Submitted by Viviane Lima da Cunha (viviane@biblioteca.ufpb.br) on 2016-08-19T14:12:14Z No. of bitstreams: 1 arquivototal.pdf: 1783924 bytes, checksum: cd370846eb175ca5a7541394c0b1e78d (MD5) / Made available in DSpace on 2016-08-19T14:12:14Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1783924 bytes, checksum: cd370846eb175ca5a7541394c0b1e78d (MD5) Previous issue date: 2016-03-31 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Episodic memory is a declarative type of memory rich in temporal and spatial contexts. This type of memory has been atributed only to humans, but animals have been demonstrating an episodic-like memory, based on behavioural criteria and, considered as a memory for a particular event (“what”) that happened in a particular place (“where”) and in a particular time (“when”). To be considered as an episodic-like memory, these behavioural aspects must be evoked in an integrative and associative way, excluding any possibility of being evoked separately. For a long time it has been demonstrated that the medial temporal lobe (MTL) is important for processes involving episodic-like memory characteristics and, the hippocampus and other areas, such as the perirhinal, postrhinal, entorhinal and medial prefrontal cortices seem to be involved in one or more of episodic-like memory behavioural aspects. In this work we sought to investigate the role of the hippocampal subfield CA1 with bilateral infusions of the GABAA agonist muscimol, in an integrative episodic-like memory task. 24 naïve male wistar rats, ranging from 3 to 4 months, weighing 270-360g and kept in controlled coditions, were used as subjects. This task is done in an open-field and it depends on the tendency of rats to explore novelty. There were three trials: sample 1, sample 2 and test. Each one had a duration of five minutes and the intertrial interval was of 1 hour. In sample 1, rats were allowed to explore four novel objects (A) in specific locations. In sample 2, four new objects (B) were disposed in the open-field, where two of them were placed in locations previously occupied by objects “A”, and two of them were placed in new positions. In the test trial, animals were exposed to four copies of previously seen objects, where two of them were stationary to its initial position (A1 and B1) and another two were displaced (A2 and B2). The pattern of exploration expected to this task is of A1>B1 (temporal pattern), B2>B1 (spatial pattern) and A1>A2 (integrative pattern). Animals of the control group did evoked an episodic-like memory in the test trial, while the animals in the experimental group didn’t. This was not influenced by a lack of exploration in the muscimol group. Histology showed that the cannulae and niddle tips were placed in the right positions. Altogether, our data provides evidence that CA1 plays an essential role in the recollection of the episodic-like memory components, although it’s not clear if it does by having a role in the recognition of objects alone, or on the association of temporal and spatial aspects of episodic-like memory. / A memória episódica é uma memória declarativa rica em contexto espacial e temporal. Este tipo de memória tem sido atribuído apenas a humanos, mas alguns animais têm demonstrado uma memória similar à episódica, baseada em critérios que podem ser mostrados através do comportamento e, tida como a memória para eventos (“o quê”) que ocorreram em um devido local (“onde”) e num determinado espaço de tempo (“quando”). Para ser considerada uma memória similar à episódica, estes aspectos comportamentais devem ser evocados de forma integrada e associativa, não havendo a possibilidade de se recordar cada aspecto separado. Há algum tempo tem sido demonstrado que o lobo temporal medial (LTM) é importante para processos que envolvem características da memória similar à episódica e, o hipocampo e áreas como os córtices perirrinal, pósrrinal, entorrinal e pré-frontal medial parecem estar envolvidas em um ou mais dos aspectos comportamentais deste tipo de memória. Neste trabalho nós procuramos avaliar o papel da área hipocampal CA1 em uma tarefa de memória similar à episódica integrativa dos três aspectos comportamentais através da inativação bilateral com o agonista GABAA muscimol. Para tal, utilizamos 24 ratos wistar machos de 3 a 4 meses de idade, pesando entre 270-360g e mantidos em condições controladas. Esta tarefa é realizada em uma arena circular e é baseada no paradigma da novidade, que aponta que em estado saudável, ratos sempre vão preferir explorar algo novo. Foram realizadas três sessões na tarefa: a sessão de amostra 1, amostra 2 e teste. Cada sessão teve duração de cinco minutos e o intervalo entre sessões foi de uma hora. Na sessão de amostra 1 foi permitido que o animal explorasse quatro objetos novos (A) em disposições específicas. Na sessão de amostra 2 quatro novos objetos (B) foram expostos, sendo dois alocados em posições ocupadas pelos objetos “A” e dois em novas posições. Na sessão de teste os animais entraram em contato dois objetos da primeira sessão e, dois objetos da segunda sessão, onde um objeto de cada sessão era estacionário em relação à sua posição inicial (A1 e B1) e outro objeto era deslocado (A2 e B2). O padrão de exploração esperado para esta tarefa é de A1>B1 (padrão temporal), B2>B1 (padrão espacial) e A1>A2 (padrão integrativo). Os animais do grupo controle conseguiram evocar o episódio na sessão de teste da tarefa, enquanto que os animais do grupo experimental não conseguiram e, isto não foi influenciado por uma falta de motivação em explorar por parte do grupo experimental. Um exame histológico verificou a posição correta das cânulas e agulhas de infusão para a área CA1. Concluímos que CA1 é importante para a resolução da tarefa, mas não fica claro se o é por influenciar no reconhecimento de objetos, ou porque influenciou diretamente no processamento dos aspectos espacial e temporal.

Previous research has shown that individuals who are inconsistently handed (IH) outperform consistently handed (IH) individuals on episodic and spatial memory tasks as well as many others. This current study examines whether handedness is related to a person’s ability to recall autobiographical memories (AM) - episodic memories about oneself. Participants were first asked to recall seven memories that will be cued by seven cue words: earth, friend, dream, power, love, trouble, and opinion. They later expanded on those memories to include more detail, then self-rated how well they were able to remember them on five aspects of AM (spatial layout, content, reliving, vividness, and belief) using a modified version of the Autobiographical Memory Questionnaire (AMQ). Ninety-seven participants (44.3% female, Age: 19 to 69 years) were included in the data analysis. All ninety-seven were recruited through Amazon’s Mechanical Turk system and were financially compensated for their time. Results showed no main effect of handedness on AM in regards to all five AM aspects tested, meaning IH’s did not outperform CH’s in regards to autobiographical memory recall.

The primary aim of this study was to establish whether redintegrative effects can be revealed under conditions with complex sensory stimulation.  Specifically, would the cortical activity involved in the single-trial, passive encoding of a movie, be reactivated when subsequently exposed to a unisensory component of that movie, e.g. an audio- or visual-only segment?  High-density electrical neuroimaging analysis in the frequency domain was used to assist this aim.  The statistical comparisons revealed a greater number of oscillating neuronal regions across all frequency bands in participants who received audiovisual stimulation prior to unisensory exposure (compared to participants who experienced the same unisensory stimulus without prior audiovisual stimulation).   This difference between groups was significant in the alpha2 (right frontal lobe) and gamma (right frontal, sub-lobar and temporal lobes) frequencies during audio-only stimulation.    This enhanced cortical activity during unisensory stimulation suggests that participants were retrieving associated memory traces from their prior multisensory experience, although specific redintegrative effects could not be confirmed.

Understanding the mnemonic functions of the brain has been extensively facilitated by the development of functional neuroimaging techniques such as positron emission tomography (PET) and functional magnetic resonance imaging (fMRI). The present thesis aims at investigating the neural mechanisms underlying memory for personally experienced events (episodic memory), using PET. In paper I, similarities between encoding and retrieval of enacted (motor) information were explored. We observed increased retrieval activation in right premotor areas in the brain when sentences encoded by motor enactment and sentences encoded by maintenance rehearsal were contrasted. In paper II, overlap between encoding and retrieval was explicitly tested for three types of event information: spatial, item, and temporal. Using conjunction analyses, we found that encoding and retrieval of spatial information was associated with increased brain activity in bilateral inferior parietal regions. Encoding and retrieval of item information were related to increased activation in right inferior temporal cortex, and encoding and retrieval of temporal information were associated with increased activation in left inferior temporal and left inferior frontal cortex. In paper III, brain activity associated with retrieval success was examined. Conditions included three levels of retrieval success (high, medium, and low level), for two types of information (pictures and sentences). The results showed a pattern of activation that distinguished between brain regions involved in processing of sentences vs. processing of pictures. A second pattern that distinguished between brain regions involved in encoding vs. retrieval processes, irrespectively of material (sentences and pictures) and retrieval success, was also found. The manipulation of retrieval success was associated with systematic changes in the correlation between material specific regions and other areas of the brain. In study IV, changes in activation related to successful retrieval of pictures were investigated. More specifically, we expected to find decreases in infero-temporal (IT) regions of the brain that were associated with successful recognition memory. As expected, we found a region in left IT cortex that showed decreased activation related to memory for event information. This decrease in activation could be dissociated from responses related to novelty detection, and perceptual priming. The results from study I and II are discussed in relation to findings and theories regarding similarities between encoding and retrieval processes, and reactivation of modality-specific brain areas important for memory storage. The results from studies III and IV are discussed in relation to differences between encoding and retrieval processes, e.g. asymmetric frontal activation and sub-processes of episodic memory, such as retrieval mode, retrieval success, and novelty detection. Taken together, the studies show that different episodic memory processes are correlated with distinct brain areas, hence supporting the view that remembering is based on multiple component processes. / digitalisering@umu.se

Declarative memory is characterized as a conscious, explicit memory. Declarative memory consists of two essential systems, semantic memory and episodic memory. Episodic memory enables us to recall specific past events. A simplified model, so called Episodic-like memory is often used to study episodic memory mechanisms. According to this model, all events are stored in a contextual framework consisting of three basic components: identity of the object ('what' happened), temporal information ('when' it occurred) and spatial information ('where' did it happen). This type of memory is testable not only in humans but also in animal models. Aim of this diploma thesis is to study the neuronal substrate of individual components of episodic memory in healthy volunteers by means of functional magnetic resonance imaging (fMRI) and ecologically valid tasks designed in virtual reality environment. Results obtained in the fMRI paradigm show that apart from common neuronal substrate of episodic memory, additional brain structures are responsible for recollection of individual components of the episodic-like memory. Behavioral data indicate that the demands of the recollection of individual components is not equivalent. Additional analyses with parcellation of the brain to individual structures and consecutive...

Episodic memory is a key feature in learning. One must remember past events to act upon a present situation. Episodic memory has been reported to be impaired in individuals with schizophrenia. In order to have an intact episodic memory the contextual features (context) must be bound to the content of the event; this mechanism is referred to as contextual binding. It is proposed that binding errors during the encoding process are responsible for episodic memory impairments in schizophrenia. Since the hippocampal formation is considered to be the central element for contextual binding, it is hypothesized that the synaptic disorganization described in this condition results in such a deficit. Moreover, the hippocampus mediates and influences other cognitive processes such as learning and executive functioning. Hence, a contextual binding deficit can have important consequences on cognition, behaviour and emotions. The object of this dissertation was to investigate the neurofunctioning, neuroanatomy and neurofunctional connectivity of the hippocampus while performing a task that utilized contextual binding mechanisms. Since spatial relational processing is part of contextual binding and is rooted in the hippocampal regions, visuospatial navigation, more precisely a wayfinding task, was used as a probe to activate the hippocampus and its associated regions in a group of patients with schizophrenia and matched healthy controls. The following dissertation presents three original research papers contributing to our understanding of the contextual binding and hippocampal deficits in schizophrenia. The first paper investigates the neurofunctioning of the hippocampus with a wayfinding task. The second paper investigates the hippocampal structural abnormality in schizophrenia and how it relates to performance during the wayfinding task. The third paper explores effective connectivity of the hippocampus with other brain regions involved in navigation in schizophrenia with a particular interest in the prefrontal cortex. These three studies demonstrate significant neurofunctional, neuroanatomical, and neurofunctional connectivity deficits in the hippocampus of the patients with schizophrenia compared to a healthy control population. Results of all three papers are further discussed in terms of research and clinical implications.

Orientador: Elenice Aparecida de Moraes Ferrari / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-24T09:45:43Z (GMT). No. of bitstreams: 1 Mendes_RubiaAparecidaPereiradeCarvalho_M.pdf: 3863370 bytes, checksum: 488ca978a38a7cb5f131a008fc5ceac4 (MD5) Previous issue date: 2013 / Resumo: Este estudo investigou a distribuição do cronotipo (matutino, intermediário e vespertino), a sonolência diurna, o desempenho em testes de memória e de compreensão de leitura em estudantes do turno da manhã e da tarde (12 a 17 anos). Na Fase 1, foram utilizados o Questionário de Cronotipo (HO) e o formulário para identificação de queixas de sono (n = 435). Na Fase 2 (n = 81) utilizou-se a Escala de Sonolência de Karolinska (KSS) aplicada imediatamente antes da sessão de testes, que ocorreram em dois horários (7h00 e 16h45), as Escalas de Leitura (EL) e de Desempenho Escolar em Língua Portuguesa (ED), o Teste de Extensão de Dígitos direto e inverso (SPANdir; SPANinv), o Teste dos Blocos de Corsi direto e inverso (CORSIdir; CORSIinv), o Teste de Memória Episódica imediato e tardio (MEI; MET) e o Teste de compreensão da leitura (CLOZE). Os resultados mostraram uma distribuição normal para os diferentes cronotipos, com aumento na vespertinidade em adolescentes mais velhos. As queixas mais freqüentes (Teste qui-quadrado) foram insônia e muita necessidade de sono predominantes em vespertinos, independentemente do turno de estudo. Os adolescentes de cronotipo matutinos estavam menos sonolentos em relação aos vespertinos, em ambos os horários testados, sendo que os testados no horário da tarde estavam menos sonolentos que os da manhã (ANOVA; p < 0,05). A pontuação média na EL e ED classificou os adolescentes em alto nível acadêmico (ANA), média = ou > que 5 (n = 50) e baixo nível acadêmico (BNA), média < que 5 (n = 31). A análise do conjunto de dados de todos os 81 sujeitos (ANA e BNA) mostrou melhor desempenho no teste CORSIinv realizado no horário da tarde (R = -0,5) em adolescentes vespertinos e no teste MET no horário da manhã (R = -0,4) em adolescentes menos sonolentos (Teste de Spearman; p < 0,05). Quando se analisou apenas os sujeitos ANA observou-se melhor desempenho dos adolescentes matutinos nos testes SPANinv realizados no horário da manhã (R = 0,3) e no teste MEI no horário da tarde (R = 0,4). Também foi verificado melhor desempenho em adolescentes menos sonolentos nos testes CORSIinv (R = -0,6) e CLOZE (R = -0,5) realizados no horário da manhã (Teste de Spearman; p < 0,05). Em conjunto, essas análises demonstraram que o cronotipo, a sonolência diurna, o nível de leitura e o desempenho escolar exercem influência no desempenho em testes de memória. Mais ainda, mostram a importância de se avaliar o nível acadêmico do indivíduo para precisar a relação que cronotipo e a sonolência exercem sobre a memória / Abstract: This study investigated the distribution of different chronotypes (morning, indifferent and evening), the diurnal sleepiness, the performance in tests of memory and reading comprehension in students (12-17 years old) of both morning and afternoon school periods. In the Phase 1, we used the Chronotype Questionnaire (HO) and Sleep Complaints form (n = 435). In Phase 2 (n = 81) there has been used the Karolinska Sleepiness Scale (KSS) immediately before the morning (7am) and afternoon (4:45pm) testing sessions, the Reading (SR) and School Performance in Portuguese Language (SP) Scales, the Digit Span (direct, SPANdir and inverse, SPANinv), Corsi Block (direct, CORSIdir and inverse, CORSIinv), Episodic Memory (immediate, IEM and late, LEM) and the reading comprehension test (Cloze). The results showed a normal distribution of the different chronotypes, with increased eveningness in older adolescents. The most frequent sleep complaints ( x -square test) were the need for longer sleep duration and the insomnia. Those complaints were more frequent in the evening type adolescents, regardless of the school period. The morning type adolescents were less sleepier than the evening type adolescents in both testing times, but during afternoon sessions they were less sleepier than during the morning sessions (ANOVA; p < 0,05). The adolescents were classified in high (HAL, score > 5, n = 50), or low academic level (LAL, score < 5, n = 31), accordingly to their SR and SP average score. The analysis considering all the 81 adolescents (ANA e BNA) indicated that evening type had better performance than the morning type adolescents in the CORSIinv test conducted at the afternoon time (R = -0.5), whereas less sleepy adolescents showed better performance than more sleepy adolescents (R = -0.4) in the MET test during the morning session (Spearman test; p < 0.05). Data analysis of the HAL students only showed that morning type adolescents performed better than evening type adolescents in the SPANinv test conducted in the morning (R = 0.3) and MEI test conducted in the afternoon (R= 0.4). Also the performance in CORSIinv (R = -0.6) and CLOZE tests (R = -0.5) was better in less sleepy than in more sleepy adolescents during the morning sessions (Spearman test; p < 0.05). Together, these results demonstrate that the performance of adolescents in memory tests can be influencied by their chronotype, sleepiness and level of academic performance. Furthermore, this study demonstrates that assessment of the academic level helps to clarify the role that chronotype and sleepiness have on memory / Mestrado / Fisiologia / Mestra em Biologia Funcional e Molecular

Effects of episodic exposures have gained attention as the regulatory focus of the Clean Water Act has shifted away from continuous-flow effluents. Standardized laboratory toxicity tests require that exposure be held constant. However, this approach may not accurately predict organism responses in the field following episodic exposures such as those associated with rain-driven runoff events or accidental pollutant discharge. Using a modified version of the 7-day short-term chronic test recommended by the US Environmental Protection Agency, Ceriodaphnia dubia were exposed to copper or cadmium for durations ranging from 1 minute to 24 hours. In addition, adult reproductive recovery and effects on second generation individuals was assessed following select copper exposures. Finally, cadmium exposures were compared in reconstituted hard water (RHW) and municipal treated wastewater effluent (TWE). Following exposure, organisms were transferred to clean RHW or TWE and maintained for the remainder of the test. No- and lowest observed effect concentrations (NO- and LOECs) increased logarithmically with respect to logarithmic decreases in duration regardless of metal, endpoint or water type. Effective concentrations of cadmium however, were usually higher than those of copper, especially in TWE. LOECs for C. dubia survival following 24-hour and 5-minute exposures to copper were 116 and 417 µg/L, respectively. LOECs for fecundity were 58 and 374 µg/L, respectively. Neonate production of first generation adult C. dubia appeared to recover from pulsed copper exposure upon examination of individual broods. Cumulative mean neonate production however, showed almost no signs of recovery at exposure durations ≥3 hours. Pulse exposure to copper also resulted in diminished fecundity of unexposed second generation individuals. Such effects were pronounced following parental exposure for 24 hours but lacking after parental exposures ≤3 hours. LOECs for C. dubia survival following 24-hour and 5-minute exposures to cadmium in RHW were 44 and 9000 µg/L, respectively. LOECs for fecundity were 16 and 5000 µg/L, respectively. In TWE, LOECs for C. dubia survival were 83 and >10,000 µg/L, respectively. LOECs for fecundity in TWE were 48 and 7000 µg/L, respectively. Runoff pollution is site and event specific, however, data presented herein may be useful as a predictive tool under various conditions.

L’objectif de cette thèse était d’étudier les processus impliqués dans la localisation temporelle des événements personnels futurs chez les sujets sains et les patients atteints de schizophrénie. Pour cela, nous avons utilisé la méthode de réflexion à voix haute dans trois études expérimentales pour analyser les stratégies utilisées pour déterminer la localisation temporelle des événements autobiographiques. Dans l’Etude 1, nous avons constaté que les participants utilisaient principalement des processus de reconstruction/d’inférence pour dater les événements. Ils s’appuyaient le plus souvent sur des connaissances autobiographiques (c.-à-d., des périodes de vie/événements étendus) et des connaissances générales pour reconstruire ou inférer le moment des événements, à la fois pour les événements passés et futurs. Dans l'Etude 2, nous avons constaté que les buts personnels influençaient le processus de localisation temporelle en augmentant l'accès direct à la date des événements futurs importants et en favorisant l'utilisation de connaissances autobiographiques pour inférer le moment des événements lorsque les dates ne sont pas directement accessibles. Dans l’Etude 3, nous avons constaté que les patients atteints de schizophrénie avaient des difficultés à s’appuyer sur des informations épisodiques pour reconstruire ou inférer la date des événements personnels, et qu’ils commettaient davantage d’erreurs que les participants témoins lorsqu’on leur demandait de classer dans l’ordre chronologique les événements précédemment datés. Sur la base de ces nouvelles découvertes, nous proposons un modèle à double processus pour la localisation temporelle des événements autobiographiques qui articule les mécanismes cognitifs engagés dans la datation des événements passés et futurs. / The aim of this thesis was to investigate the processes involved in the temporal location of personal future events in healthy individuals and in patients with schizophrenia. To do so, we used a think-aloud procedure in three experimental studies to analyse the strategies used to determine the times of autobiographical events. In Study 1, we found that participants mostly used reconstructive/inferential processes to date events. They relied most frequently on autobiographical knowledge (i.e., lifetime periods/extended events) and general knowledge to reconstruct or infer the times of events, both for past and future events. In Study 2, we found that personal goals influenced the temporal location process by increasing the direct access to the times of important future events, and by favouring the use of autobiographical knowledge to infer the times of events when dates are not directly accessible. In Study 3, we found that patients with schizophrenia had difficulties to rely on episodic information to reconstruct or infer the times of personal events, and made more errors when they were asked to temporally order the previously dated events. Based on these novel findings, we propose a dual-process model of the temporal location of autobiographical events that articulates the cognitive mechanisms engaged in the dating of past and future events

Animal episodic-like memory tasks represent important component of episodic memory research. However, currently available episodic-like memory tasks are not based on episodic-like memory or encompass important caveats. In our laboratory, we recently devised a novel one-trial trace association task (OTTAT) to examine one-time associations of temporally discontinuous stimuli. This thesis deals with the improvement of OTTAT protocol by rat strain and compartment divider ('doors') selection which optimally promote the establishment of invariable behaviour of rats in OTTAT. Moreover, the accuracy of one-trial associations is also assessed by determining specificity of "rapid escape" response to conditioned stimulus of given sound characteristics. In Experiment 1, rats (Sprague-Dawley (SD), n = 36; Wistar (WI), n = 17; Long-Evans (LE), n = 8) were habituated 15 min daily for 3 days with standard doors (9 x 11 cm opening) to modified light and dark apparatus. The number of transfers between compartments and values of time spent in dark compartment obtained from 3rd habituation session were evaluated as indicators of invariable behaviour of rats. We found WI rats spend significantly more time in dark compartment than LE (p = 0.002) and SD rats (p = 0.001) and have significantly fewer transfers than LE rats...