Suicidal thoughts and behaviors (STBs) are a problem among young adults. Problem solving deficits have been implicated in suicide outcomes and may be especially relevant to young adults given the developmental demands and increased risk for STBs during this life stage. Emerging research suggests that problem solving and related cognitive processes (e.g., episodic memory) can be modified through a brief cognitive training session, hereafter referred to as the specificity induction. However, it is unknown whether benefits of this specificity induction extend to suicidal populations. The present study tested a web-based version of the specificity induction intended to improve problem solving skills, episodic memory and divergent thinking among suicidal young adults. We recruited and consented a sample of 105 young adults with past year STBs and randomly assigned them to receive either the specificity induction or a control condition (i.e., general impressions induction). Regarding feasibility of conducting an online study with this population 81.90% (n=86) of those who provided informed consent completed the study protocol. Regarding clinical acceptability of the web-based specificity induction, the majority of participants which received this cognitive training rated that they would be unlikely to “use again”, while endorsing that it was “easy to use” across several items of a user experience self-report questionnaire. Contrary to hypotheses,young adults assigned to complete the specificity induction did not show improvement in their performance on measures of problem solving and related cognitive processes compared to those assigned to the control condition. Through post-hoc analyses we investigated candidate sources of systematic variability in task performance (e.g., attention, mood, task order effects), but none were found to account for participants’ demonstrated problem solving performance. In sum, we conclude that testing this brief cognitive training through an online experimental study was feasible, the cognitive training was modestly acceptable in its online format, and it does not immediately improve suicidal young adults’ problem solving or related cognitive processes. By demonstrating what does not necessarily work with suicidal young adults, there remains room for future research to pursue alternative design or modes of single session interventions.

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La perception pour un individu que son fonctionnement est déterminé par ses propres actions et comportements serait l’un des facteurs clés d’un vieillissement cognitif réussi. Cette perception de contrôle conduirait à fournir des efforts soutenus pour rester performant sur le plan cognitif en dépit de l'avancée en âge, ce qui contribuerait au maintien de bonnes habiletés cognitives au fil du temps. Aujourd’hui, de nombreux travaux mettent en évidence que les personnes avec un fort sentiment de contrôle obtiennent de meilleures performances dans les tâches de mémoire épisodique que les autres. Néanmoins, l’hypothèse d’une préservation différentielle des capacités de mémoire épisodique en fonction du niveau de contrôle perçu manque encore de soutien empirique. A travers trois études expérimentales et la validation d’une nouvelle échelle de contrôle perçu spécifique à la mémoire, la présente thèse visait à déterminer si le contrôle perçu pouvait jouer un rôle positif dans l’évolution de la mémoire épisodique au fil de l’âge adulte puis à identifier les mécanismes explicatifs de la relation entre le contrôle perçu et la mémoire épisodique à différents âges de la vie adulte. Dans l’ensemble, nos études ne permettent pas de valider l’hypothèse selon laquelle un contrôle perçu plus élevé atténuerait les différences liées à l’âge en mémoire épisodique. En revanche, nos résultats suggèrent que les personnes, et en particulier les plus âgées, qui perçoivent leur mémoire comme contrôlable obtiennent de meilleures performances de mémoire épisodique que les autres grâce à une plus grande utilisation et à une exécution plus efficace de stratégies cognitives coûteuses en termes de ressources au cours de la tâche. / Perceiving one’s own functioning as determined by one’s own actions and behaviors would be one of the key factors of successful cognitive aging. Perceived control would lead to sustained efforts to maintain a high level of cognitive performance despite advancing age, which would predict a positive evolution of cognitive abilities over time. Currently, many studies show that people with higher levels of sense of control have better memory performance than people who believe that events are beyond their control. Nevertheless, there is still a lack of empirical support concerning the hypothesis of a differential preservation of memory abilities as a function of levels of perceived control. Through three experimental studies and the validation of a new scale evaluating memory control beliefs, this thesis aimed to determine whether perceived control could make a positive contribution to memory aging and to identify the mechanisms that may explain the relationship between perceived control and episodic memory at different ages. Overall, our studies do not support the hypothesis that higher perceived control would moderate age-related differences in episodic memory. However, our work suggests that individuals, especially the older ones, who perceive their memory as controllable obtain better performance during memory tasks than those who perceive their memory as uncontrollable through greater and more efficient use of resource-demanding cognitive strategies.

The diploma thesis is focused on standardization of the neuropsychological test The Free and Cued Selective Reminding Test with Immediate Recall (FCSRT-IR), this test is a one of memory tests which contains phase with controlled learning. In the theoretical part it deals with aging and cognitive functions especially memory, further episodic memory test especially FCSRT-IR and its administration and benefits of this test against other episodic memory tests. In the practical part of this diploma thesis we report norms based on population in age 60 years and older (N= 362; range of age from 61 to 97), the norms are based on National Normative Study of Cognitive Determinants of Healthy Ageing which took place from 2012 to 2015 (IGA NT13145) and the author of this diploma thesis was a member of its team. In the second part of this thesis we deal with validation study which was conducted on population of people with dementia in Alzheimer's disease (N= 37; range of age from 61 to 88) comparing with healthy control group. In this validation study we confirmed that FCSRT-IR is a sensitive method for detection dementia in Alzheimer's disease. Keywords: Episodic memory, FCSRT-IR, controlled learning, norms, validation

Our lives unfold in space and time—we are able to be aware not only of the present instant but also to recollect the past and imagine the future, and our memories tend to be not instantaneous snapshots but rather bear a temporal, sequential dimension. This faculty of time travel allows us to adjust our current actions in light of what we have previously learned and with respect to what we aspire to become. It depends upon faithful records of our personal experiences, termed episodic memory. While over the last century we have learned a great deal about the molecular changes that support this kind of learning, the circuit-level mechanisms with which the brain implements the formation of episodic memory remain to be discovered. Failures of episodic memory can be catastrophic, and unfortunately, such dysfunction is commonplace in a number of human pathologies. In the neuropsychiatric syndrome of schizophrenia, the capacity to form and utilize episodic memory is compromised, a state of affairs that likely contributes to the difficulty people with schizophrenia have adjusting their actions to meet desired goals. Attempts to understand the pathogenesis of schizophrenia’s memory deficits at the molecular level have yielded frustratingly few leads, making circuit-level inquiries a rational next step. Utilizing a genetic mouse model of schizophrenia susceptibility (Df(16)A+/- mice), we have taken a three-pronged approach to the analysis of the circuit mechanisms and missteps of episodic memory. We first developed a behavioral model of episodic memory, a variation on classical ‘trace’ fear conditioning, which involves the formation of an association between an innocuous stimulus (conditioned stimulus, CS) and a temporally separate aversive stimulus (unconditioned stimulus, US). Next, we turned to a region of the brain known to be required for trace fear conditioning and implicated in the pathogenesis of schizophrenia, dorsal CA1 of the hippocampus. Because network coordination and plasticity in dorsal hippocampal CA1 relies heavily on the activity of soma-targeting, parvalbumin-positive interneurons (PV+ INs), we hypothesized that they may be mediators of the associations built during trace fear conditioning. We therefore sought to characterize their activity during temporal association learning in both wild-type (WT) and Df(16)A+/- mice using two-photon calcium imaging. We simultaneously recorded local field potentials in the contralateral dorsal hippocampus to pair the discrete transformations captured through imaging with information about more global states of hippocampal activity. Finally, we manipulated the activity PV+ INs during various epochs of freely-moving trace fear conditioning to test hypotheses regarding their necessity for trace fear conditioning in healthy and schizophrenia-susceptible mice. We found that Df(16)A+/- mice have severe deficits in trace fear conditioning when compared to mice that do not carry their defining mutation. Calcium imaging of PV+, peri-somatic boutons in dorsal CA1 over the course of trace fear conditioning revealed a marked increase in the number of detected boutons that initiate activity during the presentation of the CS and that sustain their activity across the time gap preceding delivery of the US. This shift in activity was notably absent in recordings from Df(16)A+/- mice. Consistent with the observations of others, analysis of local field potentials indicated that successful learning was associated with modulation of amplitude and theta-phase relation in mid- and fast-gamma frequency oscillations. This modulation was compromised in Df(16)A+/- mice. Finally, we found that inhibition of PV+ INs during encoding in Df(16)A+/- mice restores their response to the CS to near-WT levels of fear expression. Our results support the thesis that temporary downregulation of PV+ IN activity during encoding is essential for the formation of complex, hippocampus-dependent associations including temporal association memory. We suggest that this transient disinhibition may serve to allow for the generation of new pyramidal cell ensembles to represent the associated stimuli. The heightened, sustained inhibition observed during post-learning trials in the calcium imaging experiments is consistent with a transition of the PV+ INs into a role of stabilizing the fledgling memory trace during consolidation. Our results also support the hypothesis that in our model of schizophrenia susceptibility, impairments in learning complex associations may be due to the inability of PV+ INs to modulate their activity appropriately over the changing phases of memory formation. We identify PV+ INs as a promising therapeutic target for schizophrenia as we were able to restore behavior of the susceptible mice during our assay of temporal association memory. Further studies combining pharmacogenetic or optogenetic manipulations with calcium imaging and LFP recording could shed light on the mechanisms of these shifts in network plasticity and may help to identify new approaches to the treatment of the debilitating cognitive deficits associated with schizophrenia.

Two experiments are presented in this dissertation to investigate the effect a schema may have on mnemonic discrimination. We developed stimuli composed of a foreground item on a background that was either schematically congruent or incongruent. For the encoding phase of both experiments, these stimuli were presented to 98 participants, who were tasked with determining the congruency of each foreground-background pair. Next, the two experiments diverged for the retrieval phase, where participants were presented with either the same object as before (Target) or one that was similar (Lure). Forty-six participants in Experiment 1 saw stimuli with the same background as initially presented during the retrieval phase. For Experiment 2, fifty-two participants saw the foreground item presented only on a white background. Behavioral, eye tracking, and whole-brain, high-resolution fMRI data were acquired for both experiments and both phases of the task. We found memory discriminability (d-prime) scores were larger for incongruent stimuli when target-lure pairs were less similar and only when the background was present during retrieval. Critically, we found evidence of recognition in the hippocampal subregions as opposed to lure detection. These findings support the notion of a congruency benefit due to the "generate-and-recognize" model and an incongruency benefit due to increased initial attention.

Two projects are presented in this dissertation. First, we investigated the impact of false memories on the original trace and whether recovery of the original is possible. Second, we tested whether mnemonic discrimination for temporal duration is possible. Both projects incorporated fMRI techniques in order to implicate any potential neural correlates of these memory behaviors. Project One. To elicit false memories and study a potential recovery therefrom, thirty-five healthy, young adults performed multiple recognition memory tests where they were induced to make errors in a first test and then participants were tested again in a surprise, second test. These two tests allowed us to determine which memory error would be corrected, if any. Further, fMRI signal associated with the encoding and retrieval processes during the experiment allowed us to implicate the regions associated with false memory correction. We found that false memories do not overwrite the original trace in all instances, as recovery of the original information was possible. Critically, we determined that recovery of the original information was dependent on activity in regions associated with retrieval, saliency attention, and bottom-up attention during the formation of the false memory, and not on processing at the time of encoding or the second test episode. Project Two. We developed a novel paradigm to test episodic memory for temporal duration. Thirty-five healthy, young adults completed a temporal discrimination task that consisted of a continuous-recognition paradigm in which visual objects were presented one at a time for either 1 or 1.5 seconds. Certain items repeated (Targets and Lures) where Targets were presented for the same duration while the duration of Lures was altered by ±0.5 seconds. Participants were asked to identify whether the stimulus duration changed. Whole-brain high-resolution fMRI data were acquired. Behavioral results indicate that participants were sensitive to both increases and decreases in duration. Further, fMRI analyses revealed that the left entorhinal and perirhinal cortices were differentially involved in encoding and retrieval, respectively, of correct duration representations. These findings support the notion of the entorhinal cortex supporting temporal representations in memory as well as the perirhinal cortex representing the conjunction of item and context.

The purpose of this study was to describe the relationship between mental, physical, and social activity, and episodic memory (EM) of cognitively intact older persons. The specific aims were (a) to describe the relationship between EM and mental, physical, and social activity, (b) to describe the role of gender, marital status, and race on EM, (c) to describe the moderating effects of each activity on the relationship between each of the remaining two activities and EM, and (d) to describe the moderating effects of gender, marital status, and race on the relationship between each activity and EM. Two theoretical frameworks: Cognitive Reserve Theory (Stern, 2002) and Theory of Nursing as Caring (Boykin & Schoenhofer, 1993) guided the study. This study was designed as a correlational and retrospective secondary analysis of data sets from the Health and Retirement Study. The sample consisted of 3,903 cognitively intact persons who were 50 years and older and completed immediate and delayed recall tests in the 2016 HRS and the 2015 Consumptions and Activities Mail Survey. Descriptive statistics included the means for age: 67 (SD 9.54), education:13.85 (SD 5.89), and total cognition 16.86 (SD 3.11). The sample was predominantly Caucasian (78.3%), female (59.8%), and married (60.9%). / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2020. / FAU Electronic Theses and Dissertations Collection

This study investigated memory in children with temporal lobe epilepsy and the ability to discern hippocampal dysfunction with conventional memory tests that are typically used to detect more global memory impairment. All data was obtained retrospectively from the epilepsy surgery program at a local children’s hospital. The research population consisted of 54 children with intractable epilepsy of temporal onset, balanced across pathology types (with and without hippocampal disease) and other demographics. Each was given a clinical battery prior to surgical intervention, which included the WRAML/WRAML2 Verbal Learning subtest from which the dependent variables for this study were extracted. The research hypothesis had predicted that memory retention between verbal learning and recall would be worse for participants with pathology that included hippocampal sclerosis than for those with non-hippocampal temporal lobe pathology. A two-way mixed-design ANOVA was used to test the hypothesis, which allowed incorporation of variables of interest related to memory factors, pathology type, and hemispheric laterality, as well as their various interactions. There was a significant main effect for change in the number of words retained from the final learning trial to the delayed recall. Although the interaction between memory retention and pathology type was not statistically significant, the average of the memory scores as it related to pathology by side did show significance. Thus, results did not support the hypothetical relationship between retention and hippocampal function. However, additional exploratory analyses revealed that the final learning trial by itself was associated with hippocampal pathology, which applied only to those participants with left-hemisphere lesions. Logistic regression with the final learning trial correctly classified 74 percent of participants into the appropriate pathology category, with 81 percent sensitivity to hippocampal dysfunction. Mean participant memory scores were nearly one standard deviation below the normative mean for both delayed recall and total learning scaled scores, regardless of pathology type or lesion hemisphericity. Thus, while the conventionally used indices of the WRAML Verbal Learning test are useful for determining overall memory status, they are not specific to pathological substrate. The within-subject main effect showed an expected loss of information across the time of the delay, but overall the recall score showed no association with hippocampal functioning. This study revealed the possibility of measuring hippocampal function at statistically significant group levels using learning scores from a widely used measure of verbal memory, even in participants with intact contralateral mesial temporal structures. It also indicated that hippocampal structures do not play a role during recall measures given after a standard time delay. Data further demonstrated a role of the hippocampus for encoding and transferring information beyond short term/working memory into long term. During the learning process, the hippocampus appears to work in concert with short-term memory systems, but does not take over the encoding process until enough repetitions have occurred to saturate the working memory buffer. This research represents a small, yet important step forward in our understanding of the hippocampus, with potentially important implications for the future study of memory constructs and mensuration.

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