Mean Arterial Pressure Change Associated with Cerebral Blood Flow in Healthy Older Adults

We investigate over a 12-year period the association between regional cerebral blood flow (CBF) and cardiovascular risk factors in a prospective cohort of healthy older adults (81.96 +/- 3.82 year-old) from the Cognitive REServe and Clinical ENDOphenotype (CRESCENDO) study. Cardiovascular risk factors were measured over 12 years, and gray matter CBF was measured at the end of the study from high-resolution magnetic resonance imaging using arterial spin labeling. The association between cardiovascular risk factors, their long-term change, and CBF was assessed using multivariate linear regression models. Women were observed to have higher CBF than men (p < 0.05). Increased mean arterial pressure (MAP) over the 12-year period was correlated with a low cerebral blood flow (p < 0.05, R(2) = 0.21), whereas no association was detected between CBF and MAP at the time of imaging. High levels of glycemia tended to be associated with low cerebral blood flow values (p < 0.05). Age, alcohol consumption, smoking status, body mass index, history of cardiovascular disease, and hypertension were not associated with CBF. Our main result suggests that change in MAP is the most significant predictor of future CBF in older adults

Imaging of the optic chiasm and retrochiasmal visual pathways

International audienceThe exploration of the chiasmal and retrochiasmal visual pathways is based on magnetic resonance imaging. A bitemporal hemianopsis suggests a lesion of the optic chiasm while homonymous lateral hemianopsis should lead to a search for a lesion of the retrochiasmal visual pathways. The causes of chiasmal impairment are mainly tumoral. The exploration protocol is based on MRI with T1-weighted sagittal sections, then T2- and T1-weighted coronal sections with and without injection. In case of a retrochiasmal syndrome, the MRI exploration protocol is a function of the type of occurrence of the deficiency and the context

Cognitive Impairment and Basal Ganglia Functional Connectivity in Vascular Parkinsonism.

Patients with vascular parkinsonism have higher cognitive decline and more basal ganglia lesions. We aimed to evaluate the relationship of cognitive impairment with functional connectivity between the basal ganglia and cingulate cortex in vascular parkinsonism. Thirty patients (8 with vascular parkinsonism and 22 with Parkinson disease) and 23 controls were enrolled. The Mattis Dementia Rating Scale and the Stroop Task were used to assess cognitive decline. MR imaging examinations included T1-MPRAGE, FLAIR, and resting-state fMRI sequences. MPRAGE was segmented to obtain basal ganglia and cingulate cortex volumes. FLAIR was segmented to obtain white matter hyperintensity lesion volume. Resting-state fMRI sequences were used to compare basal ganglia functional connectivity with the cingulate cortex between patients and controls. Patients with vascular parkinsonism exhibited impaired attention, resistance to interference, and inhibitory control and an increased number of errors on the Stroop Task. They also had higher caudate nucleus and white matter hyperintensity lesion volumes, which were positively correlated (ρ = 0.75, P &lt; .0001). Caudate nucleus functional connectivity with the perigenual anterior cingulate cortex was increased in patients with vascular parkinsonism compared with controls and patients with Parkinson disease, and it was positively correlated with the caudate nucleus volume (ρ = 0.44, P = .016). Caudate nucleus functional connectivity with the posterior cingulate cortex was decreased in patients with vascular parkinsonism compared with controls and negatively correlated with the number of errors on the Stroop test (ρ = -0.51, P = .0003). In patients with vascular parkinsonism, cognitive decline could be related to changes of caudate nucleus functional connectivity with the cingulate cortex at resting-state, which may be induced by ischemia-related remodelling

MRI volumetric morphometry in vascular parkinsonism.

Vascular parkinsonism is a difficult clinical differential diagnosis in elderly subjects. We aimed at identifying morphometric markers in the brain of elderly patients with vascular parkinsonism (VP) compared with age-matched patients with Parkinson's disease (PD) and healthy controls. In this multicenter prospective study, 46 patients (80 ± 5 years old; male 32) with parkinsonism (32 PD and 14 VP) and 29 controls (mean age 78 ± 3 years; male 21) underwent brain MRI on a 3-T scanner including T1 MPRAGE and FLAIR sequences. Volumetric morphometry was obtained using Morphobox software and compared between patients and controls. Receiver operating characteristics curve analysis with computation of area under the curve (AUC) was used to compare diagnostic values. Caudate nucleus and white matter hyperintense lesions (WMHL) volumes appeared significantly higher in patients with VP. Normalized caudate volume of at least 0.67% and normalized WMHL of at least 1.11% identified patients with VP from patients with PD and controls with similar performances (p &gt; 0.25). Caudate nucleus and WMHL volumes were positively correlated (ρ = 0.74, p &lt; 0.0001), suggesting vascular disease related remodelling in elderly subjects. Caudate nucleus and WMHL MRI volumes might be used as additional markers to help identify patients with VP in the initial workup of elderly subjects with parkinsonian symptoms

Kinematics in the brain: The additional value of motor performance analysis during fMRI measurements

ObjectiveTo evaluate the additional value of adding movement kinematics into the design matrix in order to gain fine-grained insight in motor control strategies.MethodsTen healthy volunteers (age 41.8±14.5, 5 males) performed a continuous elbow flexion/extension within a 1.5 MRI system. Movement kinematics were registered with the Zebris, a MRI compatible 3D motion capture system.ResultsWithout taking the movement kinematics into consideration we found the expected systematic activation of the primary sensorimotor network, thought to generate movement execution [1]. By adding the kinematics to the fMRI design matrix we unmasked the involvement of fronto-cerebellar circuits and of the sensory cortex, as a function of both the irregularity and the frequency of movement, highlighting underlying processes of error-control to ensure optimal execution [2].DiscussionOur results reveal the modular and hierarchical structure of rhythmic motor control within brain networks: rhythmical movement generation relies on the activation of the primary sensorimotor network and error control of that movement results from the trade-off between automatically driven intermittent control involving cerebellar-frontal loops and continuous feedback involving the sensory cortex. Motor planning and error-control are important process involved in recovery post-stroke, and the detailed kinematic analysis during fMRI measurements seems to have an additional value possibly contributing to further understanding motor learning post-stroke

Réorganisation de la connectivité fonctionnelle des réseaux de l’état de repos en fonction de la performance de la mémoire de travail chez des individus âgés sains.

National audience..