scholarly journals The strength of attentional biases reduces as visual short-term memory load increases

2013 ◽  
Vol 110 (1) ◽  
pp. 12-18 ◽  
Author(s):  
A. Shimi ◽  
D. E. Astle
Keyword(s):  
Visual Processing ◽  
Short Term Memory ◽  
Memory Load ◽  
Attentional Biases ◽  
Perceptual Similarity ◽  
Top Down ◽  
Short Term ◽  
Term Memory ◽  
Trade Off ◽  
Visual Short Term Memory

Despite our visual system receiving irrelevant input that competes with task-relevant signals, we are able to pursue our perceptual goals. Attention enhances our visual processing by biasing the processing of the input that is relevant to the task at hand. The top-down signals enabling these biases are therefore important for regulating lower level sensory mechanisms. In three experiments, we examined whether we apply similar biases to successfully maintain information in visual short-term memory (VSTM). We presented participants with targets alongside distracters and we graded their perceptual similarity to vary the extent to which they competed. Experiments 1 and 2 showed that the more items held in VSTM before the onset of the distracters, the more perceptually distinct the distracters needed to be for participants to retain the target accurately. Experiment 3 extended these behavioral findings by demonstrating that the perceptual similarity between target and distracters exerted a significantly greater effect on occipital alpha amplitudes, depending on the number of items already held in VSTM. The trade-off between VSTM load and target-distracter competition suggests that VSTM and perceptual competition share a partially overlapping mechanism, namely top-down inputs into sensory areas.

scholarly journals Attention Modulates Maintenance of Representations in Visual Short-term Memory

2012 ◽  
Vol 24 (1) ◽  
pp. 51-60 ◽  
Author(s):  
Bo-Cheng Kuo ◽  
Mark G. Stokes ◽  
Anna Christina Nobre
Keyword(s):  
Neural Activity ◽  
Short Term Memory ◽  
Memory Load ◽  
Spatial Location ◽  
Relevant Information ◽  
Maintenance Period ◽  
Top Down ◽  
Short Term ◽  
Term Memory ◽  
Visual Short Term Memory

Recent studies have shown that selective attention is of considerable importance for encoding task-relevant items into visual short-term memory (VSTM) according to our behavioral goals. However, it is not known whether top–down attentional biases can continue to operate during the maintenance period of VSTM. We used ERPs to investigate this question across two experiments. Specifically, we tested whether orienting attention to a given spatial location within a VSTM representation resulted in modulation of the contralateral delay activity (CDA), a lateralized ERP marker of VSTM maintenance generated when participants selectively encode memory items from one hemifield. In both experiments, retrospective cues during the maintenance period could predict a specific item (spatial retrocue) or multiple items (neutral retrocue) that would be probed at the end of the memory delay. Our results revealed that VSTM performance is significantly improved by orienting attention to the location of a task-relevant item. The behavioral benefit was accompanied by modulation of neural activity involved in VSTM maintenance. Spatial retrocues reduced the magnitude of the CDA, consistent with a reduction in memory load. Our results provide direct evidence that top–down control modulates neural activity associated with maintenance in VSTM, biasing competition in favor of the task-relevant information.

scholarly journals Visual short-term memory for 3D shapes reveals similar properties to simple 2D features

2019 ◽  
Author(s):  
Joel Robitaille ◽  
Stephen Emrich
Keyword(s):  
Short Term Memory ◽  
Memory Load ◽  
Memory Performance ◽  
Delayed Response ◽  
Short Term ◽  
Complex Objects ◽  
Term Memory ◽  
Visual Short Term Memory ◽  
2D And 3D ◽  
3D Shapes

In the past two decades, significant advances have been made to understand the psychophysical properties of visual short-term memory (VSTM). Most studies, however, make inferences based on memory for simple surface features of 2D shapes. Here, we examined the role of object complexity and dimensionality on the psychophysical properties of VSTM by comparing orientation memory for 2D lines and complex 3D objects in a delayed-response continuous report task, where memory load (Experiment 1) or axis of rotation (Experiment 2) was manipulated. In both experiments, our results demonstrate an overall cost of complexity that affected participants raw errors as well as their guess rate and response precision derived from mixture modelling. We also demonstrate that participants’ memory performance is correlated between stimulus types and that memory performance for both 2D and 3D shapes is better fit to the variable precision model of VSTM than to tested competing models. Interestingly, the ability to report complex objects is not consistent across axes of rotation. These results indicate that, despite the fact that VSTM shares similar properties for 2D and 3D shapes, VSTM is far from being a unitary process and is affected by stimulus properties such as complexity and dimensionality.

scholarly journals Visual Short-term Memory Impairments in Presymptomatic Familial Alzheimer’s Disease: a Longitudinal Observational Study

2020 ◽  
Author(s):  
Ivanna M. Pavisic ◽  
Jennifer M. Nicholas ◽  
Yoni Pertzov ◽  
Antoinette O'Connor ◽  
Yuying Liang ◽  
...  
Keyword(s):  
Symptom Onset ◽  
Short Term Memory ◽  
Memory Load ◽  
Load Condition ◽  
Healthy Controls ◽  
Short Term ◽  
Cross Sectional ◽  
Term Memory ◽  
Visual Short Term Memory ◽  
Preclinical Ad

Abstract Background: Cross-sectional studies in presymptomatic familial Alzheimer’s disease (FAD), have associated binding deficits with preclinical AD. How impairments in visual-short term memory (VSTM) relate to longitudinal change and proximity to expected symptom onset (EYO) is less characterized.Methods: Thirty-two FAD mutation carriers (23 presymptomatic; 9 symptomatic) carrying a mutation in either presenilin 1 or amyloid precursor protein genes and 67 healthy controls were included in an extension VSTM cross-sectional study. Forty-eight participants (23 presymptomatic carriers, 6 symptomatic and 19 healthy controls) who had at least two annual visits (median= 3), were included in the longitudinal study. Participants completed the “What was where?” relational binding task (which measures memory for object identification, localisation and object-location binding under different conditions of memory load and delay), neuropsychology assessments and genetic testing. Results: While cross-sectionally only symptomatic carriers (N=9) showed significant impairments in VSTM performance, longitudinally, presymptomatic carriers within 8.5 years of estimated symptom onset (mean=5.8 years ±SD [1.8], N=11) showed a faster rate of decline in localisation performance in long-delay conditions (4s) compared to controls: increase/year in localisation error was 6.9% greater in the high-memory load condition (p=0.008) and 7.0% greater for the low-memory load condition (p=0.043). Change in this metric preceded presymptomatic changes in traditional measures of verbal episodic memory. Symptomatic carriers had 15% faster reduction in identification performance per year compared to controls (p=0.036) and some evidence of faster increase in localisation error (6.5% increase/year; p=0.066). The earliest significant difference in VSTM performance between FAD mutation carriers (presymptomatic and symptomatic) and controls was in localisation performance, six years prior to estimated symptom onset (p=0.024). Conclusions: This longitudinal study of FAD, suggests changes in VSTM resolution, which measure precision and thus quality of recall of the memory presentation, may be sensitive markers for tracking and predicting cognitive decline in preclinical AD.

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