In contrast to effortful cognitive functions, emotional functioning may remain stable or even be enhanced in older adults. It is unclear how affective functions in aging correspond to subjective experiences and physiological changes. In Study I, ratings of emotional intensity and neural activity to facial expressions using functional magnetic resonance imaging (fMRI) were analyzed in younger and older adults. Negative expressions resulted in increased neural activity in the right amygdala and hippocampus in younger adults, and increased activation in the right insular cortex in older adults. There were no age differences in subjective ratings. In Study II, subjective ratings of, and skin conductance response (SCR) to, neutral and negative pictures were studied. The ratings of negative pictures were higher for older adults compared to younger adults. SCRs increased in both age groups for the negative pictures, but magnitude of SCRs was significantly larger in younger adults. Finally, in Study III, emotional memory after a one-year retention interval was tested. The memory performance of both age groups was higher in response to negative pictures compared to neutral ones, although the performance was generally higher for younger adults. SCR at encoding was the better arousal predictor for memory, but only in younger adults. The results indicate age-related changes in affective processing. Age differences may involve a gradual shift from bottom-up processes, to more top-down processes. The results are discussed in a wider lifespan perspective taking into consideration the accumulated life experience of older adults.

Orientadora: Profª Drª Raquel Vecchio Fornari / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Neurociência e Cognição, 2015. / O cortex insular (CI), ou insula, conquistou nos ultimos anos um lugar de destaque na area cientifica por seu suposto envolvimento em processos emocionais e cognitivos. No rato, como nos seres humanos, o CI pode ser dividido em duas sub-regioes funcionalmente heterogeneas. Embora a maioria dos estudos realizados em animais tenha mostrado um envolvimento da regiao mais rostral (CI anterior) na memoria gustativa, outros sugerem um papel mais amplo, abrangendo desde o reconhecimento de objetos ate o processamento de memorias espaciais e aversivas. A regiao mais caudal (CI posterior), por sua vez, recebe aferencias multissensoriais e supoe-se que esteja envolvida em processamento multissensorial e nociceptivo. Entretanto, pouquissimos trabalhos avaliaram a participacao dessa sub-regiao posterior em tarefas de memoria, com resultados inconclusivos. Nao havia, ate o momento, nenhum trabalho que tivesse investigado isoladamente o papel de ambas as sub-regioes do CI na consolidacao da memoria emocional. Portanto, o objetivo deste estudo foi investigar os efeitos da inativacao temporaria do CI anterior e posterior sobre a consolidacao da memoria de medo de tarefas de condicionamento de medo ao contexto e ao som. Ratos Wistar de 3 meses de idade passaram por cirurgia estereotaxica para implante de canulas-guia bilaterais no CI anterior ou posterior. Os animais tiveram pelo menos 7 dias de recuperacao e foram manipulados por 3 dias antes do inicio do procedimento comportamental. Para o treino de condicionamento de medo ao contexto e ao som, os ratos foram colocados individualmente em um caixa de condicionamento. Apos 120 segundos de livre exploracao, um som (90 decibeis, 2 kHz) foi emitido por 30 segundos, co-terminando com um choque nas patas (0,7 mA, 1s). Imediatamente apos, cada rato recebeu uma microinfusao bilateral de muscimol (agonista gabaergico, 0,5¿Êg/0,5¿ÊL por hemisferio) ou salina (grupo controle). O teste de condicionamento de medo ao contexto (CMC) ocorreu 48 horas apos o treino e consistiu na re-exposicao a caixa de condicionamento por 5 minutos, sem apresentacao de som ou choque. 24 horas depois, os mesmos animais foram submetidos ao teste de condicionamento de medo ao som (CMS), o qual ocorreu em uma caixa modificada, com duracao de 5 minutos. Ao final do segundo e terceiro minutos, o mesmo estimulo sonoro apresentado no treino foi emitido por 30 segundos. O tempo de congelamento e o comportamento motor foram utilizados como medidas de condicionamento. No CMS, os ratos que receberam a microinfusao de muscimol no CI anterior e posterior apresentaram uma media de tempo de congelamento menor durante o periodo pos-som. Entretanto, no CMC nao houve diferencas entre grupos para ambas as subregioes do CI. Portanto, os resultados deste estudo indicam que a inativacao pos-treino do CI como um todo prejudica exclusivamente o CMS. Entretanto, o prejuizo deste tipo de memoria, provocado pela inativacao do CI posterior, foi maior, evidenciando, portanto, que esta subregiao esta mais importantemente envolvida na circuitaria neural responsavel pela consolidacao do medo condicionado a um estimulo sonoro discreto. / The insular cortex (IC), or insula, has achieved over the last years an eminent position in the scientific literature due to its involvement in emotional and cognitive processes. In the rat, as in humans, the IC can be divided into two functionally heterogeneous sub-regions. Although most animal studies have shown an involvement of the rostral subregion (anterior IC) in gustatory memory, others suggest a broader role in memory, ranging from object recognition to the processing of spatial and aversive memories. In addition, even though the most caudal area (posterior IC) seems to be involved in multisensory and nociceptive processing, very few studies have evaluated its role in mnemonic processes and the results so far are unclear. Nevertheless, no work, to the best of our knowledge, had investigated the specific role of both sub-regions of the IC on consolidation of fear conditioning tasks. Thus, the aim of the present study was to investigate the effects of temporary inactivation of the anterior and posterior IC on memory consolidation of contextual and tone fear conditioning tasks. 3-month-old male Wistar rats underwent stereotaxic surgery for implantation of bilateral guide cannulae aimed directly above the anterior or posterior IC. The animals were allowed at least 7 days of recovery and were handled once a day for 3 days prior to behavioral sessions. For the contextual and tone fear conditioning training session, the rats were individually placed in the conditioning box. After 120 seconds of free exploration, a tone (90 decibels, 2 kHz) was delivered for 30 seconds, coterminating with a footshock (0.7 mA, 1 s). Immediately after, each rat received a bilateral microinjection of muscimol (GABAergic agonist, 0.5 ìg/0.5ìL by hemisphere) or saline (control group) into the intended IC subregion. The contextual fear conditioning test (CFC) was performed 48 hours after training and consisted in the re-exposure to the conditioning box for 5 minutes, without delivery of tone and shock. After 24 hours, the same animals were submitted to tone fear conditioning test (TFC), which occurred in a modified chamber, for 5 minutes. At the end of the second and third minutes, the same tone stimulus presented in the training session was delivered for 30 seconds. Freezing time and motion behavior were used as measures of conditioning. In TFC, the rats that had received muscimol microinfusion into the anterior and posterior IC displayed a lower freezing time during the post-tone period. However, for both IC subregions, there were no differences between groups in the CFC. Thus, our findings indicate that the posttraining inactivation of both IC subregions impaired the TFC. However, the impairment in this kind of memory, caused by the the inactivation of the posterior IC, was higher, thus, highlighting that this subregion is more importantly involved in the neural circuitry related to the consolidation of the discrete tone conditioned fear.

Made available in DSpace on 2016-06-02T20:18:22Z (GMT). No. of bitstreams: 1 5721.pdf: 10685553 bytes, checksum: b8c33e77b08071259076d9ba53ebc334 (MD5) Previous issue date: 2014-02-10 / Universidade Federal de Minas Gerais / This study investigated the function of cerebellar histaminergic system on emotional memory consolidation. The cerebellar vermis of male mice were implanted with guide cannulae, and after three days of recovery, the animals were submitted to the elevated plus maze (EPM) or the inhibitory avoidance test (IA) on two consecutive days. Immediately after the first day, animals received a microinjection of histaminergic drugs into the cerebellar vermis: experiment 1, animals received microinjections of saline (SAL) or histamine (HA) (0.54, 1.36, 2.72, and 4.07 nmol/0.1 microliter); experiment 2, animals received a microinjection of SAL or the H1 antagonist chlorpheniramine (CPA, 0.016, 0.052 or 0.16 nmol/0.1 μl); experiment 3, SAL or the H2 antagonist ranitidine (RA, 0.57, 2.85 or 5.7 nmol/0.1 μl); experiment 4, SAL or HA 5 minutes after a pretreatment with 0.16 nmol CPA or SAL; and experiment 5, SAL or HA 5 minutes after a pretreatment with 2.85 nmol ranitidine (RA) or SAL. In the EPM, the decrease of open arm exploration (% entries and % time spent in the open arms) in Trial 2 relative to Trial 1 was used as a measure of learning and memory; while in the IA, latency to cross to the dark compartment was used to evaluate memory retention. Data were analyzed using ANOVA and Duncan‟s test. The results of experiment 1 showed that animals microinjected SAL and 0.54 and 1.36 nmol HA reduced percentage of open arm entries and time, while mice microinjected with HA 2.72 and 4.07 nmol did not decrease open arm exploration on trial 2; which indicates that histamine induced a dose-dependent inhibitory effect on memory consolidation. In the IA task, results showed that 1.36 nmol histamine facilitated memory consolidation, suggesting a different action of HA in a memory model that uses punishment. In the experiment 2, microinjections with CPA did not present behavioral effects in the EPM or in the IA at the doses used (0.016, 0.052 and 0.16 nmol). The results of experiment 3 showed that 5.7 nmol RA impaired memory consolidation on both protocols. The experiment 4 demonstrated that animals treated with HA did not reduce the avoidance to the open arms on retesting, and indicated that CPA did not altered behavioral parameters by itself, but the pretreatment with CPA reverted histamine-induced impairment on memory consolidation, which suggests that histamine effect on the EPM was mediated by H1 receptors. In the IA test, the results showed that the groups that received CPA+HA and SAL+HA showed a significant difference in latency on the second day of testing in relation to group SAL+SAL , while the group treated with CPA + SAL showed no difference with the control group. These results show that microinjection of histamine in the cerebellar vermis increased latency time and that pretreatment with CPA did not reverse this effect. For the fifth experiment, the results showed that animals microinjected with SAL+SAL and RA+SAL reduced the percentage of entries and time spent in open arms in the EPM while the groups treated with RA+HA and SAL+HA showed no difference between test days. These results show that RA did not alter memory consolidation and was unable to reverse the effect of histamine. In the IA, there was significant difference between SAL+SAL and SAL+HA groups, showing the facilitatory effect of histamine on memory consolidation of IA. The groups that received combined injection of RA+SAL and RA+HA showed no significant difference compared to control, which shows that the RA had no effect by itself, but when applied before histamine was able to reverse its effect. Our results suggest different histamine effects in tasks involving anxiety or fear. / Esse trabalho teve como objetivo investigar a atuação do sistema neural histaminérgico na consolidação da memória emocional de camundongos. Foi realizada cirurgia esterotáxica para implantação da cânula no vérmis cerebelar de camundongos machos. No terceiro dia de recuperação, foram realizados os testes comportamentais Labirinto em Cruz Elevado (LCE) e Esquiva Inibitória (EI) em dois dias consecutivos. Imediatamente após o primeiro dia de teste, os animais receberam o tratamento farmacológico com a microinjeção de drogas histaminérgicas no vérmis cerebelar. No experimento 1, foi verificado o efeito da histamina (HA) microinjetada nas doses de 0,54 nmol, 1,36 nmol, 2,72 nmol e 4,07 nmol em camundongos submetidos ao LCE (experimento 1a) e ao teste EI (experimento 1b). No experimento 2 foi realizada microinjeção de antagonista H1 (Clorfeniramina, CPA) nas doses de 0,016 nmol, 0,052 nmol e 0,16 nmol em camundongos submetidos ao LCE (experimento 2a) e ao teste EI (experimento 2b). No experimento 3, microinjeção de antagonista H2 (Ranitidina, RA) nas doses de 0,57 nmol, 2,85 nmol e 5,7 nmol em camundongos submetidos ao LCE (experimento 3a) e ao teste EI (experimento 3b). No experimento 4, foi realizada microinjeção combinada de antagonista H1 e HA em camundongos submetidos ao LCE (experimento 4a) e ao teste EI (experimento 4b); e no experimento 5, foi realizada microinjeção combinada de antagonista H2 e HA no LCE (experimento 5a) e EI (experimento 5b). O índice de memória dos animais no LCE foi definido pela redução da exploração dos braços abertos na reexposição (T1/T2). Para o Teste de EI, o aumento ou a redução das latências foi considerado indicativo de facilitação ou prejuízo na retenção da memória. Os resultados do experimento 1a mostraram que no LCE, os animais do grupo controle (SAL) e dos grupos HA nas doses de 0,54 nmol e 1,36 nmol apresentaram redução da exploração dos braços abertos (BA) na reexposição, enquanto os animais que receberam HA nas doses de 2,72 e 4,07 não apresentaram diferença significativa em relação a T2. Esses resultados indicam uma inibição da memória emocional quando a histamina foi injetada no vérmis cerebelar em animais submetidos ao LCE. No experimento 1b, a análise estatística mostrou um aumento significativo na latência no teste de EI para os animais que receberam histamina na dose de 1,36 nmol em relação ao grupo controle. Além disso, houve diferença significativa entre os grupos microinjetados com 1,36 nmol e com 2,72 nmol e 4,07 nmol. Estes resultados indicam que a histamina microinjetada na dose de 1,36 nmol facilitou a consolidação da memória de EI em camundongos, sugerindo um papel diferente da histamina em um modelo que usa punição. No experimento 2a, os resultados mostraram que os grupos microinjetados com salina e CPA nas doses de 0,016 nmol, 0,052 nmol e 0,16 nmol reduziram a exploração dos BA na reexposição, o que sugere a CPA não apresentou efeitos sobre a consolidação da memória emocional. No experimento 2b, a CPA também não apresentou efeito nas doses utilizadas no teste de EI. No experimento 3a, a análise estatística indicou que os animais que receberam RA na dose de 5,7 não apresentaram redução na exploração dos BA, o que sugere prejuízo na consolidação da memória. Os resultados do experimento 3b mostraram que a RA na dose de 5,7 nmol prejudicou a consolidação da memória emocional no teste de EI. Os resultados do estudo 4a com injeção combinada de antagonista H1 e HA em camundongos reexpostos ao LCE mostraram que os animais microinjetados com SAL+SAL, CPA+SAL e CPA+HA reduziram a porcentagem de entradas e de tempo nos braços abertos, enquanto que os animais do grupo SAL+HA não apresentaram diferença significativa na exploração dos BA na reexposição, confirmando os resultados do experimento 1a em que animais injetados com HA (4,07 nmol) apresentam prejuízo na consolidação da memória emocional. Além disso, os resultados mostraram que a CPA não alterou os parâmetros comportamentais quando aplicada por si só, e que foi capaz de reverter o déficit produzido pela histamina na consolidação da memória emocional em camundongos no LCE. No experimento 4b no teste de EI, os resultados mostraram que os grupos que receberam injeção combinada de antagonista H1 e histamina (CPA+HA) e a injeção de SAL+HA apresentaram diferença significativa no tempo de latência no segundo dia de teste em relação ao grupo controle SAL+SAL, enquanto o grupo tratado com CPA+SAL não apresentou diferença com o grupo SAL+SAL. Esses resultados mostram que a microinjeção de histamina no vérmis cerebelar aumentou o tempo de latência, e que o pré-tratamento com CPA não reverteu esse efeito. Para o experimento 5a, com microinjeção combinada de antagonista H2 e HA em camundongos submetidos ao LCE, os resultados mostraram que animais microinjetados com SAL+SAL e RA+SAL reduziram a porcentagem de entrada e de tempo nos braços abertos, enquanto os grupos tratados com RA+HA e SAL+RA não apresentaram diferença entre os dias de teste nesse parâmetros. Estes resultados mostraram que a RA não alterou a consolidação da memória e não foi capaz de reverter o efeito da histamina. Já no experimento 5b com a microinjeção combinada de RA e HA no teste de EI, houve diferença significativa entre os grupos SAL+SAL e SAL+HA, mostrando novamente o efeito facilitador da histamina na consolidação da memória de EI. Os grupos que receberam injeção combinada de antagonista H2 e histamina (RA+HA) e o grupo de recebeu RA+SAL não apresentaram diferença significativa em relação ao controle no tempo de latência no segundo dia de teste, o que mostra que a RA não apresentou efeito por si só, mas quando aplicada pré histamina foi capaz de reverter seu efeito. Os resultados dos diversos experimentos realizados parecem indicar efeitos da histamina em circuitos neurais diferentes em tarefas envolvendo medo ou ansiedade.

Ce travail de thèse explore la mémoire de stimuli émotionnels au cours de quatre études en adoptant une approche pluridisciplinaire chez l’enfant sain et consécutivement à une chirurgie de l’épilepsie du lobe temporal (ELT). Nos objectifs étaient (1) de comparer l’influence des émotions sur la mémoire verbale et non verbale au cours du développement sain et en cas d’ELT, (2) de décrire les bases cérébrales des processus de la mémoire de visages exprimant la peur au cours du développement au moyen de l’IRMf, (3) de s’intéresser à l'impact de l’ELT droit sur ce réseau (4) d’illustrer l’impact d’une chirurgie de l’ELT droite sur la mémoire émotionnelle et les caractéristiques cognitivo-émotionnelles en phase pré- puis post-opératoire. Nos résultats montrent que La reconnaissance mnésique de stimuli émotionnels est perturbée chez les jeunes patients présentant un dysfonctionnement du LTM, sauf pour les visages exprimant la peur. Chez les sujets sains, l’activation de l’amygdale basolatérale qui se met en place au moment de l’adolescence, serait notamment la signature cérébrale du phénomène de modulation émotionnelle des souvenirs associée à la recollection, et la maturation fonctionnelle des structures de la mémoire au sein du lobe temporal médian (LTM) suivrait un gradient caudo-rostral. Des capacités de réorganisation controlatérale sont néanmoins observées chez les patients avec ELT droite, au niveau de l’amygdale et des structures mnésiques du LTM, avec une sur-compensation au niveau du cortex parahippocampique. Ces adaptations permettraient de soutenir la mémoire de visage exprimant la peur sur la base d’un sentiment de familiarité, notamment après le contrôle des crises. Ce travail de thèse a permis de mettre en évidence des résultats novateurs à propos de l’implication du LTM du développement du lien entre mémoire et émotion. / In this multidisciplinary work, four studies were conducted to examine the memory for emotional stimuli in healthy children and post-surgery for temporal lobe epilepsy (TLE). The aims were (1) to compare emotional influences on memory for faces and words in healthy and TLE children, (2) to explore age-related neural networks of fear faces memory with fMRI, (3) to elicit the effect of childhood right-TLE on these developing networks and (4) to illustrate the impact of right-TLE surgery on emotional memory and cognitive-emotional features in a pre- vs. post-surgery case study. Our results show that patients suffering from a MTL dysfunction are impaired in emotional memory, except for fear faces. In heathly participants, emotional modulation of recollected memories is associated with an activation of basolateral amygdala in adolescents and that functional maturation through the mesial temporal lobe (MTL) is characterized by a caudo-rostral gradient. In right-TLE patients, controlateral recovery abilities are nonetheless observed, in amygdala and memory structures in MTL, with an over-activation in parahippocampal cortex. This reorganization would allow sustaining memory for fear faces supported with familiarity process. This thesis highlights new results about MTL involvement in memory-emotions interactions during development.

La schizophrénie est une psychopathologie largement hétérogène caractérisée entre autres par d’importantes défaillances dans le fonctionnement cognitif et émotionnel. En effet, par rapport à la population générale, forte proportion de ces individus présentent une mémoire déficitaire pour les événements émotionnels. À ce jour, le peu d’études qui se sont penchées sur la mémoire émotionnelle épisodique dans la schizophrénie, ont uniquement mis l’emphase sur l'effet de la valence des stimuli (c’est-à-dire le caractère agréable ou désagréable du stimulus). Toutefois, aucune n’a investigué spécifiquement l’intensité de la réaction aux stimuli (c’est-à-dire une faible par rapport à une forte réaction) malgré quantité de preuves faisant montre, dans la population générale, de différents processus de mémoire émotionnelle pour des stimuli suscitant une forte réaction par rapport à ceux évoquant une faible réponse. Ce manque est d’autant plus flagrant étant donné le nombre d’études ayant rapporté un traitement et un encodage atypiques des émotions spécifiquement au niveau de l’intensité de la réponse subjective chez des patients atteints de schizophrénie. Autre fait important, il est étonnant de constater l’absence de recherches sur les différences de sexe dans la mémoire émotionnelle étant donné l’ensemble des divergences entre hommes et femmes atteints de schizophrénie au niveau de la prévalence, de l’âge de diagnostic, de la manifestation clinique, de l’évolution de la maladie, de la réponse au traitement et des structures cérébrales. Pour pallier à ces lacunes, ce mémoire a évalué : (1) l’effet de la valence des stimuli et de l'intensité de la réaction émotionnelle au niveau des fonctions cérébrales correspondant à la mémoire émotionnelle chez des patients atteints de schizophrénie comparativement à des participants sains; et (2) les possibles différences de sexe dans les processus cérébraux impliqués dans la mémoire émotionnelle chez des patients atteints de schizophrénie par rapport à des volontaires sains. Ainsi, la première étude a comparé les activations cérébrales de patients atteints de schizophrénie par rapport à des participants sains au cours d’une tâche de mémoire émotionnelle dont les stimuli variaient à la fois au niveau de la valence et de l'intensité de la réaction subjective. 37 patients atteints de schizophrénie ainsi que 37 participants en bonne santé ont effectué cette tâche de mémoire émotionnelle lors d’une session d’imagerie par résonance magnétique fonctionnelle (IRMf). Pour toutes les conditions étudiées (images négatives, positives, de faible et de forte intensité), le groupe atteint de schizophrénie a performé significativement moins bien que les volontaires sains. Comparativement aux sujets sains, ils ont montré moins d’activations cérébrales dans les régions limbiques et préfrontales lors de la reconnaissance des images négatives, mais ont présenté un patron d'activations similaire à celui des participants sains lors de la reconnaissance des images chargées positivement (activations observées dans le cervelet, le cortex temporal et préfrontal). Enfin, indépendamment de la valence des stimuli, les deux groupes ont démontré une augmentation des activations cérébrales pour les images de forte intensité par rapport à celles de plus faible intensité. La seconde étude a quant à elle exploré les différences de sexe potentielles au niveau des activations cérébrales associées à la mémoire émotionnelle dans la schizophrénie et dans la population en général. Nous avons comparé 41 patients atteints de schizophrénie (20 femmes) à 41 participants en bonne santé (19 femmes) alors qu’ils effectuaient la même tâche de mémoire émotionnelle mentionnée plus haut. Or, pour cette étude, nous nous sommes concentrés sur les conditions suivantes : la reconnaissance d’images positives, négatives et neutres. Nous n'avons pas observé de différences entre les hommes et les femmes au niveau des performances à la tâche de mémoire pour aucune des conditions. En ce qui a trait aux données de neuroimagerie, comparativement aux femmes en bonne santé, celles atteintes de schizophrénie ont montré une diminution des activations cérébrales dans les régions corticales du système limbique (p. ex. cortex cingulaire moyen) et dans les régions sous-corticales (p. ex. amygdale) lors de la reconnaissance d'images négatives. Pour ce qui est de la condition positive, elles ont présenté, comparativement au groupe de femmes saines, des diminutions d’activations spécifiquement dans le cervelet ainsi que dans le gyrus frontal inférieur et moyen. Les hommes atteints de schizophrénie, eux, ont montré une augmentation d’activations par rapport aux hommes sains dans le gyrus préfrontal médian lors de la reconnaissance des stimuli négatifs ; ainsi que dans les régions pariétales, temporales et limbiques lors de la reconnaissance des stimuli positifs. Dans un autre ordre d’idées, notre analyse corrélationnelle a mis en évidence, chez les femmes, un lien significatif entre l’activité cérébrale et les symptômes au cours de la mémoire des stimuli positifs, alors que chez les hommes atteints schizophrénie, ce lien a été observé au cours de la mémoire des stimuli négatifs. Bref, l’ensemble de nos résultats suggère, chez les patients atteints de schizophrénie, un fonctionnement cérébral atypique spécifiquement lors de la reconnaissance d’images négatives, mais un fonctionnement intact lors de la reconnaissance de stimuli positifs. De plus, nous avons mis en évidence la présence de différences de sexe dans les activations cérébrales associées à la mémoire épisodique émotionnelle soulignant ainsi l'importance d’étudier séparément les hommes et les femmes atteints de schizophrénie dans le cadre de recherches sur les plans cognitif et émotionnel. / Schizophrenia is characterized by prominent disturbances in cognitive and emotional functioning. For instance, individuals with schizophrenia are often impaired in their memory for emotional events compared to healthy subjects. To date, the limited research on emotional episodic memory in schizophrenia has focused on the effect of valence of affective stimuli (e.g., pleasant vs. unpleasant), while overall ignoring the effect of arousal (e.g., low vs. high) despite evidence of distinct emotional memory processes for high versus low arousing stimuli in the general population, as well as reports of abnormal processing of arousing stimuli in schizophrenia. What’s more, there has yet to be examination of sex differences in the behavioral and neural correlates of emotional memory in this complex psychiatric disorder, which is astonishing considering the substantial evidence of sex differences in almost all features of schizophrenia from prevalence, mean age at onset, clinical presentation, course of illness, response to treatment and brain structure. Accordingly, this thesis examined: (1) the effect of both affective valence and arousal intensity on the brain activations associated with emotional memory in patients with schizophrenia and in healthy control participants and (2) potential sex differences in brain function during emotional memory. The first study aimed to compare cerebral activations in patients with schizophrenia and healthy controls during memory retrieval of emotional images that varied in both valence and arousal. Using fMRI, 37 patients with schizophrenia (% male = 51; mean age =32.46) were compared to 37 healthy participants (% male = 51; mean age =31.81) while performing an emotional memory task. patients with schizophrenia performed worse than healthy controls in all experimental conditions. They showed less cerebral activations in limbic and prefrontal regions than controls during retrieval of negatively valenced stimuli, but had a similar pattern of brain activations to controls during retrieval of positively valenced stimuli (particularly in the high arousal condition) in the cerebellum, temporal and prefrontal cortex. Both groups demonstrated increased brain activations in the high relative to low arousing conditions. The second study explored potential sex differences in the brain activations associated with the recognition of emotional images in schizophrenia and healthy controls. 41 patients with schizophrenia (20 women) were compared to 41 healthy participants (19 women) while performing a yes/no recognition paradigm with positive, negative and neutral images in an fMRI scan. We did not observe sex differences in performance. Compared to healthy women, women with schizophrenia showed a decrease in brain activations in cortical (e.g. middle cingulate) and subcortical limbic structures (e.g. amygdala) during recognition of negative images and decreased activations during the positive condition in the cerebellar vermis, middle and inferior frontal gyrus. Men with schizophrenia had increased activations compared to healthy men in the medial prefrontal gyrus during recognition of negative stimuli and a substantial increase in brain activity during the recognition of positive pictures in parietal, temporal and limbic structures. Correlation analysis revealed significant relationships between brain function and symptoms during positive emotional memory in women and during negative emotional memory primarily in men. Taken as a whole, our results suggest atypical brain function during retrieval of negative pictures, but intact functional circuitry of positive affect during episodic memory retrieval in patients with schizophrenia compared to healthy subjects. Moreover, our findings revealed sex differences in the brain activations associated with emotional recognition memory in patients with schizophrenia; which further highlights the importance of investigating men and women with schizophrenia separately in the context of emotional and cognitive tasks.

Vários estudos utilizando modelos animais têm demonstrado que estruturas límbicas como amídala (AMD), hipocampo dorsal (HD) e córtex pré-frontal medial (CPFm) participam na consolidação da memória associada às emoções. Considerando que a síntese de novas proteínas é necessária para o processo de consolidação de memórias, e que a combinação entre o uso de inibidores de síntese proteica e diferentes intensidades de estímulo incondicionado têm gerado respostas comportamentais distintas com relação à consolidação da memória emocional, o presente trabalho se propôs a investigar a hipótese de a consolidação da memória aversiva na AMD, no HD e no CPFm, associada a síntese proteica, ocorre de maneira diferenciada nessas três estruturas, de acordo com a intensidade do estímulo aversivo, bem como se a expressão de genes envolvidos na transmissão histaminérgica seria modificada ao longo das fases da memória emocional aversiva. O objetivo do presente estudo foi avaliar o papel da síntese proteica na AMD, HD e CPFm no processo de consolidação de uma memória aversiva baseada em condicionamento aversivo moderado ou intenso; investigar a expressão de genes ligados a transmissão histaminérgica na AMD, HD e CPFm após o condicionamento aversivo intenso. Para este fim dois experimentos foram realizados: No experimento 1 a anisomicina (ANI) foi microinjetada bilateralmente na AMD ou HD ou CPFm de camundongos antes de serem submetidos a tarefa de esquiva inibitória do tipo step-down utilizando duas intensidades de estímulo incondicionado: moderada ou intensa. No experimento 2, as variações da expressão dos genes da enzima HDC (histidina descarboxilase responsável pela síntese de histamina) e dos receptores H1, H2 e H3 foram analisadas em diferentes espaços temporais através da reação de polimerase em cadeia em tempo real. Os resultados do experimento 1 demonstram que microinjeção de ANI no CPFm prejudica a consolidação da memória de esquiva inibitória com estímulo incondicionado moderado ou intenso, porém quando administrada intra-AMD e intra-HD, a ANI só prejudica a consolidação da memória de esquiva inibitória com estímulo incondicionado intenso. No experimento 2 demonstra que durante a consolidação da memória aversiva intensa há diminuição nos níveis de expressão dos genes: HDC no HD, Hrh3 na AMD, Hrh1 e Hrh3 no CPFm. Já na fase de evocação, na AMD há aumento e diminuição na expressão dos genes HDC e Hrh3, respectivamente; no HD há aumento na expressão dos genes Hrh2 e Hrh3 e no CPFm há aumento na expressão do gene HDC e diminuição nos genes Hrh1 e Hrh3. Durante a reconsolidação há diminuição na expressão dos genes HDC e Hrh3 e aumento do gene Hrh1 na AMD. No DH há aumento com relação ao gene Hrh1, e no CPFm há aumento do gene HDC e diminuição na expressão dos genes Hrh1 e Hrh3. No presente estudo conclui-se que em situações com moderado grau de aversividade, a consolidação dessa experiência não dependerá de síntese proteica na AMD e no HD, mas sim no CPFml. No entanto, em situações com elevado grau de aversividade, a síntese proteica na AMD, HD e CPFm é essencial para a consolidação de tal experiência. Além disso, os genes HDC, Hrh1, Hrh2 e Hrh3 se expressam distintamente na AMD, HD e CPFm ao longo da escala temporal da consolidação, evocação e reconsolidação da formação de memórias de medo. / Several studies using animal models have shown that limbic structures like the amygdala (AMG), dorsal hippocampus (DH) and medial prefrontal cortex (mPFC) are involved in emotional memory consolidation. Whereas the synthesis of new proteins is necessary for memory consolidation process, and that opposite results related to the interaction of protein synthesis inhibitors and foot-shock intensity on memory consolidation have been reported, the present study aims to investigate the hypothesis of protein synthesis in AMG, the DH and mPFC associated with the consolidation of aversive memory occurs differently in these three structures, according to the intensity of the aversive stimulus and the expression of proteins involved in histaminergic transmission would be modified during the process of consolidation and emotional expression of aversive memory. The aim of this study was to evaluate the role of protein synthesis in AMG, DH and mPFC in consolidation of aversive memory based on moderate and intense conditioning; to investigate the expression of proteins related to histaminergic transmission in AMG, DH and mPFC after intense aversive conditioning. For this purpose two experiments were performed: in experiment 1 the anisomycin (ANI) was bilaterally microinjected into AMG or DH or mPFC of mice before being submitted the step-down inhibitory avoidance task using two unconditioned stimulus intensities: moderate or intense. In experiment 2, the variations in the gene expression of HDC enzyme (histidine decarboxylase - responsible for histamine synthesis) and the H1, H2 and H3 receptors were analyzed at different temporal spaces by real-time polymerase chain reaction (RT-PCR). The results of the first experiment demonstrate that microinjection of ANI in mPFC impairs the consolidation of inhibitory avoidance memory with moderate or intense unconditioned stimulus, however when administered intra-AMG and intra DH, ANI only impairs the consolidation of inhibitory avoidance memory under an intensive unconditioned stimulus. The experiment 2 demonstrates that during the consolidation of intense aversive memory there is a decrease of the genes expression levels: HDC in the dorsal hippocampus, Hrh3, Hrh1 in the amygdala, and Hrh3 in the medial prefrontal cortex. During retrieval the HDC and Hrh3 genes expression levels are increased and decreased, respectively in the AMG; the Hhr2 and Hrh3 genes expression levels are increased in the DH, and in the mPFC the HDC gene expression level is increased, and the Hrh1 and Hrh3 are decreased. During reconsolidation the amygdalas HDC and Hrh3 genes expression levels are decreased and the Hrh1 gene is increased. In the DH the Hrh1 gene levels are elevated and in the mPFC the HDC gene expression level is increased and the Hrh1 and Hrh3 are decreased. In the current study we conclude that under moderate aversiveness situations, the consolidation of this experience does not depend on protein synthesis in the AMG and in the DH, but in the mPFC. However, in situations with a high level of adversity, protein synthesis in this three structures are essential for the consolidation of such experience. In addition, the histaminergic genes are distinctly expressed in the AMG, DH and mPFC along the time scale of consolidation, retrieval and reconsolidation of the formation of fear memories.

La schizophrénie est une psychopathologie largement hétérogène caractérisée entre autres par d’importantes défaillances dans le fonctionnement cognitif et émotionnel. En effet, par rapport à la population générale, forte proportion de ces individus présentent une mémoire déficitaire pour les événements émotionnels. À ce jour, le peu d’études qui se sont penchées sur la mémoire émotionnelle épisodique dans la schizophrénie, ont uniquement mis l’emphase sur l'effet de la valence des stimuli (c’est-à-dire le caractère agréable ou désagréable du stimulus). Toutefois, aucune n’a investigué spécifiquement l’intensité de la réaction aux stimuli (c’est-à-dire une faible par rapport à une forte réaction) malgré quantité de preuves faisant montre, dans la population générale, de différents processus de mémoire émotionnelle pour des stimuli suscitant une forte réaction par rapport à ceux évoquant une faible réponse. Ce manque est d’autant plus flagrant étant donné le nombre d’études ayant rapporté un traitement et un encodage atypiques des émotions spécifiquement au niveau de l’intensité de la réponse subjective chez des patients atteints de schizophrénie. Autre fait important, il est étonnant de constater l’absence de recherches sur les différences de sexe dans la mémoire émotionnelle étant donné l’ensemble des divergences entre hommes et femmes atteints de schizophrénie au niveau de la prévalence, de l’âge de diagnostic, de la manifestation clinique, de l’évolution de la maladie, de la réponse au traitement et des structures cérébrales. Pour pallier à ces lacunes, ce mémoire a évalué : (1) l’effet de la valence des stimuli et de l'intensité de la réaction émotionnelle au niveau des fonctions cérébrales correspondant à la mémoire émotionnelle chez des patients atteints de schizophrénie comparativement à des participants sains; et (2) les possibles différences de sexe dans les processus cérébraux impliqués dans la mémoire émotionnelle chez des patients atteints de schizophrénie par rapport à des volontaires sains. Ainsi, la première étude a comparé les activations cérébrales de patients atteints de schizophrénie par rapport à des participants sains au cours d’une tâche de mémoire émotionnelle dont les stimuli variaient à la fois au niveau de la valence et de l'intensité de la réaction subjective. 37 patients atteints de schizophrénie ainsi que 37 participants en bonne santé ont effectué cette tâche de mémoire émotionnelle lors d’une session d’imagerie par résonance magnétique fonctionnelle (IRMf). Pour toutes les conditions étudiées (images négatives, positives, de faible et de forte intensité), le groupe atteint de schizophrénie a performé significativement moins bien que les volontaires sains. Comparativement aux sujets sains, ils ont montré moins d’activations cérébrales dans les régions limbiques et préfrontales lors de la reconnaissance des images négatives, mais ont présenté un patron d'activations similaire à celui des participants sains lors de la reconnaissance des images chargées positivement (activations observées dans le cervelet, le cortex temporal et préfrontal). Enfin, indépendamment de la valence des stimuli, les deux groupes ont démontré une augmentation des activations cérébrales pour les images de forte intensité par rapport à celles de plus faible intensité. La seconde étude a quant à elle exploré les différences de sexe potentielles au niveau des activations cérébrales associées à la mémoire émotionnelle dans la schizophrénie et dans la population en général. Nous avons comparé 41 patients atteints de schizophrénie (20 femmes) à 41 participants en bonne santé (19 femmes) alors qu’ils effectuaient la même tâche de mémoire émotionnelle mentionnée plus haut. Or, pour cette étude, nous nous sommes concentrés sur les conditions suivantes : la reconnaissance d’images positives, négatives et neutres. Nous n'avons pas observé de différences entre les hommes et les femmes au niveau des performances à la tâche de mémoire pour aucune des conditions. En ce qui a trait aux données de neuroimagerie, comparativement aux femmes en bonne santé, celles atteintes de schizophrénie ont montré une diminution des activations cérébrales dans les régions corticales du système limbique (p. ex. cortex cingulaire moyen) et dans les régions sous-corticales (p. ex. amygdale) lors de la reconnaissance d'images négatives. Pour ce qui est de la condition positive, elles ont présenté, comparativement au groupe de femmes saines, des diminutions d’activations spécifiquement dans le cervelet ainsi que dans le gyrus frontal inférieur et moyen. Les hommes atteints de schizophrénie, eux, ont montré une augmentation d’activations par rapport aux hommes sains dans le gyrus préfrontal médian lors de la reconnaissance des stimuli négatifs ; ainsi que dans les régions pariétales, temporales et limbiques lors de la reconnaissance des stimuli positifs. Dans un autre ordre d’idées, notre analyse corrélationnelle a mis en évidence, chez les femmes, un lien significatif entre l’activité cérébrale et les symptômes au cours de la mémoire des stimuli positifs, alors que chez les hommes atteints schizophrénie, ce lien a été observé au cours de la mémoire des stimuli négatifs. Bref, l’ensemble de nos résultats suggère, chez les patients atteints de schizophrénie, un fonctionnement cérébral atypique spécifiquement lors de la reconnaissance d’images négatives, mais un fonctionnement intact lors de la reconnaissance de stimuli positifs. De plus, nous avons mis en évidence la présence de différences de sexe dans les activations cérébrales associées à la mémoire épisodique émotionnelle soulignant ainsi l'importance d’étudier séparément les hommes et les femmes atteints de schizophrénie dans le cadre de recherches sur les plans cognitif et émotionnel. / Schizophrenia is characterized by prominent disturbances in cognitive and emotional functioning. For instance, individuals with schizophrenia are often impaired in their memory for emotional events compared to healthy subjects. To date, the limited research on emotional episodic memory in schizophrenia has focused on the effect of valence of affective stimuli (e.g., pleasant vs. unpleasant), while overall ignoring the effect of arousal (e.g., low vs. high) despite evidence of distinct emotional memory processes for high versus low arousing stimuli in the general population, as well as reports of abnormal processing of arousing stimuli in schizophrenia. What’s more, there has yet to be examination of sex differences in the behavioral and neural correlates of emotional memory in this complex psychiatric disorder, which is astonishing considering the substantial evidence of sex differences in almost all features of schizophrenia from prevalence, mean age at onset, clinical presentation, course of illness, response to treatment and brain structure. Accordingly, this thesis examined: (1) the effect of both affective valence and arousal intensity on the brain activations associated with emotional memory in patients with schizophrenia and in healthy control participants and (2) potential sex differences in brain function during emotional memory. The first study aimed to compare cerebral activations in patients with schizophrenia and healthy controls during memory retrieval of emotional images that varied in both valence and arousal. Using fMRI, 37 patients with schizophrenia (% male = 51; mean age =32.46) were compared to 37 healthy participants (% male = 51; mean age =31.81) while performing an emotional memory task. patients with schizophrenia performed worse than healthy controls in all experimental conditions. They showed less cerebral activations in limbic and prefrontal regions than controls during retrieval of negatively valenced stimuli, but had a similar pattern of brain activations to controls during retrieval of positively valenced stimuli (particularly in the high arousal condition) in the cerebellum, temporal and prefrontal cortex. Both groups demonstrated increased brain activations in the high relative to low arousing conditions. The second study explored potential sex differences in the brain activations associated with the recognition of emotional images in schizophrenia and healthy controls. 41 patients with schizophrenia (20 women) were compared to 41 healthy participants (19 women) while performing a yes/no recognition paradigm with positive, negative and neutral images in an fMRI scan. We did not observe sex differences in performance. Compared to healthy women, women with schizophrenia showed a decrease in brain activations in cortical (e.g. middle cingulate) and subcortical limbic structures (e.g. amygdala) during recognition of negative images and decreased activations during the positive condition in the cerebellar vermis, middle and inferior frontal gyrus. Men with schizophrenia had increased activations compared to healthy men in the medial prefrontal gyrus during recognition of negative stimuli and a substantial increase in brain activity during the recognition of positive pictures in parietal, temporal and limbic structures. Correlation analysis revealed significant relationships between brain function and symptoms during positive emotional memory in women and during negative emotional memory primarily in men. Taken as a whole, our results suggest atypical brain function during retrieval of negative pictures, but intact functional circuitry of positive affect during episodic memory retrieval in patients with schizophrenia compared to healthy subjects. Moreover, our findings revealed sex differences in the brain activations associated with emotional recognition memory in patients with schizophrenia; which further highlights the importance of investigating men and women with schizophrenia separately in the context of emotional and cognitive tasks.

Made available in DSpace on 2016-06-02T20:18:16Z (GMT). No. of bitstreams: 1 4093.pdf: 1119616 bytes, checksum: e2ff33f63d45e943c166e8047c606c07 (MD5) Previous issue date: 2012-01-27 / Universidade Federal de Minas Gerais / This study investigated the role of H1 amygdala receptors in state-dependent memory deficits induced by L-histidine (LH).To address this question, we investigated the effects of H1 antagonist chlorpheniramine (CPA) microinjected into the amygdala on anxiety and emotional memory retrieval in mice submitted to the EPM. Experimental subjects were 117 adult male Swiss mice weighing 25-32g at testing. Tests using an elevated plus-maze (EPM) were performed on two consecutive days: Trial 1 (T1) and Trial 2 (T2). Before each trial, mice were intraperitoneally (IP) injected with LH (500mg/kg), a histaminergic precursor. Two hours later, they were microinjected with chlorpheniramine (CPA; 0.016, 0.052, or 0.16 nmol/ 0.1 &#956;l), or saline (SAL) into the amygdala, and five minutes later reexposed to the EPM. For each CPA dose administered, the animals were randomly assigned to four groups based on drug treatment: control (i.p injection and i.a SAL), LH-SAL (i.p injection LH and i.a SAL), SAL-CPA (i.p injection SAL and i.a CPA) and LH-CPA (i.p injection of LH and i.a CPA). The data were analyzed using two-way analysis of variance (ANOVA) and Fisher LSD tests. IP injection of LH and microinjection of CPA into the amygdala did not induce significant T1 differences between groups for percentages of open arm entries (%OAE) or open arm time (%OAT) (ANOVA, p > 0.05), which indicated that the drugs did not affect anxiety. In T2, the control group and the groups that received IP injection of SAL and an 0.016- or 0.052-mnol infusion of CPA (SAL-CPA) demonstrated significant reductions in open arm exploration (%OAE and %OAT) (p < 0.05), suggesting a retrieval of aversive information concerning the open arms. Importantly, the LH groups that received an injection of SAL (LH-SAL) or CPA (LH-CPA) did not exhibit decreased open arm activity; no significant differences in %OAE and %OAT (p > 0.05) were observed between T1 and T2, suggesting that the LH-induced deficit in emotional memory retrieval was not reversed by CPA injection. Furthermore, animals that received IP injections of SAL and 0.16 nmol infusion of CPA (SAL-CPA) did not exhibit decreased open arm exploration in T2 compared to T1 (p > 0.05). No significant changes were observed in the number of enclosed arm entries (EAE), an EPM index of general exploratory activity. Taken together, these results suggest that the H1 receptors in the amygdala are not implicated in anxiety-like behaviors but are involved in emotional memory deficits induced by the T1/T2 EPM protocol in mice. / O objetivo do presente estudo foi investigar o papel dos receptores histaminérgicos H1 sobre o déficit de evocação da memória emocional induzido pela Lhistidina. Para essa investigação, foi verificado o efeito da Clorfeniramina (CPA), antagonista H1, administrada na amídala, sobre a ansiedade e a evocação da memória emocional em camundongos submetidos ao labirinto em cruz elevado (LCE). Foram utilizados 117 camundongos machos da cepa Suíço-Albino, pesando entre 25 e 32 g. O teste comportamental foi realizado em dois dias consecutivos: teste 1 (T1) e teste 2 (T2). Em ambos os dias, as drogas foram administradas pré-teste. Os animais receberam injeção intraperitoneal (i.p) de Lhistidina (LH), precursor histaminérgico, na dose de 500mg/kg, e duas horas depois receberam injeções na amídala (i.a) de SAL ou CPA, nas doses de 0,016nmol/0,1 &#956;l; 0,052nmol/0,1&#956;l e 0,16 nmol /0,1&#956;l. Após cinco minutos da injeção central os animais foram expostos ao LCE. Para cada dose de CPA administrada os animais foram divididos aleatoriamente em 4 grupos experimentais de acordo com o tratamento farmacológico: controle (injeção i.p SAL e i.a SAL); LH-SAL (injeção i.p LH e i.a SAL); SAL-CPA (injeção i.p SAL e i.a CPA); LH-CPA (injeção i.p LH e i.a CPA). Os dados foram analisados usando a ANOVA de duas vias e o teste post hoc de Fisher LSD. A injeção i.p de LH e a infusão de CPA não induziram diferenças significativas entre os grupos em T1 para as medidas de ansiedade (%entradas nos braços abertos, %EBA; % tempo gasto nos braços abertos, %TBA), nas diferentes doses de CPA utilizadas (ANOVA, p > 0.05), indicando que as drogas não induziram efeitos nas medidas de ansiedade. Em T2 houve uma redução significativa na exploração dos braços abertos (%EBA e %TBA) em relação a T1, para os grupos controle e SAL-CPA nas doses de CPA de 0,016 nmol e 0,052 nmo/0,1 &#956;l (p < 0,05), sugerindo uma evocação da aprendizagem aversiva relacionada aos braços abertos. Os grupos LH que receberam infusão de SAL (LH-SAL) ou CPA (LH-CPA) não diminuíram significativamente as %EBA e %TBA (ANOVA, p > 0,05) nas três doses de CPA. Adicionalmete, na maior dose de CPA (0,16 nmol/0,1 &#956;l), apenas o grupo controle diminuiu as %EBA e %TBA (p < 0,05) em T2. Não houve mudanças significativas nas entradas dos braços fechados (EBF) (ANOVA, p > 0,05), medida representativa da atividade locomotora dos animais. Nossos resultados sugerem que a L-histidina e os receptores H1 presentes na amídala não participam dos estados de ansiedade, mas estão envolvidos no comprometimento da memória emocional em camundongos reexpostos ao LCE.

Made available in DSpace on 2016-06-02T20:19:25Z (GMT). No. of bitstreams: 1 6542.pdf: 976115 bytes, checksum: f044b79bc4aa03baa6d20c50be943d15 (MD5) Previous issue date: 2015-02-06 / Universidade Federal de Sao Carlos / This study investigated the effects of bilateral intra-amygdala microinjections of PNU-282987, which is a nicotinic cholinergic agonist, on anxiety and emotional memory as well as the reversal of amnesia induced by an H1 histaminergic antagonist (CPA) in mice subjected to the elevated plus-maze (EPM). For this purpose, two experiments were performed. The subjects were seventynine adult male Swiss mice weighing 25-40g at testing. Behavioral testing was performed on two consecutive days (T1 and T2). In both experiments, the drugs were administered prior to testing. In Experiment 1, the animals received bilateral microinjections of saline (SAL) or PNU-282987 (0.1 nmol) and four experimental groups were tested; i.e., SAL-SAL, SAL-PNU, PNU-SAL and PNU-PNU groups. In Experiment 2, the animals received combined bilateral microinjections of CPA (0.16 nmol) and PNU-282987 on T1 and they were re-exposed to the EPM 24 hours later. Four experimental groups were tested; i.e., SAL-SAL, PNU-SAL, CPA-SAL and CPA-PNU groups. ANOVA followed by Duncan´s tests revealed no significant differences between the SAL and treated groups at T1 in the measurements of anxiety (i.e., % open arm entries and % open arm time, ANOVA, p > 0.05), which indicates that the CPA and PNU did not induce effects on anxiety. The isolated microinjections of PNU-282987 did not produce effects on emotional memory; however, the combined microinjections of PNU-282987 and CPA were able to reverse the deficit in memory induced by CPA (ANOVA, p < 0.05). There were no significant changes in the numbers of enclosed arm entries which served as a measure of locomotor activity (ANOVA, p > 0.05). Taken together, these results suggest that intra-amygdala injections of PNU-282987 did not induce effects on anxiety and emotional memory per se; however, the combined injections of CPA and PNU-282987 reversed the amnesic effects caused by CPA, which is suggestive of an interaction between the histaminergic and cholinergic systems in the modulation of emotion memory acquisition in mice subjected to the EPM. / Os objetivos do presente estudo foram verificar os efeitos das microinjeções bilaterais de agonista colinérgico nicotínico PNU-282987, na amídala, sobre a ansiedade e memória emocional, e analisar se as microinjeções do PNU-282987 revertem o efeito amnésico provocado pelo antagonista histaminérgico H1 Clorfeniramina (CPA) em camundongos submetidos ao labirinto em cruz elevado (LCE). Para essas investigações foram realizados dois experimentos. Foram utilizados 79 camundongos da cepa Suíço-Albino, machos, pesando entre 25 e 40g. O teste comportamental foi realizado em dois dias consecutivos: T1 e T2. No experimento 1, os animais receberam microinjeções bilaterais intra-amídala de salina (SAL) ou PNU (0,1 nmol) pré-T1 e pré-T2. Após cinco minutos da microinjeção, os animais foram expostos ao LCE. Foram formados quatro grupos experimentais: SAL-SAL; SAL-PNU; PNU-SAL; PNU-PNU. No experimento 2, os animais receberam microinjeções combinadas bilaterais intra-amídala de CPA (0,16 nmol) ou PNU (0,1 nmol) apenas pré-T1 Após cinco minutos os animais foram expostos ao LCE; em T2 houve apenas a reexposição. Foram formados quatro grupos experimentais: SALSAL; PNU-SAL; CPA-SAL; CPA-PNU. Os dados foram analisados usando a ANOVA de duas vias e o teste post hoc Duncan. A ANOVA não mostrou diferenças significativas entre os grupos em T1 para as medidas de ansiedade [% entradas nos braços abertos (%EBA); % tempo gasto nos braços abertos (%TBA), p > 0,05]. O PNU, microinjetado per se, não apresentou efeitos na aquisição da memória emocional, entretanto no experimento 2, as microinjeções combinadas de PNU e CPA, foram capazes de reverter o déficit na memória induzido pela CPA (ANOVA, p < 0,05), sugerindo a interação entre esses sistemas na amídala de camundongos reexpostos ao LCE. Não houve mudanças significativas nas entradas dos braços fechados (ANOVA, p > 0,05), medida representativa da atividade locomotora. Os resultados do presente estudo sugerem que as microinjeções do PNU-282987 intra-amídala não apresentaram efeitos sobre a aquisição da memória emocional, entretanto houve uma interação entre os sistemas histaminérgico e colinérgico na amídala na modulação da aquisição da memória emocional em camundongos reexpostos ao LCE.

Vários estudos utilizando modelos animais têm demonstrado que estruturas límbicas como amídala (AMD), hipocampo dorsal (HD) e córtex pré-frontal medial (CPFm) participam na consolidação da memória associada às emoções. Considerando que a síntese de novas proteínas é necessária para o processo de consolidação de memórias, e que a combinação entre o uso de inibidores de síntese proteica e diferentes intensidades de estímulo incondicionado têm gerado respostas comportamentais distintas com relação à consolidação da memória emocional, o presente trabalho se propôs a investigar a hipótese de a consolidação da memória aversiva na AMD, no HD e no CPFm, associada a síntese proteica, ocorre de maneira diferenciada nessas três estruturas, de acordo com a intensidade do estímulo aversivo, bem como se a expressão de genes envolvidos na transmissão histaminérgica seria modificada ao longo das fases da memória emocional aversiva. O objetivo do presente estudo foi avaliar o papel da síntese proteica na AMD, HD e CPFm no processo de consolidação de uma memória aversiva baseada em condicionamento aversivo moderado ou intenso; investigar a expressão de genes ligados a transmissão histaminérgica na AMD, HD e CPFm após o condicionamento aversivo intenso. Para este fim dois experimentos foram realizados: No experimento 1 a anisomicina (ANI) foi microinjetada bilateralmente na AMD ou HD ou CPFm de camundongos antes de serem submetidos a tarefa de esquiva inibitória do tipo step-down utilizando duas intensidades de estímulo incondicionado: moderada ou intensa. No experimento 2, as variações da expressão dos genes da enzima HDC (histidina descarboxilase responsável pela síntese de histamina) e dos receptores H1, H2 e H3 foram analisadas em diferentes espaços temporais através da reação de polimerase em cadeia em tempo real. Os resultados do experimento 1 demonstram que microinjeção de ANI no CPFm prejudica a consolidação da memória de esquiva inibitória com estímulo incondicionado moderado ou intenso, porém quando administrada intra-AMD e intra-HD, a ANI só prejudica a consolidação da memória de esquiva inibitória com estímulo incondicionado intenso. No experimento 2 demonstra que durante a consolidação da memória aversiva intensa há diminuição nos níveis de expressão dos genes: HDC no HD, Hrh3 na AMD, Hrh1 e Hrh3 no CPFm. Já na fase de evocação, na AMD há aumento e diminuição na expressão dos genes HDC e Hrh3, respectivamente; no HD há aumento na expressão dos genes Hrh2 e Hrh3 e no CPFm há aumento na expressão do gene HDC e diminuição nos genes Hrh1 e Hrh3. Durante a reconsolidação há diminuição na expressão dos genes HDC e Hrh3 e aumento do gene Hrh1 na AMD. No DH há aumento com relação ao gene Hrh1, e no CPFm há aumento do gene HDC e diminuição na expressão dos genes Hrh1 e Hrh3. No presente estudo conclui-se que em situações com moderado grau de aversividade, a consolidação dessa experiência não dependerá de síntese proteica na AMD e no HD, mas sim no CPFml. No entanto, em situações com elevado grau de aversividade, a síntese proteica na AMD, HD e CPFm é essencial para a consolidação de tal experiência. Além disso, os genes HDC, Hrh1, Hrh2 e Hrh3 se expressam distintamente na AMD, HD e CPFm ao longo da escala temporal da consolidação, evocação e reconsolidação da formação de memórias de medo. / Several studies using animal models have shown that limbic structures like the amygdala (AMG), dorsal hippocampus (DH) and medial prefrontal cortex (mPFC) are involved in emotional memory consolidation. Whereas the synthesis of new proteins is necessary for memory consolidation process, and that opposite results related to the interaction of protein synthesis inhibitors and foot-shock intensity on memory consolidation have been reported, the present study aims to investigate the hypothesis of protein synthesis in AMG, the DH and mPFC associated with the consolidation of aversive memory occurs differently in these three structures, according to the intensity of the aversive stimulus and the expression of proteins involved in histaminergic transmission would be modified during the process of consolidation and emotional expression of aversive memory. The aim of this study was to evaluate the role of protein synthesis in AMG, DH and mPFC in consolidation of aversive memory based on moderate and intense conditioning; to investigate the expression of proteins related to histaminergic transmission in AMG, DH and mPFC after intense aversive conditioning. For this purpose two experiments were performed: in experiment 1 the anisomycin (ANI) was bilaterally microinjected into AMG or DH or mPFC of mice before being submitted the step-down inhibitory avoidance task using two unconditioned stimulus intensities: moderate or intense. In experiment 2, the variations in the gene expression of HDC enzyme (histidine decarboxylase - responsible for histamine synthesis) and the H1, H2 and H3 receptors were analyzed at different temporal spaces by real-time polymerase chain reaction (RT-PCR). The results of the first experiment demonstrate that microinjection of ANI in mPFC impairs the consolidation of inhibitory avoidance memory with moderate or intense unconditioned stimulus, however when administered intra-AMG and intra DH, ANI only impairs the consolidation of inhibitory avoidance memory under an intensive unconditioned stimulus. The experiment 2 demonstrates that during the consolidation of intense aversive memory there is a decrease of the genes expression levels: HDC in the dorsal hippocampus, Hrh3, Hrh1 in the amygdala, and Hrh3 in the medial prefrontal cortex. During retrieval the HDC and Hrh3 genes expression levels are increased and decreased, respectively in the AMG; the Hhr2 and Hrh3 genes expression levels are increased in the DH, and in the mPFC the HDC gene expression level is increased, and the Hrh1 and Hrh3 are decreased. During reconsolidation the amygdalas HDC and Hrh3 genes expression levels are decreased and the Hrh1 gene is increased. In the DH the Hrh1 gene levels are elevated and in the mPFC the HDC gene expression level is increased and the Hrh1 and Hrh3 are decreased. In the current study we conclude that under moderate aversiveness situations, the consolidation of this experience does not depend on protein synthesis in the AMG and in the DH, but in the mPFC. However, in situations with a high level of adversity, protein synthesis in this three structures are essential for the consolidation of such experience. In addition, the histaminergic genes are distinctly expressed in the AMG, DH and mPFC along the time scale of consolidation, retrieval and reconsolidation of the formation of fear memories.