Modified impact of emotion on temporal discrimination in a transgenic rat model of Huntington disease

Huntington\u27s disease (HD) is characterized by triad of motor, cognitive, and emotional symptoms along with neuropathology in fronto-striatal circuit and limbic system including amygdala. Emotional alterations, which have a negative impact on patient well-being, represent some of the earliest symptoms of HD and might be related to the onset of the neurodegenerative process. In the transgenic rat model (tgHD rats), evidence suggest emotional alterations at the symptomatic stage along with neuropathology of the central nucleus of amygdala (CE). Studies in humans and animals demonstrate that emotion can modulate time perception. The impact of emotion on time perception has never been tested in HD, nor is it known if that impact could be part of the presymptomatic emotional phenotype of the pathology. The aim of this paper was to characterize the effect of emotion on temporal discrimination in presymptomatic tgHD animals. In the first experiment, we characterized the acute effect of an emotion (fear) conditioned stimulus on temporal discrimination using a bisection procedure, and tested its dependency upon an intact central amygdala. The second experiment was aimed at comparing presymptomatic homozygous transgenic animals at 7-months of age and their wild-type littermates (WT) in their performance on the modulation of temporal discrimination by emotion. Our principal findings show that (1) a fear cue produces a short-lived decrease of temporal precision after its termination, and (2) animals with medial CE lesion and presymptomatic tgHD animals demonstrate an alteration of this emotion-evoked temporal distortion. The results contribute to our knowledge about the presymptomatic phenotype of this HD rat model, showing susceptibility to emotion that may be related to dysfunction of the central nucleus of amygdala

Fully automated and adaptive detection of amyloid plaques in stained brain sections of Alzheimer transgenic mice

Automated detection of amyloid plaques (AP) in post mortem brain sections of patients with Alzheimer disease (AD) or in mouse models of the disease is a major issue to improve quantitative, standardized and accurate assessment of neuropathological lesions as well as of their modulation by treatment. We propose a new segmentation method to automatically detect amyloid plaques in Congo Red stained sections based on adaptive thresholds and a dedicated amyloid plaque/tissue modelling. A set of histological sections focusing on anatomical structures was used to validate the method in comparison to expert segmentation. Original information concerning global amyloid load have been derived from 6 mouse brains which opens new perspectives for the extensive analysis of such a data in 3-D and the possibility to integrate in vivo-post mortem information for diagnosis purposes

A standardized Method to Automatically Segment Amyloid Plaques in Congo Red Stained Sections from Alzheimer Transgenic Mice

International audienceAutomated detection of amyloid plaques (AP) in post mortem brain sections of patients with Alzheimer disease (AD) or in mouse models of the disease is a major issue to improve quantitative, standardized and accurate assessment of neuropathological lesions as well as of their modulation by treatment. We propose a new segmentation method to automatically detect amyloid plaques in Congo Red stained sections based on adaptive thresholds and a dedicated amyloid plaque/tissue modelling. A set of histological sections focusing on anatomical structures was used to validate the method in comparison to expert segmentation

Additional file 1: of Altered social behavior and ultrasonic communication in the dystrophin-deficient mdx mouse model of Duchenne muscular dystrophy

Supplementary method section. Semi-automatic classification of mouse USVs. (PDF 144 kb

Additional file 3: of Altered social behavior and ultrasonic communication in the dystrophin-deficient mdx mouse model of Duchenne muscular dystrophy

Supplementary result section. Correlation analyses. (PDF 37 kb

Impaired neurogenesis, neuronal loss, and brain functional deficits in the APPxPS1-Ki mouse model of Alzheimer's disease

International audienceAmyloid-β peptide species accumulating in the brain of patients with Alzheimer's disease are assumed to have a neurotoxic action and hence to be key actors in the physiopathology of this neurodegenerative disease. We have studied a new mouse mutant (APPxPS1-Ki) line developing both early-onset brain amyloid-β deposition and, in contrast to most of transgenic models, subsequent neuronal loss. In 6-month-old mice, we observed cell layer atrophies in the hippocampus, together with a dramatic decrease in neurogenesis and a reduced brain blood perfusion as measured in vivo by magnetic resonance imaging. In these mice, neurological impairments and spatial hippocampal dependent memory deficits were also substantiated and worsened with aging. We described here a phenotype of APPxPS1-Ki mice that summarizes several neuroanatomical alterations and functional deficits evocative of the human pathology. Such a transgenic model that displays strong face validity might be highly beneficial to future research on AD physiopathogeny and therapeutics

Prevenção da AIDS no período de iniciação sexual: aspectos da dimensão simbólica das condutas de homens jovens AIDS prevention in the period of sexual initiation: aspects of the symbolic dimension of the conduct of young men

Para aprofundar a compreensão sobre o uso não consistente do preservativo, objetivou-se caracterizar aspectos das significações simbólicas das práticas sexuais de jovens do sexo masculino. Entrevistas de 42 sujeitos, cujas iniciações sexuais começaram no final dos anos 90, foram abordadas qualitativamente por meio de análise de enunciados e interpretadas sob as perspectivas teóricas dos roteiros sexuais e do habitus masculino. Eles enfatizaram a importância de exames sorológicos e da análise biográfica das parceiras (para gerar "confiança") e tenderam a utilizar uma semiotécnica não fundamentada para avaliar o estado de saúde delas. Estabeleceram uma tipologia diádica: parcerias "não fixas" e "fixas", exercitando respectivamente dois tipos de roteiros quanto ao uso do preservativo: para prevenção de AIDS-DST e gravidez ou somente para prevenir gravidez. As narrativas resultariam, dentre outros fatores, de um processo de biomedicalização de aspectos de suas sexualidades e de anseios de relacionamentos afetivo-sexuais estáveis e monogâmicos. Entre os participantes, as importantes e recentes mudanças nos roteiros sexuais intrapsíquico e interpessoal não parecem ser, por ora, acompanhadas de mudanças igualmente profundas nos roteiros culturais ou de habitus masculino.<br>To acquire an in-depth grasp of the non-consistent use of condoms, an attempt was made to characterize aspects of the symbolic meanings of sexual conduct in a group of young males. Interviews with forty-two subjects whose sexual initiation occurred in the late 1990s were qualitatively assessed by an analysis of statements interpreted under the theoretical perspectives of sexual scripts and male lifestyle and values. Participants emphasized the importance of blood testing and a biographical analysis of their partners (to generate 'trust') and tended to use personal criteria to assess the state of their partners' health. They established a dyadic typology of these relationships divided into "infrequent" and "steady" partners respectively, exercising two kinds of approaches to condom use, namely prevention of AIDS-STD and pregnancy on the one hand and only for pregnancy prevention on the other. The narratives seem to result, among other factors, from a biomedical approach to aspects of their sex lives and a desire for a stable and monogamous sexual-affective relationship. The important and recent changes in the intrapsychic and interpersonal sexual scripts do not seem to be currently accompanied by equally profound changes in cultural scripts or male lifestyle and values