Perception and memory loss of item and order information in short-term memory

Recognition probes given before or after a series of letters presented at varying rates were used to evaluate perception and memory loss of order and item information. For both order and item information pre- and postprobe functions converged at fast rates of presentation. Performance decrement at fast rates is attributable to perceptual factors and is greater for order than for item information.     

Patterns of semantic memory impairment in Mild Cognitive Impairment

Although the semantic memory impairment has been largely documented in Alzheimer's disease, little is known about semantic memory in the preclinical phase of the disease (Mild Cognitive Impairment). The purpose of this study was to document the nature of semantic breakdown using a battery of tests assessing different aspects of conceptual knowledge: knowledge about common objects, famous people and famous public events. Results indicate that all domains of semantic memory were impaired in MCI individuals but knowledge about famous people and famous events was affected to a greater extent than knowledge about objects. This pattern of results suggests that conceptual entities with distinctive and unique properties may be more prone to semantic breakdown in MCI. In summary, results of this study support the view that genuine semantic deficits are present in MCI. It could be useful to investigate the etiological outcome of patients failing or succeeding at such tests.     

Priming and semantic memory loss in Alzheimer's disease

Semantic memory (SM) was investigated in six patients with probable Alzheimer's disease (AD) by on-line measurement of semantic priming in a lexical decision task, and off-line tests of comprehension. Detailed assessment was carried out on naming, name comprehension, and probes of semantic knowledge with a battery of 150 items. The patients performed normally on perceptual tests and displayed an item-specific loss of knowledge on the semantic tests. In a primed lexical decision task, greater semantic priming was found relative to age-matched normals. The priming was substantially greater for items with "degraded" representations as determined by the off-line tests. Lexical decision was also performed more slowly on these items. These unexpected results demand a reevaluation of the concepts of the lexicon and semantic memory structure and their possible alteration in dementia.     

Subjective memory loss in age-associated memory impairment: Family history and neuropsychological correlates

Abstract

Empiricist and rationalist approaches to data-quality control in meta-analyses are discussed, and a compromise approach advocated by Strube and Hartmann (1983) for theoretically driven meta-analyses is applied to Laver and Burke's (1993) data sets. When older adults' response times (RTs) and semantic priming effects (SPEs) are regressed on young adults' RTs and SPEs, the slopes of the regression lines are approximately 1.5 as long as the age difference is held constant and performance is reasonably accurate. Both increases and decreases in RTs following unrelated and related primes, relative to RTs following baseline primes, were analyzed. The results, like those regarding RTs and SPEs, support the hypothesis that, compared with young adults who are 50 years younger, older adults take approximately 50% longer to process lexical information     

主观记忆减退老年人情节记忆的行为表现及其脑机制

情节记忆是个体对特定时间,特定地点所经历的特定事件的记忆.主观报告情节记忆下降是主观记忆减退老年人最典型的表现.与健康对照组老年人相比, 主观记忆减退老年人情节记忆下降的速率更快, 罹患老年性痴呆的风险更高, 但其情节记忆加工的脑机制尚不明确.前人研究提示, 主观记忆减退老年人在外在记忆行为尚未出现损伤的情况下, 其大脑情节记忆相关脑区的神经活动已经出现异常.探究主观记忆减退的记忆神经环路关键节点和路径的异常, 揭示神经环路在老年痴呆发生发展中的变化规律, 对深入理解老年痴呆的发病机制有重要的科学意义.同时, 主观记忆减退老年人作为特殊的记忆损伤群体, 对其神经环路的深入探究, 也必将为揭示人类记忆的神经机制做出独特的贡献.     

Experience and information loss in auditory and visual memory

Recent studies show that recognition memory for sounds is inferior to memory for pictures. Four experiments were conducted to examine the nature of auditory and visual memory. Experiments 1–3 were conducted to evaluate the role of experience in auditory and visual memory. Participants received a study phase with pictures/sounds, followed by a recognition memory test. Participants then completed auditory training with each of the sounds, followed by a second memory test. Despite auditory training in Experiments 1 and 2, visual memory was superior to auditory memory. In Experiment 3, we found that it is possible to improve auditory memory, but only after 3 days of specific auditory training and 3 days of visual memory decay. We examined the time course of information loss in auditory and visual memory in Experiment 4 and found a trade-off between visual and auditory recognition memory: Visual memory appears to have a larger capacity, while auditory memory is more enduring. Our results indicate that visual and auditory memory are inherently different memory systems and that differences in visual and auditory recognition memory performance may be due to the different amounts of experience with visual and auditory information, as well as structurally different neural circuitry specialized for information retention.     

Specificity of the 21-Item Test in two elderly samples

ABSTRACT The purpose of this study was to measure the specificity of the 21-Item Test for detecting malingering in an elderly sample. The 21-Item Test was administered to 20 community-dwelling elderly individuals with means for age, education, and Short Portable Mental Status Questionnaire (SPMSQ) error scores of 76.25 years (SD?=?7.19), 14.30 years (SD?=?3.89), and 0.30 (SD?=?4.70). None of these healthy elderly participants were cognitively impaired. A second group of 53 nursing home residents had means for age, education, and SPMSQ error scores of 82.79 years (SD?=?8.56), 11.14 years (SD = 2.46), and 3.17 (SD?=?2.46). Approximately 60% of the nursing home participants had cognitive impairment based on the SPMSQ. The cut offs provided by Iverson (1998 , 21 Item Test Research Manual) for interpretation of the forced-choice component of the 21-Item Test were insensitive to age and relatively insensitive to cognitive deficits. Specificity was 100% since no elderly participant from either group scored in the range indicative of sub-optimal effort or biased responding.     

Specificity of the 21-Item Test in two elderly samples

ABSTRACT

The purpose of this study was to measure the specificity of the 21-Item Test for detecting malingering in an elderly sample. The 21-Item Test was administered to 20 community-dwelling elderly individuals with means for age, education, and Short Portable Mental Status Questionnaire (SPMSQ) error scores of 76.25 years (SD?=?7.19), 14.30 years (SD?=?3.89), and 0.30 (SD?=?4.70). None of these healthy elderly participants were cognitively impaired. A second group of 53 nursing home residents had means for age, education, and SPMSQ error scores of 82.79 years (SD?=?8.56), 11.14 years (SD = 2.46), and 3.17 (SD?=?2.46). Approximately 60% of the nursing home participants had cognitive impairment based on the SPMSQ. The cut offs provided by Iverson (1998 Iverson, G. L. 1998. 21 Item Test Research Manual, Vancouver, BC: Author.  [Google Scholar], 21 Item Test Research Manual) for interpretation of the forced-choice component of the 21-Item Test were insensitive to age and relatively insensitive to cognitive deficits. Specificity was 100% since no elderly participant from either group scored in the range indicative of sub-optimal effort or biased responding.     

Movement and working memory: Patterns and positions in space

Five experiments are reported in which subjects were asked to remember short, visually presented sequences of whole body movement patterns, words, and spatial positions. The items were recalled in order in a memory span paradigm. During presentation of the items to be remembered subjects simply watched, or they carried out a concurrent activity involving articulatory suppression, movement to external spatial targets, or body-related movement. When the movement patterns to be remembered were familiar to subjects, movement span was not disrupted by articulatory suppression or movement to spatial targets but was disrupted by body-related movement. This movement suppression task, however, did not interfere with performance on a spatial span task or on verbal span. It is concluded that the memory for patterns of limb movement differs from memory for movement to spatial targets and that accounts of visuo-spatial processes in working memory involve the latter type of movement.     

Hippocampal region-specific contributions to memory performance in normal elderly

To investigate the relationship between regional hippocampal volume and memory in healthy elderly, 147 community-based volunteers, aged 55–83 years, were evaluated using magnetic resonance imaging, the Groton Maze Learning Test, Visual Reproduction and the Rey Auditory Verbal Learning Test. Hippocampal volumes were determined by interactive volumetry. We found greater age-related reduction in the volume of the hippocampal head relative to the tail. Right hippocampal tail volume correlated with spatial memory on the Groton Maze Learning Test while left hippocampal body volume was associated with delayed verbal memory. These associations were independent of age, sex, education and speed of processing and support the notion of functional differentiation along the long axis of the hippocampus.     

Memory complaint and memory performance in the depressed elderly

Depressed and nondepressed elderly subjects recruited in the context of a large epidemiological study of health were compared on measures of self-reported memory disturbance and an objective index of memory performance (free recall). Three groups were studied including (a) subjects meeting Research Diagnostic Criteria (RDC) for major depression, (b) subjects with high levels of self-reported depressive symptoms who did not meet RDC for major depression, and (c) subjects with low levels of self-reported depressive symptoms. Subjects with high depression symptom levels reported significantly higher levels of memory complaint than did subjects with low symptom levels. However, there were no differences in self-reported memory disturbance as a function of depression diagnosis. Further, there were no significant differences between groups on the free-recall measure, either as a function of symptom level or diagnosis. It is argued that symptom severity rather than diagnosis of depression is important in determining impairment in depressed elderly people.     

Interactive effects of subjective memory complaints and hypertension on learning and memory performance in the elderly

This study evaluated whether the relation between subjective memory complaints and cognitive performance is influenced by the presence of hypertension in the elderly. One hundred and five healthy older adults, 70–89 years of age, with and without hypertension treatment or diagnosis, completed a scale of subjective memory complaints. Participants were divided into those with mild memory concerns and those with minimal or no complaints. All participants completed a battery of neuropsychological tests including measures of verbal and nonverbal memory. After controlling for differences in age, gender, education, and overall intellectual ability, there were significant main effects for memory concerns and significant interactions for memory complaints and hypertension on several measures of memory performance. There were no main effects for hypertension on memory performance. Simple effects analyses of the interactions showed that the hypertensive complainers demonstrated poorer performance on measures of long-term memory and greater reliance on short-term recall than the hypertensive non-complainers. There were no differences in memory performance for the non-hypertensive groups. Among healthy elderly community-dwelling adults, those with mild subjective memory complaints in the context of hypertension demonstrated greater objective cognitive difficulties than those without hypertension as well as a greater reliance on a less efficient learning strategy. These findings suggest that memory concerns in the presence of hypertension may be important when evaluating treatment efficacy in these individuals and for identifying differences in cognitive aging.     

Identifying child temperament types using cluster analysis in three samples

Although previous research has explored the existence of temperament clusters in children, these studies have used single samples, reducing generalizability, and broad temperament constructs to identify clusters, obscuring fine-grained dimensional differences. To address these limitations, the current study identified a common cluster structure across two diverse samples of preschool children using the same fine-grained temperament measure (ns = 96, 187), then verified the cluster structure on a large, nationally-representative sample (n = 757). A consistent six-cluster solution was identified across the three samples: Unregulated, Regulated, High Reactive, Bold, Average, and Well-Adjusted. Demonstration of a replicable typology advances the understanding of temperament in childhood, and provides a parsimonious way to communicate complex information about a child’s temperament to parents and caregivers.     

Patterns of brain-electrical activity during declarative memory performance in 10-month-old infants

This study of infant declarative memory concurrently examined brain-electrical activity and deferred imitation performance in 10-month-old infants. Continuous electroencephalogram (EEG) measures were collected throughout the activity-matched baseline, encoding (modeling) and retrieval (delayed test) phases of a within-subjects deferred imitation task. Infants were divided into two memory performance groups based on the exhibition of ordered-recall after a 24-h delay. Whereas no group differences were found in EEG collected during encoding, performance-group differences in EEG were present during retrieval. Infants who successfully displayed ordered-recall showed a pattern of increasing EEG from baseline to task at anterior temporal scalp locations, whereas infants showing no ordered-recall displayed no changes in EEG from baseline to task. These findings are discussed with respect to the biobehavioral developments underlying declarative memory abilities.     

Patterns of brain-electrical activity during declarative memory performance in 10-month-old infants

This study of infant declarative memory concurrently examined brain-electrical activity and deferred imitation performance in 10-month-old infants. Continuous electroencephalogram (EEG) measures were collected throughout the activity-matched baseline, encoding (modeling) and retrieval (delayed test) phases of a within-subjects deferred imitation task. Infants were divided into two memory performance groups based on the exhibition of ordered-recall after a 24-h delay. Whereas no group differences were found in EEG collected during encoding, performance-group differences in EEG were present during retrieval. Infants who successfully displayed ordered-recall showed a pattern of increasing EEG from baseline to task at anterior temporal scalp locations, whereas infants showing no ordered-recall displayed no changes in EEG from baseline to task. These findings are discussed with respect to the biobehavioral developments underlying declarative memory abilities.     

Associative memory in three aplysiids: correlation with heterosynaptic modulation

Much recent research on mechanisms of learning and memory focuses on the role of heterosynaptic neuromodulatory signaling. Such neuromodulation appears to stabilize Hebbian synaptic changes underlying associative learning, thereby extending memory. Previous comparisons of three related sea-hares (Mollusca, Opisthobranchia) uncovered interspecific variation in neuromodulatory signaling: strong in Aplysia californica, immeasureable in Dolabrifera dolabrifera, and intermediate in Phyllaplysia taylori. The present study addressed whether this interspecific variation in neuromodulation is correlated with memory of associative (classical conditioning) learning. We differentially conditioned the tail-mantle withdrawal reflex of each of the three species: Mild touch to one side of the tail was paired with a noxious electrical stimulus to the neck. Mild touch to the other side served as an internal control. Post-training reflex amplitudes were tested 15-30 min after training and compared with pre-test amplitudes. All three species showed conditioning: training increased the paired reflex more than the unpaired reflex. However, the temporal pattern of conditioning varied between species. Aplysia showed modest conditioning that grew across the post-test period. Dolabrifera showed distinctly short-lived conditioning, present only on the first post-test. The time course of memory in Phyllaplysia was intermediate, although not statistically distinguishable from the other two species. Taken together, these experiments suggest that evolutionary changes in nonassociative heterosynaptic modulation may contribute to evolutionary changes in the stability of the memory of classical conditioning.