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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Time Until Subsequent Pregnancy After Intrauterine Fetal Demise and Early Infant Death Based on Grieving Strategies

Delhomme, Gertride 01 January 2023 (has links) (PDF)
The purpose of this research is to evaluate the coping strategies of families and childbearing women after intrauterine fetal demise and early infant death. The secondary purpose is to examine the effect of grieving strategies after intrauterine fetal demise compared to early infant death on time until subsequent pregnancy in women of childbearing age. A literature review exploring parental grief and coping strategies to cope with loss and its effect on the subsequent pregnancy was conducted from various online databases. All reviewed articles in the analysis indicated that coping strategies consist of a diverse number of mechanisms during the bereavement process. Results show that positive mechanism such as talking about the experience of fetal and infant death was beneficial in the grieving journey and showed a positive correlation to a shorter time to subsequent pregnancy. Identification of strategies to improve mental health in women after fetal demise and early infant death are of value to pregnancy counseling following demise and improving time to conception outcomes after emotional trauma caused by perinatal loss. There is great value in understanding the connection between conception after the early death of an infant and intrauterine fetal demise in helping healthcare providers support family planning goals.
22

Analysis of the effectiveness of the Circle of Care Program in increasing life outcomes among teen mothers in Troup County, Georgia

Brace, Andrea Michelle 02 May 2009 (has links)
Troup County, Georgia has been afflicted with elevated teen pregnancy and subsequent teen pregnancy rates. As a result, Circle of Care was developed to reduce the subsequent teen pregnancy rate within Troup County. Circle of Care works with pregnant and parenting teens and their families to enhance their quality of life. A case manager provides information, education and support to enable the teens to stay in school, prevent subsequent teen pregnancies, and prevent child abuse and neglect. This study evaluates the effectiveness of Circle of Care by determining if intensity and duration of program participation have an impact on achieving the desired outcomes for program participants. The results of this research suggest that Circle of Care is reducing subsequent teen pregnancies, increasing educational attainment and decreasing child abuse and neglect among program participants.
23

Residues in Succession U-Net for Fast and Efficient Segmentation

Sultana, Aqsa 11 August 2022 (has links)
No description available.
24

Maternidade e relação mãe-bebê no contexto do luto materno

Silva, Priscila Nassif da 31 January 2012 (has links)
Submitted by Maicon Juliano Schmidt (maicons) on 2015-07-10T14:41:57Z No. of bitstreams: 1 Priscila Nassif da Silva.pdf: 877431 bytes, checksum: 2e187b6f20ed2dbf73423d5ff3e0a022 (MD5) / Made available in DSpace on 2015-07-10T14:41:57Z (GMT). No. of bitstreams: 1 Priscila Nassif da Silva.pdf: 877431 bytes, checksum: 2e187b6f20ed2dbf73423d5ff3e0a022 (MD5) Previous issue date: 2012-01-31 / Nenhuma / Esta Dissertação de Mestrado aborda a maternidade e a relação mãe-bebê no contexto do luto materno. Compõe-se de dois artigos, um teórico e um empírico. O artigo teórico é uma revisão sistemática da literatura sobre luto materno e filho subsequente e, para sua realização, foi efetuada uma busca nas bases de dados nacionais Scielo, Lilacs e BVS-Psi com as palavras-chave luto materno, mãe enlutada e mãe e luto. Realizou-se, também, uma busca nas bases de dados internacionais Scopus, ScienceDirect e Pubmed, com as palavras-chave grieving mother, bereaved mother e mourning mother, compreendendo o período de 2000 a 2012. Do total de 1953 encontrados, apenas 17 preencheram os critérios de inclusão. Os resultados indicam que a relação com o filho subsequente é mais abordada em estudos internacionais do que em estudos nacionais. Além disso, o número de estudos internacionais que abordaram a gravidez após a perda é maior do que aqueles que investigaram a relação com o filho após o nascimento. O estudo empírico teve como objetivo investigar de que forma a mãe vivencia a nova maternidade após a perda de um filho e compreender como essa vivência pode repercutir na relação com o novo bebê na primeira metade do primeiro ano de vida do mesmo. As participantes foram quatro mulheres adultas, com idades entre 20 e 38 anos. Eram mães de recém-nascidos de até seis meses de idade, com histórico de perda anterior de um filho, independente da idade e do tempo decorrido da perda. Foram utilizados como instrumentos o Instrumento de Avaliação da Perturbação de Luto Prolongado (PG-13), entrevistas semi-estruturadas sobre o luto materno, e sobre a experiência da maternidade atual e a relação com o novo bebê, além da observação da interação mãe-bebê. Cada caso foi analisado individualmente, buscando-se as suas particularidades, e depois comparado aos demais, a fim de investigar as convergências e divergências entre eles. Os resultados apontam que embora as mães ainda estejam apresentando indícios de luto, três delas parecem estar constituindo vínculo adequado com seus filhos subsequentes. Apenas uma das participantes parece apresentar bastante dificuldade de vinculação com a filha. / This Master ́s Dissertation discusses motherhood and mother-infant relationship in the context of maternal grief. It consists of two papers, one theoretical and one empirical. The theoretical paper is a systematic review of the literature on maternal and child bereavement and subsequent to its execution, a search was conducted in national databases Scielo, Lilacs and BVS-Psi with keywords grieving mother, bereaved mother and mother and mourning. Was performed also a search in international databases Scopus, ScienceDirect and PubMed with the keywords Grieving mother, bereaved mother and mourning mother, comprising the period from 2000 to 2012. Of the total of 1953 found only 17 met the inclusion criteria. The results indicate that the relationship with his son addressed in subsequent studies is more international than in national studies. Furthermore, the number of international studies that addressed the pregnancy after loss is greater than those who investigated the relationship with the child after birth.The empirical study aimed at investigating how the mother experiences the new maternity after the loss of a child and understand how this experience may influence the relationship with the new baby in the first half of the first year of life the same. The participants were four adult women, aged between 20 and 38 years. They were mothers of newborns up to six months of age, with a history of previous loss of a child, regardless of age and elapsed time of loss. Were used as instruments of the Assessment Instrument Prolonged Grief Disorder (PG-13), semi-structured interviews about the grieving mother, and about the experience of motherhood and current relationship with the new baby, and the observation of mother-infant interaction. Each case was analyzed individually, seeking their particularities, and then compared to the others in order to investigate the similarities and differences between them. The results indicate that although mothers are still showing signs of mourning, three of them seem to constitute adequate link with subsequent children. Only one of participants seems to have enough trouble linking with his daughter.
25

Role sester v pooperační péči u pacientů s karcinomem plic / Role of nurses in postoperative care in patients with lung cancer.

PLECEROVÁ, Jana January 2019 (has links)
The objectives of the work The objective of this work has been set as the mapping of degree of patient's contentment/ rate of patient's satisfaction in view of the nurse's approach within the scope of the post-thoracic operation care and the evaluation/ assessment whether the needs of the aforementioned patients have been satisfied. Another objective of the research enquiry has been set as finding out the level of the nurse's awareness regarding the ways and possibilities of the subsequent care. Methodology For the purpose of the research enquiry the form of qualitative research has been chosen and adopted, which has been applied and performed by means of using a method of interviewing i.e. putting questions which have been prepared beforehand, well in advance. Research array of patients consisted of 10 patients from one hospital (which is not going to be specified in this work) as well as 8 nurses whose job was to take care of the post-operative patients/ the post-thoracic operation patients. The results of the research have been processed by applying the method of open coding, pencil-paper method. Assets and Benefits of this Work The research enquiry has showed certain level of absence of desirable knowledge as well as ignorance of the staff taking care of the patients regarding the ways of subsequent care. Nurses should be educated about the possibilities of home care, hospice care as an integral part of their profession. The results gained by research enquiry process could be presented at seminars, conferences aimed at the subsequent care.
26

Injuries among individuals with pre-existing spinal cord injury: understanding injury patterns, burdens, and prevention

Heiden, Erin Ose 01 December 2013 (has links)
As a growing body of research has focused on the individual, social, and environmental factors that facilitate life after spinal cord injury (SCI), particular emphasis has been placed on health conditions that are modifiable and preventable. Subsequent injuries are a serious health problem for individuals with SCI. They are a direct threat to further morbidity and mortality, and are both a cause and consequence other secondary health conditions. As a first step toward understanding this public health problem, the purpose of this dissertation research was to describe the patterns, burdens, and prevention of subsequent injury among individuals with SCI. In three distinct, but related studies, this dissertation examined the characteristics of hospitalizations due to an injury among individuals with paraplegia, and compared the differences in length of stay (LOS) and hospital costs of injury hospitalizations between individuals with quadriplegia versus paraplegia. In addition, it explored the experience of subsequent injury among individuals with SCI who return to work and examined perceptions of threat and efficacy in preventing subsequent injury using the Extended Parallel Process Model. Using discharge level weighting available in the Nationwide Inpatient Sample, Study 1 calculated national estimates of injury hospitalizations for individuals with paraplegia by patient, hospital, and injury characteristics. Most injury hospitalizations occurred among males, to individuals 35-49 years, and were due to falls, poisonings, or motor vehicle traffic. With the same dataset, Study 2 used logistic regression to estimate the effect of patient characteristics on odds of hospitalized patients with quadriplegia versus paraplegia, and linear regression to estimate predicted differences in hospital costs for individuals with quadriplegia compared to paraplegia. Fewer injury hospitalizations but longer hospital stays, and higher hospital costs per discharge were found for individuals with quadriplegia compared to individuals with paraplegia. Males, younger age, and the uninsured were significant predictors of higher hospital costs. Finally, Study 3 used in-depth interviews to qualitatively explore the perceptions on subsequent injury among individuals with SCI who return to work, and found individuals with SCI who return to work recognized the importance of preventing subsequent injury, and were taking actions to prevent subsequent injury in their daily life and in the workplace. The significance of this research is that it is the first description of injury hospitalizations for all causes of injury by specific type of SCI, and the associated medical outcomes of LOS and direct medical costs. Prevention of subsequent injury should be a priority. The perceptions of individuals with SCI about the severity of and their susceptibility to injury and the efficacy of individual and environmental actions to prevent subsequent injury described in this research should be used to inform the development of interventions that prevent subsequent injury.
27

The Pathway From School to the Criminal Justice System: Predicting School Expulsion and Subsequent Adult Arrest Via A Longitudinal Model

Gentile, Danielle 18 December 2013 (has links)
Exclusionary discipline policies (Casella, 2003; Christle, Jolivette & Nelson, 2005; Tuzzolo & Hewitt, 2007), academic failure and school dropout are some of the most salient factors in the school to prison pipeline (Christle, Jolivette & Nelson, 2005). While previous research has explored the variability in existing exclusionary discipline policies and identified numerous factors associated with expulsion or criminal justice outcomes among youth, there has been little effort to bring these individual and school level factors together into a single predictive model that is informed by existing criminological theories. In this context, the proposed study will use multiple waves of data from the National Longitudinal Study of Adolescent Health to consider how school discipline policies, demographics, and competing criminological explanations affect the risk of expulsion and then future contact with the criminal justice system. Findings reveal that school-level factors such as severe disciplinary policies, school size, and school type are weak predictors of expulsion and adult arrest. Conversely, measures of social bonding, low self-control, learning, and strain theories show promise in predicting expulsion and arrest outcomes. A history of school disciplinary actions and self-reported delinquency present themselves as the strongest predictors of expulsion and subsequent arrest. Theoretical and policy implications are considered.
28

O cartaz de propaganda do Estado Novo-1930-1940

Rosa, Pedro Miguel Aparício Alves January 2000 (has links)
No description available.
29

Investigando os aprendizados subsequentes : mecanismos plásticos e dependência temporal

Crestani, Ana Paula January 2018 (has links)
A formação de memórias de medo contextuais, como as estudadas no presente trabalho, requer a indução da plasticidade sináptica iniciada pela ativação de receptores transmembrana localizados nos neurônios de estruturas encefálicas como o hipocampo. O fluxo iônico mediado pelos receptores N-metil-D-aspartato (NMDARs) é essencial para ativar vias de sinalização intracelular que darão suporte à formação da memória. No entanto, esses receptores parecem não ser necessários em situações onde os animais passaram por uma experiência prévia similar a que está sendo aprendida. Dessa forma, um aprendizado anterior pode modificar os mecanismos de plasticidade que serão utilizados para codificar uma nova informação, caracterizando um fenômeno de metaplasticidade. Esse fenômeno ocorre quando os animais são pré-expostos ao local onde posteriormente serão submetidos a um aprendizado associativo ou quando são re-submetidos a mesma tarefa comportamental com dicas contextuais/espaciais diferentes. No presente trabalho, investigamos (i) os mecanismos de plasticidade sináptica (receptores) e de plasticidade não-sináptica (excitabilidade neuronal) recrutados para a formação do segundo aprendizado e (ii) se a independência dos NMDARs é mantida quando a memória anterior foi adquirida remotamente. Os animais utilizados nesse trabalho (camundongos ou ratos) foram expostos a dois aprendizados sequenciais realizados na tarefa de condicionamento aversivo ao contexto (CAC). O intervalo entre os condicionamentos foi de dois dias nos experimentos do Capítulo I e de três ou quarenta dias nos experimentos do Capítulo II. Cada aprendizado ocorreu em uma caixa de condicionamento com características próprias de formato, odor e iluminação (contexto A ou contexto B), sendo que o primeiro aprendizado ocorreu no contexto A e o segundo no contexto B. Nos experimentos do Capítulo I foram avaliadas no hipocampo dorsal as modificações na excitabilidade neuronal hipocampal induzidas pelo primeiro condicionamento, bem como os receptores envolvidos com a aquisição da memória subsequente e a sobreposição neuronal entre os dois aprendizados. Com a utilização do camundongo transgênico Teg-Tag foi possível identificar os neurônios recrutados para o primeiro aprendizado. Esse animal tem a expressão da proteína fluorescente verde (GFP, do inglês, green fluorescent protein) controlada pela ativação do gene c-fos, que é fisiologicamente transcrito após a atividade neuronal. Dessa forma, os neurônios ativados pelo aprendizado são marcados com GFP. Através da técnica de patch clamp foi observado que os neurônios GFP+ mantiveram a excitabilidade elevada por até dois dias após o treinamento no CAC. Além disso, a identificação dos neurônios recrutados 8 para o aprendizado subsequente foi realizada através da marcação imunofluorescente da proteína Fos, no seu pico de expressão endógena, noventa minutos após o re-treino. Foi observada uma maior sobreposição neuronal (GFP+, Fos+) quando os animais foram retreinados no mesmo contexto dois dias após o primeiro treino. Uma sobreposição intermediária (GFP+, Fos+) foi vista quando os animais tiveram o segundo condicionamento no contexto B, sendo ela significativamente maior do que a sobreposição nos animais não re-treinados. Adicionalmente, foi demonstrado que a aquisição do aprendizado subsequente é mediada por receptores metabotrópicos glutamatérgicos (mGluRs) ao invés de NMDARs. No Capítulo II foi investigado se uma memória remota, adquirida há quarenta dias, ainda seria capaz de influenciar nos mecanismos de plasticidade recrutados para aquisição do aprendizado subsequente. A dinâmica da consolidação sistêmica foi considerada nesses experimentos já que a evocação da memória remota passa a depender de estruturas encefálicas neocorticais, sem recrutar a atividade hipocampal. Apesar da evocação da memória remota não requerer a atividade hipocampal, foi observado que a aquisição do aprendizado subsequente a uma memória remota necessita a atividade de pelo menos uma sub-região do hipocampo (dorsal ou ventral). Complementarmente, os resultados indicaram que, quando o intervalo entre os aprendizados é aumentado (de três para quarenta dias), a formação do aprendizado subsequente, que era independente de NMDARs, volta a depender da plasticidade sináptica mediada por esses receptores no hipocampo (dorsal e ventral). Juntos, nossos resultados sugerem que o primeiro aprendizado causa um aumento da excitabilidade neuronal e modifica a plasticidade sináptica recrutada para o aprendizado subsequente, sendo este último mediado por mGluRs ao invés de NMDARs. Além disso, a metaplasticidade induzida pelo primeiro condicionamento é transiente; quando o intervalo entre as exposições é aumentado, o segundo aprendizado passa a depender novamente da ativação dos NMDARs. / Contextual fear memory formation, like the ones explored in the current work, requires the induction of the synaptic plasticity mediated by the activation of transmembrane receptors that are present in the brain structures as the hippocampus. The ionic flux through the N-methylaspartate- D-aspartate is crucial for activation of the intracellular signaling pathways that will support memory formation. However, these receptors are not necessary when animals had a prior similar learning. In this way, a previous learning can modify the plasticity mechanism that will be recruited to encode a new information, featuring a metaplasticity phenomenon. This phenomenon occurs when animals are pre-exposed to an environment where they will learn an associative learning later or when animals are re-exposed to the same behavioral task with distinct contextual/spatial cues. In the present study, we investigated (i) the synaptic plasticity mechanisms (receptors) and the non-synaptic plasticity mechanisms (neuronal excitability) required for the acquisition of the second learning and (ii) whether a subsequent learning that occurs in a remote time-point is still NMDAR-independent. The animals used in this study (mice or rats) were exposed to two sequential learnings that were performed in the contextual fear conditioning (CFC). The interval between conditionings were two days in the experiments of Chapter I and three or forty days in the experiments of the Chapter II. Each learning was performed in a box with differences on shape, odor and illumination (context A or context B). The first learning occurred in the context A followed by learning on context B. In the experiments of Chapter I it was evaluated the changes in the hippocampal neuronal excitability induced by the first conditioning, the receptors involved with the acquisition of the subsequent memory and the neuronal overlapping between the two sequential learnings. The Teg-Tag transgenic mouse allowed to identify the neurons activated for the first learning experience. This animal has the GFP expression under control of c-fos promoter that is activated by neuronal activity. It was shown by patch clamp that GFP+ neurons are still more excitable two days after learning. Also, the identification of neurons recruited for the subsequent learning was made through immunofluorescent staining of the Fos protein in its peak of endogenous expression, ninety minutes after learning. A greater overlapping (GFP+, Fos+) was observed when animals were retrained in the same context two days after first training. An intermediate overlapping was observed when animals were conditioned in the context B and this expression was significantly higher when compared to animals that were not 10 retrained in either context. Additionally, it was shown that acquisition of the subsequent learning is mediated by metabotropic glutamate receptors (mGluRs) instead of NMDARs In the Chapter II it was investigated whether a remote memory, acquired forty days earlier, is still able to influence in the synaptic plasticity mechanisms recruited for the acquisition of the subsequent learning. Systems consolidation dynamics was considered in these experiments because memory retrieval of a remote memory depends on neocortical brain regions, it not requires hippocampal activity. It was confirmed that hippocampus is not necessary for remote memory retrieval, however at least one longitudinal division of the hippocampus (dorsal or ventral) is essential for learning following a prior remote memory. Moreover, the results indicate that acquisition of the second learning is once again mediated by NMDARs in the hippocampus when the interval between learnings is extended from three to forty days. Altogether, our results suggest that the first learning lead to an increase in the neuronal excitability and modify the synaptic plasticity mechanism recruited for following learning, mGluR are required instead of NMDAR. Furthermore, the metaplasticity induced by first conditioning is transient; the second learning once again requires NMDARs activation when the interval between learnings is longer.
30

Investigando os aprendizados subsequentes : mecanismos plásticos e dependência temporal

Crestani, Ana Paula January 2018 (has links)
A formação de memórias de medo contextuais, como as estudadas no presente trabalho, requer a indução da plasticidade sináptica iniciada pela ativação de receptores transmembrana localizados nos neurônios de estruturas encefálicas como o hipocampo. O fluxo iônico mediado pelos receptores N-metil-D-aspartato (NMDARs) é essencial para ativar vias de sinalização intracelular que darão suporte à formação da memória. No entanto, esses receptores parecem não ser necessários em situações onde os animais passaram por uma experiência prévia similar a que está sendo aprendida. Dessa forma, um aprendizado anterior pode modificar os mecanismos de plasticidade que serão utilizados para codificar uma nova informação, caracterizando um fenômeno de metaplasticidade. Esse fenômeno ocorre quando os animais são pré-expostos ao local onde posteriormente serão submetidos a um aprendizado associativo ou quando são re-submetidos a mesma tarefa comportamental com dicas contextuais/espaciais diferentes. No presente trabalho, investigamos (i) os mecanismos de plasticidade sináptica (receptores) e de plasticidade não-sináptica (excitabilidade neuronal) recrutados para a formação do segundo aprendizado e (ii) se a independência dos NMDARs é mantida quando a memória anterior foi adquirida remotamente. Os animais utilizados nesse trabalho (camundongos ou ratos) foram expostos a dois aprendizados sequenciais realizados na tarefa de condicionamento aversivo ao contexto (CAC). O intervalo entre os condicionamentos foi de dois dias nos experimentos do Capítulo I e de três ou quarenta dias nos experimentos do Capítulo II. Cada aprendizado ocorreu em uma caixa de condicionamento com características próprias de formato, odor e iluminação (contexto A ou contexto B), sendo que o primeiro aprendizado ocorreu no contexto A e o segundo no contexto B. Nos experimentos do Capítulo I foram avaliadas no hipocampo dorsal as modificações na excitabilidade neuronal hipocampal induzidas pelo primeiro condicionamento, bem como os receptores envolvidos com a aquisição da memória subsequente e a sobreposição neuronal entre os dois aprendizados. Com a utilização do camundongo transgênico Teg-Tag foi possível identificar os neurônios recrutados para o primeiro aprendizado. Esse animal tem a expressão da proteína fluorescente verde (GFP, do inglês, green fluorescent protein) controlada pela ativação do gene c-fos, que é fisiologicamente transcrito após a atividade neuronal. Dessa forma, os neurônios ativados pelo aprendizado são marcados com GFP. Através da técnica de patch clamp foi observado que os neurônios GFP+ mantiveram a excitabilidade elevada por até dois dias após o treinamento no CAC. Além disso, a identificação dos neurônios recrutados 8 para o aprendizado subsequente foi realizada através da marcação imunofluorescente da proteína Fos, no seu pico de expressão endógena, noventa minutos após o re-treino. Foi observada uma maior sobreposição neuronal (GFP+, Fos+) quando os animais foram retreinados no mesmo contexto dois dias após o primeiro treino. Uma sobreposição intermediária (GFP+, Fos+) foi vista quando os animais tiveram o segundo condicionamento no contexto B, sendo ela significativamente maior do que a sobreposição nos animais não re-treinados. Adicionalmente, foi demonstrado que a aquisição do aprendizado subsequente é mediada por receptores metabotrópicos glutamatérgicos (mGluRs) ao invés de NMDARs. No Capítulo II foi investigado se uma memória remota, adquirida há quarenta dias, ainda seria capaz de influenciar nos mecanismos de plasticidade recrutados para aquisição do aprendizado subsequente. A dinâmica da consolidação sistêmica foi considerada nesses experimentos já que a evocação da memória remota passa a depender de estruturas encefálicas neocorticais, sem recrutar a atividade hipocampal. Apesar da evocação da memória remota não requerer a atividade hipocampal, foi observado que a aquisição do aprendizado subsequente a uma memória remota necessita a atividade de pelo menos uma sub-região do hipocampo (dorsal ou ventral). Complementarmente, os resultados indicaram que, quando o intervalo entre os aprendizados é aumentado (de três para quarenta dias), a formação do aprendizado subsequente, que era independente de NMDARs, volta a depender da plasticidade sináptica mediada por esses receptores no hipocampo (dorsal e ventral). Juntos, nossos resultados sugerem que o primeiro aprendizado causa um aumento da excitabilidade neuronal e modifica a plasticidade sináptica recrutada para o aprendizado subsequente, sendo este último mediado por mGluRs ao invés de NMDARs. Além disso, a metaplasticidade induzida pelo primeiro condicionamento é transiente; quando o intervalo entre as exposições é aumentado, o segundo aprendizado passa a depender novamente da ativação dos NMDARs. / Contextual fear memory formation, like the ones explored in the current work, requires the induction of the synaptic plasticity mediated by the activation of transmembrane receptors that are present in the brain structures as the hippocampus. The ionic flux through the N-methylaspartate- D-aspartate is crucial for activation of the intracellular signaling pathways that will support memory formation. However, these receptors are not necessary when animals had a prior similar learning. In this way, a previous learning can modify the plasticity mechanism that will be recruited to encode a new information, featuring a metaplasticity phenomenon. This phenomenon occurs when animals are pre-exposed to an environment where they will learn an associative learning later or when animals are re-exposed to the same behavioral task with distinct contextual/spatial cues. In the present study, we investigated (i) the synaptic plasticity mechanisms (receptors) and the non-synaptic plasticity mechanisms (neuronal excitability) required for the acquisition of the second learning and (ii) whether a subsequent learning that occurs in a remote time-point is still NMDAR-independent. The animals used in this study (mice or rats) were exposed to two sequential learnings that were performed in the contextual fear conditioning (CFC). The interval between conditionings were two days in the experiments of Chapter I and three or forty days in the experiments of the Chapter II. Each learning was performed in a box with differences on shape, odor and illumination (context A or context B). The first learning occurred in the context A followed by learning on context B. In the experiments of Chapter I it was evaluated the changes in the hippocampal neuronal excitability induced by the first conditioning, the receptors involved with the acquisition of the subsequent memory and the neuronal overlapping between the two sequential learnings. The Teg-Tag transgenic mouse allowed to identify the neurons activated for the first learning experience. This animal has the GFP expression under control of c-fos promoter that is activated by neuronal activity. It was shown by patch clamp that GFP+ neurons are still more excitable two days after learning. Also, the identification of neurons recruited for the subsequent learning was made through immunofluorescent staining of the Fos protein in its peak of endogenous expression, ninety minutes after learning. A greater overlapping (GFP+, Fos+) was observed when animals were retrained in the same context two days after first training. An intermediate overlapping was observed when animals were conditioned in the context B and this expression was significantly higher when compared to animals that were not 10 retrained in either context. Additionally, it was shown that acquisition of the subsequent learning is mediated by metabotropic glutamate receptors (mGluRs) instead of NMDARs In the Chapter II it was investigated whether a remote memory, acquired forty days earlier, is still able to influence in the synaptic plasticity mechanisms recruited for the acquisition of the subsequent learning. Systems consolidation dynamics was considered in these experiments because memory retrieval of a remote memory depends on neocortical brain regions, it not requires hippocampal activity. It was confirmed that hippocampus is not necessary for remote memory retrieval, however at least one longitudinal division of the hippocampus (dorsal or ventral) is essential for learning following a prior remote memory. Moreover, the results indicate that acquisition of the second learning is once again mediated by NMDARs in the hippocampus when the interval between learnings is extended from three to forty days. Altogether, our results suggest that the first learning lead to an increase in the neuronal excitability and modify the synaptic plasticity mechanism recruited for following learning, mGluR are required instead of NMDAR. Furthermore, the metaplasticity induced by first conditioning is transient; the second learning once again requires NMDARs activation when the interval between learnings is longer.

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