisms. Herein, we investigated whether retro-cue validity modulated the mechanisms underlying the retro-cue effect in VWM by using EEGs. We manipulated retro-cue validity by using blocks in a color change detection task. Contralateral delay activity (CDA) and lateralized alpha power were used assess spatial attention and memory storage, respectively. Significant retro-cue effects were observed under both high- and low-validity conditions. More importantly, although the retro-cue could redirect spatial attention under both high- and low-validity conditions, we found that participants maintained the non-cued items during a measured time interval under the low-validity condition, but dropped them out of VWM under the high-validity condition. Our results resolve previous contradictory findings. The retro-cue effect in our study can be explained by the removal hypothesis, prioritization hypothesis, and protection-during-retrieval hypothesis. This work suggests that the mechanisms underlying the retro-cue effect are not mutually exclusive, but determined by the cue validity. Individuals can voluntarily choose different mechanisms based on the expected retro-cue validity.

scholarly journals Game elements improve performance in a working memory training task

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Manuel Ninaus ◽  
Gonçalo Pereira ◽  
René Stefitz ◽  
Rui Prada ◽  
Ana Paiva ◽  
...  
Keyword(s):  
Working Memory ◽  
Working Memory Capacity ◽  
Memory Task ◽  
Working Memory Training ◽  
Memory Training ◽  
Control Group ◽  
Training Task ◽  
Level Indicator ◽  
Game Elements ◽  
The Impact

The utilization of game elements in a non-game context is currently used in a vast range of different domains. However, research on game elements’ effects in cognitive tasks is still sparse. Thus, in this study we implemented three game elements, namely, progress bar, level indicator, and a thematic setting, in a working memory training task. We evaluated the impact of game elements on user performance and perceived state of flow when compared to a conventional version of the task. Participants interacting with game elements showed higher scores in the working memory training task than participants from a control group who completed the working memory training task without the game elements. Moreover, game elements facilitated the individuals’ performance closer to their maximum working memory capacity. Finally, the perceived flow did not differ between the two groups, which indicates that game elements can induce better performance without changing the perception of being “in the zone”, that is without an increase in anxiety or boredom. This empirical study indicates that certain game elements can improve the performance and efficiency in a working memory task by increasing users’ ability and willingness to train at their optimal performance level. 

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