Plusieurs facteurs de risque de développement de troubles intériorisés, tels que les troubles d’anxiété et de l’humeur, ont été identifiés dans la littérature. Les deux plus importants facteurs de risques regroupent l’adversité vécue durant l’enfance (par exemple la maltraitance) et le risque parental (c’est-à-dire la présence d’un trouble intériorisé chez l’un ou les deux parents). Ces facteurs de risque ont été liés à des changements neuroanatomiques similaires à ceux observés en lien avec les troubles intériorisés. Ainsi, en présence de ces facteurs de risque, des anomalies anatomiques pourraient laisser présager l’apparition prochaine d’une symptomatologie de troubles intériorisés chez des individus encore asymptomatiques. Chez les quelques populations de jeunes investiguées, les participants présentaient des comorbidités et/ou étaient sous médication, ce qui rend difficile l’interprétation des atteintes cérébrales observées. Ce travail de thèse s’est intéressé aux liens entre ces deux facteurs de risque et les substrats neuroanatomiques associés à chacun d’eux, chez des adolescents asymptomatiques et n’étant sous aucune médication. Une première étude a examiné le lien entre le niveau de pratiques parentales coercitives et le niveau de symptômes d’anxiété, mesurés de manière longitudinale depuis la naissance, et les différences neuroanatomiques observées à l’adolescence (voir Chapitre 2). Une deuxième étude a examiné le lien entre le risque parental de développer des troubles d’anxiété et les différences neuroanatomiques observées à l’adolescence (voir Chapitre 3). Une troisième étude s’est intéressée au lien entre le risque parental de développer un trouble de dépression ou un trouble bipolaire et les différences neuroanatomiques observées à l’adolescence (voir Chapitre 4). Les résultats démontrent des différences de volume et/ou d’épaisseur corticale dans plusieurs structures clés impliquées dans le traitement et la régulation des émotions. C’est le cas du cortex préfrontal, de l’amygdale, de l’hippocampe et du striatum. Ces résultats suggèrent que certaines des différences neuroanatomiques observées dans les troubles intériorisés peuvent être présentes avant que le trouble ne se manifeste, et représenter des marqueurs neuronaux du risque de développer le trouble. Les implications théoriques et les limites de ces trois études sont finalement discutées dans le Chapitre 5. / Several risk factors for the development of internalized disorders such as anxiety, depression, and bipolar disorders have been identified in the literature. The two most important risk factors include adversity during childhood (i.e. abuse, neglect and harsh parenting) and parental risk (i.e. the presence of an internalized disorder in one or both parents). These risk factors have been linked to anatomical changes in several brain structures, which are similar to those observed in internalized disorders. Thus, in the presence of these risk factors, anatomical abnormalities may predict the appearance of internalized disorders in asymptomatic individuals. In the few studies that have investigated the influence of these risk factors in a youth population, participants often had comorbidities and/or were medicated, which makes the observed anatomical changes difficult to interpret. This work has focused on these two risk factors (i.e. adversity during childhood, in the form of harsh parenting, and the parental risk) and their link with the anatomical cerebral substrates, in asymptomatic and un-medicated adolescents. A first study examined the link between harsh parenting, levels of anxiety symptoms, as measured longitudinally from birth, and neuroanatomical differences in adolescents (see Chapter 2). A second study examined the link between parental risk of developing anxiety disorders, and neuroanatomical differences in adolescents (see Chapter 3). A third study looked at the link between parental risk for developing depressive disorder or bipolar disorder, and neuroanatomical differences in adolescents (see Chapter 4). Results show differences in volume and/or cortical thickness of several key cerebral structures involved in emotional processing and regulation. This is the case of the prefrontal cortex, orbitofrontal cortex, anterior cingulate cortex, the amygdala, hippocampus and striatum. These results suggest that some neuroanatomical differences in internalized disorders may be present before the disorder emerges, and represent neuronal markers denoting the risk of developing the disorder. The theoretical implications and limitations of these three studies are discussed in Chapter 5.

Orientadores: Marcondes Cavalcante França Junior, Gabriela Castellano / Texto em português e inglês / Dissertação (mestrado profissional) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-24T20:36:08Z (GMT). No. of bitstreams: 1 Rezende_ThiagoJunqueiraRibeirode_M.pdf: 1634329 bytes, checksum: 78c3b3cb6bd66174acfe01359a6cb758 (MD5) Previous issue date: 2014 / Resumo: A doença de Machado-Joseph (SCA3/MJD) é a ataxia espinocerebelar mais frequente no mundo, resultante de uma expansão de tripletos CAG no gene MJD1 localizado no cromossomo 14q. Clinicamente ela é caracterizada por danos nos gânglios da base, tronco e cerebelo. Atualmente existem poucos estudos baseados em imagens de ressonância magnética (MRI) que investigam danos no córtex cerebral em pacientes com SCA3/MJD. O objetivo deste estudo foi investigar danos no córtex cerebral na SCA3/MJD usando MRI e correlacionar as possíveis áreas afetadas com dados clínicos, genéticos e neuropsicológicos. Foram recrutados para este estudo 49 pacientes com teste molecular de SCA3/MJD e 49 controles sadios. Os pacientes foram avaliados com a escala de ataxia SARA. Imagens de MR ponderadas em T1 foram adquiridas para todos os voluntários e usadas para a extração das medidas de espessura cortical, realizadas com o software FreeSurfer. O tamanho da expansão CAG médio, SARA e idade de início foram 72,1±4,2, 14,7±7,2 e 37,5±12,5, respectivamente. Os pacientes apresentaram redução de espessura nos córtex precentral e paracentral bem como nos hipocampos e lobos temporal e occipital. Também encontramos redução volumétrica no cerebelo, tálamo, caudado, putamen, globo pálido, tronco e diencéfalo ventral. A gravidade da doença apresentou correlação negativa com a espessura do giro precentral esquerdo (r=-0,302, p=0,035) e com o volume do tronco (r=-0,414, p=0,003). A espessura do giro angular direito apresentou correlação com a duração da doença (r=0,587, p=0,001), mas não com a expansão do tripleto de CAG. O subteste de semelhança de WAIS III apresentou uma correlação com a espessura do sulco central esquerdo (r=0,752, p=0,004) e como o giro occipital superior direito (r=0,704, p=0,016). Estes resultados sugerem que pacientes com SCA3/MJD apresentam dano cortical e subcortical difuso. Os achados estruturais se correlacionaram com as manifestações clínicas da doença, o que apoia a hipótese que a piora nas funções motora e cognitiva e o dano cerebral estão relacionados na SCA3/MJD / Abstract: Machado-Joseph disease (SCA3/MJD) is the most frequent spinocerebellar ataxia worldwide caused by an abnormal expansion of a CAG triplet at the MDJ1 gene located on chromosome 14q. Clinically, it is characterized by brainstem, basal ganglia and cerebellar damage. There are few MRI-based studies that investigated cerebral cortex damage in SCA3/MJD. The objectives of this study are to investigate cerebral cortex damage in SCA3/MJD and to correlate affected areas with clinical, genetics and neuropsychological data. We included 49 patients with molecular confirmation of SCA3/MJD and 49 healthy controls. The scale for assessment and rating of ataxia (SARA) was employed to quantify disease severity. We also performed a comprehensive neuropsychological battery to assess cognitive deficits. Volumetric T1 magnetic resonance images of the brain were acquired for all volunteers and used to calculate cortical thickness measures, performed using the FreeSurfer package. Mean CAG expansion, SARA score and age-at-onset were 72.1±4.2, 14.7±7.2 and 37.5±12.5, respectively. Patients had atrophy at precentral and paracentral cortices as well as the hippocampi, temporal and occipital lobes. We also found volumetric reduction of the cerebellum, thalamus, caudate, putamen, pallidum, brainstem and ventral diencephalon. SARA scores inversely correlated with left precentral gyrus thickness (r=-0.302, p=0.035) and brainstem volume (r=-0.414, p=0.003). Right angular gyrus thickness correlated with disease duration (r=0.587, p=0.001), but not (CAG) expansion. Similarity subscore of WAIS III presented a correlation with thickness of Left central sulcus (r=0.752, p=0.004) and Right superior occipital gyrus (r=0.704, p=0.016). Therefore, patients with MJD/SCA3 have widespread cortical and subcortical atrophy. These structural findings correlate with clinical manifestations of the disease, which support the concept that cognitive/motor impairment and cerebral damage are related in MJD/SCA3 / Mestrado / Fisiopatologia Médica / Mestre em Ciências

One of the few areas in the brain that still exhibits experience-dependent neuroplasticity in adulthood is found in the medial temporal lobe (MTL) system. Within the MTL, this plasticity has been observed in the hippocampus in both humans and animal models. Rodent model studies focusing on the effect of aerobic exercise have shown a positive increase of neuroplasticity in the dentate gyrus subregion of the hippocampus. Another area in the MTL, the entorhinal cortex (EC), serves as a primary input to the hippocampus, and studies on environmental enrichment have reported greater EC volume in rodents supplied with toys and running wheels. Previous work in our lab working with healthy young adults showed a positive correlation between right EC volume, and aerobic fitness (VO2 max). In this thesis, I examined two aims, first whether aerobic fitness predicts changes in thickness or volume of the MTL as well as performance in an MTL dependent task in healthy young adults. Additionally, whether the brain morphology measures of the MTL can predict performance on the memory task. The second aim looks at the longitudinal effect a 12-week exercise intervention has on thickness or volume in the MTL and performance on an MTL dependent task in the same population. Results indicate that there is a positive baseline correlation between aerobic fitness and thickness of the EC on the left hemisphere but there are no longitudinal changes in morphology after the exercise intervention. These data extend previous work on the effects aerobic exercise has on MTL structure and offer interesting venues to combat neurodegenerative diseases that affect the MTL memory system like Alzheimer’s disease.

Background The amygdala is a subcortical limbic structure consisting of histologically and functionally distinct subregions. New automated structural magnetic resonance imaging (MRI) segmentation tools facilitate the in vivo study of individual amygdala nuclei in clinical populations such as patients with anorexia nervosa (AN) who show symptoms indicative of limbic dysregulation. This study is the first to investigate amygdala nuclei volumes in AN, their relationships with leptin, a key indicator of AN-related neuroendocrine alterations, and further clinical measures. Methods T1-weighted MRI scans were subsegmented and multi-stage quality controlled using FreeSurfer. Left/right hemispheric amygdala nuclei volumes were cross-sectionally compared between females with AN (n = 168, 12–29 years) and age-matched healthy females (n = 168) applying general linear models. Associations with plasma leptin, body mass index (BMI), illness duration, and psychiatric symptoms were analyzed via robust linear regression. Results Globally, most amygdala nuclei volumes in both hemispheres were reduced in AN v. healthy control participants. Importantly, four specific nuclei (accessory basal, cortical, medial nuclei, corticoamygdaloid transition in the rostral-medial amygdala) showed greater volumetric reduction even relative to reductions of whole amygdala and total subcortical gray matter volumes, whereas basal, lateral, and paralaminar nuclei were less reduced. All rostral-medially clustered nuclei were positively associated with leptin in AN independent of BMI. Amygdala nuclei volumes were not associated with illness duration or psychiatric symptom severity in AN. Conclusions In AN, amygdala nuclei are altered to different degrees. Severe volume loss in rostral-medially clustered nuclei, collectively involved in olfactory/food-related reward processing, may represent a structural correlate of AN-related symptoms. Hypoleptinemia might be linked to rostral-medial amygdala alterations.

As técnicas de morfometria baseadas em imagens ressonância magnética desde o início do século XXI tem sido uma importante ferramenta para estudar doenças neurológicas. Um dos benefícios desta técnica é prover medidas de parâmetros que manualmente são difíceis de estimar e com um grande viés de operador. Este trabalho teve como objetivo descrever as alterações corticais em duas doenças, uma malformação do desenvolvimento cortical, e outra neurodegenerativa utilizando as técnicas de morfometria por estudo de superfície cortical. As imagens de ressonância magnética foram obtidas por sequências volumétricas ponderadas em T1 e analisadas através de um algoritmo específico, implementado no software FreeSurfer (Fischl et al., Harvard University - Estados Unidos). De um grupo de pacientes com malformação do desenvolvimento cortical foram analisados 3 pacientes com polimicrogiria (PMG), comparados com um grupo de 14 pessoas saudáveis e de idade similar. Foram também analisados 14 pacientes com alteração degenerativa (Doença de Alzheimer - DA) com manifestação recente, idade avançada e alto nível de escolaridade comparados com 20 idosos saudáveis. Este dado foi posteriormente utilizado para separar os dois grupos através de uma técnica de classificação multivariada, implementada pelo autor. A análise de cada um dos indivíduos com PMG comparados ao grupo controle apresentou aumento de espessura cortical nas áreas com polimicrogiria e redução também estatisticamente significante de espessura cortical em áreas sem polimicrogiria. No estudo do grupo de pacientes com DA observou-se redução de espessura cortical nas regiões do córtex para hipocampal, entorrinal, córtex límbico e córtex temporal superior. Além disso, a volumetria de estruturas subcorticais obtidas apresentou poder de classificação de 84,6% na comparação de pacientes com DA e controles saudáveis. Concluímos que as técnicas de análise de imagens baseadas em superfície cortical se mostram promissoras no estudo de doenças cerebrais que, de maneiras distintas, afetam a espessura cortical. Descritores: 1.Imagem por ressonância magnética 2.Processamento automatizado de dados 3.Doença de Alzheimer 4.Malformações do desenvolvimento cortical / The techniques of brain morphometry based on magnetic resonance images since the beginning of the twenty-first century has been an important tool for studying neurological diseases. One of the benefits of this technique is to provide measures of parameters that are difficult to estimate manually and subject to operator bias. This study aimed to describe the changes in the cortex in two diseases, a malformation of cortical development and a neurodegenerative one, using surface based morphometry techniques. From a group of patients with malformation of cortical development were analyzed 3 with polymicrogyria (PMG), compared to a group of 14 healthy age matched subjects. The images from a T1 weighted volume were analyzed using a specific algorithm, implemented in the software FreeSurfer (Fischl et al., Harvard University - United States). We analyzed 14 patients with degenerative changes (Alzheimers disease - AD) with recent onset, advanced age and high level of education compared to 20 healthy age matched elderly. The images of this study were also obtained from a T1 weighted volume and were analyzed with the same software package. This analyzed data was used to separate the two groups through a multivariate classifier, implemented by the author. The analysis of each individual with PMG compared to the control group showed a statistically significant increase in cortical thickness in the areas with polymicrogyria and also a statistically significant reduction of cortical thickness in some areas without polymicrogyria. In the study group of AD patients the result was a cortical thinning statistically significant in hippocampal, entorhinal, limbic and superior temporal cortex. Moreover, the volume of subcortical structures has provided a classification power of 84.6% discriminating AD patients from healthy controls. We conclude that the surface based cortical analysis have shown a good potential in the study of brain diseases that affect, in different ways, the cortical thickness.

Stereology supplies image sampling rules to estimate geometric quantities such as volume, surface area, feature length and number. The method is well suited to non-invasive image acquisition methods such as Magnetic Resonance Imaging (MRI). Meanwhile, in Magnetic Resonance (MR) images analysis area, automated software packages have been continuously developed and become well-established tools especially in human brainMR images processing. The aims of the thesis are (1) to combine proper rules to sample MR images with automated or semi-automated data acquisition methods, in order to implement four different design unbiased stereological volume estimators in the study of the human brain, and (2) to compare volume estimates with those obtained from automated software packages.

O transtorno de identidade de gênero (TIG) carateriza-se pela persistente convicção de pertencer ao sexo oposto. Apesar das diferentes abordagens metodológicas e de inúmeros estudos, sua etiologia ainda permanece desconhecida. Sabe-se da influência de fatores ambientais, hormonais, genéticos e de alterações neuroanatômicas. A literatura em neuroimagem ainda é extremamente restrita, e estudos com foco em espessura cortical inexistem. Achados neuroanatômicos de morfometria baseada em voxels com maior volume de massa cinzenta já foram relatados em regiões ligadas ao circuito neural da senso-percepção. Hipotetizamos que diferenças de espessura cortical estariam localizadas nas regiões desse circuito. Estudamos um par de gêmeos monozigóticos masculinos discordantes para TIG (masculino-para-feminino) aplicando VBM e SBM (FreeSurfer). Evidenciamos maior volume de substância cinzenta e maior espessura cortical na junção tempo-parietal direita, córtex frontal inferior direito e córtex da insula direito no gêmeo TIG-MTF em relação ao seu irmão. O presente estudo agrega o achado de espessura cortical na caracterização das alterações neuroanatômicas do TIG. / Gender Identity Disorder (GID) is characterized by the persistent conviction of belonging to the opposite sex. Despite all the different technical approaches and the several studies performed, its etiology still remains unknown. There is knowledge about the influence of environmental hormonal, genetic and neuroanatomic factors involved. The literature about GID neuroimaging is extremely restrict and there are no studies focusing on cortical thickness. The neuroanatomical findings from Voxel-Based Morphometry (VBM) have reported regions within the sense-perception network with increased grey matter volume. We hypothesized that differences of cortical thickness would be found in the cortical areas of this network. Thus we studied a male monozigotic twin pair discordant for GID (male-to-female) using VBM and SBM (FreeSurfer). We found increased grey matter volume and thicker cortex in the right temporo-parietal junction, right inferior frontal cortex and right insular cortex in the affected twin in comparison to his brother. The present study adds the findings on cortical thickness to the characterization of the neuroanatomic alterations in Gender Identity Disorder.

As técnicas de morfometria baseadas em imagens ressonância magnética desde o início do século XXI tem sido uma importante ferramenta para estudar doenças neurológicas. Um dos benefícios desta técnica é prover medidas de parâmetros que manualmente são difíceis de estimar e com um grande viés de operador. Este trabalho teve como objetivo descrever as alterações corticais em duas doenças, uma malformação do desenvolvimento cortical, e outra neurodegenerativa utilizando as técnicas de morfometria por estudo de superfície cortical. As imagens de ressonância magnética foram obtidas por sequências volumétricas ponderadas em T1 e analisadas através de um algoritmo específico, implementado no software FreeSurfer (Fischl et al., Harvard University - Estados Unidos). De um grupo de pacientes com malformação do desenvolvimento cortical foram analisados 3 pacientes com polimicrogiria (PMG), comparados com um grupo de 14 pessoas saudáveis e de idade similar. Foram também analisados 14 pacientes com alteração degenerativa (Doença de Alzheimer - DA) com manifestação recente, idade avançada e alto nível de escolaridade comparados com 20 idosos saudáveis. Este dado foi posteriormente utilizado para separar os dois grupos através de uma técnica de classificação multivariada, implementada pelo autor. A análise de cada um dos indivíduos com PMG comparados ao grupo controle apresentou aumento de espessura cortical nas áreas com polimicrogiria e redução também estatisticamente significante de espessura cortical em áreas sem polimicrogiria. No estudo do grupo de pacientes com DA observou-se redução de espessura cortical nas regiões do córtex para hipocampal, entorrinal, córtex límbico e córtex temporal superior. Além disso, a volumetria de estruturas subcorticais obtidas apresentou poder de classificação de 84,6% na comparação de pacientes com DA e controles saudáveis. Concluímos que as técnicas de análise de imagens baseadas em superfície cortical se mostram promissoras no estudo de doenças cerebrais que, de maneiras distintas, afetam a espessura cortical. Descritores: 1.Imagem por ressonância magnética 2.Processamento automatizado de dados 3.Doença de Alzheimer 4.Malformações do desenvolvimento cortical / The techniques of brain morphometry based on magnetic resonance images since the beginning of the twenty-first century has been an important tool for studying neurological diseases. One of the benefits of this technique is to provide measures of parameters that are difficult to estimate manually and subject to operator bias. This study aimed to describe the changes in the cortex in two diseases, a malformation of cortical development and a neurodegenerative one, using surface based morphometry techniques. From a group of patients with malformation of cortical development were analyzed 3 with polymicrogyria (PMG), compared to a group of 14 healthy age matched subjects. The images from a T1 weighted volume were analyzed using a specific algorithm, implemented in the software FreeSurfer (Fischl et al., Harvard University - United States). We analyzed 14 patients with degenerative changes (Alzheimers disease - AD) with recent onset, advanced age and high level of education compared to 20 healthy age matched elderly. The images of this study were also obtained from a T1 weighted volume and were analyzed with the same software package. This analyzed data was used to separate the two groups through a multivariate classifier, implemented by the author. The analysis of each individual with PMG compared to the control group showed a statistically significant increase in cortical thickness in the areas with polymicrogyria and also a statistically significant reduction of cortical thickness in some areas without polymicrogyria. In the study group of AD patients the result was a cortical thinning statistically significant in hippocampal, entorhinal, limbic and superior temporal cortex. Moreover, the volume of subcortical structures has provided a classification power of 84.6% discriminating AD patients from healthy controls. We conclude that the surface based cortical analysis have shown a good potential in the study of brain diseases that affect, in different ways, the cortical thickness.

O transtorno de identidade de gênero (TIG) carateriza-se pela persistente convicção de pertencer ao sexo oposto. Apesar das diferentes abordagens metodológicas e de inúmeros estudos, sua etiologia ainda permanece desconhecida. Sabe-se da influência de fatores ambientais, hormonais, genéticos e de alterações neuroanatômicas. A literatura em neuroimagem ainda é extremamente restrita, e estudos com foco em espessura cortical inexistem. Achados neuroanatômicos de morfometria baseada em voxels com maior volume de massa cinzenta já foram relatados em regiões ligadas ao circuito neural da senso-percepção. Hipotetizamos que diferenças de espessura cortical estariam localizadas nas regiões desse circuito. Estudamos um par de gêmeos monozigóticos masculinos discordantes para TIG (masculino-para-feminino) aplicando VBM e SBM (FreeSurfer). Evidenciamos maior volume de substância cinzenta e maior espessura cortical na junção tempo-parietal direita, córtex frontal inferior direito e córtex da insula direito no gêmeo TIG-MTF em relação ao seu irmão. O presente estudo agrega o achado de espessura cortical na caracterização das alterações neuroanatômicas do TIG. / Gender Identity Disorder (GID) is characterized by the persistent conviction of belonging to the opposite sex. Despite all the different technical approaches and the several studies performed, its etiology still remains unknown. There is knowledge about the influence of environmental hormonal, genetic and neuroanatomic factors involved. The literature about GID neuroimaging is extremely restrict and there are no studies focusing on cortical thickness. The neuroanatomical findings from Voxel-Based Morphometry (VBM) have reported regions within the sense-perception network with increased grey matter volume. We hypothesized that differences of cortical thickness would be found in the cortical areas of this network. Thus we studied a male monozigotic twin pair discordant for GID (male-to-female) using VBM and SBM (FreeSurfer). We found increased grey matter volume and thicker cortex in the right temporo-parietal junction, right inferior frontal cortex and right insular cortex in the affected twin in comparison to his brother. The present study adds the findings on cortical thickness to the characterization of the neuroanatomic alterations in Gender Identity Disorder.

O transtorno de identidade de gênero (TIG) carateriza-se pela persistente convicção de pertencer ao sexo oposto. Apesar das diferentes abordagens metodológicas e de inúmeros estudos, sua etiologia ainda permanece desconhecida. Sabe-se da influência de fatores ambientais, hormonais, genéticos e de alterações neuroanatômicas. A literatura em neuroimagem ainda é extremamente restrita, e estudos com foco em espessura cortical inexistem. Achados neuroanatômicos de morfometria baseada em voxels com maior volume de massa cinzenta já foram relatados em regiões ligadas ao circuito neural da senso-percepção. Hipotetizamos que diferenças de espessura cortical estariam localizadas nas regiões desse circuito. Estudamos um par de gêmeos monozigóticos masculinos discordantes para TIG (masculino-para-feminino) aplicando VBM e SBM (FreeSurfer). Evidenciamos maior volume de substância cinzenta e maior espessura cortical na junção tempo-parietal direita, córtex frontal inferior direito e córtex da insula direito no gêmeo TIG-MTF em relação ao seu irmão. O presente estudo agrega o achado de espessura cortical na caracterização das alterações neuroanatômicas do TIG. / Gender Identity Disorder (GID) is characterized by the persistent conviction of belonging to the opposite sex. Despite all the different technical approaches and the several studies performed, its etiology still remains unknown. There is knowledge about the influence of environmental hormonal, genetic and neuroanatomic factors involved. The literature about GID neuroimaging is extremely restrict and there are no studies focusing on cortical thickness. The neuroanatomical findings from Voxel-Based Morphometry (VBM) have reported regions within the sense-perception network with increased grey matter volume. We hypothesized that differences of cortical thickness would be found in the cortical areas of this network. Thus we studied a male monozigotic twin pair discordant for GID (male-to-female) using VBM and SBM (FreeSurfer). We found increased grey matter volume and thicker cortex in the right temporo-parietal junction, right inferior frontal cortex and right insular cortex in the affected twin in comparison to his brother. The present study adds the findings on cortical thickness to the characterization of the neuroanatomic alterations in Gender Identity Disorder.