Emotion attribution and memory in the ageing brain

Episodic memory is influenced by emotions and ageing. While emotional events elicit superior memory than neutral ones, older adults (OA) are better in shifting the valence of an episode to make it more positive. This thesis investigated the interaction between episodic memory, emotion and ageing using behavioural and event-related potentials measures. The first aim was to identify which steps in the memory process are affected by emotion and ageing. Experiment 1 showed that emotion influences encoding, and ageing influences retrieval. Experiment 2 showed that prestimulus encoding-related activity is influenced by the time available to process the upcoming emotional stimulus, suggesting that preparatory activity is a flexible, but effortful mechanism. The second aim was to use a novel evaluative conditioning procedure to investigate how neutral information acquires emotional valence and is encoded and retrieved by younger adults (YA) and OA. Participants created emotional or neutral sentences with neutral words and completed memory and likeability tasks. Experiments 3 and 4 revealed that spontaneous emotion attribution is influenced by personality traits and elicits stronger likeability changes than forced attribution. Experiments 5 and 6 showed that YA and OA can change their feelings about neutral information by attributing positive emotions. The likeability changes survive a one-week delay and are related to source memory for the attributed emotion. Experiment 7 showed that retrieval of positive emotions elicited brain activity usually related to imagery. In conclusion, emotion attribution and its relationship with memory are preserved in OA, being affected by spontaneity and individual differences. The link between likeability changes and memory may be related to the use of imagery. This thesis enhances the understanding of how episodic memory and its brain correlates are influenced by ageing when the to-be-retrieved information is intrinsically emotional or has acquired emotionality

Influência da valência emocional de estímulos na memória operacional visuo-espacial de humanos e macacos-prego (Cebus libidinosus)

Dissertação (mestrado)—Universidade de Brasília, Instituto de Ciências Biológicas, Departamento de Ciências Fisiológicas, Programa de Pós-Graduação em Biologia Animal, 2013.O compartilhamento de estruturas cerebrais pelos circuitos neurais relacionados ao processo mnemônico e ao sistema límbico faz da emoção um dos principais moduladores da memória. Expressões faciais são consideradas as mais importantes manifestações emocionais em primatas humanos e não-humanos. Este trabalho objetivou verificar a influência das valências emocionais (positivo, negativo, neutro) de estímulos faciais no desempenho de humanos e macacos-prego e na atividade elétrica cortical de humanos em um teste de memória operacional visuo-espacial. Seis animais (cinco adultos, uma fêmea idosa) e 55 humanos (27 jovens, 13 homens; 25 idosos, 14 homens) realizaram, em tela sensível ao toque, o Teste de Reconhecimento Espacial com Atraso, que exige a discriminação de um estímulo em uma nova localização dentro de um número crescente de estímulos idênticos apresentados sequencialmente. O teste foi composto por quatro etapas, cada uma com uma categoria de estímulo: geométricos, faces neutras, faces positivas e faces negativas. Foi calculada a média do número de acertos (NA) e, para os humanos, também do tempo de resposta (TR) para cada etapa. A atividade cortical foi aferida com uso de um eletroencefalograma (EEG) e dividida em bandas teta (4-8Hz), alfa (8-13Hz), beta (13-30Hz) e gama (30-70Hz). Apenas a fêmea idosa realizou o teste abaixo do nível do acaso e não houve diferença no desempenho do grupo de macacos adultos em função da categoria dos estímulos. Os gêneros não diferiram no desempenho, tanto em macacos quanto em humanos. Para todas as categorias, o NA dos jovens humanos foi superior ao dos idosos, mas o TR foi similar. TR foi maior para estímulos geométricos do que para faciais e maior para faces emocionais (negativas, positivas) do que para neutras. Houve maior NA para faces negativas em relação às positivas. Quanto aos dados de EEG, as maiores ativações foram registradas nos córtices pré-frontal e frontal e na região central do escalpo, além de maior ativação no hemisfério esquerdo em relação ao direito. Em idosos, as diferenças entre os hemisférios nas bandas beta e gama foram menores do que em jovens, assim como a ativação nas bandas alfa e teta na região frontal central. Houve maior lateralização para o hemisfério esquerdo nas mulheres do que nos homens. Não houve diferenças significativas nas ativações frente às faces positivas e negativas ou frente às neutras e emocionais. Estímulos faciais geraram maior atividade na região pré-frontal esquerda em comparação aos geométricos. O melhor desempenho de humanos jovens em relação aos idosos era esperado devido às pioras cognitivas com o envelhecimento. O desempenho inferior da fêmea idosa indica que este déficit também está presente em macacos-prego, entretanto, estudos com número maior de indivíduos são necessários. A similaridade entre homens e mulheres e entre machos e fêmeas no desempenho, mas não na atividade cortical, sugere que os gêneros utilizam estratégias cognitivas diferentes, mas igualmente eficientes em testes de memória. Realizar análises de EEG em macacos seria útil para elucidar esta questão. O melhor desempenho para faces era esperado, devido a sua importância evolutiva. O maior TR para faces emocionais indica que o processamento das emoções focou a atenção dos sujeitos no conteúdo da imagem e não na informação espacial. O maior NA para faces negativas em relação às positivas está de acordo com o Viés da Negatividade, no qual tal valência é associada a eventos com maior influência no valor adaptativo. Por outro lado, como este resultado ocorreu tanto para jovens quanto para idosos, a hipótese do Efeito da Positividade, em que idosos focariam sua atenção e se lembrariam melhor de eventos positivos, não foi corroborada. _______________________________________________________________________________________ ABSTRACTEmotion is one of the most important memory modulators, mainly because the limbic system and the neural circuitry related to mnemonic processes share several brain structures. Facial expressions are considered the most important emotional displays in humans and non-human primates. This research aimed at verifying the influence of emotional valences (positive, negative, neutral) of facial stimuli on the behavior of humans and capuchin monkeys and on the cortical electrical activity of humans in a visuo-spatial working memory task. Six animals (five adults, one old female) and 55 humans (28 young, 13 men; 27 elderly, 14 men) performed, on a touch screen, the Spatial Delayed Recognition Span Task, which requires the discrimination of one stimulus in a new location among an increasing number of identical stimuli presented in sequence. The task had four stages, each with a different stimuli category: geometric, neutral faces, positive faces and negative faces. For each stage, mean of scores was calculated for both species and mean Response Time (RT) was measured for humans. Cortical activity was measured by an electroencephalogram (EEG) and splitted into the traditional frequency bands: theta (4-8Hz), alpha (8-13Hz), beta (13-30Hz) and gamma (30-70Hz). Only the old monkey female performed the task below chance level and all adult animals performed equally in all categories. There was no difference between performance of genders, both in humans and in monkeys. Young humans had more scores than the elderly, but the RT was the same. RT was larger for geometric stimuli than to facial stimuli and larger to emotional faces (negative, positive) than to neutral faces. Scores for negative faces were greater than for positive faces. Regarding the EEG data, the highest activations were found in pre-frontal and frontal cortices, in the central region of the scalp, and in the left hemisphere compared to the right hemisphere. In the old subjects, there was a lower activation of alpha and theta bands on the frontal region and a less evident asymmetry of activations on beta and gamma bands. Women showed a greater lateralization to the left hemisphere. There were no significant differences in the activity when subjects were answering to positive and negative faces or to neutral and emotional faces. Facial stimuli induced a greater activity on the left pre-frontal region when compared to geometric figures. The superior performance of young human subjects was expected due to the natural cognitive deficits with aging. The low performance of the old female indicates that this deficit also happens in capuchin monkeys. Nevertheless, studies with a larger number of subjects are necessary. Similarity between men and women and between males and females on performance but not on the cortical activity suggest that genders use different but equally efficient cognitive strategies to respond to memory tasks. Performing an EEG analysis on monkeys would help clarify this question. Better performance with facial stimuli was expected due to the evolutionary importance of faces. Larger RT to emotional faces indicates that emotion processing focused subjects’ attention to the images but not to their spatial location. Greater scores to negative faces than to positive faces is in line with the Negativity Bias, in which it is claimed that this emotional valence is related to events with more influence in the adaptive value. This pattern of results, however, was seen in both young and old subjects so, the Positivity Effect hypothesis, according to which old people would focus their attention on positive events and remember these better, was not supported

RISCO DE DOENÇA TROMBOLÍTICAS APÓS O USO DE ALGESTONA ACETOFENIDA E ENANTATO DE ESTRADIOL

Muitos estudos tem demonstrado que há um risco acentuado de doenças trombolíticas, que podem ser agravadas com predisposições a obesidade, fatores genéticos, fumantes e entre outros. No entanto, estes riscos não são, normalmente citados antes do uso métodos contraceptivos hormonais. Sendo assim, muitas mulheres estão expostas a riscos graves a saúde durante o uso de contraceptivos hormonais. Logo, o intuito do nosso estudo foi avaliar uso prolongado da substância algestona acetofenida e enantato de estradiol sobre o ciclo menstrual de fêmeas cativas de Sapajus libidinosus (macaco-prego). Para tal, foram usadas 06 fêmeas adultas de macaco-prego mantidas no Centro de Primatologia da Universidade de Brasília CP/UnB. Para fins experimentais, as fêmeas receberam uma dose única de 0,10 ml do contraceptivo injetável, que foi administrado a cada 21 dias. Sendo assim, cada fêmea recebeu 05 administrações de contraceptivo consecutivas. Também foram realizadas 12 coletas de sanguíneas de cada fêmea, por meio deste material biológico foram analisados os fatores de coagulação sanguínea, por exemplos, número de plaquetas, fibrinogênio e tempos de protrombina (TP) e tromboplastina (TTPa). Os resultados obtidos permitiram identificar que houve alterações nos fatores de coagulação sanguínea, pois foi registrado um aumento no número de plaquetas (F1,61=450.92; p<0.05) e redução nos tempos de TP (F1,61=91.77; p<0.001) e TTPa (F1,61=42.94; p<0.001). Diante disso é possível mencionar que o contraceptivo administrado nas fêmeas de macaco-prego promoveu alterações nos parâmetros fisiológicos, que são relacionados nos fatores de coagulação. Neste sentido, as fêmeas de macaco-prego podem ser um modelo animal importante, para estudos sobre o tema na medida em que os resultados aqui obtidos demonstram que, fisiologicamente, elas apresentam alterações semelhantes àquelas, que também são encontradas nas mulheres usuárias de contraceptivo hormonal combinado

Negative Facial Expressions – But Not Visual Scenes – Enhance Human Working Memory in Younger and Older Participants

Many studies have investigated the influence of emotion on memory processes across the human lifespan. Some results have shown older adults (OA) performing better with positive stimuli, some with negative items, whereas some found no impact of emotional valence. Here we tested, in two independent studies, how younger adults (YA) and OA would perform in a visuospatial working memory (VSWM) task with positive, negative, and neutral images. The task consisted of identifying the new location of a stimulus in a crescent set of identical stimuli presented in different locations in a touch-screen monitor. In other words, participants should memorize the locations previously occupied to identify the new location. For each trial, the number of occupied locations increased until 8 or until a mistake was made. In study 1, 56 YA and 38 OA completed the task using images from the International Affective Picture System (IAPS). Results showed that, although YA outperformed OA, no effects of emotion were found. In study 2, 26 YA and 25 OA were tested using facial expressions as stimuli. Data from this study showed that negative faces facilitated performance and this effect did not differ between age groups. No differences were found between men and women. Taken together, our findings suggest that YA and OA’s VSWM can be influenced by the emotional valence of the information, though this effect was present only for facial stimuli. Presumably, this may have happened due to the social and biological importance of such stimuli, which are more effective in transmitting emotions than IAPS images. Critically, our results also indicate that the mixed findings in the literature about the influence of aging on the interactions between memory and emotion may be caused by the use of different stimuli and methods. This possibility should be kept in mind in future studies about memory and emotion across the lifespan

Continuous Use of Combined Hormonal Contraceptive and the Effect on Blood Coagulation Factors in Female Capuchin Monkeys (Sapajus libidinosus)

This study aimed at evaluating the availability of the primate Sapajus libidinosus as an animal model for research assessing the physiological effects of the continuous use of combined hormonal contraceptives. In order to do this, six reproductively active female S. libidinosus from the Primate Research Center of the University of Brasília were selected to take part in this experiment. Every 21 days or so, each female received a single dose of combined hormonal contraceptive (algestone acetophenide and 17-enanthate estradiol) in a total of five doses throughout the experiment. The physiological parameters were accessed by means of 13 blood samples from each female, whereas three were gathered during the baseline and 10 samples were collected during the treatment phase. The results showed that the contraceptive use provoked changes in hematological coagulation factors such as an increase in the amount of platelets (p=0.039) and a reduction in both prothrombin (p<0.001) and thromboplastin coagulation time (p<0.001). These results are similar to what has been observed in human patients; thus, it is concluded that S. libidinosus can be successfully used in studies about the physiological impact of hormonal contraceptives

Relative topographic power spectrum distribution for specific bands with type of stimulus and age group.

<p>Types of stimulus are: geometric pictures and facial photos. Age groups are: young adults (YA) and older adults (OA). Alpha activity: 8 to 13 Hz, Beta activity: 13 to 30 Hz, Gamma activity: 30 to 70 Hz, Theta activity: 4 to 8 Hz. Red dots indicate significant statistical differences (p<0.05; parametrical tests) related to age groups and to types of stimulus in electrode location.</p

Experimental design for the Spatial Delayed Recognition Span Task.

<p>The full procedure included 40 trials of up to a maximum of 8 identical stimuli, 10 trials for each stimulus category (geometric pictures, positive, neutral and negative faces). The participant had to identify the stimulus in the new location. There was a 3-second interval of configuration (IC) between each new stimulus is presented on the touch screen.</p

Relative topographic power spectrum distribution for specific bands with each stimulus category and age group.

<p>Stimulus categories are: geometric pictures, negative, neutral and positive faces. Age groups are: young adults (YA) and older adults (OA). Alpha activity: 8 to 13 Hz, Beta activity: 13 to 30 Hz, Gamma activity: 30 to 70 Hz, Theta activity: 4 to 8 Hz. Red dots indicate significant statistical differences (p<0.05; parametrical tests) related to age groups in electrode location.</p

Demographic and clinical characteristics.

<p>YA = Young adults; OA = Older adults; MMES = Mini Mental State Examination; PBAC = Philadelphia Brief Assessment of Cognition; GDS = Geriatric Depression Scale. Values are mean±SD. * p<0.001 vs. OA (Student's t test).</p