Supervised Learning Occurs in Visual Perceptual Learning of Complex Natural Images.

There have been long-standing debates regarding whether supervised or unsupervised learning mechanisms are involved in visual perceptual learning (VPL) [1-14]. However, these debates have been based on the effects of simple feedback only about response accuracy in detection or discrimination tasks of low-level visual features such as orientation [15-22]. Here, we examined whether the content of response feedback plays a critical role for the acquisition and long-term retention of VPL of complex natural images. We trained three groups of human subjects (n = 72 in total) to better detect "grouped microcalcifications" or "architectural distortion" lesions (referred to as calcification and distortion in the following) in mammograms either with no trial-by-trial feedback, partial trial-by-trial feedback (response correctness only), or detailed trial-by-trial feedback (response correctness and target location). Distortion lesions consist of more complex visual structures than calcification lesions [23-26]. We found that partial feedback is necessary for VPL of calcifications, whereas detailed feedback is required for VPL of distortions. Furthermore, detailed feedback during training is necessary for VPL of distortion and calcification lesions to be retained for 6 months. These results show that although supervised learning is heavily involved in VPL of complex natural images, the extent of supervision for VPL varies across different types of complex natural images. Such differential requirements for VPL to improve the detectability of lesions in mammograms are potentially informative for the professional training of radiologists.

Vicarious social exclusion and memory in young children.

We investigated whether witnessing social exclusion influenced memory recall in preschool children. A sample of 81 children (Mage = 5 years, 4 months) first watched priming videos either depicting social exclusion or not. Subsequently, they participated in two memory tasks, one testing recall of numbers and the other testing recall of previously heard story events. These consisted of social (e.g., "brother") and nonsocial (e.g., "circus") items. In addition, a language-screening test was conducted to ensure that in both conditions (i.e., social exclusion and control), children's language levels were similar. In both conditions, children scored comparably on number recall and overall recall of story events. However, only children who observed social exclusion remembered more social than nonsocial items. The findings suggest that vicarious social exclusion triggers selective retention of social information in preschool age, in accord with findings of older children and adults who directly experienced social exclusion. Social exclusion affects the need to belong in young children, not only indicated by means of increased attempts to affiliate, but also by an increased memory for social events. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Repeated testing, item selection, and relearning: the benefits of testing outweigh the costs.

In the present study we investigated the effect of repeated testing on item selection, retention, and delayed relearning of paired associates. Participants learned both related (easy) and unrelated (difficult) word pairs under conditions of repeated study and repeated testing. A retention test was given after both a 5-min and a 1-week interval. Following the 1-week retention test, participants received a relearning task. During the initial learning phase of the experiment, more related word pairs were successfully recalled on the practice tests compared to unrelated word pairs. Also, long-term retention benefits were found for items that were repeatedly tested compared to items that were repeatedly studied, regardless of item difficulty. The results suggest that the testing benefit following conditions of repeated testing cannot be attributed to mere item selection. Secondly, we found that delayed relearning was faster for previously restudied items compared to previously tested items. However, at the end of the relearning phase, repeated study and repeated testing 1 week prior to relearning resulted in comparable levels of recall performance. The results suggest that repeated testing can enhance delayed recall performance with little additional cost in terms of delayed relearning.

Relearning attenuates the benefits and costs of spacing.

The literature on spacing effects is vast, but no prior research has examined the effects of initial spacing when students learn to criterion and then subsequently relearn items. In addition, minimal research has evaluated the costs associated with spaced practice as well as the benefits. Accordingly, in the current research, we examined the benefits and costs of initial spacing using Bahrick's (1979) method of successive relearning. Across 3 experiments, 567 students practiced key term definitions via test-restudy practice until items were correctly recalled 1 or 3 times during initial learning. Practice trials during initial learning were either massed or spaced (including relatively longer lags in all experiments as well as intermediate lags in Experiment 1). All students then relearned items in 2-3 subsequent relearning sessions (across experiments, almost 40,000 short-answer recall responses were collected and hand scored). The benefits of initial spacing were measured by interim cued recall tests and a final test administered days or weeks after relearning, and costs were measured by total practice time across sessions. A consistent qualitative pattern emerged: The benefits of initial spacing were substantial prior to relearning but were significantly attenuated after relearning. Moreover, the costs associated with achieving criterion via spaced practice during initial learning were also substantially attenuated by faster relearning in subsequent sessions.

Assessment of long-term knowledge retention following single-day simulation training for uncommon but critical obstetrical events.

OBJECTIVE: The objectives were to determine (i) whether simulation training results in short-term and long-term improvement in the management of uncommon but critical obstetrical events and (ii) to determine whether there was additional benefit from annual exposure to the workshop. METHODS: Physicians completed a pretest to measure knowledge and confidence in the management of eclampsia, shoulder dystocia, postpartum hemorrhage and vacuum-assisted vaginal delivery. They then attended a simulation workshop and immediately completed a posttest. Residents completed the same posttests 4 and 12 months later, and attending physicians completed the posttest at 12 months. Physicians participated in the same simulation workshop 1 year later and then completed a final posttest. Scores were compared using paired t-tests. RESULTS: Physicians demonstrated improved knowledge and comfort immediately after simulation. Residents maintained this improvement at 1 year. Attending physicians remained more comfortable managing these scenarios up to 1 year later; however, knowledge retention diminished with time. Repeating the simulation after 1 year brought additional improvement to physicians. CONCLUSION: Simulation training can result in short-term and contribute to long-term improvement in objective measures of knowledge and comfort level in managing uncommon but critical obstetrical events. Repeat exposure to simulation training after 1 year can yield additional benefits.

Ecological prospective memory assessment in patients with traumatic brain injury.

PRIMARY OBJECTIVE: Prospective memory (PM) impairments are often observed after traumatic brain injury (TBI). Although PM is crucial for daily functioning, few sensitive, valid and ecological clinical tests are available. To address these concerns, the authors developed a PM task, the TEMP, using naturalistic stimuli, in which each PM phase and component is evaluated independently in time- and event-based conditions. MAIN OUTCOMES AND RESULTS: The results show that moderate and severe TBI patients (n = 30), evaluated after spontaneous neurological recovery, experienced problems in learning the delayed intentions content and retrieving these intentions in the right context (prospective component), especially in the time-based condition. They also recalled fewer associated actions (retrospective component), but only in the time-based condition. Correlations revealed that the retrospective component was mainly supported by episodic retrospective memory processes, while the prospective component was supported by episodic retrospective memory processes, along with attentional and executive functions. Moreover, there was a significant correlation between performance on the TEMP and results on a questionnaire assessing PM functioning in daily living completed by participants' relatives. CONCLUSIONS: The TEMP therefore appears to be a sensitive tool for assessing PM problems that combines internal and ecological validity.

Neuropsychological assessment of dementia.

Neuropsychological studies show that cognitive deficits associated with Alzheimer's disease (AD) are distinct from age-associated cognitive decline. Quantitative and qualitative differences are apparent across many cognitive domains, but are especially obvious in episodic memory (particularly delayed recall), semantic knowledge, and some aspects of executive functions. The qualitatively distinct pattern of deficits is less salient in very old AD patients than in younger AD patients. Although decline in episodic memory is usually the earliest cognitive change that occurs prior to the development of the AD dementia syndrome, asymmetry in cognitive abilities may also occur in this "preclinical" phase of the disease and predict imminent dementia. Discrete patterns of cognitive deficits occur in AD and several neuropathologically distinct age-associated neurodegenerative disorders. Knowledge of these differences helps to clinically distinguish among various causes of dementia and provides useful models for understanding brain-behavior relationships that mediate cognitive abilities affected in various neurodegenerative diseases.

On the costs of refocusing items in working memory: a matter of inhibition or decay?

The present study investigates the mental processes that are applied to previously attended items of working memory. In an object-switching task, participants counted the number of sequentially presented objects. In Experiment 1 the processing time increased when the object category switched from the prior trial compared to a repetition. More importantly, the further in the past the last instance of a current category was presented, the more processing time was necessary - an observation suggesting passive decay rather than inhibition of previously attended items. However, results differed when only two object categories were employed. Experiment 2 suggests that the lack of a clear indication of decay with small numbers of categories was due to participants' expectancy of category switches rather than repetitions. Taken together, the results suggest that working memory items become less accessible the longer they have not been attended to, when strategic processes are controlled.

The cognitive neuroscience of working memory: relevance to CNTRICS and schizophrenia.

Working memory is one of the central constructs in cognitive science and has received enormous attention in the theoretical and empirical literature. Similarly, working memory deficits have long been thought to be among the core cognitive deficits in schizophrenia, making it a ripe area for translation. This article provides a brief overview of the current theories and data on the psychological and neural mechanisms involved in working memory, which is a summary of the presentation and discussion on working memory that occurred at the first Cognitive Neuroscience Treatment Research to Improve Cognition in Schizophrenia (CNTRICS) meeting (Washington, D.C.). At this meeting, the consensus was that the constructs of goal maintenance and interference control were the most ready to be pursued as part of a translational cognitive neuroscience effort at future CNTRICS meetings. The constructs of long-term memory reactivation, capacity, and strategic encoding were felt to be of great clinical interest but requiring more basic research. In addition, the group felt that the constructs of maintenance over time and updating in working memory had growing construct validity at the psychological and neural levels but required more research in schizophrenia before these should be considered as targets for a clinical trials setting.

Assessment of single and bound features in a working memory task in schizophrenia.

If disturbance of binding in long term memory is well established in schizophrenia, data concerning working memory maintenance are less clear. Feature binding in working memory was investigated in 19 patients with schizophrenia and 19 healthy controls. Binding was assessed by comparing two conditions in which participants had to retain four letters and four spatial locations. These features were presented either bound or separate. Results showed that both groups had better performances for bound than separate features, despite the fact that patients performed significantly worse than controls. When maintenance for isolated features was assessed, patients were severely disturbed for spatial locations but not for letters. Such a result suggests that reduced working memory performance in patients with schizophrenia for bound features is probably a consequence of a spatial deficit rather than a specific deficit of the binding process. Thus, not all form of binding are disturbed in schizophrenia.

The quantitative assessment of apraxic deficits in Alzheimer's disease.

The purpose of this study was to devise quantitative methods for the assessment of praxic skills of the upper limbs by developing a computerised task which permits each component of a sequence of actions to be timed precisely. Furthermore, two versions of such a quantitative measure were developed to investigate the relationship between meaningful and meaningless movements. The praxic skills of 35 patients with Alzheimer's disease (AD) and 75 healthy controls were assessed on two 3-item sequential movement tasks involving either meaningful or meaningless actions. A qualitative rating scale assessment of gesture imitation and pantomime was also administered. AD patients were significantly slower than controls on both the sequential movement tasks. Indeed, the correlation between AD patients' abilities on the novel and traditional tasks provided evidence that the sequential movement tasks constitute valid measures of praxis. Within the AD population, disease severity was also found to have a minimal and inconsistent influence upon praxis. The apraxia assessment results are considered in relation to the debate over whether apraxia constitutes an early or late feature of AD, and also to theoretical claims about the cognitive neuropsychological deficit underlying ideational apraxia.

Comparison of the Alzheimer's Disease Assessment Scale Cognitive Subscale and the Vascular Dementia Assessment Scale in differentiating elderly individuals with different degrees of white matter changes. The LADIS Study.

BACKGROUND/AIMS: The Alzheimer's Disease Assessment Scale cognitive subscale (ADAS-cog) is a widely used rating instrument. The Vascular Dementia Assessment Scale cognitive subscale (VADAS-cog) includes additional tests reflecting mental speed and executive functions. The objective of this study was to compare the results of the two scales among subjects with various degrees of white matter hyperintensities (WMHs). METHODS: In the multicentre, multinational Leukoaraiosis and Disability in the Elderly (LADIS) study, 616 non-disabled subjects between the ages of 65 and 84 were examined using MRI, the ADAS-cog and VADAS-cog. The WMH rating from the MRI divided the patients into groups of mild (n = 280), moderate (n = 187) and severe (n = 149) degrees of change. RESULTS: Covariance analysis controlling for the effect of age and education revealed that the ADAS-cog differentiated only the mild and severe WMH groups, while the differences between all three groups were highly significant with the VADAS-cog. CONCLUSIONS: The VADAS-cog significantly differentiated between all the white matter groups. In comparison, the ADAS-cog differentiated only severe changes. Accordingly, the VADAS-cog may be a more sensitive endpoint in studies of patients with white matter load and vascular burden of the brain.

Time ordering in frontal lobe patients: a stochastic model approach.

Frontal lobe patients reproduced a sequence of capital letters or abstract shapes. Immediate and delayed reproduction trials allowed the analysis of short- and long-term memory for time order by means of suitable Markov chain stochastic models. Patients were as proficient as healthy subjects on the immediate reproduction trial, thus showing spared encoding and short-term memory. They failed, instead, on the delayed trials with capital letters, but not with random shapes, suggesting that their long-term memory impairment did not depend on primary deficits for ordering, but on inability to benefit from the organisational strategies that improve the retention and retrieval in normal subjects.

Signal-detection analyses of conditional discrimination and delayed matching-to-sample performance.

Quantitative analyses of stimulus control and reinforcer control in conditional discriminations and delayed matching-to-sample procedures often encounter a problem; it is not clear how to analyze data when subjects have not made errors. The present article examines two common methods for overcoming this problem. Monte Carlo simulations of performance demonstrated that both methods introduced systematic deviations into the results, and that there were genuine risks of drawing misleading conclusions concerning behavioral models of signal detection and animal short-term memory.

Verbal declarative memory dysfunction in schizophrenia: from clinical assessment to genetics and brain mechanisms.

The recent literature on the neuropsychology of schizophrenia has emphasized memory deficits as a key area of impairment. Abnormalities in the medial temporal lobe, a brain region crucial for long-term memory formation, have also consistently been reported. We conducted a comprehensive review of verbal declarative memory (VDM) in schizophrenia with the aim of systematically addressing the nature of this impairment. We conclude that verbal declarative memory is significantly impaired in schizophrenia and is largely accounted for by deficits in the encoding stage. Subtle impairments in increased rates of forgetting are present, but are mild compared with those in amnestic disorders. Impairment in other cognitive domains studied thus far (e.g., attention), medication effects, or fluctuations in symptoms do not completely account for the deficit. VDM is among the most impaired neurocognitive domains in schizophrenia (along with attention and executive functions). Milder encoding deficits are present in high-risk subjects and non-psychotic relatives of individuals with schizophrenia suggesting that components of the deficit are associated with a genetic vulnerability to the illness, and are independent of the frank psychotic illness. Furthermore, VDM is observed in individuals experiencing their first-psychotic episode and it remains fairly consistent over time. Preliminary imaging studies and other work suggest abnormalities in prefrontal-hippocampal processing networks. Future work should emphasize delineating specific information processing components contributing to the deficit. This would allow imaging studies to determine which brain regions contribute to specific information processing deficits in schizophrenia.

Wavelet-generalized least squares: a new BLU estimator of linear regression models with 1/f errors.

Long-memory noise is common to many areas of signal processing and can seriously confound estimation of linear regression model parameters and their standard errors. Classical autoregressive moving average (ARMA) methods can adequately address the problem of linear time invariant, short-memory errors but may be inefficient and/or insufficient to secure type 1 error control in the context of fractal or scale invariant noise with a more slowly decaying autocorrelation function. Here we introduce a novel method, called wavelet-generalized least squares (WLS), which is (to a good approximation) the best linear unbiased (BLU) estimator of regression model parameters in the context of long-memory errors. The method also provides maximum likelihood (ML) estimates of the Hurst exponent (which can be readily translated to the fractal dimension or spectral exponent) characterizing the correlational structure of the errors, and the error variance. The algorithm exploits the whitening or Karhunen-Loéve-type property of the discrete wavelet transform to diagonalize the covariance matrix of the errors generated by an iterative fitting procedure after both data and design matrix have been transformed to the wavelet domain. Properties of this estimator, including its Cramèr-Rao bounds, are derived theoretically and compared to its empirical performance on a range of simulated data. Compared to ordinary least squares and ARMA-based estimators, WLS is shown to be more efficient and to give excellent type 1 error control. The method is also applied to some real (neurophysiological) data acquired by functional magnetic resonance imaging (fMRI) of the human brain. We conclude that wavelet-generalized least squares may be a generally useful estimator of regression models in data complicated by long-memory or fractal noise.

Taking a computational approach to aging: the SPAN theory of working memory.

The decline of working memory capacity associated with normal adult aging is well-known. What is less well established is the cause of this decline. One prominent proposal is that working memory decline is caused by a reduction in basic information-processing speed, but this account has lacked a demonstration that general slowing is computationally sufficient to produce a decrease in working memory capacity. This article presents a production system theory of working memory (SPAN) based on established mechanisms: slowing, decay, and displacement. Models of 2 tasks--digit symbol and computation span--which have been prominent in research on slowing, are presented in detail. These models demonstrate that slowing is sufficient to produce differences in these tasks, and they provide a quantitative match to observed young-old differences as well. This advance for slowing theory also demonstrates the viability of computational tools in aging research.

Learning and forgetting processes in Parkinson's disease: a model-based approach to disentangling storage, retention and retrieval contributions.

Learning and forgetting a prose passage was studied in 20 patients with Parkinson's disease and in 20 normal control subjects by means of stochastic models, with the aim of identifying the learning and retaining abilities that are affected by Parkinson's disease. Results suggested that Parkinson's disease patients are impaired in developing automatic processing both during learning and retaining, while functions that require active attention are spared. The automatic/intentional dissociation, which is the hallmark of motor disturbance in Parkinson's disease, extends to memory abilities, and, on the grounds of neuroanatomical, neurochemical and neurophysiological correlates, suggests that the memory deficit in Parkinson's disease may be contingent on a dysfunction of the medial prefrontal-cingulate cortex.

Neuropsychological assessment in MS: clinical, neurophysiological and neuroradiological relationships.

We assessed cognitive performance and its relationship with clinical and anatomic disease severity in MS with mild to moderate handicap; 34 definite MS and 18 healthy subjects matched for age and education were submitted to a neuropsychological test battery. Both groups were examined for anxiety. MS patients underwent magnetic resonance imaging examination. MS performed worse than controls on all WAIS-P subtests and had learning, short- and long-term verbal memory impairment. Cognitive deficits were not related to abnormal emotional states, but were found to be associated with attentional process and information-processing speed impairment. Cognitive impairment did not correlate with severity of physical disability. The most severe memory deficits were found in patients with extensive periventricular damage.