scholarly journals The roles of prefrontal brain regions in components of working memory: Effects of memory load and individual differences

1999 ◽  
Vol 96 (11) ◽  
pp. 6558-6563 ◽  
Author(s):  
B. Rypma ◽  
M. D'Esposito
Keyword(s):  
Working Memory ◽  
Individual Differences ◽  
Memory Load ◽  
Brain Regions ◽  
Memory Effects

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.

Parametric manipulation of working memory load in traumatic brain injury: Behavioral and neural correlates

2004 ◽  
Vol 10 (5) ◽  
pp. 724-741 ◽  
Author(s):  
WILLIAM M. PERLSTEIN ◽  
MICHAEL A. COLE ◽  
JASON A. DEMERY ◽  
PAUL J. SEIGNOUREL ◽  
NEHA K. DIXIT ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Working Memory ◽  
Brain Injury ◽  
Memory Load ◽  
Brain Regions ◽  
Small Subset ◽  
Chronic Patients ◽  
Mild Tbi ◽  
Severe Tbi ◽  
High Level

Traumatic brain injury (TBI) is often associated with enduring impairments in high-level cognitive functioning, including working memory (WM). We examined WM function in predominantly chronic patients with mild, moderate and severe TBI and healthy comparison subjects behaviorally and, in a small subset of moderate-to-severe TBI patients, with event-related functional magnetic resonance imaging (fMRI), using a visualn-back task that parametrically varied WM load. TBI patients showed severity-dependent and load-related WM deficits in performance accuracy, but not reaction time. Performance of mild TBI patients did not differ from controls; patients with moderate and severe TBI were impaired, relative to controls and mild TBI patients, but only at higher WM-load levels. fMRI results show that TBI patients exhibit altered patterns of activation in a number of WM-related brain regions, including the dorsolateral prefrontal cortex and Broca's area. Examination of the pattern of behavioral responding and the temporal course of activations suggests that WM deficits in moderate-to-severe TBI are due to associative or strategic aspects of WM, and not impairments in active maintenance of stimulus representations. Overall, results demonstrate that individuals with moderate-to-severe TBI exhibit WM deficits that are associated with dysfunction within a distributed network of brain regions that support verbally mediated WM. (JINS, 2004,10, 724–741.)

scholarly journals Brain Processing of Complex Geometric Forms in a Visual Memory Task Increases P2 Amplitude

2020 ◽  
Vol 10 (2) ◽  
pp. 114
Author(s):  
Héctor A. Cepeda-Freyre ◽  
Gregorio Garcia-Aguilar ◽  
Jose R. Eguibar ◽  
Carmen Cortes
Keyword(s):  
Working Memory ◽  
Visual Working Memory ◽  
Cognitive Processing ◽  
Visual Memory ◽  
Memory Load ◽  
Memory Task ◽  
Event Related Potentials ◽  
Brain Regions ◽  
Test Phase ◽  
Related Potentials

We study the cognitive processing of visual working memory in three different conditions of memory load and configuration change. Altering this features has been shown to alter the brain’s processing in memory tasks. Most studies dealing with this issue have used the verbal-phonological modality. We use complex geometric polygons to assess visual working memory in a modified change detection task. Three different types of backgrounds were used to manipulate memory loading and 18 complex geometric polygons to manipulate stimuli configuration. The goal of our study was to test whether the memory load and configuration affect the correct-recall ratios. We expected that increasing visual items loading and changing configuration of items would induce differences in working memory performance. Brain activity related to the task was assessed through event-related potentials (ERP), during the test phase of each trial. Our results showed that visual items loading and changing of item configuration affect working memory on test phase on ERP component P2, but does not affect performance. However frontal related ERP component—P3—was minimally affected by visual memory loading or configuration changing, supporting that working memory is related to a filtering processing in posterior brain regions.

scholarly journals Complementary Correlational Profiles between Slow Wave Brain Oscillations and Working Memory Capacity

2020 ◽  
pp. 1-4
Author(s):  
Eddy J. Davelaar ◽  
Eddy J. Davelaar
Keyword(s):  
Working Memory ◽  
Individual Differences ◽  
Spectral Power ◽  
Working Memory Capacity ◽  
Memory Capacity ◽  
Brain Regions ◽  
Cognitive Resources ◽  
Operation Span ◽  
Eyes Closed ◽  
Electrophysiological Recordings

Working memory involves a range of functions, including maintenance of information and processing that information undisturbed by distraction. Neuroscientific studies have observed critical contributions from frontal and parietal brain regions during processing of cognitive demanding tasks. However, less is known about individual differences in the resting state and their association with working memory capacity. In this study, electrophysiological recordings were taken from thirty volunteers in eyes closed and eyes open conditions after completing the automated version of the operation span task. The results reveal two clusters of correlations: a midline-theta cluster and a parieto-temporal alpha cluster. The theta and alpha clusters have a negative and a positive correlation with operation span performance, respectively. These results are interpreted as individual differences in cognitive preparedness, with the centro-parietal region being critical in switching between outward and inward attention, with the balance of theta and alpha spectral power at Pz indicating to where cognitive resources are directed.

scholarly journals An Omics-Inspired Elastic Net Approach Drastically Improves Out-of-Sample Prediction and Regional Inference of Task-Based fMRI

2020 ◽  
Author(s):  
Narun Pornpattananangkul ◽  
Adam Bartonicek ◽  
Yue Wang ◽  
Argyris Stringaris
Keyword(s):  
Working Memory ◽  
Individual Differences ◽  
Large Scale ◽  
Brain Regions ◽  
Elastic Net ◽  
Polygenic Scores ◽  
Out Of Sample ◽  
Out Of Sample Prediction ◽  
Univariate Approach ◽  
Do So

AbstractPredicting individual differences in cognitive processes is crucial, but the ability of task-based fMRI to do so remains dubious, despite decades of costly research. We tested the ability of working-memory fMRI in predicting working-memory, using the Adolescent Brain Cognitive Development (n = 4,350). The conventionally-used mass-univariate approach led to poor out-of-sample prediction (Mean r = .1-.12). However, the multivariate ‘Elastic Net’, which draws information across brain regions, enhanced out-of-sample prediction (r = .47) by several folds. The Elastic Net also enabled us to predict cognitive performance from various tasks collected outside of the scanner, highlighting its generalizability. Moreover, using an omics-inspired approach, we combined Elastic Net with permutation, allowing us to statistically infer which brain regions contribute to individual differences while accounting for collinearity. Accordingly, our framework can build an easy-to-interpret predictive fMRI model that transfers knowledge learned from large-scale datasets to smaller samples, akin to polygenic scores in genomics.

scholarly journals Auditory cortex supports verbal working memory capacity

2020 ◽  
Author(s):  
Gavin M. Bidelman ◽  
Jane A. Brown ◽  
Pouya Bashivan
Keyword(s):  
Working Memory ◽  
Individual Differences ◽  
Auditory Cortex ◽  
Memory Load ◽  
Memory Task ◽  
Verbal Working Memory ◽  
Human Cognition ◽  
Source Analysis ◽  
Neural Basis

AbstractWorking memory (WM) is a fundamental construct of human cognition. The neural basis of auditory WM is thought to reflect a distributed brain network consisting of canonical memory and central executive brain regions including frontal lobe, prefrontal areas, and hippocampus. Yet, the role of auditory (sensory) cortex in supporting active memory representations remains controversial. Here, we recorded neuroelectric activity via EEG as listeners actively performed an auditory version of the Sternberg memory task. Memory load was taxed by parametrically manipulating the number of auditory tokens (letter sounds) held in memory. Source analysis of scalp potentials showed that sustained neural activity maintained in auditory cortex (AC) prior to memory retrieval closely scaled with behavioral performance. Brain-behavior correlations revealed lateralized modulations in left (but not right) AC predicted individual differences in auditory WM capacity. Our findings confirm a prominent role of auditory cortex, traditionally viewed as a sensory-perceptual processor, in actively maintaining memory traces and dictating individual differences in behavioral WM limits.

The Influence of Working-Memory Demand and Subject Performance on Prefrontal Cortical Activity

2002 ◽  
Vol 14 (5) ◽  
pp. 721-731 ◽  
Author(s):  
Bart Rypma ◽  
Jeffrey S. Berger ◽  
Mark D'Esposito
Keyword(s):  
Working Memory ◽  
Individual Differences ◽  
Memory Load ◽  
Response Speed ◽  
Memory Storage ◽  
Memory Organization ◽  
Retrieval Task ◽  
High Performing ◽  
Behavioral Studies ◽  
Storage Buffer

Brain imaging and behavioral studies of working memory (WM) converge to suggest that the ventrolateral prefrontal cortex (PFC) mediates a capacity-limited storage buffer and that the dorsolateral PFC mediates memory organization processes that support supracapacity memory storage. Previous research from our laboratory has shown that the extent to which such memory organization processes are required depends on both task factors (i.e., memory load) and subject factors (i.e., response speed). Task factors exert their effects mainly during WM encoding while subject factors exert their effects mainly during WM retrieval. In this study, we sought to test the generalizability of these phenomena under more difficult memory-demand conditions than have been used previously. During scanning, subjects performed a WM task in which they were required to maintain between 1 and 8 letters over a brief delay. Neural activity was measured during encoding, maintenance, and retrieval task periods using event-related functional magnetic resonance imaging. With increasing memory load, there were reaction time increases and accuracy rate decreases, ventrolateral PFC activation decreases during encoding, and dorsolateral PFC activation increases during maintenance and retrieval. These results suggest that the ventrolateral PFC mediates WM storage and that the dorso-lateral PFC mediates strategic memory organization processes that facilitate supracapacity WM storage. Additionally, high-performing subjects showed overall less activation than low-performing subjects, but activation increases with increasing memory load in the lateral PFC during maintenance and retrieval. Low-performing subjects showed overall more activation than high-performing subjects, but minimal activation increases in the dorsolateral PFC with increasing memory load. These results suggest that individual differences in both neural efficiency and cognitive strategy underlie individual differences in the quality of subjects' WM performance.

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