Microstructural changes in memory and reticular formation neural pathway after simple concussion

Patients with concussion often present with temporary disturbance of consciousness. The microstructural and functional changes in the brain associated with concussion, as well as the relationship with transient cognitive disorders, are currently unclear. In the present study, a rabbit model of simple concussion was established. Magnetic resonance-diffusion tensor imaging results revealed that the corona radiata and midbrain exhibited significantly decreased fractional anisotropy values in the neural pathways associated with memory and the reticular formation. In addition, the apparent diffusion coefficient values were significantly increased following injury compared with those before injury. Following a 1-hour period of quiet rest, the fractional anisotropy values significantly increased, and apparent diffusion coefficient values significantly decreased, returning to normal pre-injury levels. In contrast, the fractional anisotropy values and apparent diffusion coefficient values in the corpus callosum, thalamus and hippocampus showed no statistical significant alterations following injury. These findings indicate that the neural pathways associated with memory and the reticular formation pathway exhibit reversible microstructural white matter changes when concussion occurs, and these changes are exhibited to a different extent in different regions.

Microstructural white matter lesion in Alzheimer's disease: a diffusion tensor imaging study using voxel-based analysis

Objective To study the microscopic changes of white matter and the relationship between white matter changes and cognitive impairment in Alzheimer’s disease(AD)using voxel-based analysis of DTI.Methods Thirty-seven patients with probable AD,and 32 normal controls(NC)were all examined by MMSE scores,and un-

Microstructural brain abnormalities,affective temperaments,and suicidal behavior in patients with major depression

According to magnetic resonance imaging(MRI)studies,brain white matter(WM)abnormalities have been suggested to play a critical role in the pathogenesis of major depressive disorder(MDD)and related suicidal behavior.However,MRI findings may be limited by low spatial resolution;therefore,an important contribution to the understanding of the role and significance of WM alterations derived by the development of the most recent magnetic resonance techniques,such as diffusion tensor imaging(DTI).Several DTI studies reported an association between altered WM integrity and MDD/suicidal behavior.Microstructural WM abnormalities may be located in neural circuits critically implicated in emotional processes and mood regulation resulting in enhanced vulnerability to psychiatric morbidity.WM abnormalities detected using DTI may contribute to functional deficits and help to clarify the pathophysiological mechanisms underlying MDD as well as suicidal behavior.By a clinical point of view,research also suggested that affective temperaments may play a relevant role in the psychopathological characteristics of mood disorders,clinical trajectory of episodes and polarity,long‑term outcome and suicidality.Unfortunately,only few studies investigated the association between affective temperaments and WM abnormalities and discussed their possible implications in patients with MDD and suicidal behavior.Using a comprehensive search of Medline database,the aim of the present study was to critically review the current literature on the association between WM alterations as assessed by MRI and DTI techniques,affective temperaments,MDD and suicidal behavior.