scholarly journals Effects of Memory Load and Distraction on Performance and Event-Related Slow Potentials in a Visuospatial Working Memory Task

1997 ◽  
Vol 9 (6) ◽  
pp. 743-757 ◽  
Author(s):  
Gina M. Geffen ◽  
Margaret J. Wright ◽  
Heather J. Green ◽  
Nicole A. Gillespie ◽  
David C. Smyth ◽  
...  
Keyword(s):  
Working Memory ◽  
Memory Load ◽  
Brain Activity ◽  
Memory Task ◽  
Delayed Response ◽  
Visuospatial Working Memory ◽  
Computer Screen ◽  
Slow Potentials ◽  
The Difference ◽  
Response Task

Brain electrical activity related to working memory was recorded at 15 scalp electrodes during a visuospatial delayed response task. Participants (N = 18) touched the remembered position of a target on a computer screen after either a 1 or 8 sec delay. These memory trials were compared to sensory trials in which the target remained present throughout the delay and response periods. Distractor stimuli identical to the target were briefly presented during the delay on 30% of trials. Responses were less accurate in memory than sensory trials, especially after the long delay. During the delay slow potentials developed that were significantly more negative in memory than sensory trials. The difference between memory and sensory trials was greater at anterior than posterior electrodes. On trials with distractors, the slow potentials generated by memory trials showed further enhancement of negativity, whereas there were minimal effects on accuracy of performance. The results provide evidence that engagement of visuospatial working memory generates slow wave negativity with a timing and distribution consistent with frontal activation. Enhanced brain activity associated with working memory is required to maintain performance in the presence of distraction.

Prefrontal Cortical Representation of Visuospatial Working Memory in Monkeys Examined by Local Inactivation With Muscimol

2001 ◽  
Vol 86 (4) ◽  
pp. 2041-2053 ◽  
Author(s):  
Toshiyuki Sawaguchi ◽  
Michiyo Iba
Keyword(s):  
Working Memory ◽  
Functional Organization ◽  
Visual Fields ◽  
Local Injection ◽  
Delayed Response ◽  
Visually Guided ◽  
Visuospatial Working Memory ◽  
Prefrontal Cortical ◽  
Response Task ◽  
Spatial Locations

In primates, dorsolateral areas of the prefrontal cortex (PFC) play a major role in visuospatial working memory. To examine the functional organization of the PFC for representing visuospatial working memory, we produced reversible local inactivation, with the local injection of muscimol (5 μg, 1 μl), at various sites ( n = 100) in the dorsolateral PFC of monkeys and observed the behavioral consequences in an oculomotor delayed-response task that required memory-guided saccades for locations throughout both visual fields. At 82 sites, the local injection of muscimol induced deficits in memory-guided saccades to a few specific, usually contralateral, target locations that varied with the location of the injection site. Such deficits depended on the delay length, and longer delays were associated with larger deficits in memory-guided saccades. The injection sites and affected spatial locations of the target showed a gross topographical relationship. No deficits appeared for a control task in which the subject was required to make a visually guided saccade to a visible target. These findings suggest that a specific site in the dorsolateral PFC is responsible for the working memory process for a specific visuospatial coordinate to guide goal-directed behavior. Further, memoranda for specific visuospatial coordinates appear to be represented in a topographical memory mapwithin the dorsolateral PFC to represent visuospatial working memory processes.

scholarly journals To CRUNCH or not to CRUNCH: Task Difficulty Affects Functional Brain Reorganisation during Visuospatial Working Memory Performance in Premanifest Huntington’s Disease

2018 ◽  
Author(s):  
Maria V. Soloveva ◽  
Sharna D. Jamadar ◽  
Dennis Velakoulis ◽  
Govinda Poudel ◽  
Nellie Georgiou Karistianis
Keyword(s):  
Working Memory ◽  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Memory Load ◽  
Disease Onset ◽  
Memory Task ◽  
List Type ◽  
Intraparietal Sulcus ◽  
Visuospatial Working Memory ◽  
Functional Brain

AbstractPresymptomatic Huntington’s disease (pre-HD) individuals tend to increase functional brain activity to compensate for HD-related brain anomalies. We used a quantitative model of compensation, known as the CRUNCH (Compensation-Related Utilization of Neural Circuits Hypothesis) to explicitly characterise compensation in pre-HD. We acquired functionalmagnetic resonance imaging (fMRI) data (n = 15 pre-HD; n = 15 controls) during performance of an 18-minute fMRI visuospatial working memory task with low, intermediate-1, intermediate-2, and high memory loads. Consistent with the CRUNCH prediction, pre-HD individuals showed decreased fMRI activity in left intraparietal sulcus at high memory load, compared to healthy controls who showed increased fMRI activity in left intraparietal sulcus at high memory load. Contrary to the other CRUNCH prediction, the pre-HD group did not show compensatory increase in fMRI activity at lower levels of memory loads in left intraparietal sulcus. Our findings provide partial support for the validity of CRUNCH in pre-HD.HighlightsVisuospatial working memory deficits in pre-HD occur 25 years prior to predicted disease onsetTask demands differentially affect fMRI activity in left intraparietal sulcusCRUNCH can partially apply in Huntington’s disease

scholarly journals Dissociative Effects of Methylphenidate in Nonhuman Primates: Trade-offs between Cognitive and Behavioral Performance

2012 ◽  
Vol 24 (6) ◽  
pp. 1371-1381 ◽  
Author(s):  
Abigail Z. Rajala ◽  
Jeffrey B. Henriques ◽  
Luis C. Populin
Keyword(s):  
Working Memory ◽  
Target Location ◽  
Memory Performance ◽  
Memory Task ◽  
Delayed Response ◽  
Impaired Performance ◽  
Healthy Humans ◽  
Trade Offs ◽  
Accuracy And Precision ◽  
Response Task

Low doses of methylphenidate reduce hyperactivity and improve attention in individuals with attention deficit hyperactivity disorder (ADHD) as well as in healthy humans and animals. Despite its extensive use, relatively little is known about its mechanisms of action. This study investigated the effects of methylphenidate on working memory performance, impulsivity, response accuracy and precision, and the ability to stay on task in rhesus monkeys using an oculomotor delayed response task. Methylphenidate affected task performance in an inverted-U manner in all three subjects tested. The improvements resulted from a reduction in premature responses and, importantly, not from improvement in the memory of target location. The length of time subjects participated in each session was also affected dose dependently. However, the dose at which the length of participation was maximally increased significantly impaired performance on the working memory task. This dissociation of effects has implications for the treatment of ADHD, for the nonprescription use of methylphenidate for cognitive enhancement, and for furthering the basic understanding of the neural substrate underlying these processes.

Modulation of Alpha Activity in the Parieto-occipital Area by Distractors during a Visuospatial Working Memory Task: A Magnetoencephalographic Study

2015 ◽  
Vol 27 (3) ◽  
pp. 453-463 ◽  
Author(s):  
Satoe Ichihara-Takeda ◽  
Shogo Yazawa ◽  
Takashi Murahara ◽  
Takanobu Toyoshima ◽  
Jun Shinozaki ◽  
...  
Keyword(s):  
Working Memory ◽  
Information Processing ◽  
Brain Activity ◽  
Memory Task ◽  
Alpha Activity ◽  
Delay Period ◽  
Visuospatial Working Memory ◽  
Occipital Area ◽  
Spectral Evolution ◽  
Oscillatory Brain Activity

Oscillatory brain activity is known to play an essential role in information processing in working memory. Recent studies have indicated that alpha activity (8–13 Hz) in the parieto-occipital area is strongly modulated in working memory tasks. However, the function of alpha activity in working memory is open to several interpretations, such that alpha activity may be a direct neural correlate of information processing in working memory or may reflect disengagement from information processing in other brain areas. To examine the functional contribution of alpha activity to visuospatial working memory, we introduced visuospatial distractors during a delay period and examined neural activity from the whole brain using magnetoencephalography. The strength of event-related alpha activity was estimated using the temporal spectral evolution (TSE) method. The results were as follows: (1) an increase of alpha activity during the delay period as indicated by elevated TSE curves was observed in parieto-occipital sensors in both the working memory task and a control task that did not require working memory; and (2) an increase of alpha activity during the delay period was not observed when distractors were presented, although TSE curves were constructed only from correct trials. These results indicate that the increase of alpha activity is not directly related to information processing in working memory but rather reflects the disengagement of attention from the visuospatial input.

scholarly journals Task Difficulty Regulates How Conscious and Unconscious Monetary Rewards Boost the Performance of Working Memory: An Event-Related Potential Study

2022 ◽  
Vol 15 ◽  
Author(s):  
Shiyang Xu ◽  
Senqing Qi ◽  
Haijun Duan ◽  
Juan Zhang ◽  
Miriam Akioma ◽  
...  
Keyword(s):  
Working Memory ◽  
Memory Load ◽  
Memory Task ◽  
Reward Processing ◽  
Event Related Potential ◽  
Difficulty Level ◽  
Monetary Rewards ◽  
Complex Process ◽  
The Difference ◽  
Back Task

The performance of working memory can be improved by the corresponding high-value vs. low-value rewards consciously or unconsciously. However, whether conscious and unconscious monetary rewards boosting the performance of working memory is regulated by the difficulty level of working memory task is unknown. In this study, a novel paradigm that consists of a reward-priming procedure and N-back task with differing levels of difficulty was designed to inspect this complex process. In particular, both high-value and low-value coins were presented consciously or unconsciously as the reward cues, followed by the N-back task, during which electroencephalogram signals were recorded. It was discovered that the high-value reward elicited larger event-related potential (ERP) component P3 along the parietal area (reflecting the working memory load) as compared to the low-value reward for the less difficult 1-back task, no matter whether the reward was unconsciously or consciously presented. In contrast, this is not the case for the more difficult 2-back task, in which the difference in P3 amplitude between the high-value and low-value rewards was not significant for the unconscious reward case, yet manifested significance for the conscious reward processing. Interestingly, the results of the behavioral analysis also exhibited very similar patterns as ERP patterns. Therefore, this study demonstrated that the difficulty level of a task can modulate the influence of unconscious reward on the performance of working memory.

scholarly journals Is heart rate variability related to cognitive performance in visuospatial working memory?

2015 ◽  
Author(s):  
Muthukrishnan Suriya-Prakash ◽  
Gurja John-Preetham ◽  
Ratna Sharma
Keyword(s):  
Heart Rate ◽  
Working Memory ◽  
Heart Rate Variability ◽  
Cognitive Performance ◽  
Memory Load ◽  
Memory Task ◽  
Daily Activities ◽  
Visuospatial Working Memory ◽  
Working Memory Load

In the current study, we investigated the relation between cognitive performance and heart rate variability in visuospatial working memory. We used a visuospatial working memory paradigm involving simultaneous encoding, maintenance, active manipulation and retrieval to simulate routine daily activities. Subjects performed the visuospatial working memory paradigm which had 3 memory loads and simultaneous ECG recording was acquired for measuring heart rate variability. Based on the performance in the visuospatial working memory task, subjects were segregated into two groups: Good performers and poor performers. Two major findings emerged in this study. First, the heart rate variability decreased with an increase in the working memory load. Second, good performers had relatively higher heart rate variability compared to poor performers while performing the visuospatial working memory task. Our results highlighted the influence of cognitive performance on heart rate variability. In summary, the current study indicates that the heart rate variability during the visuospatial working memory task could predict the qualitative differences in the cognitive performance between the individuals.

scholarly journals Is heart rate variability related to cognitive performance in visuospatial working memory?

2015 ◽  
Author(s):  
Muthukrishnan Suriya-Prakash ◽  
Gurja John-Preetham ◽  
Ratna Sharma
Keyword(s):  
Heart Rate ◽  
Working Memory ◽  
Heart Rate Variability ◽  
Cognitive Performance ◽  
Memory Load ◽  
Memory Task ◽  
Daily Activities ◽  
Visuospatial Working Memory ◽  
Working Memory Load

In the current study, we investigated the relation between cognitive performance and heart rate variability in visuospatial working memory. We used a visuospatial working memory paradigm involving simultaneous encoding, maintenance, active manipulation and retrieval to simulate routine daily activities. Subjects performed the visuospatial working memory paradigm which had 3 memory loads and simultaneous ECG recording was acquired for measuring heart rate variability. Based on the performance in the visuospatial working memory task, subjects were segregated into two groups: Good performers and poor performers. Two major findings emerged in this study. First, the heart rate variability decreased with an increase in the working memory load. Second, good performers had relatively higher heart rate variability compared to poor performers while performing the visuospatial working memory task. Our results highlighted the influence of cognitive performance on heart rate variability. In summary, the current study indicates that the heart rate variability during the visuospatial working memory task could predict the qualitative differences in the cognitive performance between the individuals.

Visual Search Facilitation in Repeated Displays Depends on Visuospatial Working Memory

2012 ◽  
Vol 59 (1) ◽  
pp. 47-54 ◽  
Author(s):  
Angela A. Manginelli ◽  
Franziska Geringswald ◽  
Stefan Pollmann
Keyword(s):  
Working Memory ◽  
Visual Search ◽  
Control Experiment ◽  
Memory Load ◽  
Contextual Cueing ◽  
Long Term Memory ◽  
Visuospatial Working Memory ◽  
Working Memory Load ◽  
Memory Resources

When distractor configurations are repeated over time, visual search becomes more efficient, even if participants are unaware of the repetition. This contextual cueing is a form of incidental, implicit learning. One might therefore expect that contextual cueing does not (or only minimally) rely on working memory resources. This, however, is debated in the literature. We investigated contextual cueing under either a visuospatial or a nonspatial (color) visual working memory load. We found that contextual cueing was disrupted by the concurrent visuospatial, but not by the color working memory load. A control experiment ruled out that unspecific attentional factors of the dual-task situation disrupted contextual cueing. Visuospatial working memory may be needed to match current display items with long-term memory traces of previously learned displays.

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