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Memory Paradigm (memory + paradigm)
Selected AbstractsRequirement of NMDA receptor reactivation for consolidation and storage of nondeclarative taste memory revealed by inducible NR1 knockoutEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 3 2005Zhenzhong Cui Abstract We employed an inducible, reversible and region-specific gene knockout technique to investigate the requirements for cortical NMDA receptors (NMDAR) during the various stages (acquisition, consolidation and storage, and retrieval) of nondeclarative, hippocampal-independent memory in mice using a conditioned taste aversion memory paradigm. Here we show that temporary knockout of the cortical NMDAR during either the learning or postlearning consolidation stage, but not during the retrieval stage, causes severe performance deficits in the 1-month taste memory retention tests. More importantly, we found that the consolidation and storage of the long-term nondeclarative taste memories requires cortical NMDAR reactivation. Thus, the dynamic engagement of the NMDAR during the postlearning stage leads us to postulate that NMDAR reactivation-mediated synaptic re-entry reinforcement is crucial for overcoming the destabilizing effects intrinsic to synaptic protein turnover and for achieving consolidation and storage of nondeclarative memories in the brain. [source] A parallel advancing front grid generation schemeINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 6 2001Rainald Löhner Abstract A parallel advancing front scheme has been developed. The domain to be gridded is first subdivided spatially using a relatively coarse octree. Boxes are then identified and gridded in parallel. A scheme that resembles closely the advancing front technique on scalar machines is recovered by only considering the boxes of the active front that generate small elements. The procedure has been implemented on the SGI origin class of machines using the shared memory paradigm. Timings for a variety of cases show speedups similar to those obtained for flow codes. The procedure has been used to generate grids with tens of millions of elements. Copyright © 2001 John Wiley & Sons, Ltd. [source] Characterizing the ERP Old,New effect in a short-term memory taskPSYCHOPHYSIOLOGY, Issue 5 2008Jared F. Danker Abstract The early and late components of the event-related potential (ERP) Old,New effect are well characterized with respect to long-term memory, and have been associated with processes of familiarity and recollection, respectively. Now, using a short-term memory paradigm with verbal and nonverbal stimuli, we explored the way that these two components respond to variation in recency and stimulus type. We found that the amplitude of the early component (or frontal N400, FN400) showed Old,New effects only for verbal stimuli and increased with recency. In contrast, the later component (or late positive component, LPC) showed Old,New effects across a range of stimulus types and did not scale with recency. These results are consistent with the way that these same ERP components have been characterized in long-term memory, supporting the idea that some of the same processes underlie long- and short-term item recognition. [source] Source memory for the color of pictures: Event-related brain potentials (ERPs) reveal sensory-specific retrieval-related activityPSYCHOPHYSIOLOGY, Issue 3 2003Yael M. Cycowicz Abstract Remembering the context (i.e., source) in which an event occurred reveals episodic memory effects (EM) in the event-related brain potentials (ERP). In some verbal source memory experiments, a late prefrontal EM effect has been observed. In a different, pictorial source memory paradigm, a late, parieto-occipital EM effect was recorded. To assess whether these two EM effects stemmed from differences in task paradigms or from source-attribute differences, ERPs were recorded during source memory retrieval for object colors in two tasks. In the sequential task, old/new judgments were followed by source judgments (i.e., color). In the exclusion task, source memory judgments coincided with recognition judgments. For both tasks, late, parietao-occipital EM effects were observed. These findings suggest that it is not the nature of the task, but rather the perceptual characteristics of the source that lead to the presence of the parieto-occipital EM effect. The data further imply that memories for perceptual attributes such as color are stored in and retrieved from sensory-specific cortical areas. [source] An fMRI investigation of working memory and sadness in females with bipolar disorder: a brief reportBIPOLAR DISORDERS, Issue 8 2008Thilo Deckersbach Objective:, Functional magnetic resonance imaging (fMRI) studies have documented abnormalities in the dorsolateral prefrontal cortex (DLPFC) and anterior cingulate cortex in bipolar disorder in the context of working memory tasks. It is increasingly recognized that DLPFC regions play a role in mood regulation and the integration of emotion and cognition. The purpose of the present study was to investigate with fMRI the interaction between acute sadness and working memory functioning in individuals with bipolar disorder. Methods:, Nine depressed individuals with DSM-IV bipolar I disorder (BP-I) and 17 healthy control participants matched for age, gender, education, and IQ completed a 2-back working memory paradigm under no mood induction, neutral state, or acute sadness conditions while undergoing fMRI scanning. Functional MRI data were analyzed with SPM2 using a random-effects model. Results:, Behaviorally, BP-I subjects performed equally well as control participants on the 2-back working memory paradigm. Compared to control participants, individuals with BP-I were characterized by more sadness-specific activation increases in the left DLPFC (BA 9/46) and left dorsal anterior cingulate (dACC). Conclusions:, Our study documents sadness-specific abnormalities in the left DLPFC and dACC in bipolar disorder that suggest difficulties in the integration of emotion (sadness) and cognition. These preliminary findings require further corroboration with larger sample sizes of medication-free subjects. [source] Infant information processing and family history of specific language impairment: converging evidence for RAP deficits from two paradigmsDEVELOPMENTAL SCIENCE, Issue 2 2007Naseem Choudhury An infant's ability to process auditory signals presented in rapid succession (i.e. rapid auditory processing abilities [RAP]) has been shown to predict differences in language outcomes in toddlers and preschool children. Early deficits in RAP abilities may serve as a behavioral marker for language-based learning disabilities. The purpose of this study is to determine if performance on infant information processing measures designed to tap RAP and global processing skills differ as a function of family history of specific language impairment (SLI) and/or the particular demand characteristics of the paradigm used. Seventeen 6- to 9-month-old infants from families with a history of specific language impairment (FH+) and 29 control infants (FH,) participated in this study. Infants' performance on two different RAP paradigms (head-turn procedure [HT] and auditory-visual habituation/recognition memory [AVH/RM]) and on a global processing task (visual habituation/recognition memory [VH/RM]) was assessed at 6 and 9 months. Toddler language and cognitive skills were evaluated at 12 and 16 months. A number of significant group differences were seen: FH+ infants showed significantly poorer discrimination of fast rate stimuli on both RAP tasks, took longer to habituate on both habituation/recognition memory measures, and had lower novelty preference scores on the visual habituation/recognition memory task. Infants' performance on the two RAP measures provided independent but converging contributions to outcome. Thus, different mechanisms appear to underlie performance on operantly conditioned tasks as compared to habituation/recognition memory paradigms. Further, infant RAP processing abilities predicted to 12- and 16-month language scores above and beyond family history of SLI. The results of this study provide additional support for the validity of infant RAP abilities as a behavioral marker for later language outcome. Finally, this is the first study to use a battery of infant tasks to demonstrate multi-modal processing deficits in infants at risk for SLI. [source] Inactivation of the gene for the nuclear receptor tailless in the brain preserving its function in the eyeEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 8 2007Thorsten Belz Abstract During embryogenesis, tailless, an orphan member of the nuclear receptor family, is expressed in the germinal zones of the brain and the developing retina, and is involved in regulating the cell cycle of progenitor cells. Consequently, a deletion of the tailless gene leads to decreased cell number with associated anatomical defects in the limbic system, the cortex and the eye. These structural abnormalities are associated with blindness, increased aggressiveness, poor performance in learning paradigms and reduced anxiousness. In order to assess the contribution of blindness to the behavioural changes, we established tailless mutant mice with intact visual abilities. We generated a mouse line in which the second exon of the tailless gene is flanked by loxP sites and crossed these animals with a transgenic line expressing the Cre recombinase in the neurogenic area of the developing brain, but not in the eye. The resulting animals have anatomically indistinguishable brains compared with tailless germline mutants, but are not blind. They are less anxious and much more aggressive than controls, like tailless germline mutants. In contrast to germline mutants, the conditional mutants are not impaired in fear conditioning. Furthermore, they show good performance in the Morris water-maze despite severely reduced hippocampal structures. Thus, the pathological aggressiveness and reduced anxiety found in tailless germline mutants are due to malformations caused by inactivation of the tailless gene in the brain, but the poor performance of tailless null mice in learning and memory paradigms is dependent on the associated blindness. [source] | ||||||||||