Recent magnetic resonance imaging and pathological studies have indicated that axonal loss is a major contributor to disease progression in multiple sclerosis. 1 H magnetic resonance spectroscopy, through measurement of N -acetyl aspartate, a neuronal marker, provides a unique tool to investigate this. Patients with primary progressive multiple sclerosis have few lesions on conventional MRI, suggesting that changes in normal appearing white matter, such as axonal loss, may be particularly relevant to disease progression in this group. To test this hypothesis (...) NAWM was studied with MRS, measuring the concentration of N -acetyl derived groups. Single-voxel MRS using a water-suppressed PRESS sequence was carried out in 24 patients with primary progressive multiple sclerosis and in 16 age-matched controls. Ratios of metabolite to creatine concentration were calculated in all subjects, and absolute concentrations were measured in 18 patients and all controls. NA/Cr was significantly lower in NAWM in patients than in controls, as was the absolute concentration of NA. There was no significant difference in the absolute concentration of creatine between the groups. This study supports the hypothesis that axonal loss occurs in NAWM in primary progressive multiple sclerosis and may well be a mechanism for disease progression in this group. (shrink)

Extensive research has demonstrated that rs1360780, a common single nucleotide polymorphism within the FKBP5 gene, interacts with early-life stress in predicting psychopathology. Previous results suggest that carriers of the TT genotype of rs1360780 who were exposed to child abuse show differences in structure and functional activation of emotion-processing brain areas belonging to the salience network. Extending these findings on intermediate phenotypes of psychopathology, we examined if the interaction between rs1360780 and child abuse predicts resting-state functional connectivity (rsFC) between the amygdala (...) and other areas of the salience network. We analyzed data of young European adults from the general population (N = 774; mean age = 18.76 years) who took part in the IMAGEN study. In the absence of main effects of genotype and abuse, a significant interaction effect was observed for rsFC between the right centromedial amygdala and right posterior insula (p <.025, FWE-corrected), which was driven by stronger rsFC in TT allele carriers with a history of abuse. Our results suggest that the TT genotype of rs1360780 may render individuals with a history of abuse more vulnerable to functional changes in communication between brain areas processing emotions and bodily sensations, which could underlie or increase the risk for psychopathology. (shrink)