Emerging evidence suggests that hippocampal memory processing is modulated by midbrain regions under conditions of reward, resulting in enhanced encoding of episodic information—long-term memory for events. Current theories further suggest that hippocampal subregions may have distinct roles in episodic memory formation, and may be differentially influenced by dopaminergic midbrain inputs. Using high-resolution functional magnetic resonance imaging (fMRI), the present study investigated hippocampal subregional function as well as activation in surrounding medial temporal lobe (MTL) cortex, midbrain, and nucleus accumbens during associative encoding and cued recall under varying conditions of reward. A high-value or low-value monetary cue preceded a pair of objects indicating potential reward for successful retrieval of the association. At test, participants performed cued recall followed by match (correct association) or mismatch (incorrect association) probe decisions and received feedback on their performance. Behaviorally, cued recall performance was superior for pairs preceded by high reward cues at encoding relative to pairs preceded by low reward cues. FMRI analysis revealed regions within hippocampus, parahippocampal cortex, nucleus accumbens, and midbrain showing subsequent memory effects (greater encoding activation for remembered, compared to forgotten associations) and reward effects (greater activation for high-value, compared to low-value associations) during stimulus encoding. Within several of these regions, individual differences in reward-related encoding activation were correlated with the degree of the behavioral reward effect (better memory for high-value compared to low-value object pairs). At retrieval, regions in midbrain and subiculum predicted successful associative recall, and regions within hippocampus, parahippocampal cortex, nucleus accumbens, and midbrain showed reward effects in the absence of explicit reward cues. Within several MTL regions, activation was greater for match than mismatch probes. These findings are consistent with theories suggesting that reward-based motivation influences memory formation through interactions between dopaminergic midbrain and hippocampus. / text

Conventional theories of diencephalic amnesia have focused on a single thalamic region as a critical factor in the origins of anterograde amnesia. A more contemporary view is that different thalamic regions might contribute in unique ways to normal diencephalic functioning and therefore provide distinct contributions to the learning and memory. This study directly compared the effects of AT and MT lesions on a spatial pattern separation task, a spatial working memory task and a conditioned place preference task. AT lesions but not MT lesions produces deficits on the spatial working memory task on a cheeseboard. No group AT, MT or control rats acquired a conditioned place preference on the AT/MT lesion conditioned place preference task. Furthermore, this study determined the effect of systematic procedural variations on control rats in a conditioned place preference control task. The only variation that acquired a condition place preference was a separate arms conditioned place preference with one pre-exposure and three training trials. The results of this study provide new information regarding the role of thalamic lesions in spatial memory and suggests a revision of the current theories regarding learning and memory to incorporate the thalamic involvement that has been highlighted

No description available.

A series of recognition memory experiments using masterwork paintings and words are reported in which participants were reliably conservative in endorsing images of paintings as “studied”. The current paper establishes the historical context of this materials-based bias effect (MBBE) and presents two new experiments aimed at characterizing the underlying mechanisms. Nine previous experiments are reviewed to illustrate the MBBE’s robustness to various encoding and test manipulations and the insufficiency of two prior hypotheses to account for its origins. Meta-analyses of response bias and sensitivity and analysis of these measures by test quartile are presented and discussed along with receiver operating characteristics and response time data for all of these experiments. In one new experiment, the response scale on the recognition test was modified to allow participants to choose from not only “studied” or “not studied” options, but also options indicating uncertainty due to the similarity among test items. The hypothesis that these similarity/confusability-related responses would be chosen more for paintings was not supported. A second new experiment aimed to better characterize the time course of the MBBE by implementing a 1-s respond deadline, which it was hypothesized would reduce the effect, but this hypothesis was also not supported. Results of all experiments are discussed in the context of unequal variance and dual process models of recognition memory. / Graduate / 0633 / 0623 / kmfallow@uvic.ca

Memory performance was measured in 48 persons between the ages of 40 - 65 with Type II diabetes. Correlations between performance on the California Verbal Learning Test, tests of Working Memory, Priming Memory, and Prospective Memory and several predictor variables were examined. These variables included the Slosson Intelligence Test Scores, demographic variables, presence of diabetic complications, finger-stick and HbA1c measures. Subjects performed worse than the normative sample on the California Verbal Learning Test. Higher chronic and acute blood glucose tended to be associated with worse performance on the CVLT, Priming, and Working Memory. However, after the effects of intelligence, education, and sex were statistically controlled, glycemic status predicted performance on just a few memory measures. These were short-delay recall compared with recall on List A trial 5, and List B on the CVLT, and recall accuracy on digit forward of the Working Memory Test. Glucose status was unrelated to performance on a prospective memory test. Several other demographic and diabetic complication factors predicted performance beyond the contribution of intelligence. These results contrast with previous studies which found strong effects of glycemic control, but did not statistically control for the contribution of intelligence. Differential effects of diabetic status on different aspects of memory were discussed.

Modern smartphones integrate ubiquitous access to voice, data, and email communication and allow users to rapidly handle both personal and corporate business affairs. This is possible because of the smartphone’s constant connectivity with the Internet. Digital forensic investigators have long understood the value of smartphones as forensic evidence, and this thesis seeks to provide new tools to increase the amount of evidence that one can obtain and analyze from an Android smartphone. Specifically, by using proven data carving algorithms we try to uncover information about the phone’s connection to wireless access points in a capture of the device’s volatile memory.

APOE ε4 is the major genetic risk factor for Alzheimer’s disease, a dementia characterized by memory impairment and hippocampal atrophy. While associated with episodic impairment and reduced hippocampal volume in healthy aging, APOE ε4 has been related to increased episodic memory performance in young adults. The effect of APOE ε4 on hippocampal volume in young age is uncertain, with studies showing comparable or smaller volumes in ε4 carriers. This thesis aims to further explore the effects of APOE ε4 on episodic memory and hippocampal volume in young adults. In addition to episodic memory, spatial memory will also be assessed, as both these memory types are hippocampus-dependent. Furthermore, potential modulating effects of sex are assessed, as sex differences has been found in relation to APOE-related pathology, episodic and spatial memory and hippocampal volume. Study I examined the effects of APOE ε4 on episodic and spatial memory and hippocampal volume in young adults. Hippocampal volume was assessed by manual tracing of the hippocampal head, body and tail. Study II considered whole-brain structural covariance patterns of the anterior and posterior hippocampus. Furthermore, the association between these patterns and episodic and spatial memory performance was assessed. Study III investigated the effects of APOE ε4 on episodic and spatial memory and hippocampal volume in three different age groups. This was done in order to further explore the different effects of APOE ε4 on cognition and hippocampal volume seen in young and older age. In summary, APOE ε4 was positively associated with spatial function and episodic memory in young adults. Although there were no effects of APOE ε4 on hippocampal volume, structural covariance patterns of the anterior and posterior hippocampus differed as a function of APOE ε4 and sex. Thus, structural covariance may provide an early measure of APOE ε4-related effects on brain structure. Moreover, sex was found to modulate the effects of APOE ε4 to the disadvantage of women. This was seen in both age-related hippocampal volume effects and in structural covariance patterns in young adults, as well as in spatial memory performance across age groups.

The types of intrusion errors (Prior List, Semantically Related, and Unrelated) made on the LASSI-L verbal memory task were compared across three diagnostic groups (N = 160, 61 % female), Cognitively Normal (CN), amnestic Mild Cognitive Impairment (aMCI), and Alzheimer’s disease (AD). Errors related to Proactive, Recovery from Proactive, and Retroactive Interference were also analyzed, as well as the relationship of errors to Amyloid load, a biomarker of AD. Results suggest that the types of error made indicated the level of cognitive decline. It appears that as deficits increase, impaired semantic networks result in the simultaneous activation of items that are semantically related to LASSI-L words. In the aMCI group, providing a semantic cue resulted in an increased production of Semantically Related intrusions. Unrelated intrusions occurred rarely, although, a small number occurred even in the CN group, warranting further investigation. Amyloid load correlated with all intrusion errors. / Includes bibliography. / Thesis (M.A.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection

by Yung, Chan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1995. / Includes bibliographical references (leaves 107-110). / Abstract --- p.i / Acknowledgement --- p.iii / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Cache --- p.1 / Chapter 1.1.1 --- Introduction --- p.1 / Chapter 1.1.2 --- Data Prefetching --- p.2 / Chapter 1.2 --- Register --- p.2 / Chapter 1.3 --- Problems and Challenges --- p.3 / Chapter 1.3.1 --- Overhead of registers --- p.3 / Chapter 1.3.2 --- EReg --- p.5 / Chapter 1.4 --- Organization of the Thesis --- p.6 / Chapter 2 --- Previous Studies --- p.8 / Chapter 2.1 --- Introduction --- p.8 / Chapter 2.2 --- Data aliasing --- p.9 / Chapter 2.3 --- Data prefetching --- p.12 / Chapter 2.3.1 --- Introduction --- p.12 / Chapter 2.3.2 --- Hardware Prefetching --- p.12 / Chapter 2.3.3 --- Prefetching with Software Support --- p.13 / Chapter 2.3.4 --- Reducing Cache Pollution --- p.14 / Chapter 3 --- BASIC and ADM Models --- p.15 / Chapter 3.1 --- Introduction of Basic Model --- p.15 / Chapter 3.2 --- Architectural and Operational Detail of Basic Model --- p.18 / Chapter 3.3 --- Discussion --- p.19 / Chapter 3.3.1 --- Implicit Storing --- p.19 / Chapter 3.3.2 --- Associative Logic --- p.22 / Chapter 3.4 --- Example for Basic Model --- p.22 / Chapter 3.5 --- Simulation Results --- p.23 / Chapter 3.6 --- Temporary Storage Problem in Basic Model --- p.29 / Chapter 3.6.1 --- Introduction --- p.29 / Chapter 3.6.2 --- Discussion on the Solutions --- p.31 / Chapter 3.7 --- Introduction of ADM Model --- p.35 / Chapter 3.8 --- Architectural and Operational Detail of ADM Model --- p.37 / Chapter 3.9 --- Discussion --- p.39 / Chapter 3.9.1 --- File Partition --- p.39 / Chapter 3.9.2 --- STORE Instruction --- p.39 / Chapter 3.10 --- Example for ADM Model --- p.40 / Chapter 3.11 --- Simulation Results --- p.40 / Chapter 3.12 --- Temporary storage Problem of ADM Model --- p.46 / Chapter 3.12.1 --- Introduction --- p.46 / Chapter 3.12.2 --- Discussion on the Solutions --- p.46 / Chapter 4 --- ADS Model and ADSM Model --- p.49 / Chapter 4.1 --- Introduction of ADS Model --- p.49 / Chapter 4.2 --- Architectural and Operational Detail of ADS Model --- p.50 / Chapter 4.3 --- Discussion --- p.52 / Chapter 4.3.1 --- Prefetching Priority --- p.52 / Chapter 4.3.2 --- Data Prefetching --- p.53 / Chapter 4.3.3 --- EReg File Splitting --- p.53 / Chapter 4.3.4 --- Compiling Procedure --- p.53 / Chapter 4.4 --- Example for ADS Model --- p.54 / Chapter 4.5 --- Simulation Results --- p.55 / Chapter 4.6 --- Discussion on the Architectural and Operational Variations for ADS Model --- p.62 / Chapter 4.6.1 --- Temporary storage Problem --- p.62 / Chapter 4.6.2 --- Operational variation for Data Prefetching --- p.63 / Chapter 4.7 --- Introduction of ADSM Model --- p.64 / Chapter 4.8 --- Architectural and Operational Detail of ADSM Model --- p.65 / Chapter 4.9 --- Discussion --- p.67 / Chapter 4.10 --- Example for ADSM Model --- p.67 / Chapter 4.11 --- Simulation Results --- p.68 / Chapter 4.12 --- Discussion on the Architectural and Operational Variations for ADSM Model --- p.71 / Chapter 4.12.1 --- Temporary storage Problem --- p.71 / Chapter 4.12.2 --- Operational variation for Data Prefetching --- p.73 / Chapter 5 --- IADSM Model and IADSMC&IDLC Model --- p.75 / Chapter 5.1 --- Introduction of IADSM Model --- p.75 / Chapter 5.2 --- Architectural and Operational Detail of IADSM Model --- p.76 / Chapter 5.3 --- Discussion --- p.79 / Chapter 5.3.1 --- Implicit Loading --- p.79 / Chapter 5.3.2 --- Compiling Procedure --- p.81 / Chapter 5.4 --- Example for IADSM Model --- p.81 / Chapter 5.5 --- Simulation Results --- p.84 / Chapter 5.6 --- Temporary Storage Problem of IADSM Model --- p.87 / Chapter 5.7 --- Introduction of IADSMC&IDLC Model..........: --- p.88 / Chapter 5.8 --- Architectural and Operational Detail of IADSMC & IDLC Model --- p.89 / Chapter 5.9 --- Discussion --- p.90 / Chapter 5.9.1 --- Additional Operations --- p.90 / Chapter 5.9.2 --- Compiling Procedure --- p.93 / Chapter 5.10 --- Example for IADSMC&IDLC Model --- p.93 / Chapter 5.11 --- Simulation Results --- p.94 / Chapter 5.12 --- Temporary Storage Problem of IADSMC&IDLC Model --- p.96 / Chapter 6 --- Compiler and Memory System Support for EReg --- p.99 / Chapter 6.1 --- Impact on Compiler --- p.99 / Chapter 6.1.1 --- Register Usage --- p.99 / Chapter 6.1.2 --- Effect of Unrolling --- p.100 / Chapter 6.1.3 --- Code Scheduling Algorithm --- p.101 / Chapter 6.2 --- Impact on Memory System --- p.102 / Chapter 6.2.1 --- Memory Bottleneck --- p.102 / Chapter 6.2.2 --- Size of EReg Files --- p.103 / Chapter 7 --- Conclusions --- p.104 / Chapter 7.1 --- Summary --- p.104 / Chapter 7.2 --- Future Research --- p.105 / Bibliography --- p.107 / Chapter A --- Source code of the Kernels --- p.111 / Chapter B --- Program Analysis --- p.126 / Chapter B.1 --- Program analysed by Basic Model --- p.126 / Chapter B.2 --- Program analysed by ADM Model --- p.133 / Chapter B.3 --- Program analysed by ADS Model --- p.140 / Chapter B.4 --- Program analysed by ADSM Model --- p.148 / Chapter B.5 --- Program analysed by IADSM Model --- p.156 / Chapter B.6 --- Program analysed by IADSMC&IDLC Model --- p.163 / Chapter C --- Cache Simulation on Prefetching of ADS model --- p.174

The research reported was inspired by the Perfect and Maylor (2000) chapter ‘Rejecting the Dull Hypothesis’. This suggested that cognitive ageing research should not focus purely on whether younger adults outperform older adults on a given task. Hartley, Speer, Jonides, Reuter-Lorez and Smith (2001) showed that older adults do not maintain the dissociability of naming identity, visual identity, and spatial location abilities that is seen in younger adults. Away from the ageing literature, Brown, Forbes and McConnell (2006) demonstrated improvement in visual task performance when the availability of verbal coding was increased. The hypothesis that older adults are less likely to use task specific cognitive mechanisms during short-term visual memory tasks was explored. This was carried out by means of a series of 8 experiments (outlined below), which broadly looked at differences in verbal interference effects on visual task performance, differences in Visual Patterns Task performance based on the availability of verbal encoding, and assessed for age-related differences in interference from an executive task in Visual Patterns Task performance. Data was interpreted through the prism of the Scaffolding Theory of Aging (Park & Reuter-Lorenz, 2009), which suggests that compensatory recruitment is employed both young and older adults in response to extrinsic challenges such as task difficulty, and intrinsic challenges, such as declining performance with age. Experiments 1-3 focused on differential effects of articulatory suppression on visual task performance between young (18-25) and older (60-75) adults. Older adults showed negative effects of suppression in short-term maintenance tasks that were not present in younger adults. Both age groups showed negative effects in a mental image rotation task. This suggested a level of verbal activation in visual tasks for both age groups, but that this activation was more common in older adults. Experiments 4-5 assessed differences in Visual Patterns Task performance between both age-groups depending on the availability of verbal encoding. Younger adults displayed the benefit of available verbal encoding with simultaneous but not sequential presentation of information. Older adults showed a benefit of verbal coding in the simultaneous task if the sequential task featured ordered, not randomised presentation pathways. This suggested that older adult task performance may be affected by all conditions within an experiment, not just the current manipulation condition. Experiments 6-7 demonstrated that older adults’ performance in the simultaneous presentation version of the Visual Patterns Task is affected by the availability of verbal encoding in the first task presented to them. Mean performance on subsequent conditions was higher when ‘high verbal coding’ patterns were seen in the first instance. This was not the case for younger adults. The demonstration of a benefit to performance from the ‘high-verbal coding’ pattern set compared to the ‘low-verbal coding’ set was a marker of higher overall performance across all task conditions for younger adults, but not for the older group. This suggested that even if verbal activation during visual task performance was an occurrence for older adults, it was not necessarily a marker for improved performance. Experiment 8 demonstrated that there were no age-related differences in the level of interference from an executive task (Random Month Generation) on Visual Patterns Task performance. This suggested that older adults do not try to actively recruit executive processes during Visual Patterns Task performance to any greater extent than younger adults do. It is suggested that older adults do use specialised task mechanisms to a lesser extent than younger adults in visual memory task performance. It is likely that this is a passive outcome of a decreased inhibition of verbal coding mechanisms, rather than an active attempt to maintain performance through the recruitment of executive cognitive resources. This is seen by the lack of age-group effects from executive interference tasks.