Brain activation and deactivation during location and color working memory tasks in 11-13-year-old children

Using functional magnetic resonance imaging (fMRI) and n-back tasks we investigated whether, in 11-13-year-old children, spatial (location) and nonspatial (color) information is differentially processed during visual attention (0-back) and working memory (WM) (2-back) tasks and whether such cognitive task performance, compared to a resting state, results in regional deactivation. The location 0-back task, compared to the color 0-back task, activated segregated areas in the frontal, parietal and occipital cortices whereas no differentially activated voxels were obtained when location and color 2-back tasks were directly contrasted. Several midline cortical areas were less active during 0- and 2-back task performance than resting state. The task-induced deactivation increased with task difficulty as demonstrated by larger deactivation during 2-back than 0-back tasks. The results suggest that, in 11-13-year-old children, the visual attentional network is differently recruited by spatial and nonspatial information processing, but the functional organization of cortical activation in WM in this age group is not based on the type of information processed. Furthermore, 11-13-year-old children exhibited a similar pattern of cortical deactivation that has been reported in adults during cognitive task performance compared to a resting state.     

Musical and verbal memory in Alzheimer’s disease: A study of long-term and short-term memory

Musical memory was tested in Alzheimer patients and in healthy older adults using long-term and short-term memory tasks. Long-term memory (LTM) was tested with a recognition procedure using unfamiliar melodies. Short-term memory (STM) was evaluated with same/different judgment tasks on short series of notes. Musical memory was compared to verbal memory using a task that used pseudowords (LTM) or syllables (STM). Results indicated impaired musical memory in AD patients relative to healthy controls. The deficit was found for both long-term and short-term memory. Furthermore, it was of the same magnitude for both musical and verbal domains whether tested with short-term or long-term memory tasks. No correlation was found between musical and verbal LTM. However, there was a significant correlation between verbal and musical STM in AD participants and healthy older adults, which suggests that the two domains may share common mechanisms.     

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.     

The assessment of recognition memory using the Remember/Know procedure in amnestic mild cognitive impairment and probable Alzheimer’s disease

This study used the Remember/Know (R/K) procedure combined with signal detection analyses to assess recognition memory in 20 elders with amnestic mild cognitive impairment (aMCI), 10 patients with probable Alzheimer’s disease (AD) as well as matched healthy older adults. Signal detection analyses first indicated that aMCI and control participants were comparable on general recognition performance. As regards AD patients, they were impaired relative to both aMCI and healthy elders. When assessing Remember and Know responses the aMCI group showed diminished sensitivity for Remember responses but intact Know responses compared to healthy elders. In contrast, AD patients showed decreased sensitivity for both Remember and Know responses compared to control and aMCI participants. The response bias index revealed that AD patients were more liberal than aMCI and control participants when providing Know responses. On the other measures, response bias was comparable between the groups. Overall, this study indicates that the R/K procedure can characterize different aspects of recognition memory performance in persons with aMCI or AD.     

时序信息和空间信息在工作记忆中的分离存储

采用相对新近性判断范式（judgments of relative recency）,通过三个实验探讨了工作记忆中时序信息和空间信息的存储方式及其关系。实验一比较了有无空间线索两种条件下时序信息的记忆绩效,结果发现,有无空间线索并不影响对时序信．E-的记忆。实验二和实验三通过控制刺激呈现的视野范围和减少呈现位置的不确定性来利化空间线索,结果表明,时序信息的记忆绩效也不受空间线索的影响。由此推论,工作记忆中的时序信息和空间信息是分离编码存储的,加入空间线索并不能提高时序信息的记忆绩效。     

压力和认知方式对基于事件错误记忆的影响

运用合作者误导信息干扰范式,通过3个实验探讨了不同压力（引导压力、警告压力和反馈压力）对不同认知方式个体的错误记忆的影响。结果表明：（1）正确引导减少了错误记忆,对改善错误记忆具有积极的作用,而错误引导则增加了错误记忆;（2）在引导压力条件下,社会警告可减少错误记忆,减少误导信息的效应;（3）肯定反馈可减少错误记忆,而否定反馈则明显增加了错误记忆;（4）不同认知方式个体在不同压力下的错误记忆方面存在差异,场依存个体受各种压力影响较大,场独立个体受影响较小。     

Self-regulation and the hypothesis of experience-based selection: Investigating indirect conscious control

The assumption that the contents of our conscious visual experience directly control our fine-tuned, real-time motor activity has been challenged by neurological and psychophysical evidence that suggest the two processes work semi-independently of each other. Clark [Clark, A. (2001). Visual experience and motor action: Are the bonds too tight? The Philosophical Review, 110, 495–519; Clark, A. (2002). Is seeing all it seems? Action, reason and the grand illusion. Journal of Consciousness Studies, 9, 181–202; Clark, A. (2006). Vision as dance? Three challenges for sensori-motor contingency theory. PSYCHE, 12 (1). Available from http://www.psyche.cs.monash.edu.au] argues that such evidence implies a more indirect relationship between conscious visual experience and motor-control where the function of visual consciousness is not to control action but to select what actions are to be controlled. In this paper, I argue that this type of dynamic also exists at the wider level of self-regulation where conscious intent appears to indirectly control the enactment of the intended behaviour. I argue that by drawing parallels between Clark’s proposed dynamic and self-regulation, the former is not only bolstered by a previously unrecognised source of support but our understanding of the latter can help to further elucidate Clark’s proposed mechanism of indirect conscious control.     

The influence of instructions and terminology on the accuracy of remember–know judgments

The remember–know paradigm is one of the most widely used procedures to examine the subjective experience associated with memory retrieval. We examined how the terminology and instructions used to describe the experiences of remembering and knowing affected remember–know judgments. In Experiment 1 we found that using neutral terms, i.e., Type A memory and Type B memory, to describe the experiences of remembering and knowing reduced remember false alarms for younger and older adults as compared to using the terms Remember and Know, thereby increasing overall memory accuracy in the neutral terminology condition. In Experiment 2 we found that using what we call source-specific remember–know instructions, which were intended to constrain remember judgments to recollective experiences arising only from the study context, reduced remember hits and false alarms, and increased know hits and false alarms. Based on these data and other considerations, we conclude that researchers should use neutral terminology and source-specific instructions to collect the most accurate reports of the experiences of remembering and knowing arising from the study context.     

Verbal predicates foster conscious recollection but not familiarity of a task-irrelevant perceptual feature – An ERP study

Research on the effects of perceptual manipulations on recognition memory has suggested that (a) recollection is selectively influenced by task-relevant information and (b) familiarity can be considered perceptually specific. The present experiment tested divergent assumptions that (a) perceptual features can influence conscious object recollection via verbal code despite being task-irrelevant and that (b) perceptual features do not influence object familiarity if study is verbal-conceptual. At study, subjects named objects and their presentation colour; this was followed by an old/new object recognition test. Event-related potentials (ERP) showed that a study-test manipulation of colour impacted selectively on the ERP effect associated with recollection, while a size manipulation showed no effect. It is concluded that (a) verbal predicates generated at study are potent episodic memory agents that modulate recollection even if the recovered feature information is task-irrelevant and (b) commonly found perceptual match effects on familiarity critically depend on perceptual processing at study.     

The effects of total sleep deprivation on recognition memory processes: A study of event-related potential

This study examined the memorization of information after a night of normal sleep and total sleep deprivation (TSD) by means of event-related potentials (ERPs). We expected a disfacilitatory effect of TSD on memory processing. Eighteen subjects were tested twice in a counterbalanced fashion. During the study session, subjects were presented with unfamiliar face stimuli and asked to memorize them for a subsequent memory test. At the test session, the subjects were presented with the studied faces intermixed with “new” faces and asked to indicate the previously presented stimuli. The N100 was used as a covariate to control for the differences in level of vigilance between the two sessions. Sleep deprivation decreased subjects’ ability to discriminate new from previously studied stimuli and decreased the peak amplitude of the early component (N200) to the decrement of performance. In addition, following TSD the amplitude of the late frontal component (LFC), which is thought to reflect contextual processing, was decreased in covariance with the N100 vigilance component. The amplitude of the late posterior component (LPC/P600) was also reduced but was unrelated to the vigilance component of the ERP. Based on prior studies, this LPC reduction can be interpreted to indicate a decrease in information retrieved after TSD. In summary, a night of TSD decreased the amplitude of the ERPs associated with complex episodic memory task stimuli, affected the frontal cortex during episodic retrieval, and prevented the elaboration process. Furthermore, there was an inability to discriminate what is and what is not in memory, possibly due to less local processing of details.