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2177 – Neuroanatomical Changes Associated With Subthreshold Depression In Adolescents
- H. Vulser, M.-L. Paillere-Martinot, H. Lemaitre, R. Miranda, E. Artiges, R. Goodman, J. Penttilä, M. Struve, T. Fadai, V. Kappel, L. Poustka, P. Conrod, T. Banaschewski, A. Barbot, G.J. Barker, C. Büchel, H. Flor, J. Gallinat, H. Garavan, A. Heinz, B. Ittermann, C. Lawrence, E. Loth, K. Mann, T. Paus, Z. Pausova, M. Rietschel, T.W. Robbins, M. Smolka, G. Schumann, J.-L. Martinot, IMAGEN Consortium
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- Journal:
- European Psychiatry / Volume 28 / Issue S1 / 2013
- Published online by Cambridge University Press:
- 15 April 2020, 28-E1340
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Introduction
Although neuroimaging studies suggest brain regional abnormalities in depressive disorders, it remains unclear whether abnormalities are present at illness onset or reflect disease progression.
ObjectivesWe hypothesized that cerebral variations were present in adolescents with subthreshold depression known to be at high risk for later full-blown depression.
AimsWe examined brain structural and diffusion-weighted magnetic resonance images of adolescents with subthreshold depression.
MethodsThe participants were extracted from the European IMAGEN study cohort of healthy adolescents recruited at age 14. Subthreshold depression was defined as a distinct period of abnormally depressed or irritable mood, or loss of interest, plus two or more depressive symptoms but without diagnosis of Major Depressive Episode. Comparisons were performed between adolescents meeting these criteria and control adolescents within the T1-weighted imaging modality (118 and 475 adolescents respectively) using voxel-based morphometry and the diffusion tensor imaging modality (89 ad 422 adolescents respectively) using tract-based spatial statistics. Whole brain analyses were performed with a statistical threshold set to p< 0.05 corrected for multiple comparisons.
ResultsCompared with controls, adolescents with subthreshold depression had smaller gray matter volume in caudate nuclei, medial frontal and cingulate cortices; smaller white matter volume in anterior limb of internal capsules, left forceps minor and right cingulum; and lower fractional anisotropy and higher radial diffusivity in the genu of corpus callosum.
ConclusionsThe findings suggest that adolescents with subthreshold depression have volumetric and microstructural gray and white matter changes in the emotion regulation frontal-striatal-limbic network.
Resilience and corpus callosum microstructure in adolescence
- A. Galinowski, R. Miranda, H. Lemaitre, M.-L. Paillère Martinot, E. Artiges, H. Vulser, R. Goodman, J. Penttilä, M. Struve, A. Barbot, T. Fadai, L. Poustka, P. Conrod, T. Banaschewski, G. J. Barker, A. Bokde, U. Bromberg, C. Büchel, H. Flor, J. Gallinat, H. Garavan, A. Heinz, B. Ittermann, V. Kappel, C. Lawrence, E. Loth, K. Mann, F. Nees, T. Paus, Z. Pausova, J.-B. Poline, M. Rietschel, T. W. Robbins, M. Smolka, G. Schumann, J.-L. Martinot, the IMAGEN Consortium
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- Journal:
- Psychological Medicine / Volume 45 / Issue 11 / August 2015
- Published online by Cambridge University Press:
- 30 March 2015, pp. 2285-2294
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Background
Resilience is the capacity of individuals to resist mental disorders despite exposure to stress. Little is known about its neural underpinnings. The putative variation of white-matter microstructure with resilience in adolescence, a critical period for brain maturation and onset of high-prevalence mental disorders, has not been assessed by diffusion tensor imaging (DTI). Lower fractional anisotropy (FA) though, has been reported in the corpus callosum (CC), the brain's largest white-matter structure, in psychiatric and stress-related conditions. We hypothesized that higher FA in the CC would characterize stress-resilient adolescents.
MethodThree groups of adolescents recruited from the community were compared: resilient with low risk of mental disorder despite high exposure to lifetime stress (n = 55), at-risk of mental disorder exposed to the same level of stress (n = 68), and controls (n = 123). Personality was assessed by the NEO-Five Factor Inventory (NEO-FFI). Voxelwise statistics of DTI values in CC were obtained using tract-based spatial statistics. Regional projections were identified by probabilistic tractography.
ResultsHigher FA values were detected in the anterior CC of resilient compared to both non-resilient and control adolescents. FA values varied according to resilience capacity. Seed regional changes in anterior CC projected onto anterior cingulate and frontal cortex. Neuroticism and three other NEO-FFI factor scores differentiated non-resilient participants from the other two groups.
ConclusionHigh FA was detected in resilient adolescents in an anterior CC region projecting to frontal areas subserving cognitive resources. Psychiatric risk was associated with personality characteristics. Resilience in adolescence may be related to white-matter microstructure.
Resource partitioning among African savanna herbivores in North Cameroon: the importance of diet composition, food quality and body mass
- H. H. de Iongh, C. B. de Jong, J. van Goethem, E. Klop, A. M. H. Brunsting, P. E. Loth, H. H. T. Prins
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- Journal:
- Journal of Tropical Ecology / Volume 27 / Issue 5 / September 2011
- Published online by Cambridge University Press:
- 02 August 2011, pp. 503-513
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The relationship between herbivore diet quality, and diet composition (the range of food plants consumed) and body mass on resource partitioning of herbivores remains the subject of an ongoing scientific debate. In this study we investigated the importance of diet composition and diet quality on resource partitioning among eight species of savanna herbivore in north Cameroon, with different body mass. Dung samples of four to seven wild herbivore and one domesticated species were collected in the field during the dry and wet period. Diet composition was based on microhistological examination of herbivore droppings, epidermis fragments were identified to genus or family level. In addition, the quality of the faecal droppings was determined in terms of phosphorus, nitrogen and fibre concentrations. The results showed that there was no significant correlation between body mass and (differences in) diet composition for wet and dry season. When all species are considered, only significant relationships are found by the Spearman rank correlation analyses during the wet season between body mass and phosphorus and nitrogen, but this relationship did not exist during the dry season. When the analyses focuses on ruminants only (thus leaving out hippo), none of the relationships between body mass and diet quality was significant in either season. During the dry season the proportion of graminoids ranged between 10% (small unidentified herbivore species) to 90% (hippopotamus), during the wet season this proportion ranged from 60% (zebu) to 90% (hippopotamus). All species but zebu had more graminoids in their dung during wet season compared with dry season. However all species but hartebeest had more graminoids old stems in their dung during the dry season, compared with the wet season. The niche breadth for food categories consumed by kob (0.300), hippo (0.090), hartebeest (0.350), roan (0.510) and zebu (0.300) was much greater in the dry season than in the wet season for kob (0.120), hippo (0.020), hartebeest (0.190), roan (0.090) and zebu (0.200). When looking at grass taxa consumed, the niche breadth of kob (0.220), hartebeest (0.140), and roan (0.250) was also greater in the dry season when compared with the wet season for kob (0.050), hartebeest (0.120) and roan (0.120). The opposite was found for zebu and hippo. Comparison of the species’ diet compositions with randomized data showed that dietary overlap between different herbivore species was much higher than what would be expected on the basis of chance, demonstrating surprisingly limited niche separation between species. This offers potential for competition, but it is more likely that the high niche overlap indicates absence of competition, due to low herbivore densities and abundant food resources, permitting species to share non-limiting resources. With increasing herbivore densities and subsequent increasing scarcity of resources, the relationship between diet quality and body mass in combination with increased niche separation is expected to become more visible.