Visual Long-term Memory Research Articles

The Effects of Changing Attention and Context in an Awake Offline Processing Period on Visual Long-Term Memory

There is accumulating evidence that sleep as well as awake offline processing is important for the transformation of new experiences into long-term memory (LTM). Yet much remains to be understood about how various cognitive factors influence the efficiency of awake offline processing. In the present study we investigated how changes in attention and context in the immediate period after exposure to new visual information influences LTM consolidation. After presentation of multiple naturalistic scenes within a working memory paradigm, recognition was assessed 30 min and 24 h later in three groups of subjects. One group of subjects engaged in a focused attention task [the Revised Attentional Network Task (R-ANT)] in the 30 min after exposure to the scenes. Another group of subjects remained in the testing room during the 30 min after scene exposure and engaged in no goal- or task-directed activities. A third group of subjects left the testing room and returned 30 min later. A signal detection analysis revealed no significant differences among the three groups in hits, false alarms, or sensitivity on the 30-min recognition task. At the 24-h recognition test, the group that performed the R-ANT made significantly fewer hits compared to the group that left the testing room and did not perform the attention ask. The group that performed the R-ANT and the group that remained in the testing room during the 30-min post-exposure interval made significantly fewer false alarms on the 24-h recognition test compared to the group that left the testing room. The group that stayed in the testing room and engaged in no goal- or task-directed activities exhibited significantly higher sensitivity (d′) compared to the group that left the testing room and the group that performed the R-ANT task. Staying in the same context after exposure to new information and resting quietly with minimal engagement of attention results in the best ability to distinguish old from novel visual stimuli after 24 h. These findings suggest that changes in attentional demands and context during an immediate post-exposure offline processing interval modulate visual memory consolidation in a subtle but significant manner.

Caracterización neuropsicológica en niños entre seis y ocho años con antecedente de muy bajo peso al nacer y prematurez

Objective: Medical and neonatal ICU efforts have made it possible to preserve the life of patients born prematurely. The main serious disorders associated with very low birth weight are cerebral palsy, deafness, blindness, developmental delay, mental retardation, and epilepsy. Of these children, 50% show intellectual disability, a high incidence of communication or learning disabilities, academic failure, attention deficit/hyperactivity disorder, specific neuropsychological deficits, and behavioral issues. This study analyzed the neuropsychological characteristics of 45 children between the ages of six and eight who were premature and had very low weight at birth. Methods: Observational, cross-sectional study in children born between 2005 and 2006. Upon parents’ informed consent, tests were applied to measure IQ and superior intellectual ability (WISC-IV and ENI). Results: Adequate performance is observed regarding intellectual capacity, where better performance was observed in those with greater gestational age with statistically significant differences in perceptive reasoning. In extremely premature babies, there was below average performance in metalinguistic abilities, long-term visual memory, verbal fluency, and cognitive flexibility. This reduced performance, along with lower IQ scores, was more notorious in children with a history of sepsis and intraventricular hemorrhage. Conclusions: Preterm birth and very low birth weight has a negative effect on neuropsychological functions. Below average neuropsychological performance (metalinguistic abilities, visual memory, verbal fluency, and cognitive flexibility) could explain neuropsychiatric problems present during growth.

Recognition-induced forgetting is not due to category-based set size.

What are the consequences of accessing a visual long-term memory representation? Previous work has shown that accessing a long-term memory representation via retrieval improves memory for the targeted item and hurts memory for related items, a phenomenon called retrieval-induced forgetting. Recently we found a similar forgetting phenomenon with recognition of visual objects. Recognition-induced forgetting occurs when practice recognizing an object during a two-alternative forced-choice task, from a group of objects learned at the same time, leads to worse memory for objects from that group that were not practiced. An alternative explanation of this effect is that category-based set size is inducing forgetting, not recognition practice as claimed by some researchers. This alternative explanation is possible because during recognition practice subjects make old-new judgments in a two-alternative forced-choice task, and are thus exposed to more objects from practiced categories, potentially inducing forgetting due to set-size. Herein I pitted the category-based set size hypothesis against the recognition-induced forgetting hypothesis. To this end, I parametrically manipulated the amount of practice objects received in the recognition-induced forgetting paradigm. If forgetting is due to category-based set size, then the magnitude of forgetting of related objects will increase as the number of practice trials increases. If forgetting is recognition induced, the set size of exemplars from any given category should not be predictive of memory for practiced objects. Consistent with this latter hypothesis, additional practice systematically improved memory for practiced objects, but did not systematically affect forgetting of related objects. These results firmly establish that recognition practice induces forgetting of related memories. Future directions and important real-world applications of using recognition to access our visual memories of previously encountered objects are discussed.

Massive memory revisited: Limitations on storage capacity for object details in visual long-term memory.

Previous work suggests that visual long-term memory (VLTM) is highly detailed and has a massive capacity. However, memory performance is subject to the effects of the type of testing procedure used. The current study examines detail memory performance by probing the same memories within the same subjects, but using divergent probing methods. The results reveal that while VLTM representations are typically sufficient to support performance when the procedure probes gist-based information, they are not sufficient in circumstances when the procedure requires more detail. We show that VLTM capacity, albeit large, is heavily reliant on gist as well as detail. Thus, the nature of the mnemonic representations stored in VLTM is important in understanding its capacity limitations.

Storing and updating non-visual features in visual long-term memory

Storing and updating non-visual features in visual long-term memory

Visual Metamemory: Metacognitive Control and Monitoring of Long-Term Visual Memory for Objects and People

Visual Metamemory: Metacognitive Control and Monitoring of Long-Term Visual Memory for Objects and People

Relating sustained attention to visual long-term memory

Relating sustained attention to visual long-term memory

Visual long-term memory has weaker fidelity than working memory

ABSTRACTRecent research suggests that visual long-term memory (VLTM) and visual working memory (VWM) possess similar resolution for feature memory. We investigated resolution in more holistic terms, exploiting a two alternative forced choice (2AFC) procedure and injecting noise into stimuli. Participants were exposed to two real-world objects per trial in a VWM experiment. One object was tested after a short delay. The other object (from each trial) was tested in a later session. We observed better performance for VWM, and the two systems were affected by noise in distinct ways. These results have broad implications for theories of visual memory.

Does multicomponent physical exercise with simultaneous cognitive training boost cognitive performance in older adults? A 6-month randomized controlled trial with a 1-year follow-up.

BackgroundCognitive impairment is a health problem that concerns almost every second elderly person. Physical and cognitive training have differential positive effects on cognition, but have been rarely applied in combination. This study evaluates synergistic effects of multicomponent physical exercise complemented with novel simultaneous cognitive training on cognition in older adults. We hypothesized that simultaneous cognitive–physical components would add training specific cognitive benefits compared to exclusively physical training.MethodsSeniors, older than 70 years, without cognitive impairment, were randomly assigned to either: 1) virtual reality video game dancing (DANCE), 2) treadmill walking with simultaneous verbal memory training (MEMORY), or 3) treadmill walking (PHYS). Each program was complemented with strength and balance exercises. Two 1-hour training sessions per week over 6 months were applied. Cognitive performance was assessed at baseline, after 3 and 6 months, and at 1-year follow-up. Multiple regression analyses with planned comparisons were calculated.ResultsEighty-nine participants were randomized to the three groups initially, 71 completed the training, while 47 were available at 1-year follow-up. Advantages of the simultaneous cognitive–physical programs were found in two dimensions of executive function. “Shifting attention” showed a time×intervention interaction in favor of DANCE/MEMORY versus PHYS (F[2, 68] =1.95, trend P=0.075, r=0.17); and “working memory” showed a time×intervention interaction in favor of DANCE versus MEMORY (F[1, 136] =2.71, trend P=0.051, R2=0.006). Performance improvements in executive functions, long-term visual memory (episodic memory), and processing speed were maintained at follow-up in all groups.ConclusionParticular executive functions benefit from simultaneous cognitive–physical training compared to exclusively physical multicomponent training. Cognitive–physical training programs may counteract widespread cognitive impairments in the elderly.

Activating learned exemplars in children impairs memory for related exemplars in visual long-term memory

A popular educational method when teaching children new information is encouraging children to activate previously learned information held in long-term memory. A potential downside of this practice is the considerable evidence that there are negative consequences of accessing long-term memory representations. Specifically, it has been shown that accessing information in long-term memory can actually impair related memories. This impairment has classically been demonstrated with verbal material (i.e., retrieval-induced forgetting) and more recently with visual material in adults (i.e., recognition-induced forgetting). The goal of the present study was to examine whether recognition-induced forgetting exists in visual long-term memory for children aged 6–10 years old, the age at which retrieval-induced forgetting appears to emerge. To this end, we presented children with an abbreviated, age-appropriate recognition-induced forgetting paradigm. If children suffer recognition-induced forgetting, practicing a subset of objects from a category of objects will impair memory for the other, non-practiced objects from the same category. The results showed that children across all ages showed impaired memory for non-practiced objects from practiced categories and no benefit from recognition practice for the younger children. These findings show that children's visual long-term memory is vulnerable to recognition-induced forgetting and does not appear to benefit from recognition practice.

Anatomical pathways for auditory memory II: information from rostral superior temporal gyrus to dorsolateral temporal pole and medial temporal cortex

Auditory recognition memory in non-human primates differs from recognition memory in other sensory systems. Monkeys learn the rule for visual and tactile delayed matching-to-sample within a few sessions, and then show one-trial recognition memory lasting 10–20 min. In contrast, monkeys require hundreds of sessions to master the rule for auditory recognition, and then show retention lasting no longer than 30–40 s. Moreover, unlike the severe effects of rhinal lesions on visual memory, such lesions have no effect on the monkeys' auditory memory performance. The anatomical pathways for auditory memory may differ from those in vision. Long-term visual recognition memory requires anatomical connections from the visual association area TE with areas 35 and 36 of the perirhinal cortex (PRC). We examined whether there is a similar anatomical route for auditory processing, or that poor auditory recognition memory may reflect the lack of such a pathway. Our hypothesis is that an auditory pathway for recognition memory originates in the higher order processing areas of the rostral superior temporal gyrus (rSTG), and then connects via the dorsolateral temporal pole to access the rhinal cortex of the medial temporal lobe. To test this, we placed retrograde (3% FB and 2% DY) and anterograde (10% BDA 10,000 mW) tracer injections in rSTG and the dorsolateral area 38DL of the temporal pole. Results showed that area 38DL receives dense projections from auditory association areas Ts1, TAa, TPO of the rSTG, from the rostral parabelt and, to a lesser extent, from areas Ts2-3 and PGa. In turn, area 38DL projects densely to area 35 of PRC, entorhinal cortex (EC), and to areas TH/TF of the posterior parahippocampal cortex. Significantly, this projection avoids most of area 36r/c of PRC. This anatomical arrangement may contribute to our understanding of the poor auditory memory of rhesus monkeys.

High-precision visual long-term memory in children with high-functioning autism.

Domain-general theories of autism rest on evidence that the disorder impacts not only social communication skills but also nonsocial functions such as memory. Yet recognition memory deficits have been inconsistently documented, especially for stimuli other than faces and sentences. Here we tested school-age children with high-functioning autism (ASD) and IQ, and age-matched comparison children on a visual long-term memory task involving more than 100 photographs of objects, faces, cats, houses, and abstract stimuli. Children viewed each photograph for 2 s. After a 10-min filled delay, we assessed recognition memory for object category as well as for specific exemplars. Data supported the presence of a high-capacity and high-precision visual memory in children with ASD. Both category memory and exemplar memory accuracies were above 90% for categories for which a single exemplar had been encoded. When more exemplars per category were encoded, category memory improved, but exemplar memory declined. An exception was face memory, which remained highly accurate even after many faces had been encoded. Our study provided no evidence that visual memory in general, and face memory in particular, is impaired in children with ASD.

Detailed and gist-like visual memories are forgotten at similar rates over the course of a week.

A number of recent studies have highlighted the exceptional capacity and fidelity of visual long-term memory. For instance, Brady, Konkle, Alvarez, and Oliva (Proceedings of the National Academy of Sciences, 105, 14325-14329, 2008) presented participants with thousands of images for nearly 6 h and then tested their memory in a two-alternative forced choice (2AFC) task. Participants were 87% accurate, even when the foil was extremely similar to the target (e.g., when the same object was presented in a different state). In the present investigation, we extended these findings by including a one-week delay condition and by testing memory in a yes-no as well as a 2AFC task. We replicated the exceptional memory results at a short delay. However, following a week delay, recognition accuracy was greatly reduced in both tasks, with comparable reductions in performance when the foils were both similar and dissimilar. These findings suggest that detailed and gist-like visual memories decay at similar rates, which highlights important limitations of visual long-term memory.

Visual recognition memory, manifested as long-term habituation, requires synaptic plasticity in V1.

Familiarity with stimuli that bring neither reward nor punishment, manifested through behavioural habituation, enables organisms to detect novelty and devote cognition to important elements of the environment. Here we describe in mice a form of long-term behavioural habituation to visual grating stimuli that is selective for stimulus orientation. Orientation-selective habituation (OSH) can be observed both in exploratory behaviour in an open arena, and in a stereotyped motor response to visual stimuli in head-restrained mice. We show that the latter behavioural response, termed a vidget, requires V1. Parallel electrophysiological recordings in V1 reveal that plasticity, in the form of stimulus-selective response potentiation (SRP), occurs in layer 4 of V1 as OSH develops. Local manipulations of V1 that prevent and reverse electrophysiological modifications likewise prevent and reverse memory demonstrated behaviourally. These findings suggest that a form of long-term visual recognition memory is stored via synaptic plasticity in primary sensory cortex.

Visual memory for objects following foveal vision loss.

Allocation of visual attention is crucial for encoding items into visual long-term memory. In free vision, attention is closely linked to the center of gaze, raising the question whether foveal vision loss entails suboptimal deployment of attention and subsequent impairment of object encoding. To investigate this question, we examined visual long-term memory for objects in patients suffering from foveal vision loss due to age-related macular degeneration. We measured patients' change detection sensitivity after a period of free scene exploration monocularly with their worse eye when possible, and under binocular vision, comparing sensitivity and eye movements to matched normal-sighted controls. A highly salient cue was used to capture attention to a nontarget location before a target change occurred in half of the trials, ensuring that change detection relied on memory. Patients' monocular and binocular sensitivity to object change was comparable to controls, even after more than 4 intervening fixations, and not significantly correlated with visual impairment. We conclude that extrafoveal vision suffices for efficient encoding into visual long-term memory.

The target effect: Visual memory for unnamed search targets

Search targets are typically remembered much better than other objects even when they are viewed for less time. However, targets have two advantages that other objects in search displays do not have: They are identified categorically before the search, and finding them represents the goal of the search task. The current research investigated the contributions of both of these types of information to the long-term visual memory representations of search targets. Participants completed either a predefined search or a unique-object search in which targets were not defined with specific categorical labels before searching. Subsequent memory results indicated that search target memory was better than distractor memory even following ambiguously defined searches and when the distractors were viewed significantly longer. Superior target memory appears to result from a qualitatively different representation from those of distractor objects, indicating that decision processes influence visual memory.

Visual long-term memory and change blindness: Different effects of pre- and post-change information on one-shot change detection using meaningless geometric objects.

To clarify the relationship between visual long-term memory (VLTM) and online visual processing, we investigated whether and how VLTM involuntarily affects the performance of a one-shot change detection task using images consisting of six meaningless geometric objects. In the study phase, participants observed pre-change (Experiment 1), post-change (Experiment 2), or both pre- and post-change (Experiment 3) images appearing in the subsequent change detection phase. In the change detection phase, one object always changed between pre- and post-change images and participants reported which object was changed. Results showed that VLTM of pre-change images enhanced the performance of change detection, while that of post-change images decreased accuracy. Prior exposure to both pre- and post-change images did not influence performance. These results indicate that pre-change information plays an important role in change detection, and that information in VLTM related to the current task does not always have a positive effect on performance.

Evaluation and analysis of cognitive function in chronic renal failure patients

To explore the characteristics of cognitive impairment and correlation analysis in patients with chronic renal failure (CRF). The Addenbrooke's cognitive examination revised (ACE-R) scale was used to evaluate the cognitive function for 101 cases of chronic renal failure patients (group CRF) receiving outpatient and inpatient treatments and selected 30 individuals with normal renal function as normal controls (group NC) for cross-sectional analysis. T test, receiver operating characteristic (ROC) curve and other statistical methods were adopted for comparing differences. (1) Compared with group NC (83.4 ± 6.5), group CRF (71.9 ± 17.6) showed significantly statistical difference on Addenbrooke's cognitive examination revised (ACE-R) scale scores (P < 0.01); (2)compared with normal controls, the patients with CRF had significantly statistical difference on the scores of visual spatial ability (11.5 ± 3.2, 14.0 ± 3.0 respectively), language fluency (7.0 ± 2.6, 8.7 ± 1.9) (P < 0.01) and memory (18.1 ± 7.0, 21.5 ± 3.6 respectively) (P < 0.05); (3) the cognitive function of patients with CRF were significantly positive correlated with glomerular filtration rate (GFR) (r = 0.614, P < 0.01) and negatively correlated with the duration of illness (r = -0.492, P < 0.01); (4) From ROC curve and the area under curve (AUC), ACE-R scale (AUC = 0.680) showed a higher sensitivity than mini-mental state examination scale (AUC = 0.576) in assessing cognitive function in patients with CRF (P < 0.01). (1) Under similar basic conditions of age, level of education and background, CRF patients showed significant damage overall cognitive function, cognitive impairment in visual spatial ability, executive function, long-term memory and logical judgment ability was particularly impaired. Immediate and delayed memory, attention, orientation and language ability also manifested different degrees of decline; (2) the severity of cognitive impairment in patients with CFR was closely related with the level of GFR; (3) the ACE-R scale showed a higher sensitivity than mini-mental state examination scale in assessing cognitive function in patients with CRF.

Image Memory for Faces and Objects

There exists both in the literature, and in the wider world, an assumption that humans are good at recognising faces. Many tasks have been used to show, however, that although this may be the case for familiar faces, it does not appear to be so for unfamiliar faces. Memory has been shown to be accurate for faces when small numbers of images are used, however recent research has demonstrated that long-term visual memory capacity for objects is very good even for vast numbers of images. In the current study, we compare memory for specific images of objects and faces, and show that memory for objects is better than for faces. Familiar faces are remembered better than unfamiliar faces, but not as well as objects. Where previous studies seemed to show an advantage for faces over objects in memory tasks, the requirement to remember a specific image appears to reverse this effect.

Cognitive, Genetic, and Brain Perfusion Factors Associated with Four Year Incidence of Alzheimer's Disease from Mild Cognitive Impairment

There is a range of factors that predict the development of Alzheimer's disease (AD) dementia among patients with amnestic mild cognitive impairment (MCI). To identify the neuropsychological, genetic, and functional brain imaging data that best predict conversion to AD dementia in patients with amnestic MCI. From an initial group of 42 amnestic MCI patients assessed with neurological, neuropsychological, and brain SPECT, 39 (25 converters, 14 non-converters) were followed for 4 years, and 36 had APOE ε4 genotyping. Baseline neuropsychological data and brain SPECT data were used to predict which of the MCI patients would develop dementia by the end of the 4 years of observation. The MCI patients who had converted to AD dementia had poorer performance on long-term visual memory and Semantic Fluency tests. The MCI subjects who developed dementia were more likely to carry at least one copy of the APOE ε4 allele (Hazard Risk = 4.22). There was lower brain perfusion in converters than non-converters, mainly in postcentral gyrus. An additional analysis of the SPECT data found differences between the MCI subjects and controls in the posterior cingulate gyrus and the basal forebrain. When the brain imaging and neuropsychological test data were combined in the same Cox regression model, only the neuropsychological test data were significantly associated with time to dementia. Although the presence of reduced brain perfusion in postcentral gyrus and basal forebrain indicated an at-risk condition, it was the extent of memory impairment that was linked to the speed of decline from MCI to AD.