title: White matter changes in microstructure associated with a maladaptive response to stress in rats.
abstract: In today's society, every individual is subjected to stressful stimuli with different intensities and duration. This exposure can be a key trigger in several mental illnesses greatly affecting one's quality of life. Yet not all subjects respond equally to the same stimulus and some are able to better adapt to them delaying the onset of its negative consequences. The neural specificities of this adaptation can be essential to understand the true dynamics of stress as well as to design new approaches to reduce its consequences. In the current work, we employed ex vivo high field diffusion magnetic resonance imaging (MRI) to uncover the differences in white matter properties in the entire brain between Fisher 344 (F344) and Sprague-Dawley (SD) rats, known to present different responses to stress, and to examine the effects of a 2-week repeated inescapable stress paradigm. We applied a tract-based spatial statistics (TBSS) analysis approach to a total of 25 animals. After exposure to stress, SD rats were found to have lower values of corticosterone when compared with F344 rats. Overall, stress was found to lead to an overall increase in fractional anisotropy (FA), on top of a reduction in mean and radial diffusivity (MD and RD) in several white matter bundles of the brain. No effect of strain on the white matter diffusion properties was observed. The strain-by-stress interaction revealed an effect on SD rats in MD, RD and axial diffusivity (AD), with lower diffusion metric levels on stressed animals. These effects were localized on the left side of the brain on the external capsule, corpus callosum, deep cerebral white matter, anterior commissure, endopiriform nucleus, dorsal hippocampus and amygdala fibers. The results possibly reveal an adaptation of the SD strain to the stressful stimuli through synaptic and structural plasticity processes, possibly reflecting learning processes.
authors.affiliation: Physiopathologie des Maladies Psychiatriques, UMR_S 894 Inserm, Centre de Psychiatrie et Neurosciences, Paris, France.|Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus de Gualtar, Braga, Portugal.|ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal.
authors.forename: R
authors.initials: R
authors.lastname: Magalhães
authors.affiliation: Physiopathologie des Maladies Psychiatriques, UMR_S 894 Inserm, Centre de Psychiatrie et Neurosciences, Paris, France.|Université Paris Descartes, Sorbonne Paris Cité, Paris, France.|Faculté de Médecine Paris Descartes, Service Hospitalo Universitaire, Centre Hospitalier Sainte-Anne, Paris, France.
authors.forename: J
authors.initials: J
authors.lastname: Bourgin
authors.affiliation: Neurospin, I2BM, CEA, Gif/Yvette, France.
authors.forename: F
authors.initials: F
authors.lastname: Boumezbeur
authors.affiliation: Physiopathologie des Maladies Psychiatriques, UMR_S 894 Inserm, Centre de Psychiatrie et Neurosciences, Paris, France.|Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus de Gualtar, Braga, Portugal.|ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal.
authors.forename: P
authors.initials: P
authors.lastname: Marques
authors.affiliation: Neurospin, I2BM, CEA, Gif/Yvette, France.
authors.forename: M
authors.initials: M
authors.lastname: Bottlaender
authors.affiliation: Neurospin, I2BM, CEA, Gif/Yvette, France.
authors.forename: C
authors.initials: C
authors.lastname: Poupon
authors.affiliation: Neurospin, I2BM, CEA, Gif/Yvette, France.
authors.forename: B
authors.initials: B
authors.lastname: Djemaï
authors.affiliation: Neurospin, I2BM, CEA, Gif/Yvette, France.
authors.forename: E
authors.initials: E
authors.lastname: Duchesnay
authors.affiliation: Neurospin, I2BM, CEA, Gif/Yvette, France.
authors.forename: S
authors.initials: S
authors.lastname: Mériaux
authors.affiliation: Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus de Gualtar, Braga, Portugal.|ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal.
authors.forename: N
authors.initials: N
authors.lastname: Sousa
authors.affiliation: Physiopathologie des Maladies Psychiatriques, UMR_S 894 Inserm, Centre de Psychiatrie et Neurosciences, Paris, France.|Université Paris Descartes, Sorbonne Paris Cité, Paris, France.|Faculté de Médecine Paris Descartes, Service Hospitalo Universitaire, Centre Hospitalier Sainte-Anne, Paris, France.
authors.forename: T M
authors.initials: TM
authors.lastname: Jay
authors.affiliation: Physiopathologie des Maladies Psychiatriques, UMR_S 894 Inserm, Centre de Psychiatrie et Neurosciences, Paris, France.|Université Paris Descartes, Sorbonne Paris Cité, Paris, France.|Laboratoire de Psychologie du développement et de l'Education de l'Enfant, CNRS UMR 8240, Paris, France.|Institut Universitaire de France, Paris, France.
authors.forename: A
authors.initials: A
authors.lastname: Cachia
mesh_terms: D000222:Adaptation, Physiological; D000679:Amygdala / Q000000981:diagnostic imaging; D000818:Animals; D016880:Anisotropy; D066240:Anterior Commissure, Brain / Q000000981:diagnostic imaging; D001921:Brain / Q000000981:diagnostic imaging*; D003337:Corpus Callosum / Q000000981:diagnostic imaging; D003345:Corticosterone / Q000378:metabolism; D038524:Diffusion Magnetic Resonance Imaging; D066271:External Capsule / Q000000981:diagnostic imaging; D006624:Hippocampus / Q000000981:diagnostic imaging; D008297:Male; D051381:Rats; D011916:Rats, Inbred F344; D017207:Rats, Sprague-Dawley; D013315:Stress, Psychological / Q000000981:diagnostic imaging* / Q000378:metabolism; D066127:White Matter / Q000000981:diagnostic imaging*
chemical_list: D003345:Corticosterone