Visual Sensory Memory Research Articles

Contrast Induced Encephalopathy: Case Report and Review of The Literature

Background: Contrast Induced Encephalopathy is a known but rare complication of endovascular procedures. Patients show neurologic symptoms mimicking a stroke and include visual disturbances, motor or sensory deficits, headache, seizures, memory loss, confusion, aphasia, and coma. Irreversible neurological symptoms are rare and fatal encephalopathy is even more so. Case Report: In this article we present a case of a 75-year-old female patient who showed neurological symptoms mimicking a stroke post cerebral Digital Subtraction Angiography that was done with Iohexol as a contrast agent, as a diagnostic work up to rule out a ruptured aneurysm. Further investigations showed no arterial spasms nor dissection. Symptoms reappeared after the second contrast administration but completely resolved after the administration of steroids and fluids. Conclusion: Contrast Induced Encephalopathy should be further investigated with imaging to rule out other thromboembolic or hemorrhagic causes. Treatment via the administration of steroids and fluids have shown to be effective with complete remission of symptoms.

Drivers’ Attention to Preview and Its Momentary Persistence

Participants used a position control system to track the center of a simulated winding roadway with preview that ranged from 0.3 to 1.0 s. Participants’ spatial distributions of attention were measured by perturbing the roadway with different frequency sinusoids at different roadway positions and then measuring the degree to which those frequencies were present in their tracking movements. Consistent with Miller's optimal control theory analysis of tracking with preview, participants exhibited a continuous range of attention, and it lengthened with the amount of displayed preview. When the displayed preview disappeared for 5 s, the time to reach a steady-state level of tracking error based only on feedback control was measured. More displayed preview was strongly correlated with longer times to regress to feedback control. One interpretation of this finding is that when preview is withdrawn, visual sensory memory of the previewed roadway can be used for a fraction of a second to prolong the period of feedforward control. Attention can be shifted to relevant positions of the sensory memory image to anticipate the roadway curvature. However, the quality and usefulness of sensory memory gradually diminishes until the participant can only perform feedback control. When preview was restored, the time to reach steady-state feedforward control was correlated with the range of attention. These findings characterize some of the dynamic aspects of attention when drivers are briefly interrupted from viewing the upcoming roadway. This measurement technique may be useful for characterizing spatially distributed attention in other active control contexts.

Attentional distraction affects maintenance of information in visual sensory memory

Classical theoretical models suggest that visual short-term memory can be divided in two main memory systems: sensory memory, a short-lasting but high-capacity memory storage and working memory, a long-lasting but low-capacity memory store. Whilst, previous research has systematically shown a strong interplay between attentional mechanisms and working memory, less clear is the role of attention in sensory memory. In the present study we approach this issue by asking whether withdrawing attentional resources by a dual task (Experiment 1) or by presenting task irrelevant information during memory maintenance (Experiment 2 and 3) similarly or differently affect sensory and working memory. Overall, results showed that sensory memory content was undermined not only by a simultaneous high-demanding cognitive task but even when purely task-irrelevant and non-masking visual distractors were presented during maintenance. Our data provide support against theories that consider sensory memories as a case of visual awareness free of attention.

A Population-based Study of Temporal Lobe Malignancies

Background: Temporal lobe malignancies can pose a challenge given the important functions of the temporal lobe including auditory and visual sensory processing, language recognition, and memory formation. This study aimed to utilize the 1973-2015 Surveillance, Epidemiology, and End Results (SEER) to identify demographic and treatment differences affecting overall survival in patients with temporal lobe malignancies. Methods: A search of the SEER database for patients with malignant temporal lobe tumors was performed. The Kaplan Meier method was used to analyze univariate factors affecting overall survival. Logistic regression analysis was used to perform a multivariate analysis of overall survival. Results: A total of 12,690 patients were identified. The male to female ratio was 1.5:1. The majority of patients were treated with surgery as part of their treatment regimen. On univariate analysis surgical vs. nonsurgical treatment, tumor histology, sex, and race significantly affected overall survival. On multivariate analysis race, sex, and surgical vs. nonsurgical treatment significantly affected overall survival. Conclusions: Surgical treatment, non-white race, and female sex were associated with significantly increased overall survival in patients with temporal lobe malignancies.

Attention can operate on object representations in visual sensory memory.

Numerous studies have shown that attention can be allocated to various types of objects, such as low-level objects developed by perceptual organization and high-level objects developed by semantic associations. However, little is known about whether attention can also be affected solely by object representations in the brain, after the disappearance of physical objects. Here, we used a modified double-rectangle paradigm to investigate how attention is affected by object representation in visual sensory memory when the physical objects disappear for a short period of time before the target onset. By manipulating the interstimulus interval (ISI) between the offset of the objects and the onset of the target, an object-based attention effect, with shorter reaction times (RTs) for within-object relative to between-object conditions, was observed in the short-ISI (within 500 ms in Experiments 1a, 1b, 2, and 3) conditions while disappearing in the long-ISI (800 ms in Experiment 4) conditions. This result demonstrated that the mere presence of object representation in visual sensory memory, or the sensory memory-maintained object, can serve as an object unit that attention can operate on. This provides evidence for the relationship between object-based attention and visual sensory memory: object representation in visual sensory memory could affect attentional allocation, or attention can operate on a sensory memory-maintained object.

Fast CU Partition Decision Strategy Based on Human Visual System Perceptual Quality

A fast Coding Unit (CU) partition decision strategy based on Human Visual System (HVS) perception quality is proposed in this paper. Considering that it is difficult for existing fast algorithms to further improve compression efficiency, perceptual coding technology has been tried to remove visual redundancy for achieving the purpose of reducing the bit rate on the basis of maintaining subjective visual quality. However, the existing perceptual coding model is still insufficient to reflect the characteristics of the HVS, which has limited improvement in coding efficiency, especially in fast algorithms. In this method, the characteristics of the limited human capacity for spatial-temporal resolution and the visual sensory memory are used to improve coding performance. First, the color complexity is used as a control factor to optimize the Just Noticeable Difference (JND) model to remove visual redundancy in a way that is more in line with the characteristics of visual perception. Second, a classification model of motion patterns based on human visual saliency is designed to provide a basis for CU classification, which effectively improves the coding accuracy. Finally, an offline Decision Tree (DT) classifier is designed based on the above model, and texture features are incorporated into the classifier as another key attribute to further reduce the computational complexity. The results of performance evaluation confirm that the proposed method achieves significantly improved coding performance compared with original Versatile Test Model (VTM). Compared with existing algorithms, our method not only improves coding efficiency, but also improves subjective visual quality.

Recency memory effects in Macaques during sequential delayed match-to-sample task with visual noise

Visual object recognition requires both visual sensory information and memory, and its mechanisms are often studied using old-world monkeys. Wittig et al. (2014, 2016) reported that Rhesus monkeys and humans seem to adopt different strategies in a short-term visual memory task. The Rhesus monkeys seemed to rely on recency of stimulus repetition, whereas humans relied on specific memorization. We conducted experiments using a sequential delayed match-to-sample task with random dot visual noise using Rhesus and Japanese monkeys and found that recency effect was observed in both species. There were differences in the noise effect on behavioral performances across species.

Attention scaling modulates the effective capacity of visual sensory memory.

Visual sensory memory (VSM) has a high capacity, but its contents are fleeting. Recent evidence that the breadth of attention strongly influences the efficiency of visual processing suggests that it might also modulate the effective capacity of VSM. We manipulated the breadth of attention with different cue sizes and used the partial-report technique to estimate the capacity of VSM. Whether attention was deployed voluntarily or captured by a salient cue, narrowly focused attention increased the effective capacity of VSM. This study reveals, for the first time, a direct influence of the breadth of attention on the effective capacity of VSM.

A New Conceptualization of Human Visual Sensory-Memory.

Memory is an essential component of cognition and disorders of memory have significant individual and societal costs. The Atkinson–Shiffrin “modal model” forms the foundation of our understanding of human memory. It consists of three stores: Sensory Memory (SM), whose visual component is called iconic memory, Short-Term Memory (STM; also called working memory, WM), and Long-Term Memory (LTM). Since its inception, shortcomings of all three components of the modal model have been identified. While the theories of STM and LTM underwent significant modifications to address these shortcomings, models of the iconic memory remained largely unchanged: A high capacity but rapidly decaying store whose contents are encoded in retinotopic coordinates, i.e., according to how the stimulus is projected on the retina. The fundamental shortcoming of iconic memory models is that, because contents are encoded in retinotopic coordinates, the iconic memory cannot hold any useful information under normal viewing conditions when objects or the subject are in motion. Hence, half-century after its formulation, it remains an unresolved problem whether and how the first stage of the modal model serves any useful function and how subsequent stages of the modal model receive inputs from the environment. Here, we propose a new conceptualization of human visual sensory memory by introducing an additional component whose reference-frame consists of motion-grouping based coordinates rather than retinotopic coordinates. We review data supporting this new model and discuss how it offers solutions to the paradoxes of the traditional model of sensory memory.

A dual-trace model for visual sensory memory.

Visual sensory memory refers to a transient memory lingering briefly after the stimulus offset. Although previous literature suggests that visual sensory memory is supported by a fine-grained trace for continuous representation and a coarse-grained trace of categorical information, simultaneous separation and assessment of these traces can be difficult without a quantitative model. The present study used a continuous estimation procedure to test a novel mathematical model of the dual-trace hypothesis of visual sensory memory according to which visual sensory memory could be modeled as a mixture of 2 von Mises (2VM) distributions differing in standard deviation. When visual sensory memory and working memory (WM) for colors were distinguished using different experimental manipulations in the first 3 experiments, the 2VM model outperformed Zhang and Luck (2008) standard mixture model (SM) representing a mixture of a single memory trace and random guesses, even though SM outperformed 2VM for WM. Experiment 4 generalized 2VM's advantages of fitting visual sensory memory data over SM from color to orientation. Furthermore, a single trace model and 4 other alternative models were ruled out, suggesting the necessity and sufficiency of dual traces for visual sensory memory. Together these results support the dual-trace model of visual sensory memory and provide a preliminary inquiry into the nature of information loss from visual sensory memory to WM. (PsycINFO Database Record

Multimedia vs. Analogue Text: Learning Outcome and the Importance of Short-Term Memory Capacity

The purpose of this study was to investigate the importance of individual differences in short term memory capacity (STM) for learning from film (digitized video) and analogue text in a natural learning environment. The results are based on a survey of 396 students on Bachelor's level (military cadets, teachers college and psychology majors). A short-term memory test battery was developed to measure different types and capacities of several individuals simultaneously in a classroom environment Alpha. Respondents were divided into two groups, one receiving a film presentation and one reading an analogue text (the film narrative). The subject matter was the formation of the Norwegian nation in the tenth and eleventh century (history subject at high school/college level). A knowledge test measuring the total learning outcome as well as details and interconnection (understandings/ context) was developed. In total, the results showed that texts gave the best learning outcome. Both film and text had an increased learning outcome for details and understandings in correlation with increased STM capacity, with the largest increase from low to medium capacity. Progressive capacity (successive) matters more than multicapacity (processing a lot concurrently). Non-verbal intelligence (Raven/RAPM) has an underlying general importance, but less important than the total STM capacity. Different types of capacity are more important than others depending on the presentation form and learning content. Visual sensory memory capacity for learning details in text was one of the types most clearly associated with learning outcome. This was explained by code-switching (representation transformation) during processing of information.

Evidence for distinct mechanisms underlying attentional priming and sensory memory for bistable perception.

Attentional selection in visual search paradigms and perceptual selection in bistable perception paradigms show functional similarities. For example, both are sensitive to trial history: They are biased toward previously selected targets or interpretations. We investigated whether priming by target selection in visual search and sensory memory for bistable perception are related. We did this by presenting two trial types to observers. We presented either ambiguous spheres that rotated over a central axis and could be perceived as rotating in one of two directions, or search displays in which the unambiguously rotating target and distractor spheres closely resembled the two possible interpretations of the ambiguous stimulus. We interleaved both trial types within experiments, to see whether priming by target selection during search trials would affect the perceptual outcome of bistable perception and, conversely, whether sensory memory during bistable perception would affect target selection times during search. Whereas we found intertrial repetition effects among consecutive search trials and among consecutive bistable trials, we did not find cross-paradigm effects. Thus, even though we could ascertain that our experiments robustly elicited processes of both search priming and sensory memory for bistable perception, these same experiments revealed no interaction between the two.

Accurate Metacognition for Visual Sensory Memory Representations

The capacity to attend to multiple objects in the visual field is limited. However, introspectively, people feel that they see the whole visual world at once. Some scholars suggest that this introspective feeling is based on short-lived sensory memory representations, whereas others argue that the feeling of seeing more than can be attended to is illusory. Here, we investigated this phenomenon by combining objective memory performance with subjective confidence ratings during a change-detection task. This allowed us to compute a measure of metacognition—the degree of knowledge that subjects have about the correctness of their decisions—for different stages of memory. We show that subjects store more objects in sensory memory than they can attend to but, at the same time, have similar metacognition for sensory memory and working memory representations. This suggests that these subjective impressions are not an illusion but accurate reflections of the richness of visual perception.

Factors that influence the relative use of multiple memory systems

Neurobehavioral evidence supports the existence of at least two anatomically distinct "memory systems" in the mammalian brain that mediate dissociable types of learning and memory; a "cognitive" memory system dependent upon the hippocampus and a "stimulus-response/habit" memory system dependent upon the dorsolateral striatum. Several findings indicate that despite their anatomical and functional distinctiveness, hippocampal- and dorsolateral striatal-dependent memory systems may potentially interact and that, depending on the learning situation, this interaction may be cooperative or competitive. One approach to examining the neural mechanisms underlying these interactions is to consider how various factors influence the relative use of multiple memory systems. The present review examines several such factors, including information compatibility, temporal sequence of training, the visual sensory environment, reinforcement parameters, emotional arousal, and memory modulatory systems. Altering these parameters can lead to selective enhancements of either hippocampal-dependent or dorsolateral striatal-dependent memory, and bias animals toward the use of either cognitive or habit memory in dual-solution tasks that may be solved adequately with either memory system. In many learning situations, the influence of such experimental factors on the relative use of memory systems likely reflects a competitive interaction between the systems. Research examining how various factors influence the relative use of multiple memory systems may be a useful method for investigating how these systems interact with one another.

Action video game playing is associated with improved visual sensitivity, but not alterations in visual sensory memory

Action video game playing has been experimentally linked to a number of perceptual and cognitive improvements. These benefits are captured through a wide range of psychometric tasks and have led to the proposition that action video game experience may promote the ability to extract statistical evidence from sensory stimuli. Such an advantage could arise from a number of possible mechanisms: improvements in visual sensitivity, enhancements in the capacity or duration for which information is retained in visual memory, or higher-level strategic use of information for decision making. The present study measured the capacity and time course of visual sensory memory using a partial report performance task as a means to distinguish between these three possible mechanisms. Sensitivity measures and parameter estimates that describe sensory memory capacity and the rate of memory decay were compared between individuals who reported high evels and low levels of action video game experience. Our results revealed a uniform increase in partial report accuracy at all stimulus-to-cue delays for action video game players but no difference in the rate or time course of the memory decay. The present findings suggest that action video game playing may be related to enhancements in the initial sensitivity to visual stimuli, but not to a greater retention of information in iconic memory buffers.

Rapid Extraction of Lexical Tone Phonology in Chinese Characters: A Visual Mismatch Negativity Study

BackgroundIn alphabetic languages, emerging evidence from behavioral and neuroimaging studies shows the rapid and automatic activation of phonological information in visual word recognition. In the mapping from orthography to phonology, unlike most alphabetic languages in which there is a natural correspondence between the visual and phonological forms, in logographic Chinese, the mapping between visual and phonological forms is rather arbitrary and depends on learning and experience. The issue of whether the phonological information is rapidly and automatically extracted in Chinese characters by the brain has not yet been thoroughly addressed.Methodology/Principal FindingsWe continuously presented Chinese characters differing in orthography and meaning to adult native Mandarin Chinese speakers to construct a constant varying visual stream. In the stream, most stimuli were homophones of Chinese characters: The phonological features embedded in these visual characters were the same, including consonants, vowels and the lexical tone. Occasionally, the rule of phonology was randomly violated by characters whose phonological features differed in the lexical tone.Conclusions/SignificanceWe showed that the violation of the lexical tone phonology evoked an early, robust visual response, as revealed by whole-head electrical recordings of the visual mismatch negativity (vMMN), indicating the rapid extraction of phonological information embedded in Chinese characters. Source analysis revealed that the vMMN was involved in neural activations of the visual cortex, suggesting that the visual sensory memory is sensitive to phonological information embedded in visual words at an early processing stage.

Video Processing for Human Perceptual Visual Quality-Oriented Video Coding

We have developed a video processing method that achieves human perceptual visual quality-oriented video coding. The patterns of moving objects are modeled by considering the limited human capacity for spatial-temporal resolution and the visual sensory memory together, and an online moving pattern classifier is devised by using the Hedge algorithm. The moving pattern classifier is embedded in the existing visual saliency with the purpose of providing a human perceptual video quality saliency model. In order to apply the developed saliency model to video coding, the conventional foveation filtering method is extended. The proposed foveation filter can smooth and enhance the video signals locally, in conformance with the developed saliency model, without causing any artifacts. The performance evaluation results confirm that the proposed video processing method shows reliable improvements in the perceptual quality for various sequences and at various bandwidths, compared to existing saliency-based video coding methods.

Non-attended representations are perceptual rather than unconscious in nature.

Introspectively we experience a phenomenally rich world. In stark contrast, many studies show that we can only report on the few items that we happen to attend to. So what happens to the unattended objects? Are these consciously processed as our first person perspective would have us believe, or are they – in fact – entirely unconscious? Here, we attempt to resolve this question by investigating the perceptual characteristics of visual sensory memory. Sensory memory is a fleeting, high-capacity form of memory that precedes attentional selection and working memory. We found that memory capacity benefits from figural information induced by the Kanizsa illusion. Importantly, this benefit was larger for sensory memory than for working memory and depended critically on the illusion, not on the stimulus configuration. This shows that pre-attentive sensory memory contains representations that have a genuinely perceptual nature, suggesting that non-attended representations are phenomenally experienced rather than unconscious.

Cue-Elicited Craving in Heroin Addicts at Different Abstinent Time: An fMRI Pilot Study

Objective: We evaluated the effect of short-term and long-term heroin abstinence on brain responses to heroin-related cues using functional magnetic resonance imaging (fMRI). Methods: Eighteen male heroin addicts following short-term abstinence and 19 male heroin addicts following long-term abstinence underwent fMRI scanning while viewing heroin-related and neutral images. Cue-elicited craving and withdrawal symptoms in the subjects were measured. Results: Following short-term abstinence, greater activation was found in response to heroin cues compared to neutral cues in bilateral temporal, occipital, posterior cingulate, anterior cingulate, thalamus, cerebellum, and left hippocampus. In contrast, activations in bilateral temporal and occipital and deactivations in bilateral frontal, bilateral parietal, left posterior cingulate, insula, thalamus, dorsal striatum, and bilateral cerebellum were observed following long-term abstinence. Direct comparisons between conditions showed greater brain reactivity in response to smoking cues following short-term abstinence. In addition, short-term abstinence had more serious withdrawal symptoms than the long-term. Conclusion: The present findings indicate that compared to short-term, long-term abstinence manifests less serious withdrawal symptoms and significantly decreases neural responses to heroin-related cues in brain regions subserving visual sensory processing, attention, memory, and action planning. These findings suggest that long-term abstinence can decrease the salience of conditioned cues, thereby reducing the risk of relapses. The study's limitations are noted.

Differential effects of ADORA2A gene variations in pre-attentive visual sensory memory subprocesses

The ADORA2A gene encodes the adenosine A2A receptor that is highly expressed in the striatum where it plays a role in modulating glutamatergic and dopaminergic transmission. Glutamatergic signaling has been suggested to play a pivotal role in cognitive functions related to the pre-attentive processing of external stimuli. Yet, the precise molecular mechanism of these processes is poorly understood. Therefore, we aimed to investigate whether ADORA2A gene variation has modulating effects on visual pre-attentive sensory memory processing. Studying two polymorphisms, rs5751876 and rs2298383, in 199 healthy control subjects who performed a partial-report paradigm, we find that ADORA2A variation is associated with differences in the efficiency of pre-attentive sensory memory sub-processes. We show that especially the initial visual availability of stimulus information is rendered more efficiently in the homozygous rare genotype groups. Processes related to the transfer of information into working memory and the duration of visual sensory (iconic) memory are compromised in the homozygous rare genotype groups. Our results show a differential genotype-dependent modulation of pre-attentive sensory memory sub-processes. Hence, we assume that this modulation may be due to differential effects of increased adenosine A2A receptor signaling on glutamatergic transmission and striatal medium spiny neuron (MSN) interaction.