Brain stem myelination - Griffith University · Brain stem myelination and MRI changes in CFS/ME....
Transcript of Brain stem myelination - Griffith University · Brain stem myelination and MRI changes in CFS/ME....
Department name (edit in View > Header and
Footer...) Department name (edit in View > Header and Footer...)National Centre for Neuroimmunology and Emerging Diseases
Brain stem myelination
and
MRI changes in CFS/ME
Leighton BARNDEN
National Centre for Neuroimmunolgy and Emerging Diseases
Griffith Uni, Gold Coast, QLD
• Brain stem • myelination • MRI studies of CFS/ME• Results• Conclusions
Brain stem myelination and
MRI changes in CFS/ME
brain stem midbrainponsmedulla
Brain stem
where is it?
Brain stem
Multiple nuclei send fibres to the cortex where they release excitatory neuro-hormones.
This process maintains arousal and consciousness
- cognitive performance- initiation of movement
There are also inhibitory fibres that regulate the transition to sleep and the duration/intensity of pain.
Other nuclei regulateheart rate, blood pressure
also
temperature, breathing,gut & immune function … and more (autonomic).
Brain stem stress
cuneiform nucleus
vasomotor centre
to blood-pressure,heart-rate effectors
thalamus
hypothalamus
midbrain
pons
medulla
• If transmission of signals within the brain stem is impairedit may adversely affect:
arousal, cognitive performance, initiation of movement, quality of sleep, pain & bodily functions
Brain stem
Myelination
speeds up signal transmission
90% of T1 MRI contrast in WM derives from myelinStuber et al 2014 Neuroimage 93, 95
nerve fibre
Voxel-based statistics
StatisticalParametricMap
(T statistic)
Study designs
Normal controls
Compare groups
CFS group
MR image
Voxel-based statistics
Test for linear regression
MR images and clinical score
CFS group
T statistic
Study Design
Normal controls
The relationship between MRI and blood pressure
Is it different in CFS? If so, where?
• In RED normal variation in NC yields MRI – BP relationship.• relationship is abnormal in CFS• ? communication between regulatory nuclei in brainstem.
T1wSE vs PP
CnF of RAS
CnFCnF
VTA
T2wSE vs PP
WM vol vs diasBP
Barnden L, Neuroimage Clinical 2016
stress
Myelin vs CFS Severitymore severe CFS/ME -> more myelin
Barnden et al 2015NMR Biomed, 28, 404
Comparison of myelin in CFS vs HC (healthy controls)plot, for individuals,
sensorimotor vs brainstem
Brainstemvs
SensorimotorMyelin
Inverse relationship
Sensorimotor upregulated
to compensatefor weak brainstem
nerve signals
brainstem
sensori-motor
Barnden L, Neuroimage Clinical 2018
Brainstem connectivity is impaired in CFS/ME
P = 0.0002
fMRI can detect altered signal transmission (connectivity)within the brainstem
Brain stem differences in CFS/ME - other reports
- Reduced perfusion via SPECT (not reproduced)Costa, QJ Med, 1995
- Inflammation via PET (9 subjects)Nakatomi, J Nucl Med, 2014
- White Matter volume reduction via MRI (inconsistent)Finkelmeyer, Neuroimage Clinical, 2018
Barnden 2011NMR Biomed
- Conclusions -in CFS/ME
• Autonomic regressions with MRI imply impaired communication between brainstem nuclei.
• Severity-dependent upregulated myelin in frontal WM implies weakened nerve signals from the brainstem.
• A compensatory brainstem - sensorimotor myelin relationship implies upregulated sensorimotor myelin is a response to impaired brainstem nerve conduction.
• Functional MRI confirms reduced connectivity between the brainstem medulla and midbrain.
• This will affect multiple regulatory functions and may explain many symptoms of CFS/ME.
• What causes damage to the brainstem?
thank you
Barnden L, NMR Biomed 2015
MRI variation is associated with Depression, But independent of MRI variation associated with severity
Depressionadjusted
Myelinvs
CFS Severity
What is the role of Anxiety and Depression in CFS/ME?