The current study provides evidence for the dissociation between two types of asymmetries in relations within semantic memory: those due to unidirectional associative strength (e.g., Kahan, Neely & Forsythe, 1999), and the inherent asymmetry of causal relations (e.g., Fenker, Waldmann & Holyoak, 2005). By manipulating the stimulus onset asynchrony (SOA) in a relation recognition task, I demonstrate that expectancy differentially impacts the effects of these asymmetries. An asymmetrical directional response time advantage was seen with causal relations at both long (1000 ms) and short (150 ms) SOAs, but only at long SOAs for unidirectional associates. These data are taken to support the hypothesis that latencies due to unidirectional association are a result of the manner in which these relations are accessed, and latencies due to the asymmetry of causal relations are reflective of the manner in which cause-effect asymmetries are represented.

The current study provides evidence for the dissociation between two types of asymmetries in relations within semantic memory: those due to unidirectional associative strength (e.g., Kahan, Neely & Forsythe, 1999), and the inherent asymmetry of causal relations (e.g., Fenker, Waldmann & Holyoak, 2005). By manipulating the stimulus onset asynchrony (SOA) in a relation recognition task, I demonstrate that expectancy differentially impacts the effects of these asymmetries. An asymmetrical directional response time advantage was seen with causal relations at both long (1000 ms) and short (150 ms) SOAs, but only at long SOAs for unidirectional associates. These data are taken to support the hypothesis that latencies due to unidirectional association are a result of the manner in which these relations are accessed, and latencies due to the asymmetry of causal relations are reflective of the manner in which cause-effect asymmetries are represented.

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

Introduction The present study explored the nature of the semantic deterioration normally displayed in the course of Alzheimer’s disease (AD). The aim was to disentangle the extent to which semantic memory problems in patients with AD are best characterized as loss of semantic knowledge rather than difficulties in accessing semantic knowledge. Method A longitudinal approach was applied. The same semantic tests as well as same items were used across three test occasions a year apart. Twelve Alzheimer patients and 20 matched control subjects, out of a total of 25 cases in each group, remained at the final test occasion. Results and Conclusions Alzheimer patients were impaired in all the semantic tasks as compared to the matched comparison group. A progressing deterioration was evident during the study period. Our findings suggest that semantic impairment is mainly due to loss of information rather than problems in accessing semantic information.

No / Objective It has been documented that pain in people with dementia is often under-reported and poorly detected. The reasons for this are not clearly defined. This project aimed to explore semantic concepts of pain in people with dementia and whether this is associated with clinical pain report. Design Cohort study with nested cross-sectional analysis. Setting Acute general hospital medical wards for older people. Subjects People with dementia (N = 26) and control participants (N = 13). Methods Two subtests of semantic memory for pain: 1) Identifying painful situations from a standardized range of pictures; 2) Describing the concept of pain. Participants also indicated whether they were in pain or not, were observed for pain (PAINAD scale) and completed the Wong–Baker FACES scale to indicate pain severity. Results Compared with the control group, people with dementia were less able to identify painful situations and used fewer categories to define their concept of pain. In turn, the performance on these two measures was related to the reported presence and, albeit less strongly, to the reported severity of pain, indicating that a reduction in semantic memory for pain is associated with a decline in reported pain. Conclusions This study is the first to show that semantic memory for pain is diminished in dementia patients. When using clinical pain tools, clinicians should consider these effects which may bias clinical pain ratings when they evaluate and manage pain in these patients. This might improve the recognition and management of pain in people with dementia. / Alzheimer's Society and the BUPA Foundation (Grant reference number: 131).

In the present study, we conducted an event-related potentials (ERP) study to examine episodic and semantic memory. We focused on two well-known patterns: the semantic N400 and the old/new fN400. Some researchers have argued that they reflect the same neuropsychological response (Voss & Federmeier, 2011). Others have suggested that they have distinct spatial-temporal signatures and reflect different psychological processes (Bridger, Bader, Kriukova, Unger, & Mecklinger, 2012). In the present study, we analyzed data using the basic N400/fN400 paradigm. We expect to find similar results to Bridger et al. (2012) in that the N400 and fN400 to be reliably different in topography and function.

Categorisation is the process by which items, behaviours and events are compartmentalised according to their defining attributes or properties. This may be based on simple perceptual similarities or on more complex conceptual webs. Whatever their selection criteria, categories expedite inferential capabilities, facilitating behavioural predictions and subsequently enabling response. Categorisation waives conscious effort whilst preserving that which is salient and as such, provides a highly efficient means of delineating and organising information within semantic memory. An ability to categorise is therefore fundamental to an individual’s capacity to understand the world and a necessary precursor to academic achievement. This thesis comprises a series of studies that were devised in order to investigate categorisational development in children. Study 1 involved the development of a theoretically and practically valid testing mechanism. A sample of 159 children, aged 30-50 months, participated in a series of investigations aimed at establishing the impact of test format and presentation dimensionality on categorisation performance. As a result of this, a new test battery was devised which enabled more fine grain differentiation than had been possible with the tests used by previous researchers. The battery measured four different aspects of preschool children’s categorisational abilities -categorising according to shape; according to colour; when presented with drawings of items, and when presented with the same items in the form of toys. Results found that children’s ability to categorise differed significantly according to their sex, socio-economic background and the dimensionality of the item. Study 2 utilised the same battery with 190 participants from demographically diverse cohorts. Significant differences were found between high and low socio-economic groups and between boys and girls. A Mixed- Factorial ANOVA, with a post-hoc Bonferroni demonstrated a main effect of sex; a main effect of cohort and an interaction between sex and cohort. A Kruskal-Wallis Test also showed age to be significant, confirming the findings of previous researchers concerning a developmental trajectory. However, it also found that relatively sophisticated conceptual webs emerge earlier than had previously been thought. Whilst the results from Study 2 had demonstrated relative homogeneity amongst socio-economic groups, it was noted that participants from the most disadvantaged neighbourhood performed better than those from the other low socio-economic cohort. As the two Nurseries employed different approaches, with one offering a formal curriculum and the other emphasising child-led play, it was decided that the final study would focus on categorical development in these two cohorts. The final study therefore investigated conceptual development during 96 participants’ first twelve weeks of nursery education. Forty-eight participants were drawn from a Community Nursery with a strong emphasis on child-led play and 48 were drawn from a Nursery attached to a Primary School, where the emphasis was on more formalised learning. Children’s categorisational abilities were measured during their first week in Nursery using the test battery devised for Study 1. They were then re-tested using a matched battery twelve weeks later. Change scores were calculated and analysed using a series of one-way ANOVAs. As anticipated, all participants made gains but the children who had participated in play made significantly greater gains in three out of the four measures. It is thus asserted that play is a key conducer in cognitive development and a causal executant in establishing rudimentary automaticity and, as such, should be the polestar of preschool education. This is particularly important for boys from low socio-economic backgrounds who face contiguous disadvantage. Therefore, this research demonstrates that memory-based research with young children should be conducted with toys and objects, rather than images, and that the link between social and educational stratification has its roots in early childhood and is best addressed through the provision of high-quality play opportunities.

The capacity for memory is one of the most profound features of the mammalian brain, and the proper encoding and retrieval of information are the processes that form the basis of learning. The goal of this thesis is to further our understanding of the network-level mechanisms supporting learning and memory in the mammalian brain. The hippocampus has been long recognized to play a central role in learning and memory. Although being one of the most extensively studied structures in the brain, the precise circuit mechanisms underlying its function remain elusive. Principal cells in the hippocampus form complex representations of an animal's environment, but in stark contrast to the interneuron population -- and despite the apparent need for functional segregation -- these cells are largely considered a homogeneous population of coding units. Much work, however, has indicated that principal cells throughout the hippocampus, from the input node of the dentate gyrus to the output node of area CA1, differ developmentally, genetically, anatomically, and functionally. By employing in vivo two-photon calcium imaging in awake, behaving mice, we attempted to characterize the role of dened subpopulations of neurons in memory-related behaviors. In the first part of this thesis, we focus on the dentate gyrus input node of the hippocampus. Chapter 2 compares the functional properties of adult-born and mature granule cells. Chapter 3 expands on this work by comparing granule cells with mossy cells, another glutamatergic but relatively understudied cell type. The second part of this thesis focuses on the hippocampal output node, area CA1. In chapter 4, we characterize an inhibitory microcircuit that differentially targets the sublayers of area CA1. And in chapter 5, we directly compare the contributions of these sublayers to episodic and semantic memory.

<p>There is a body of research on the effect of physical activity oncognition in the old adult population. Less research areconducted on adolescents. The aim for this study is to find out ifadolescents long-term memory is affected by physical activity.144 pupils were asked to rate their physical activity each week.Thereafter their long- term memory was tested through tests onepisodic- and semantic memory. The results showed that thosewho are physically active more than 4 hours had a better scoreon part of the semantic test but no effect was found in theepisodic test. This result indicates that physical activity not onlyaffects working memory, as was shown by previous research butalso has an effect in parts of the semantic long-term memory.</p>

Lidée selon laquelle la mémoire déclarative à long terme celle qui nous permet dencoder et de récupérer sur un mode « déclaratif » des connaissances et des souvenirs acquis par le passé renvoie à deux réalités fondamentalement différentes nest pas neuve. Il y a plus de trente ans, en effet, Tulving (1972)proposait de distinguer la mémoire sémantique de la mémoire épisodique. Cette distinction est toujours admise aujourdhui et constitue une référence pour les pratiques dévaluation en neuropsychologie. Non seulement elle fournit une structure pour lanalyse clinique des troubles de la mémoire, mais elle sert également de cadre théorique pour la compréhension du syndrome amnésique (Verfaellie, 2000). Les relations quentretiennent ces deux systèmes mnésiques ainsi que les réseaux neuronaux qui les sous-tendent restent cependant encore lobjet de débats. De plus, les mécanismes impliqués dans lacquisition de nouvelles connaissances sémantiques sont peu connus. Bien que plusieurs études suggèrent que lapprentissage de nouvelles informations sémantiques dépend de mécanismes implicites (par ex., Ashby & Gott, 1988; Ashby & Maddox, 1990, 1992, Ashby, Alfonson-Reese, Turken, & Waldron, 1998; Hinton, 1981) dautres suggèrent que les mécanismes impliqués pourraient être à la fois implicite et explicites (par ex., Gopnik & Meltzoff, 1997) ou encore uniquement explicites (OConnor, Cree, & McRae, in press). En fait, limplication des mécanismes explicites et implicites pourrait dépendre du type de connaissances sémantiques à apprendre : lacquisition de labels pourrait dépendre de mécanismes plus explicites tandis que lapprentissage de catégories ou des caractéristiques de celles-ci pourrait dépendre de mécanismes plus implicites (Pitel et al., 2009). Dans cette perspective, si les mécanismes dapprentissage implicite interviennent dans lacquisition de connaissances sémantiques, il apparaît intéressant de déterminer leur rôle et les relations quentretiennent lacquisition de connaissances sémantiques et le domaine de lapprentissage implicite. Au plan théorique, cette mise en relation permettrait une meilleure compréhension du rôle joué par les processus dapprentissage implicite dans larchitecture cognitive ; par ailleurs, outre les répercussions que lon pourrait en attendre sur le plan des méthodes pédagogiques, une meilleure compréhension du rôle joué par les mécanismes dapprentissage implicite dans lapprentissage de nouvelles connaissances sémantiques devrait conduire au développement de pratiques de revalidation plus adaptées aux capacités de mémoire préservées ou résiduelles présentées par certains patients amnésiques. Dans ce travail, nous commencerons par développer les principaux modèles de la mémoire qui permettront de situer le système sémantique par rapport aux autres systèmes mnésiques. Nous développerons ensuite les modèles plus spécifiques de la mémoire sémantique qui nous aideront à mieux comprendre comment les connaissances sémantiques sont organisées et comment de nouveaux apprentissages peuvent survenir. Enfin, nous mettrons en évidence les éléments qui permettent de penser que les mécanismes dapprentissage implicite sont directement impliqués dans lacquisition de nouvelles connaissances sémantiques.