[Truncated abstract] Obesity is rapidly increasing in prevalence and has significant physical and mental health implications. Stress, a general term referring to factors indicative of psychological strain such as depression and anxiety, has been identified as both a cause and consequence of weight gain and obesity in some individuals. In previous research, overeating in response to stress has been investigated as either a means of mood regulation or as a response to strict dietary restraint. Cortisol, a steroid hormone that increases in response to stress, has also been linked with increased food intake in both animal and human studies. Thus, cortisol may be an additional factor contributing to overeating and weight gain in response to stress. If stress does lead to overeating and weight gain, it is also likely that stress will inhibit attempts made by obese individuals at weight loss. The first study of this thesis was a repeated measures treatment study in which the associations of stress and cortisol levels with baseline body mass index and subsequent weight loss were investigated among females participating in a cognitive behavioural weight management programme. A cross-sectional analysis prior to treatment commencement showed that the association of stress and depression with body mass index was moderated by the severity of obesity. Dichotomous thinking, a cognitive style in which events are viewed in polarised 'black and white' terms, mediated the associations of both depression and eating disorder symptomatology with BMI. ... The second study of this thesis was a controlled laboratory-based examination of food intake following an acute psychological stressor. It was hypothesised that high baseline levels of psychological stress, such as depression and anxiety, would be associated with greater increases in negative mood and cortisol levels in response to the acute stressor, both of which, in turn, would be associated with greater food intake. Contrary to the hypothesis, baseline levels of psychological stress were not associated with the extent to which negative mood and cortisol levels increased following the acute stressor. The extent to which negative mood, but not cortisol, increased following acute stress was significantly positively associated with food intake. The results do not support the hypothesis that high cortisol levels are predictive of increased food intake in human females, although the results may have been affected by the broad participant inclusion criteria. The results suggest that increases in negative mood lead to increases in food intake, although it is argued that this is unlikely to be a general effect and suggestions for future research are made. The overall aim of this research was to examine whether stress and cortisol were associated with weight status, acute changes in eating behaviour and changes in weight in the medium-term. The results are discussed in relation to this aim, wth particular focus on the differences between treatment-seeking and community samples, implications for the treatment of obesity (especially when the individual is also experiencing high levels of depression), prevention of weight gain and possible future studies of the effects of stress and depression on weight change and eating behaviour.

Thesis (Ph.D.)--Fairleigh Dickinson University, 1998. / Source: Dissertation Abstracts International, Volume: 59-10, Section: B, page: 5592. Chairperson: Neil A. Massoth. Includes bibliographical references (leaves [99]-111).

No description available.

Gotukola (Centella asiatica L. Urban) (Apiaceae), its extracts and the pure compound asiaticoside were studied for anxiolytic activity in thirteen standardized rat trials. High performance liquid chromatography (HPLC) was used to conduct the phytochemical analysis. Among different models tested, the most promising positive response for anxiolytic activity was observed in the elevated plus maze test conducted with: (a) whole plant materials, (b) ethyl acetate and methanol fractions and (c) asiaticoside. The results show for the first time that asiaticoside and triterpene enriched fractions of gotukola have anxiolytic effects in animal models. Therefore, they are recommended for clinical trials. The findings of this study also support the ayurvedic use of gotukola for psychiatric disorders. Other supplementary investigations conducted show that methyl jasmonate and full sunlight enhance the expression of asiaticoside in gotukola plants. The stolon explants were more successful compared to the leaf explants in in vitro propagation of gotukola.

That odors play a significant role in subhuman intraspecies communication is a generally accepted fact explained in part by the production and reception of species specific pheromones. Recently the effects of human produced odors on human communication have received research attention, particularly in the communication of such biological phenomena as menstruation onset and gender assignment. Again pheromones have been posited as the explanatory mechanism. Whether a pheromone-like odor cued process exists in the communication of human emotions is unknown, though a number of anecdotal accounts of odor-emotion interactions suggest that such may be the case. It was the purpose of the present study to investigate a possible odor-emotion interaction by determining whether humans could differentially detect other humans' odor collected under varying emotional conditions.

The purposes of the study were to examine the psychosocial variables of hostility and social support, and their independent relationships with resting physiological levels and chronic pain symptoms, and to examine the independent relationships of chronic pain chronicity and social support with hostility.

Many experiences in our daily lives are temporally structured, enabling prediction of events that will occur in the future. We can anticipate upcoming subway stops during our daily commute, or plan multiple steps ahead when cooking a meal we have made many times. Although sequences of events in daily life can be multiple steps long, like the stations along a subway line, it is unknown how extended temporal structure enables predictions over multiple timescales. The three studies reported in this dissertation investigate how extended temporal structure is flexibly represented in memory and in the brain to guide multistep prediction. Chapter 1 demonstrates that memory for temporal structure is enhanced with memory consolidation, enabling more efficient judgements about predictable future events over time. Chapter 2 shows that temporal structure is represented bidirectionally and hierarchically across the hippocampus and across visual regions during multistep anticipation. Finally, Chapter 3 addresses how internal models are updated when regularities in our environment change: the hippocampus rapidly reconfigures memories of temporal structure in response to learning new information, which supports the planning of novel trajectories. Together, the studies presented in this dissertation shed light on how we represent internal models of the world that span multiple timescales to guide adaptive behavior.

No description available.

Research in both humans and animals demonstrates that nicotine addiction is a complex disorder that can be influenced by several factors. For instance, individual differences in genetics can impact sensitivity to nicotine and can modulate the severity of nicotine withdrawal. Although nicotine alters cognitive processes such as learning and memory, it remains unknown whether genetic variability modulates the effects of nicotine on these cognitive functions. Thus, the present study characterized the effects of acute, chronic, and withdrawal from chronic nicotine administration on fear conditioning in 8 strains of inbred mice. Furthermore, nicotine withdrawal-related changes in somatic signs and the elevated plus maze were examined because nicotine withdrawal consists of multiple symptoms that can include increased somatic signs and increased anxiety. Strain-dependent effects of acute nicotine and nicotine withdrawal on contextual fear conditioning were observed in several inbred strains. However, the effects of acute nicotine on contextual fear conditioning were not associated with the effects of nicotine withdrawal, suggesting that different genetic substrates may mediate these two effects. Nicotine withdrawal produced few changes in somatic signs and exploration in the elevated plus maze. Overall, these data demonstrate that genetics contribute to variability in the effects of acute nicotine and withdrawal from chronic nicotine treatment on contextual fear conditioning. The identification of genes that may alter the effects of nicotine on cognition may lead to more efficacious treatments for nicotine addiction. The age during which nicotine use begins is a second factor that may influence the severity of nicotine addiction. Pre-adolescence and adolescence are periods of development that have an increased risk for developing addiction to nicotine. Nicotine alters contextual learning, but it remains unknown whether these effects are age-dependent. Therefore, the present study examined the effects of acute, chronic, and withdrawal from chronic nicotine on fear conditioning in pre-adolescent, adolescent, and adult mice. In addition, we investigated whether exposure to chronic nicotine during pre-adolescence or adolescence has long-lasting effects on contextual learning that occurs during adulthood. Pre-adolescent mice were more sensitive to the effects of acute nicotine than adolescents and adults, showed enhanced contextual learning when treated with high doses of chronic nicotine, and were less sensitive than adolescents and adults to nicotine withdrawal-related deficits in contextual learning. In contrast, adolescent mice were less sensitive to the effects of acute nicotine on contextual learning than pre-adolescents and adults and were more sensitive to nicotine withdrawal-related deficits in contextual learning relative to pre-adolescents and adults. Chronic nicotine exposure during pre-adolescence or adolescence also produced long-lasting impairments in contextual learning that were observed during adulthood, whereas adult chronic nicotine exposure had no effect on fear conditioning. Together, these data suggest that pre-adolescent and adolescent nicotine exposure has both short-term and long-term effects on contextual learning that may play an important role in the development and maintenance of nicotine addiction. / Psychology

Despite the common co-occurrence of the two main pathological processes in aging, vascular disease and Alzheimer's disease (AD), they are often examined in isolation. Increasing evidence of a mutually enhancing relation between these processes is supported by common risk factors including hypertension and diabetes. Therefore, both processes must be considered in characterizing the cognitive performance of older adults, particularly given high rates of vascular disease. The heterogeneity of cognitive deficits has not been systematically examined in older adults with vascular disease. In a large sample of older adults (N = 359, Mage= 74.7) with increased vascular risk associated with cardiac disease, classes of participants were identified using latent class analysis (LCA) based on their performance across neuropsychological measures of executive functions and episodic memory. The cognitively-defined classes were compared on neuroimaging variables including white matter lesion (WML) and hippocampal volumes in 203 participants and on vascular risk quantified by Framingham score in 187 participants. LCA on the cognitive variables supported a three-class model, with Class 3 (intact; n = 178) showing relatively intact cognitive test scores compared to the other classes and Classes 1 (mildly impaired; n = 136) and 2 (dysexecutive; n = 42) demonstrating uniformly low scores, with Class 2 showing the lowest and most impaired scores on two executive measures (Trails B and Mental Control). Follow-up analyses found that differences between classes on WML and hippocampal volumes did not reach statistical significance, although a trend was observed in WML volumes (p = .12) with greater levels of this pathology in Class 2 (dysexecutive). Significant differences between the classes on vascular risk were revealed, with Class 2 showing significantly higher Framingham scores (p =.02). These findings suggest meaningful heterogeneity in the cognitive presentation of older adults with increased vascular risk, with deficits in executive functions associated with potentially modifiable vascular risk factors/cerebrovascular disease. / Psychology