Why musical memory can be preserved in advanced Alzheimer's disease

Musical memory is relatively preserved in Alzheimer's disease and other dementias. In a 7 Tesla functional MRI study employing multi-voxel pattern analysis, Jacobsen et al. identify brain regions encoding long-term musical memory in young healthy controls, and show that these same regions display relatively little atrophy and hypometabolism in patients with Alzheimer's disease.See Clark and Warren (doi:10.1093/brain/awv148) for a scientific commentary on this article. Musical memory is relatively preserved in Alzheimer's disease and other dementias. In a 7 Tesla functional MRI study employing multi-voxel pattern analysis, Jacobsen et al. identify brain regions encoding long-term musical memory in young healthy controls, and show that these same regions display relatively little atrophy and hypometabolism in patients with Alzheimer's disease.See Clark and Warren (doi:10.1093/awv148) for a scientific commentary on this article

Evaluating metabolites in patients with major depressive disorder who received mindfulness-based cognitive therapy and healthy controls using short echo MRSI at 7 Tesla.

ObjectivesOur aim was to evaluate differences in metabolite levels between unmedicated patients with major depressive disorder (MDD) and healthy controls, to assess changes in metabolites in patients after they completed an 8-week course of mindfulness-based cognitive therapy (MBCT), and to exam the correlation between metabolites and depression severity.Materials and methodsSixteen patients with MDD and ten age- and gender-matched healthy controls were studied using 3D short echo-time (20 ms) magnetic resonance spectroscopic imaging (MRSI) at 7 Tesla. Relative metabolite ratios were estimated in five regions of interest corresponding to insula, anterior cingulate cortex (ACC), caudate, putamen, and thalamus.ResultsIn all cases, MBCT reduced severity of depression. The ratio of total choline-containing compounds/total creatine (tCr) in the right caudate was significantly increased compared to that in healthy controls, while ratios of N-acetyl aspartate (NAA)/tCr in the left ACC, myo-inositol/tCr in the right insula, and glutathione/tCr in the left putamen were significantly decreased. At baseline, the severity of depression was negatively correlated with my-inositol/tCr in the left insula and putamen. The improvement in depression severity was significantly associated with changes in NAA/tCr in the left ACC.ConclusionsThis study has successfully evaluated regional differences in metabolites for patients with MDD who received MBCT treatment and in controls using 7 Tesla MRSI

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Department of Biomedical EngineeringMagnetic susceptibility contrast MRI using local magnetic field gradients or inhomogeneities is expected to provide low-resolution quantification of tissue microarchitecture, as magnetic resonance (MR) transverse relaxation times (T2 and T2*) are influenced by field inhomogeneity arising from susceptibility mismatch of tissues. By aid of ultra-high field MRI scanner, MR transverse relaxation times is promising to further increase their sensitivity to detecting subtle structural changes in tissue microstructures. However, one of the main technical difficulty of ultra-high field MRI is unwanted variations of signal and contrast, or even worse, nullify the MR signal due to increased macroscopic static magnetic field inhomogeneities which are prone to misinterpretation and loss of structural information. This study focuses on improving the sensitivity and the robustness of ultra-high field MRI (particularly for 7 T) from unwanted signal variations due to magnetic field inhomogeneities and shortened MR transverse relaxation times. MR transverse relaxation times were investigated for the low-resolution assessment of tissue microstructures, such as trabecular bone microstructure and cerebral microvasculature. As a result, T2 relaxation time without having an effect of macroscopic field inhomogeneities may be suitable for the assessment of trabecular structural indices and robust with degrading spatial resolution with reduced scan time at 7 T. For the assessment of cerebral microvasculature, the diffusion-time-dependent stimulated-echo-based MR relaxation-rates was demonstrated as robust measures for assessing small (diameter < 5 ??m) cerebral microvasculature, where macroscopic field inhomogeneities from bone (air)-tissue interfaces and influences of large vessels in cortical region are significant. Finally, the quantification of MR longitudinal relaxation time (T1) was optimized by variable repetition-delay turbo-spin echo method with sparse encoding technique.clos

On-chip SQUID measurements in the presence of high magnetic fields

We report a low temperature measurement technique and magnetization data of a quantum molecular spin, by implementing an on-chip SQUID technique. This technique enables the SQUID magnetometery in high magnetic fields, up to 7 Tesla. The main challenges and the calibration process are detailed. The measurement protocol is used to observe quantum tunneling jumps of the S=10 molecular magnet, Mn12-tBuAc. The effect of transverse field on the tunneling splitting for this molecular system is addressed as well.Comment: 7 pages, 3 figure

T2 mapiranje hrskavice acetabuluma kod bolesnika s primarnim osteoartritisom i sekundarnim osteoartritisom induciranim razvojnim poremećajem kuka analizirano na mikro-MR uređaju snage 7 Tesla

The aim of our study was to compare acetabular cartilage affected by primary and DDH-induced secondary osteoarthritis (OA) using T2 mapping, which gives us information about cartilage water and collagen content, and the orientation of collagen fibrils. Samples of the osteochondral unit were obtained intraoperatively during total hip arthroplasty from the acetabulum of 15 patients with primary OA (pOA-Ac) and 15 patients with DDH-induced secondary OA (sOA-Ac). The samples were then scanned on a 7 Tesla micro-magnetic resonance imaging (micro-MRI) machine and the T2 values of all samples were calculated. The results were compared using a t-test. The average T2 values for the sOAAc and pOA-Ac groups were 57.28±31.87 ms and 37.54±11.17 ms, respectively. The calculated p-value was 0.019, making results statistically significant at p<0.05. This is one of the first studies performed ex vivo on the acetabular cartilage of human dysplastic hips, using a 7 Tesla MRI machine. Our results show that acetabular cartilage in DDH-induced secondary OA is more damaged than in primary OA, and offer 7 Tesla T2 reference values of acetabular cartilage for both the primary and DDH-induced secondary OA.Svrha ovog rada bila je usporediti acetabularnu hrskavicu prikupljenu od pacijenata s primarnim i sekundaranim osteoartritisom (OA) uzrokovanim razvojnim poremećajem kuka koristeći T2 mapiranje, koje se koristi za analizu sadržaja vode i kolagena u hrskavici, i orijentacije kolagenih vlakana. Uzorci actabuluma prikupljeni su tijekom operacije ugradnje totalne endoproteze kuka od 15 pacijenata s primarnim OA (pOA-Ac) i 15 pacijenata sa sekundarnim OA uzrokovanim razvojnim poremećajem kuka (sOA-Ac), te su snimljeni mikro-magnetskom rezonancijom (mikro-MR) na uređaju jačine 7 Tesla. Izračunate su T2 mape svih uzoraka, a rezultati su uspoređeni pomoću t-testa. Srednje T2 vrijednosti za sOA-Ac i pOA-Ac iznosile su 57.28±31.87 ms, odnosno 37.54±11.17 ms. Izračunata p vrijednost iznosila je 0.019, što znači da je razlika između skupina statistički značajna uz razinu značajnosti p<0.05. Ovo je jedna od prvih ex vivo studija acetabularne hrskavice pacijenata s razvojnim poremećajem kuka provedenih na mikro-MR uređaju jačine 7 Tesla. Naši rezultati upućuju na to da je acetabularna hrskavica pacijenata sa sekundarnim osteoartritisom uzrokovanim razvojnim poremećajem kuka više oštećena od one pacijenata s primarnim OA. Naša studija pruža informacije o referentnim T2 vrijednostima acetabularne hrskavice zahvaćene primarnim i sekundarnim OA dobivenim na MR uređaju jačine 7 Tesla