The objective of this research was to investigate the extent to which context contributes to the learning and recognition of episodic auditory-verbal memories (EAM). By combining the Hebb repetition paradigm (HRP) and continuous recognition paradigm (CRP), I capitalized on the advantages of both while manipulating the context in which EAM were retrieved. Through repetition, participants learned sequences of pseudowords in which word order and speaker were varied. A recognition test of either a pseudoword (Experiment I) or the speaker of a pseudoword (Experiment II) revealed temporal and sensory context effects. Results showed that the encoding manipulation did not impact short-term memory but did have an effect on long-term learning. This research helped to clarify the role of context in EAM in both short- and long-term memory, as well as added to the current literature of HRP and CRP. Future directions are discussed.

Although there has been over a century of research on memory and consolidation, there remains no consensus with respect to the nature of episodic memories over time. This study tests two prominent theories (Standard Consolidation Theory and Trace Transformation Hypothesis), which make opposing predictions as to the quality of remote episodic memory, by investigating memories for film clips. Using true/false questions to test recall immediately, 3 days, and 7 days after encoding, these experiments demonstrate that details (both perceptual and story-line details) are lost, while the gist of memories is maintained over time. These data also suggest that gist and detail may be maintained independently in the brain. These results broaden our understanding of recent and remote memory, and provide support for the transformation view of consolidation. In the future, the transfer of this paradigm to neuroimaging will allow us to investigate the neural basis of episodic memory over time.

Although there has been over a century of research on memory and consolidation, there remains no consensus with respect to the nature of episodic memories over time. This study tests two prominent theories (Standard Consolidation Theory and Trace Transformation Hypothesis), which make opposing predictions as to the quality of remote episodic memory, by investigating memories for film clips. Using true/false questions to test recall immediately, 3 days, and 7 days after encoding, these experiments demonstrate that details (both perceptual and story-line details) are lost, while the gist of memories is maintained over time. These data also suggest that gist and detail may be maintained independently in the brain. These results broaden our understanding of recent and remote memory, and provide support for the transformation view of consolidation. In the future, the transfer of this paradigm to neuroimaging will allow us to investigate the neural basis of episodic memory over time.

­­­Recent brain scan research has found evidence of reactivation in brain regions that suggest a reactivation of the whole experience for the subject trying to remember. Such a reactivation is seen to represent a multimodal integration of the memory representation in the brain. The purpose of the study was to test the existence of audiovisual integration in episodic memory. This was done by comparing reaction times when audiovisual information was old, new or both old and new. Results indicated quicker rejection when there was both old and new information presented in comparison to when information was all new, indicating a reactivation of the whole experience of the presentation in the learning phase, i.e. a facilitation process based on audiovisual integration in episodic memory. An extension of the study could be to increase the retention interval testing for a different type of consolidation.

Patients with dementia due to Alzheimer's disease (AD) tend to exhibit impairments in in their episodic memory. In yes-no tests of recognition memory, patients with AD often display liberal response bias, a stronger tendency to recognize unstudied items as already-studied "old" items. Such tendency is believed to be related to false memory, which can decrease the quality of life in many AD patients. In this study, we analyzed the effect of different instructional manipulations within yes-no recognition memory task on response bias. Younger healthy adults, older healthy adults and one AD patient were evaluated for recognition memory performance and response bias in three different conditions of instructional manipulation. In each session separated by a week-long interval, participants were shown 120 words to study and 240 words, half of which were studied items, to be tested for recognition memory. Instructional manipulation was added in the testing phase of each condition. In one session, the participants were asked if the words were old, studied items; in another session, they were asked if the words were new, unstudied items; finally in the third session, participants were asked to identify if the words were either old or new. Our findings corroborated previous studies by observing liberal response bias in AD and moderately conservative response bias in health adults. We found that the instructional manipulations did not have a significant effect on response bias in either control group while the effect in the AD patient was inconclusive.

A healthy memory is essential to personal identity, completion of everyday tasks, and social acceptance. As factors such as age and illness threaten this key aspect of life, scientific and commercial attention has shifted to software, pharmaceuticals, and medical devices that help stave off inevitable memory decline. There is evidence suggesting that changes in lifestyle similarly work to improve memory. Mindfulness meditation, which is a practice rooted in the spiritual beliefs of Buddhism, has emerged as a promising technique to improve facets of cognition, including memory, as well as to change structures in the brain. Pattern separation is a key process of episodic memory that allows one to keep similar memories distinct. In this study, we evaluate the efficacy of a 4-week mindfulness training program on visual object pattern separation against an active creative writing control intervention and find that mindfulness meditation improves pattern separation and promotes changes in hippocampal brain structures.

Thesis advisor: Scott D. Slotnick / Sex differences exist in both brain anatomy and neurochemistry (Cahill, 2006). Many differences have been identified in brain regions associated with long-term memory including the dorsolateral prefrontal cortex, hippocampus, and visual processing regions (Andreano & Cahill, 2009). There is, however, a paucity of research investigating whether and how these differences translate into differences in functional activity. Part 1 investigated sex differences in the patterns of functional activity in the brain during spatial long-term memory, item memory, memory confidence, and false memory. In addition, a meta-analysis was conducted to identify whether there were consistent sex differences in the brain across different long-term memory types. Part 2 determined whether there were sex differences in the patterns of functional connectivity in the brain during spatial long-term memory. Specifically, differences in functional connectivity between the hippocampus and the rest of the brain in addition to the thalamus and the rest of the brain were investigated. Finally, Part 3 investigated whether the observed differences in the patterns of activity (identified in Chapter 1) had sufficient information to classify the sex of individual participants. The results of Part 3 argue against the popular notion that the average female brain and average male brain are not significantly different (Joel et al., 2015). More broadly, the studies presented in this dissertation argue against the widespread practice of collapsing across sex in cognitive neuroscience. / Thesis (PhD) — Boston College, 2021. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Psychology.

Thesis advisor: Maureen Ritchey / Regulating negative emotions that arise while recalling an unpleasant event presents a persistent challenge. As a reconstructive process, recall offers an opportunity to ease the burden of repeated regulation by updating negative memories, with the potential for long-term reductions in the negative affect associated with a memory. However, little is known about the recall-related brain processes that support lasting effects of emotion regulation on episodic memories. Across three studies, the current project examined the behavioral and neural correlates of regulating emotionally negative memories. First, a stimulus database of real-life news videos optimized for studying naturalistic emotional memory was developed. Then, the behavioral effects of two emotion regulation strategies, memory reappraisal and memory suppression, were tested. Finally, functional magnetic resonance imaging (fMRI) was used to investigate the brain processes associated with lasting reappraisal-related changes in memory valence. We found that reappraisal was associated with lasting reductions in the negative valence of naturalistic memories, whereas suppression had no effect on memory valence. We also found that recall-related activity in lateral occipital cortex was associated with a reappraisal-mediated reduction in negative valence 24-hours after reappraisal. These results suggest that brain processes involved in the initial retrieval of negative content also support the emotion regulation of those memories, consistent with research showing that memory reactivation is critical for robust memory updating. / Thesis (PhD) — Boston College, 2022. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Psychology.

Episodic memory is a critical component of human cognition. Episodic memory involves recollection of the contextual details surrounding an event, the capacity for mental time travel of past and future events, and is characterized by the subjective awareness that an event has been personally experienced. It is fundamental to our understanding of this complex memory system to examine how episodic memory emerges during the course of development. The present investigation explored the developmental improvement in episodic memory processing assessing recollection of factual information and the source of this information (i.e., source memory) between early to middle childhood. The electrophysiological (EEG) correlates of fact and source memory processing and measures of executive function were also examined as potential sources of variation in episodic memory. The focus of Study 1 was to examine source memory development in early childhood in a sample of 4- and 6-year-olds. Results revealed that older children were better able to recall both fact and source information. Source memory measures were correlated to early executive ability, namely measures of working memory, inhibitory control and set-shifting. Frontal EEG accounted for unique variation in fact recall but not source recall, whereas temporal EEG did not predict fact or source recall performance. The focus of Study 2 was to examine source memory development in middle childhood in a sample of 6- and 8-year-olds. Older children were better on fact recall, but both ages were comparable on source recall. Frontal EEG uniquely predicted fact recall performance beyond the contribution of age and language. Both frontal and parietal EEG and executive function predicted variation in source recall performance. In contrast, temporal EEG did not uniquely predict fact or source recall performance. Lastly, Study 3 was a longitudinal investigation of source memory between early and middle childhood. Although age-related increases in performance were evident, Time 1 and Time 2 source memory measures were not correlated. This investigation contributes to our understanding of the developmental changes in source memory processing between early and middle childhood, and identifies that patterns of frontal and parietal brain activity and executive function skills contribute to early episodic memory formation. / Ph. D.

Episodic memory refers to context based explicit memory and shows vast improvements during middle childhood. In this study, episodic encoding was manipulated using stimuli that were hypothesized to require active or passive processing. Nine to eleven-year-old children were presented with a recall task using lower resolution (active processing) and clear (passive processing) images. It was hypothesized that children would recall more low resolution images than clear images. Executive function ability was also assessed to investigate possible contributions to performance. Furthermore, this study investigated whether frontal and temporal brain electrophysiology predicted unique variance in recall performance. Results suggested that overall there were no performance differences between low resolution and clear images; however, differences may exist within task blocks. Electrophysiology at temporal scalp locations and executive functions predicted unique variance in memory task performance. Specifically, set-shifting and working memory predicted a unique amount of variance in memory task performance. The results suggest that explicit memory may require certain executive processes more than others, and that active and passive processing may enhance this effect. / Master of Science