A smaller olfactory bulb in a mouse model of Down syndrome

Abstract

Persons with trisomy 21 (Down syndrome) present different phenotypes, including early neurodegeneration, which is prominent in the brain olfactory areas, and olfactory deficit. The use of in vivo techniques in animal models allows to characterize and follow up these slowly developing phenomena. We explored by means of magnetic resonance imaging the olfactory bulb of the Ts65Dn mouse, an established model of Down syndrome, searching for possible syndrome-related changes. In vivo imaging provided a first glimpse of the trisomic olfactory bulb as compared to euploid one. The olfactory bulb volume was smaller in trisomic mice, suggesting that changes in olfactory bulb may be apparent already in the young adult (2-to 8-month-old) mice, which are amenable to follow-up in vivo. These findings lead the way to future work aimed at characterizing the Down syndrome-related development of morphological alterations in the olfactory bulb and relating them to changes in olfactory performance, which were detected in this mouse model.

Resting‐state functional magnetic resonance imaging reveals functional connectivity alteration in the experimental autoimmune encephalomyelitis model of multiple sclerosis

“…Structural T 2 ‐weighted images were analyzed with FMRIB Software Library (FSL), 20 similar to our previous work 21,22 . Briefly, total brain tissue, gray matter (GM), WM, cerebellar cortex, striatum, and intraventricular cerebrospinal fluid (CSF) were segmented to obtain their volumes.…”

“…Structural T 2 -weighted images were analyzed with FMRIB Software Library (FSL), 20 similar to our previous work. 21,22 Briefly, total brain tissue, gray matter (GM), WM, cerebellar cortex, striatum, and intraventricular cerebrospinal fluid (CSF) were segmented to obtain their volumes. DTI data were denoised with MRtrix3 23 and corrected for susceptibility-induced distortions with topup 24 (part of FSL) using the reversed phase-encode blips images.…”

Age-Related In Vivo Structural Changes in the Male Mouse Olfactory Bulb and Their Correlation with Olfactory-Driven Behavior

“…Then, five contiguous 1 mm-thick slices of the whole OB were acquired using a multi-echo spin-echo sequence (MSME) with matrix size = 256 × 192, FOV = 2.5 × 2.5 cm 2 , corresponding to an in-plane resolution of 100 × 132 μm 2 , NEX = 1, 10 echoes, TR of 2611 ms, and TE ranging from 20 to 200 ms. These images were used for generating quantitative T2 mapping [ 43 ].…”