caa a22 4500 606203524 CHVBK 20210128100958.0 cr unu---uuuuu 210128e20150301xx s 000 0 eng 10.1007/s00429-013-0683-7 doi (NATIONALLICENCE)springer-10.1007/s00429-013-0683-7 Diffusion tensor imaging of hippocampal network plasticity [Elektronische Daten] [Alejandra Sierra, Teemu Laitinen, Olli Gröhn, Asla Pitkänen] Diffusion tensor imaging (DTI) has become a valuable tool to investigate white matter integrity in the brain. DTI also gives contrast in gray matter, which has been relatively little explored in studies assessing post-injury structural abnormalities. The present study was designed to compare white and gray matter reorganization in the rat hippocampus after two epileptogenic brain injuries, status epilepticus (SE) and traumatic brain injury (TBI), using ex vivo high-resolution DTI. Imaging was performed at 6-12months post-injury and findings were compared to histological analyses of Nissl, myelin, and Timm-stained preparations from the same animals. In agreement with the severity of histological damage, fractional anisotropy (FA), axial (D ||) and radial (D ⊥) diffusivities, and mean diffusivity (MD) measurements were altered in the order SE>TBI ipsilaterally>TBI contralaterally. After SE, the most severe abnormalities were found in the dentate gyrus and CA3b-c subfields, in which the mean FA was increased to 125% (p<0.001) and 143% (p<0.001) of that in controls, respectively. In both subfields, the change in FA was associated with an increase in D || (p<0.01). In the stratum radiatum of the CA1, FA was decreased to 81% of that in controls (p<0.05) which was associated with an increase in D ⊥ (p<0.01). After TBI, DTI did not reveal any major abnormalities in the dentate gyrus. In the ipsilateral CA3b-c, however, FA was increased to 126% of that in controls (p<0.01) and associated with a mild decrease in D ⊥ (p<0.05). In the stratum radiatum of the ipsilateral CA1, FA was decreased to 88% of that in controls (p<0.05). Our data demonstrate that DTI reveals subfield-specific abnormalities in the hippocampus with remarkable qualitative and quantitative differences between the two epileptogenic etiologies, suggesting that DTI could be a valuable tool for follow-up of focal circuitry reorganization during the post-injury aftermath. Springer-Verlag Berlin Heidelberg, 2013 Diffusion tensor imaging nationallicence Epilepsy nationallicence Epileptogenesis nationallicence Hippocampus nationallicence Magnetic resonance imaging nationallicence Mossy fiber sprouting nationallicence Myelin nationallicence Status epilepticus nationallicence Traumatic brain injury nationallicence D || : Axial diffusivity nationallicence D ⊥ : Radial diffusivity nationallicence DTI : Diffusion tensor imaging nationallicence FA : Fractional anisotropy nationallicence FPI : Fluid percussion injury nationallicence MD : Mean diffusivity nationallicence MRI : Magnetic resonance imaging nationallicence ROI : Region of interest nationallicence SE : Status epilepticus nationallicence TBI : Traumatic brain injury nationallicence Sierra Alejandra Department of Neurobiology, A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, PO Box 1627, 70211, Kuopio, Finland aut Laitinen Teemu Department of Neurobiology, A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, PO Box 1627, 70211, Kuopio, Finland aut Gröhn Olli Department of Neurobiology, A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, PO Box 1627, 70211, Kuopio, Finland aut Pitkänen Asla Department of Neurobiology, A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, PO Box 1627, 70211, Kuopio, Finland aut Brain Structure and Function Springer Berlin Heidelberg 220/2(2015-03-01), 781-801 1863-2653 220:2<781 2015 220 429 https://doi.org/10.1007/s00429-013-0683-7 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00429-013-0683-7 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Sierra Alejandra Department of Neurobiology, A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, PO Box 1627, 70211, Kuopio, Finland aut NATIONALLICENCE 700 1- Laitinen Teemu Department of Neurobiology, A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, PO Box 1627, 70211, Kuopio, Finland aut NATIONALLICENCE 700 1- Gröhn Olli Department of Neurobiology, A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, PO Box 1627, 70211, Kuopio, Finland aut NATIONALLICENCE 700 1- Pitkänen Asla Department of Neurobiology, A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, PO Box 1627, 70211, Kuopio, Finland aut NATIONALLICENCE 773 0- Brain Structure and Function Springer Berlin Heidelberg 220/2(2015-03-01), 781-801 1863-2653 220:2<781 2015 220 429