scholarly journals The effects of acute cannabidiol on cerebral blood flow and its relationship to memory: An arterial spin labelling magnetic resonance imaging study

2020 ◽  
Vol 34 (9) ◽  
pp. 981-989 ◽  
Author(s):  
Michael A P Bloomfield ◽  
Sebastian F Green ◽  
Chandni Hindocha ◽  
Yumeya Yamamori ◽  
Jocelyn Lok Ling Yim ◽  
...  
Keyword(s):  
Working Memory ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Episodic Memory ◽  
Task Performance ◽  
Digit Span ◽  
Memory Task ◽  
Arterial Spin Labelling ◽  
Memory Processing ◽  
Spin Labelling

Background: Cannabidiol (CBD) is being investigated as a potential treatment for several medical indications, many of which are characterised by altered memory processing. However, the mechanisms underlying these effects are unclear. Aims: Our primary aim was to investigate how CBD influences cerebral blood flow (CBF) in regions involved in memory processing. Our secondary aim was to determine if the effects of CBD on CBF were associated with differences in working and episodic memory task performance. Methods: We used a randomised, crossover, double-blind design in which 15 healthy participants were administered 600 mg oral CBD or placebo on separate days. We measured regional CBF at rest using arterial spin labelling 3 h after drug ingestion. We assessed working memory with the digit span (forward, backward) and n-back (0-back, 1-back, 2-back) tasks, and we used a prose recall task (immediate and delayed) to assess episodic memory. Results: CBD increased CBF in the hippocampus (mean (95% confidence intervals) = 15.00 (5.78–24.21) mL/100 g/min, t14 = 3.489, Cohen’s d = 0.75, p = 0.004). There were no differences in memory task performance, but there was a significant correlation whereby greater CBD-induced increases in orbitofrontal CBF were associated with reduced reaction time on the 2-back working memory task ( r= −0.73, p = 0.005). Conclusions: These findings suggest that CBD increases CBF to key regions involved in memory processing, particularly the hippocampus. These results identify potential mechanisms of CBD for a range of conditions associated with altered memory processing, including Alzheimer’s disease, schizophrenia, post-traumatic stress disorder and cannabis-use disorders.

scholarly journals Cerebral perfusion changes in presymptomatic genetic frontotemporal dementia: a GENFI study

Brain ◽  
2019 ◽  
Vol 142 (4) ◽  
pp. 1108-1120 ◽  
Author(s):  
Henri J M M Mutsaerts ◽  
Saira S Mirza ◽  
Jan Petr ◽  
David L Thomas ◽  
David M Cash ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Frontotemporal Dementia ◽  
Symptom Onset ◽  
Arterial Spin Labelling ◽  
Anterior Cingulate ◽  
Middle Temporal Gyrus ◽  
Inverse Association ◽  
Mutation Carriers ◽  
Spin Labelling

Abstract Genetic forms of frontotemporal dementia are most commonly due to mutations in three genes, C9orf72, GRN or MAPT, with presymptomatic carriers from families representing those at risk. While cerebral blood flow shows differences between frontotemporal dementia and other forms of dementia, there is limited evidence of its utility in presymptomatic stages of frontotemporal dementia. This study aimed to delineate the cerebral blood flow signature of presymptomatic, genetic frontotemporal dementia using a voxel-based approach. In the multicentre GENetic Frontotemporal dementia Initiative (GENFI) study, we investigated cross-sectional differences in arterial spin labelling MRI-based cerebral blood flow between presymptomatic C9orf72, GRN or MAPT mutation carriers (n = 107) and non-carriers (n = 113), using general linear mixed-effects models and voxel-based analyses. Cerebral blood flow within regions of interest derived from this model was then explored to identify differences between individual gene carrier groups and to estimate a timeframe for the expression of these differences. The voxel-based analysis revealed a significant inverse association between cerebral blood flow and the expected age of symptom onset in carriers, but not non-carriers. Regions included the bilateral insulae/orbitofrontal cortices, anterior cingulate/paracingulate gyri, and inferior parietal cortices, as well as the left middle temporal gyrus. For all bilateral regions, associations were greater on the right side. After correction for partial volume effects in a region of interest analysis, the results were found to be largely driven by the C9orf72 genetic subgroup. These cerebral blood flow differences first appeared approximately 12.5 years before the expected symptom onset determined on an individual basis. Cerebral blood flow was lower in presymptomatic mutation carriers closer to and beyond their expected age of symptom onset in key frontotemporal dementia signature regions. These results suggest that arterial spin labelling MRI may be a promising non-invasive imaging biomarker for the presymptomatic stages of genetic frontotemporal dementia.

scholarly journals Effects of red blood cells with reduced deformability on cerebral blood flow and vascular water transport: measurements in rats using time-resolved pulsed arterial spin labelling at 9.4 T

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Adnan Bibic ◽  
Tea Sordia ◽  
Erik Henningsson ◽  
Linda Knutsson ◽  
Freddy Ståhlberg ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Repeated Measures ◽  
Arterial Spin Labelling ◽  
Control Group ◽  
Study Group ◽  
Percentage Points ◽  
Spin Labelling

Abstract Background Our aim was to introduce damaged red blood cells (RBCs) as a tool for haemodynamic provocation in rats, hypothesised to cause decreased cerebral blood flow (CBF) and prolonged water capillary transfer time (CTT), and to investigate whether expected changes in CBF could be observed and if haemodynamic alterations were reflected by the CTT metric. Methods Damaged RBCs exhibiting a mildly reduced deformability were injected to cause aggregation of RBCs. Arterial spin labelling (ASL) magnetic resonance imaging experiments were performed at 9.4 T. Six datasets (baseline plus five datasets after injection) were acquired for each animal in a study group and a control group (13 and 10 female adult Wistar rats, respectively). For each dataset, ASL images at ten different inversion times were acquired. The CTT model was adapted to the use of a measured arterial input function, implying the use of a realistic labelling profile. Repeated measures ANOVA was used (alpha error = 0.05). Results After injection, significant differences between the study group and control group were observed for relative CBF in white matter (up to 20 percentage points) and putamen (up to 18–20 percentage points) and for relative CTT in putamen (up to 35–40 percentage points). Conclusions Haemodynamic changes caused by injection of damaged RBCs were observed by ASL-based CBF and CTT measurements. Damaged RBCs can be used as a tool for test and validation of perfusion imaging modalities. CTT model fitting was challenging to stabilise at experimental signal-to-noise ratio levels, and the number of free parameters was minimised.

A Neuroanatomical Construct for the Amnesic Effects of Propofol

2002 ◽  
Vol 97 (2) ◽  
pp. 329-337 ◽  
Author(s):  
Robert A. Veselis ◽  
Ruth A. Reinsel ◽  
Vladimir A. Feshchenko ◽  
Ann M. Dnistrian
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Episodic Memory ◽  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Regional Cerebral Blood Flow ◽  
Memory Task ◽  
Statistical Parametric Mapping ◽  
Regional Cerebral Blood ◽  
Word Memory

Background This study was designed to identify neuroanatomical locations of propofol's effects on episodic memory by producing minimal and maximal memory impairment during conscious sedation. Drug-related changes in regional cerebral blood flow (rCBF) were located in comparison with rCBF increases during a simple word memory task. Methods Regional cerebral blood flow changes were assessed in 11 healthy volunteers using H215O positron emission tomography (PET) and statistical parametric mapping (SPM99) at 600 and 1,000 ng/ml propofol target concentrations. Study groups were based on final recognition scores of auditory words memorized during PET scanning. rCBF changes during propofol administration were compared with those during the word memory task at baseline. Results Nonoverlapping memory effects were evident: low (n = 4; propofol concentration 523 +/- 138 ng/ml; 44 +/- 13% decrement from baseline memory) and high (n = 7; 829 +/- 246 ng/ml; 87 +/- 6% decrement from baseline) groups differed in rCBF reductions primarily in right-sided prefrontal and parietal regions, close to areas activated in the baseline memory task, particularly R dorsolateral prefrontal cortex (Brodmann area 46; x, y, z = 51, 38, 22). The medial temporal lobe region exhibited relative rCBF increases. Conclusions As amnesia becomes maximal, rCBF reductions induced by propofol occur in brain regions identified with working memory processes. In contrast, medial temporal lobe structures were resistant to the global CBF decrease associated with propofol sedation. The authors postulate that the episodic memory effect of propofol is produced by interference with distributed cortical processes necessary for normal memory function rather than specific effects on medial temporal lobe structures.

scholarly journals Measuring the Effects of Remifentanil on Cerebral Blood Flow and Arterial Arrival Time Using 3D Grase MRI with Pulsed Arterial Spin Labelling

2008 ◽  
Vol 28 (8) ◽  
pp. 1514-1522 ◽  
Author(s):  
Bradley J Macintosh ◽  
Kyle TS Pattinson ◽  
Daniel Gallichan ◽  
Imran Ahmad ◽  
Karla L Miller ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Arrival Time ◽  
Spin Echo ◽  
Three Dimensional ◽  
Brain Perfusion ◽  
Arterial Spin Labelling ◽  
Permutation Testing ◽  
Significant Difference ◽  
Spin Labelling

Arterial spin labelling (ASL) has proved to be a promising magnetic resonance imaging (MRI) technique to measure brain perfusion. In this study, volumetric three-dimensional (3D) gradient and spin echo (GRASE) ASL was used to produce cerebral blood flow (CBF) and arterial arrival time (AAT) maps during rest and during an infusion of remifentanil. Gradient and spin echo ASL perfusion-weighted images were collected at multiple inflow times (500 to 2,500 ms in increments of 250 ms) to accurately fit an ASL perfusion model. Fit estimates were assessed using z-statistics, allowing voxels with a poor fit to be excluded from subsequent analyses. Nonparametric permutation testing showed voxels with a significant difference in CBF and AAT between conditions across a group of healthy participants ( N = 10). Administration of remifentanil produced an increase in end-tidal CO2, an increase in CBF from 57 ± 12.0 to 77 ± 18.4 mL/100 g tissue per min and a reduction in AAT from 0.73 ± 0.073 to 0.64 ± 0.076 secs. Within grey matter, remifentanil produced a cerebrovascular response of 5.7 ± 1.60 %CBF per mm Hg. Significant differences between physiologic conditions were observed in both CBF and AAT maps, indicating that 3D GRASE-ASL has the sensitivity to study changes in physiology at a voxel level.

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