Identification of the pathways that could be targeted to alleviate ageing-related cognitive decline is of prime importance. One of the most promising target mechanisms is connected to healthy dopaminergic ageing. Extant research suggest that women may exhibit less ageing-related dopamine (DA) decline compared to men, implicating that women may suffer less from dopamine-related cognitive decline. However, to date, shortage of empirical investigations limit firm conclusions of sex differences. In the present work it is hypothesized that: (i) women as compared to men exhibit less aging-related DA losses, and (ii) less aging-related decline of episodic memory (EM), and that (iii) sex differences in episodic memory might be mediated by differences in DA integrity. To that end, sex-related differences in D1-type dopamine receptor (D1DR) integrity and episodic memory were investigated in a healthy cohort of young to old participants (age 20 – 80, n = 180, 50% women) through whole-brain voxel-wise analysis and linear regression models. Firstly, the dorsal caudate was identified as the main region of the EM-D1DR interrelation. Secondly, a significant female advantage was found for EM and D1DR in ageing. Finally, no mediation effect by D1DR on the sex-EM interaction was found. These results indicate the presence of correlational relationships between sex, cognition and D1DR, in ageing. However, D1DR was not found to be the mediating factor in the observed correlations. Future research, preferably using longitudinal design, should further investigate the underpinnings of sex differences in D1DR and EM.

The purpose of this study was to examine the hypocrisy paradigm as an experimental alcohol intervention to determine if participants who complete the hypocrisy paradigm will experience a significant reduction in the number of negative consequences associated with their alcohol use, quantity and frequency of alcohol use, and average and peak eBAC compared to college students in the control condition. Participants were 53 college students randomly assigned to an experimental hypocrisy paradigm intervention or a control condition. Contrary to prediction, the hypocrisy paradigm was not found to be significantly different than the control condition. Exploratory analyses examining within-group differences were conducted. All outcome measures decreased from pre-intervention to follow-up within the hypocrisy paradigm condition. Future directions and implications are discussed.

Age differences in metamemory accuracy obtained for episodic memory – new information – compared to semantic memory – general knowledge information were compared in this study. Younger and older adults with no known cognitive impairments viewed pictures of famous faces for semantic memory and nonamous faces for episodic memory. Participants then viewed the faces again and had to provide the name for either semantic or episodic memory. After attempting recall for each face, participants made a Feeling-of-Knowing prediction about future recognition. Finally, each face was presented with the correct answer and three alternative answers. A gamma correlation was used to calculate prediction accuracy. Younger and older adults were equally accurate at predicting their recognition for semantic and episodic memory. The findings demonstrate that using the same materials and a within-subjects design, older adults do not show deficits in metamemory accuracy, even when predicting a type of memory that is typically impaired with age.

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Rationale: Individuals with addictive disorders commonly exhibit a shortened temporal window, which interferes with treatment focusing on long-term sobriety. Episodic Future Thinking (EFT) involves generating personalized cues related to anticipated, positive events at various future time points. EFT has been shown to reduce the reinforcing value of addictive substances; however, this has only been shown in non-treatment samples. Purpose: To examine the feasibility, cumulative, and sustained effects of implementing EFT in a treatment seeking addiction sample over a 1-week protocol on decision-making and alcohol motivation. Methods: Twenty-eight treatment seeking individuals were randomly assigned to either undergo an EFT intervention or a control Episodic Recent Thinking (ERT) protocol. Assessments were completed at baseline, end of week 1, and a 1-week follow-up. Measures included a delay discounting task, hypothetical alcohol purchase task, clinical outcome measures, and cognitive mechanism measures. Results: There were significant reductions in alcohol demand indices, delay discounting rates, and an increase in mindful attention awareness after both acute and extended exposure to EFT. Furthermore, the EFT group showed greater reductions compared to the ERT group after extended exposure to their cues. Conclusion: The results suggest that early implementation of EFT in a treatment seeking addiction sample is beneficial to counteract motivating factors for relapse. This study lays the foundation for future clinical trials for EFT as a supplemental therapy for addictions treatment. / Thesis / Master of Science (MSc) / People with substance use disorders have a significantly shortened time perspective compared to healthy controls. This means that these individuals struggle with thinking about future events beyond several days to a week. Shortened time perspective can be a significant barrier to addiction treatments that typically focus on long-term positive benefits of sobriety or low-risk use. This study examined whether mindful thinking about future events impacted decision-making and motivation for alcohol and drugs. The study used an experimental protocol known as Episodic Future Thinking (EFT) that involves participants interacting with personalized cues related to positive future events. Prior research using EFT in addiction samples has found that interacting with future cues significantly increases delay of gratification, reduces cigarette use, and decreases reinforcing value of alcohol. In this study, we recruited 28 participants with an alcohol use disorder (AUD). Participants practiced EFT training over a two-week protocol. We tested decision making, alcohol craving, and other variables following a single EFT protocol, and changes in these measures over repeated practice. We found significant changes in alcohol craving, decision making, and mindfulness awareness. The study provides proof-of-concept for using EFT in an AUD treatment population and lays the foundation for future clinical trials of EFT as a complement to existing addiction treatments.

Physical inactivity is a major contributor to increased disease prevalence and reduced quality of life. Measuring behavioral economic demand for exercise may enable more effective physical activity intervention development. In study one, we developed the leisure-time-as-price exercise purchase task (LT-EPT), wherein participants (n = 175) indicate hypothetical likelihood to trade leisure time for access to exercise time. We observed weak to moderate correlations between demand indices (Q1%, α, BP1, and Pmax) generated from the LT-EPT and self-reported leisure and exercise time, demonstrating initial validation of the LT-EPT. In study two, we examine the effect of episodic future thinking (EFT; vivid, personalized prospection of future events) in adults not meeting physical activity guidelines (n = 127) on demand for exercise and delay discounting (sensitivity to delayed rewards). We observed reduced delay discounting in participants randomized to engage in EFT, but no difference between EFT and health information thinking (HIT) controls. In study three, we further examined the effect of EFT on demand for exercise in adults with type 2 diabetes and obesity participating in a 24-week randomized controlled trial (n = 71). All participants engaged in a multicomponent behavioral intervention focused on weight loss and glycemic control; additionally, participants were randomized to engage in EFT or HIT thrice daily beginning in week 3. We measured demand for exercise and delay discounting (among other outcomes) at weeks 0, 8, and 24, observing no differences between EFT or HIT groups in demand indices (Q1%, α) or delay discounting at any time point. In conclusion, early evidence suggests that the LT-EPT may be a valid method to measure behavioral economic demand for exercise; however, EFT may not be an effective intervention to increase demand for exercise. / Doctor of Philosophy / Physical inactivity poses a significant threat to our well-being, contributing to increased disease rates and a diminished quality of life. This dissertation details a novel method to measure how people value exercise and the effect of a behavioral intervention to increase exercise valuation. In the first study, we introduce the leisure-time-as-price exercise purchase task (LT-EPT), a tool designed to gauge individuals' willingness to trade leisure time for exercise time (i.e., exercise demand). Initial results show promising correlations between LT-EPT metrics and self-reported leisure and exercise time, providing a foundation for its potential as a valuable measurement tool. The second study examines the impact of episodic future thinking (EFT), a technique involving vivid and personalized visualization of future events, on exercise demand. While participants engaging in EFT showed increased preference for larger, delayed rewards over smaller, sooner rewards (i.e., reduced delay discounting), no significant difference was found between EFT and the health information thinking (HIT) control in terms of exercise demand. The third study expands our investigation to adults with type 2 diabetes and obesity undergoing a 24-week intervention. All participants engaged in a comprehensive behavioral program, while half were randomized to engage in EFT or HIT three times per day. No discernible differences were observed in exercise demand or delay discounting at any measurement point. In summary, our findings suggest that the LT-EPT may be a valid measure of exercise demand. However, the effectiveness of EFT in increasing demand for exercise remains inconclusive. These insights contribute to the ongoing efforts to develop more targeted and impactful interventions for promoting physical activity and improving overall health.

Alcohol use disorder is common, and treatments are currently inadequate. Some of the acute effects of alcohol on the brain, such as altering the decision-making and future thinking capacities, mirror the effects of chronic alcohol use. Therefore, interventions that can address these shortcomings may be useful for reducing the negative effects of alcohol use disorder in combination with other therapies. The signature of those interventions may also be evident in the signature of large-scale, dynamic brain networks, which can show whether an intervention is effective. One such intervention is episodic future thinking, which has been shown to reduce delay discounting and orient people toward pro-social, long-term outcomes. To better understand decision making in high-risk individuals, we examined delay discounting in an adolescent population. When the decision-making faculties were challenged with difficult choices, adolescents made decisions inconsistent with their predicted preference, complemented by increased brain activity in the central executive network and salience network. Using these results and the hypothesis that the default mode network would be implicated in future thinking and intertemporal choice, we examined the neural effects of a brief behavioral intervention, episodic future thinking, that seeks to address these impairments. We showed that episodic future thinking has both acute and longer-lasting effects on consequential brain networks at rest and during delay discounting compared to a control episodic thinking condition in alcohol use disorder. Our failure to show group differences in default mode network prompted us to scrutinize it more carefully, from a position where we could measure the ability to self-regulate the network rather than its resting-state tendency. We implemented a real-time fMRI experiment to test the degree to which people along the alcohol use severity spectrum can self-regulate this network. Our results showed that default mode network suppression is impaired as alcohol use disorder severity increases. In the process, we showed that direct examination of resting-state networks with these methods will provide more information than measuring them at rest alone. We also characterized the default mode network along the real-time fMRI pipeline to show the whole-brain spatial pattern of regions associated and unassociated with the network. Our results indicate that resting-state brain networks are important markers for outcomes in alcohol use disorder and that they can be manipulated under experimental conditions, potentially to the benefit of the afflicted individual. / Doctor of Philosophy / Alcohol is the most widely-used mind-altering substance in the United States. Even though most people do not develop a problem with alcohol use, many people will at some point develop drinking patterns that classify as an alcohol use disorder. Brain damage from drinking can come from the toxicity of alcohol, but also as a result of behaviors associated with drinking too much, including injury, violence, accidents, and other health-related issues. Interventions at the behavioral level can be effective at curbing drinking patterns before damage accrues, and a better understanding of those interventions at the level of the brain may make them more effective. This work investigated the decision-making processes and the ability to think clearly about the future, two faculties that begin to become diminished in alcohol use disorder. In our first set of studies, we tested a brief behavioral intervention called episodic future thinking, which helps people orient themselves away from short-term rewards like alcohol and toward long-term goals that could happen if they stopped drinking as much. We showed that one hour-long, intensive session produced changes in the connectivity between the prefrontal cortex and the lower brain. We also generated data in a long-term experiment suggesting repeated reminders of the episodic future thinking intervention produce changes in large-scale brain networks that are disrupted in substance use disorders. In a separate set of experiments, we showed that people can gain control over one of these networks, called the default mode network, to the point of being able to control a brain-machine interface just by following simple instructions. However, we demonstrated that the degree to which someone can control this brain activity was associated with their drinking severity. In other words, the more people drank, in terms of volume and frequency, the less control they had over their own brain activity. This finding is important because many researchers have shown that activity in this brain region is related to many psychopathologies, including substance use disorders. Other researchers have been developing ways in which the ability to control this brain activity can be trained. While we did not find evidence of a training effect in a small group of healthy people (5), it may be the case that people impaired by alcohol use disorder can improve through practice or through cutting back on drinking. Ultimately, we hope that the research presented here will help to guide the development of treatments for alcohol use disorder to be more effective.

Yes / It has been suggested that the isolation rearing paradigm models certain aspects of schizophrenia symptomatology. This study aimed to investigate whether isolation rearing impairs rats’ performance in two models of cognition: the novel object recognition (NOR) and attentional set-shifting tasks, tests of episodic memory and executive function, respectively. Two cohorts of female Hooded-Lister rats were used in these experiments. Animals were housed in social isolation or in groups of five from weaning, post-natal day 28. The first cohort was tested in the NOR test with inter-trial intervals (ITIs) of 1 min up to 6 h. The second cohort was trained and tested in the attentional set-shifting task. In the NOR test, isolates were only able to discriminate between the novel and familiar objects up to 1-h ITI, whereas socially reared animals remembered the familiar object up to a 4-h ITI. In the attentional set-shifting task, isolates were significantly and selectively impaired in the extra-dimensional shift phase of the task (P < 0.01). Rats reared in isolation show impaired episodic memory in the NOR task and reduced ability to shift attention between stimulus dimensions in the attentional set-shifting task. Because schizophrenic patients show similar deficits in performance in these cognitive domains, these data further support isolation rearing as a putative preclinical model of the cognitive deficits associated with schizophrenia.

Leader prototypes are our expectations for attributes a leader should possess, and these prototypes guide our perceptions and judgments of others with regard to leadership. This dissertation uses a connectionist perspective of leadership to investigate differences in perceptions and judgments of male and female leaders, and provides the first empirical test of Hogue and Lord's (2007) model for gender bias in leadership. In Study 1, leader prototypes are investigated as the mediating process through which perceptions of male and female leaders differ. Furthermore, leader and perceiver gender as investigated as contextual and person factors which impact the accessibility of leader prototypes, thus consequently impacting perceptions and judgments of leaders. The use of leader prototypes in remembering a leader's past behaviors reflects the use of a semantic memory system, where the leader behaviors recalled are influenced by our expectations of the leader, rather than whether the leader actually demonstrated those behaviors. Thus, masculine leadership behaviors demonstrated by a female leader may be discounted, and the leader behaviors recalled may be influenced by gender roles. Study 2 investigates an episodic memory intervention to increase the memory accuracy of leader behaviors as a means to reduce biases in judgments of female leaders. Overall, Study 1 results suggest that activation of agentic attributes; specifically tyranny and masculinity are impacted by leader gender, such that the accessibility of those attributes was higher for male leaders. Contrary to predictions, female leaders did not result in greater accessibility of communal attributes in the leader prototype. No impact of perceiver gender was seen on this mediation process. Subsequently, accessibility of these attributes impacts participants' perceptions and judgments of leadership. Study 2 results indicate behavior recognition accuracy of communal behaviors drives participants' negative perceptions and judgments of the female leader. Limitations and directions for future research are discussed. / Ph. D. / Gender bias in leadership perceptions and judgments of leaders is pervasive, and the reasons for this gender bias have been studied from a variety of perspectives. Hogue and Lord (2007) propose that this gender bias can be explained through our leader prototypes, which are our expectations for attributes a leader should have. Various situational and person factors differentially impact the accessibility of attributes in the leader prototype, consequently impacting our perceptions and judgments of leaders. In Study 1, I investigate leader and perceiver gender as factors that impact accessibility of leader prototype attributes. In Study 2, I investigate a memory system intervention targeting the use of episodic memory instead of the default semantic memory, in an attempt to increase the recognition accuracy of a leader‟s behavior, and thus reduce biases in judgments of the leader. Results, limitations, and avenues for future research are discussed.

Transfer-appropriate processing (TAP) proposes that retrieval success is based on the match between processing at encoding and retrieval. We propose that the processing described by TAP determines the contextual cues that are encoded with an event. At retrieval, the presence or absence of contextual cues matching the encoding cues will influence success. To implement these principles as a strategy to improve memory, the nature of future retrieval processing or cues must be known during encoding. As this is unlikely in real-world memory function, we propose that increased encoding variability – increasing the range of encoded cues – increases the likelihood of TAP when the retrieval scenario is unknown. The larger the set of encoded cues, the more likely those cues will recur during retrieval and therefore achieve TAP. Preliminary research in our lab (Diana, unpublished data) has found that increased encoding variability improves memory for item information in a novel retrieval context. To test whether this benefit to memory is due to the increased likelihood of TAP, the current experiment compared the effects of encoding variability under conditions that emphasize TAP to conditions that reduce TAP. We found main effects of encoding variability and TAP, but no interaction between the two. Planned comparisons between high and low variability encoding contexts within matching and non-matching retrieval contexts did not produce a significant difference between high and low variability when encoding-retrieval processing matched. We conclude that further studies are necessary to determine whether encoding variability has mechanisms that benefit memory beyond TAP. / M.S. / It is well accepted within the episodic memory literature that successful memory retrieval is often driven by context cues. Specifically, the cues that are stored with the memory of the event. To develop a better understanding of how episodic memory works, we must understand how manipulating context cues changes memory performance. One way to investigate the effects of context manipulation is using encoding variability, which refers to the amount of variability (i.e., change) in context cues from one repetition of an item or event, to the next. Preliminary research in our lab (Diana, unpublished data) has found that increased encoding variability improves memory retrieval in a novel context, but it is unclear why this is the case. We proposed that the mental processing described by transfer-appropriate processing (TAP) – a principle stating that memory retrieval success is determined by the match, or overlap, between the mental processing at encoding (i.e., memory formation) and memory retrieval – determines the contextual cues that are stored with the memory at encoding. We hypothesized that encoding variability works even when TAP has already been achieved by matching the processing and cues at encoding to those at retrieval. Alternatively, we hypothesized that encoding variability works by specifically achieving TAP, so that encoding variability is only helpful when the encoding and retrieval contexts do not match. Results indicated partial support for the alternative hypothesis, suggesting that encoding variability works by achieving TAP. However, these results were not sufficiently conclusive, and it is likely that there are other mechanisms that allow for encoding variability to improve memory. This study establishes the groundwork for future work examining encoding variability and its effects on memory.