Dopamine Levels in the Brain of Rat Models of Human Rheumatoid Arthritis

Research Focus. Rheumatoid arthritis (RA) is a chronic, debilitating, autoimmune disease that causes the destruction of bone tissue and the articular structures of joints. At least 30% of RA patient populations have cognitive impairment. Acidic dopamine (DA) is the principal neuroimmunotransmitter that links the central nervous system and peripheral nervous system together. The aim of the present study was to determine the levels of DA and its two acidic metabolites: 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) in arthritic induced rats, and whether their levels vary across four different parts of the brain: amygdala (AMG), front cerebral cortex (CX), hippocampus (HIP), and cerebellum (CBL). Brain protein was also assessed. Materials and Methods. 3-month old male Lewis Rats (n=16) were randomized into either control (n=6) or treatment (n=10) groups. In the treatment group, arthritis was induced in the rats using Freund’s Adjuvant and all rats were sacrificed on day 28. Dopamine, DOPAC, and HVA levels were quantified using High Performance Liquid Chromatography technique while proteins were quantified using Bicinchroninic Acid (BCA) Protein Assay, in the four brain regions. Two-way ANOVA test was performed to determine whether brain regions, induce arthritis treatment or their interactions significantly influenced the levels of the analytes (at p\u3c0.05). Research Results/Findings. Levels of brain protein (C-reactive protein) were elevated in arthritic rats across all brain regions (p\u3e0.05). Dopamine and DOPAC levels were lower in arthritic rats than controls (p\u3e0.05). HVA levels were higher in arthritic rats compared to non-arthritic controls. Conclusions from Research. The present study has demonstrated that C-reactive protein, dopamine, DOPAC and HVA are involved in the neurophysiology of arthritis. RA patients can benefit from treatment with dopamine agonists. However, more studies are warranted to determine the effect of DOPAC and HVA levels in the brain on dopamine utilization in arthritis

How Did the Shift in Chilean Cultural Memory Between 1988 to 1998 Become Politically Salient for International Human Rights?

Senior Project submitted to The Division of Social Studies of Bard College

Emotion suppression reduces hippocampal activity during successful memory encoding

People suppressing their emotions while facing an emotional event typically remember it less well. However, the neural mechanisms underlying the impairing effect of emotion suppression on successful memory encoding are not well understood. Because successful memory encoding relies on the hippocampus and the amygdala, we hypothesized that memory impairments due to emotion suppression are associated with down-regulated activity in these brain areas. 59 healthy females were instructed either to simply watch the pictures or to down-regulate their emotions by using a response-focused emotion suppression strategy. Brain activity was recorded using functional magnetic resonance imaging (fMRI), and free recall of pictures was tested afterwards. As expected, suppressing one's emotions resulted in impaired recall of the pictures. On the neural level, the memory impairments were associated with reduced activity in the right hippocampus during successful encoding. No significant effects were observed in the amygdala. In addition, functional con- nectivity between the hippocampus and the right dorsolateral prefrontal cortex was strongly reduced during emotion suppression, and these reductions predicted free-recall performance. Our results indicate that emo- tion suppression interferes with memory encoding on the hippocampal level, possibly by decoupling hippo- campal and prefrontal encoding processes, suggesting that response-focused emotion suppression might be an adaptive strategy for impairing hippocampal memory formation in highly arousing situations

THE ROLE OF CONTEXTUAL VARIABLES IN INTRA- AND INTER-INDIVIDUAL COGNITIVE FLEXIBILITY

M.A

My way or no way: Impacto da familiaridade com a estratégia de regulação emocional na qualidade do processo regulatório em contexto de stress agudo

O presente trabalho teve como objetivo verificar se a eficácia das estratégias de regulação emocional depende da congruência entre as estratégias implementadas e o repertório individual de regulação emocional em um contexto de estresse social agudo. Levantou-se a hipótese de que os participantes a quem a quem se solicitasse o uso de estratégia à qual já estão habituados teriam regulação emocional mais eficiente em relação ao grupo cujas estratégias implementadas não sejam as próprias. Para isso, os participantes (N = 47) foram avaliados previamente no que se refere ao uso habitual de estratégias de regulação emocional - reavaliação cognitiva habitual ou supressão habitual - e distribuídos aleatoriamente para o uso de uma das duas estratégias - reavaliação cognitiva implementada ou supressão implementada - durante a execução das tarefas do Trier Social Stress Test (TSST). Para tanto, foi utilizada uma avaliação trimodal (i.e. fisiológica, subjetiva e comportamental), além de considerar o desempenho na tarefa. Os resultados confirmaram que o protocolo foi eficaz em induzir estresse nos participantes, verificado através de maior variabilidade da frequência cardíaca (parâmetro RMSSD), maior atividade eletrodérmica (através da média de respostas de condutância) e maior ansiedade estado. O mesmo não foi encontrado sobre os afetos positivos, desempenho e expressão facial das emoções, o que reforça o que tem sido demonstrado sobre a assincronicidade entre os sistemas emocionais. Sobre a hipótese, concluiu-se que a congruência entre estratégia de regulação emocional habitual e aplicada não é determinante para a eficiência no processo de regulação emocional independentemente da estratégia.This research aimed to verify if the effectiveness of emotional regulation strategies depends on the congruence between the implemented strategies and the individual emotional regulation repertoire in a context of acute social stress. It was hypothesized that participants who were asked to use the strategy they are already used to would have more efficient emotional regulation in relation to the group whose implemented strategies are not their own. For this, participants (N = 47) were previously evaluated for habitual use of emotional regulation strategies - habitual cognitive reevaluation or habitual suppression - and randomly assigned to use either of the two strategies - implemented cognitive reevaluation or suppression. implemented - while performing Trier Social Stress Test (TSST) tasks. For this, A three-dimensional evaluation methodology was used (i.e. physiological, subjective and behavioral), and the performance in the task. The results confirmed that the protocol was effective in inducing stress in the participants, verified by higher heart rate variability (RMSSD parameter), higher electrodermal activity (through average conductance responses) and higher state anxiety during the task. The same was not found about the positive affects, performance and facial expression of emotions, which reinforces what has been demonstrated about the asynchronicity between emotional systems. On the hypothesis, it was concluded that the congruence between habitual and applied emotional regulation strategy is not determinant for the efficiency in the emotional regulation process independently of the strategy

Plasticity in healthy old age : a multi-domain training approach

Aging has an impact on people’s social, cognitive, and physical functioning. Despite great individual variability, healthy aging occurs along with declines in the maximal performance of several cognitive abilities including spatial navigation and memory, visuomotor skills, and executive functions, while other abilities are spared or even improve. An increasing number of older adults fears age-related losses that affect quality of life and independent functioning. Therefore, maintaining cognitive abilities is of interest from both an individual’s perspective and from a societal one since the demographic change leads to the need of keeping older adults in the workplace. Plasticity refers to the malleability of cognitive and neural functioning. This malleability is preserved across the adult lifespan until very old age and is known to be exploited by training. Considerable scientific effort has been put into finding effective interventions to improve and stabilize cognitive and brain functioning during aging. However, evidence for domain-general and long-lasting improvements has been sparse, and the mechanisms of cognitive training are not well understood. The present thesis focuses on multi-domain training, a training approach that combines exercising cognitive, physical, and social abilities. Thus, it has the potential to increase each trained domain as well as the ability to orchestrate multiple domains. First, available multi-domain training studies are reviewed. This literature review concludes that previous multi-domain training approaches have not been significantly informative regarding the impact of a particular type of multi-domain training on transfer. To fill this gap, a novel training tool has been developed. This novel training tool, called “Hotel Plastisse”, is introduced secondly. “Hotel Plastisse” is an iPad-based training specifically designed to compare the simultaneous training of three cognitive functions (multi-domain training) to the training of each single cognitive function (single-domain training). The trained domains are clearly defined and separable from each other. Thereby, training-related improvements can be related to transfer in a theoretically informed way. Furthermore, the training environment is designed as a motivating learning environment in a virtual hotel, incorporating an adaptive difficulty algorithm and providing detailed feedback. These are design aspects that are increasingly recognized as critical in the training literature. Third, a cognitive training study examines near and far transfer of single-domain and multi-domain training. Eighty-four healthy older participants aged 64 to 75 years trained either inhibition, visuomotor function, or spatial navigation (single-domain training groups), or the simultaneous combination of these three functions (multi-domain training group). With respect to near transfer, the single-domain and the multi-domain training groups did not differ. With respect to far transfer, improvements on attentional control were more pronounced in the multi- domain training group than in the single-domain training group. Furthermore, independent of training group, individuals with lower baseline performance showed higher training-related change on the transfer test battery compared to individuals with higher baseline performance. Six months after training, training-related improvements remained stable. The findings show that multi-domain training enhances functions that involve handling several different tasks at the same time, which is an everyday challenge especially for older people. Fourth, functional brain network characteristics are compared between three groups of participants that differed with respect to their training history (multi-domain training group, visuomotor function training group, participants with no training history). One year after training, participants underwent high-density electroencephalographic (EEG) measurement to examine expertise-related functional connectivity and small-world network characteristics during performance on the multi-domain training task. The multi-domain training group performed significantly better than the visuomotor function training group and the control group (no training history). In addition, the multi-domain training group showed enhanced and more efficient functional connectivity in a task-related network encompassing visual, motor, executive, and memory-associated brain areas. Hence, the findings show expertise-dependent differences in performance and neural network characteristics even a year after training. Taken together, the thesis presents evidence for cognitive and neural plasticity in healthy older adults induced by a simultaneous multi-domain training. Training regimes that target older adults’ ability to handle several tasks simultaneously may enhance the probability for an overlap with different situations. Future studies should take methodological approaches that allow researchers to relate inter-individual differences to training progress and transfer. In addition, neuroimaging will lead to a better understanding of the neurobiological bases of plasticity. Well-informed experimental paradigms combined with sophisticated behavioral and neuroimaging data analyses will provide further insights into the mechanisms of training- induced plastic changes in healthy aging, and will thereby advance the development of effective interventions