scholarly journals Neurochemical changes in the pericalcarine cortex in congenital blindness attributable to bilateral anophthalmia

2015 ◽  
Vol 114 (3) ◽  
pp. 1725-1733 ◽  
Author(s):  
Gaelle S. L. Coullon ◽  
Uzay E. Emir ◽  
Ione Fine ◽  
Kate E. Watkins ◽  
Holly Bridge
Keyword(s):  
Gray Matter ◽  
Large Scale ◽  
Occipital Cortex ◽  
Resonance Spectroscopy ◽  
Cortical Region ◽  
Structural Reorganization ◽  
Congenital Blindness ◽  
Visual Deafferentation ◽  
Biochemical Profiles ◽  
Neurochemical Changes

Congenital blindness leads to large-scale functional and structural reorganization in the occipital cortex, but relatively little is known about the neurochemical changes underlying this cross-modal plasticity. To investigate the effect of complete and early visual deafferentation on the concentration of metabolites in the pericalcarine cortex, 1H magnetic resonance spectroscopy was performed in 14 sighted subjects and 5 subjects with bilateral anophthalmia, a condition in which both eyes fail to develop. In the pericalcarine cortex, where primary visual cortex is normally located, the proportion of gray matter was significantly greater, and levels of choline, glutamate, glutamine, myo-inositol, and total creatine were elevated in anophthalmic relative to sighted subjects. Anophthalmia had no effect on the structure or neurochemistry of a sensorimotor cortex control region. More gray matter, combined with high levels of choline and myo-inositol, resembles the profile of the cortex at birth and suggests that the lack of visual input from the eyes might have delayed or arrested the maturation of this cortical region. High levels of choline and glutamate/glutamine are consistent with enhanced excitatory circuits in the anophthalmic occipital cortex, which could reflect a shift toward enhanced plasticity or sensitivity that could in turn mediate or unmask cross-modal responses. Finally, it is possible that the change in function of the occipital cortex results in biochemical profiles that resemble those of auditory, language, or somatosensory cortex.

scholarly journals Glutamine + glutamate level predicts the magnitude of microstructural organization in the gray matter in the healthy elderly

2019 ◽  
pp. 1-9
Author(s):  
Tomokazu Motegi ◽  
Kosuke Narita ◽  
Kazuyuki Fujihara ◽  
Masato Kasagi ◽  
Yusuke Suzuki ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Gray Matter ◽  
Diffusion Tensor ◽  
Early Stage ◽  
Mean Diffusivity ◽  
Posterior Cingulate Cortex ◽  
Resonance Spectroscopy ◽  
Cortical Region ◽  
Healthy Elderly

ABSTRACTBackground:Diffusion tensor imaging (DTI), which is a technique for measuring the degree and direction of movement of water molecules in tissue, has been widely used to noninvasively assess white matter (WM) or gray matter (GM) microstructures in vivo. Mean diffusivity (MD), which is the average diffusion across all directions, has been considered as a marker of WM tract degeneration or extracellular space enlargement in GM. Recent lines of evidence suggest that cortical MD can better identify early-stage Alzheimer’s disease than structural morphometric parameters in magnetic resonance imaging. However, knowledge of the relationships between cortical MD and other biological factors in the same cortical region, e.g. metabolites, is still limited.Methods:Thirty-three healthy elderly individuals [aged 50–77 years (mean, 63.8±7.4 years); 11 males and 22 females] were enrolled. We estimated the associations between cortical MD and neurotransmitter levels. Specifically, we measured levels of γ-aminobutyric acid (GABA) and glutamate + glutamine (Glx), which are inhibitory and excitatory neurotransmitters, respectively, in medial prefrontal cortex (mPFC) and posterior cingulate cortex (PCC) using MEGA-PRESS magnetic resonance spectroscopy, and we measured regional cortical MD using DTI.Results:Cortical MD was significantly negatively associated with Glx levels in both mPFC and PCC. No significant association was observed between cortical MD and GABA levels in either GM region.Conclusion:Our findings suggest that degeneration of microstructural organization in GM, as determined on the basis of cortical MD measured by DTI, is accompanied by the decline of Glx metabolism within the same GM region.

Limbic neurochemical changes in patients with functional motor symptoms

Neurology ◽  
2019 ◽  
Vol 93 (1) ◽  
pp. e52-e58 ◽  
Author(s):  
Benedetta Demartini ◽  
Orsola Gambini ◽  
Carla Uggetti ◽  
Maurizio Cariati ◽  
Marcello Cadioli ◽  
...  
Keyword(s):  
Rating Scale ◽  
Occipital Cortex ◽  
Anterior Cingulate ◽  
Motor Symptom ◽  
Resonance Spectroscopy ◽  
Motor Symptoms ◽  
Healthy Controls ◽  
Cr Content ◽  
Abnormal Movements ◽  
Neurochemical Changes

ObjectiveTo assess by magnetic resonance spectroscopy (MRS) the N-acetylaspartate, myo-inositol, choline, sum of glutamate and glutamine (Glx), and creatine (Cr) content in the anterior cingulate cortex (ACC)/medial prefrontal cortex (mPFC) and in the occipital cortex (OCC) (control region) in patients with functional motor symptoms (FMS) and healthy controls, and to determine whether neurochemical limbic changes as estimated by MRS correlate with FMS-related motor symptom severity, alexithymia, anxiety, depression, and quality of life.MethodsThis case-control study enrolled 10 patients with FMS and 10 healthy controls. Participants underwent MRS and were tested with the Mini-Mental State Examination, Hamilton Depression Rating Scale, Hamilton Anxiety Rating Scale, 20-Item Toronto Alexithymia Scale, and EuroQol 5D.ResultsIn patients with FMS, MRS showed increased Glx/Cr in the ACC/mPFC but normal content in the control OCC. All the other metabolites tested were normal in both regions. The increased Glx/Cr content in the ACC/mPFC correlated with alexithymia, anxiety, and severity of symptoms.ConclusionsThe abnormal limbic Glx increase could have a crucial pathophysiologic role in FMS, possibly by altering limbic-motor interactions, ultimately leading to abnormal movements.

23 Limbic neurochemical changes in patients with functional motor symptoms

2020 ◽  
Vol 91 (8) ◽  
pp. e17.2-e17
Author(s):  
Benedetta Demartini ◽  
Orsola Gambini ◽  
Carla Uggetti ◽  
Maurizio Cariati ◽  
MarcelloCadioli Eng ◽  
...  
Keyword(s):  
Rating Scale ◽  
Occipital Cortex ◽  
Anterior Cingulate ◽  
Motor Symptom ◽  
Resonance Spectroscopy ◽  
Motor Symptoms ◽  
Healthy Controls ◽  
Cr Content ◽  
Abnormal Movements ◽  
Neurochemical Changes

ObjectivesTo assess by magnetic resonance spectroscopy (MRS) the N-Acetyl- aspartate, myo-inositol, choline, sum of glutamate and glutamine (Glx), and creatine (Cr) content in the anterior cingulate cortex (ACC)/medial prefrontal cortex (mPFC) and in the occipital cortex (OCC) (control region) in patients with functional motor symptoms (FMS) and healthy controls, and to determine whether neurochemical limbic changes as estimated by MRS correlate with FMS-related motor symptom severity, alexithymia, anxiety, depression and quality of life.MethodsThis case-control study enrolled 10 patients with FMS and 10 healthy controls. Participants underwent MRS and were tested with the Mini Mental State Examination, Hamilton Depression Rating Scale, Hamilton Anxiety Rating Scale, 20- Item Toronto Alexithymia Scale and EuroQol 5D.ResultsIn patients with FMS, MRS showed increased Glx/Cr in the ACC/mPFC but normal content in the control OCC. All the other metabolites tested were normal in both regions. The increased Glx/Cr content in the ACC/mPFC correlated with alexithymia, anxiety and severity of symptoms.ConclusionsThe abnormal limbic Glx increase could have a crucial pathophysiological role in FMS possibly by altering limbic-motor interactions, ultimately leading to abnormal movements.

Abstract 3481: A Prospective Comparison of NMR-Measured LDL Particle Number, Apolipoprotein B100, and Standard Lipids with Incident CHD in 27,673 Initially Healthy Women

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Samia Mora ◽  
James Otvos ◽  
Julie E Buring ◽  
Nader Rifai ◽  
Paul M Ridker
Keyword(s):  
Prospective Cohort ◽  
Large Scale ◽  
Particle Number ◽  
Proton Nuclear Magnetic Resonance ◽  
Resonance Spectroscopy ◽  
Healthy Women ◽  
Prospective Comparison ◽  
Chd Risk ◽  
Hazard Ratios ◽  
Apolipoprotein B100

Background While ATP-III recommends measurement of total and HDL cholesterol (HDL-C) as part of coronary risk assessment, measurement of LDL particle number (LDL-P) is not currently recommended. Methods and Results In a prospective cohort of 27,673 initially healthy women, baseline LDL-P was measured by proton nuclear magnetic resonance spectroscopy, apolipoprotein B100 (ApoB) was measured using an immunoturbidimetric assay, and standard lipids were directly measured. LDL-P correlated with LDL cholesterol (LDL-C; r=0.62), ApoB (0.84), non HDL-C (0.74), and total:HDL-C ratio (0.80). During a mean follow-up of 11 years, 668 incident coronary heart disease (CHD) events occurred. Using the lowest quintile as the reference, and adjusting for age, smoking, blood pressure, diabetes, menopause, hormone use, and body mass index, the association of LDL-P with CHD was stronger than LDL-C (Table ), and comparable in magnitude to ApoB, non HDL-C and total:HDL-C ratio. In a subgroup analysis of women with LDL-C<100 mg/dL, elevations in LDL-P, ApoB, non HDL-C, or total:HDL-C ratio were all separately associated with higher CHD risk (P<0.001 for all). Both LDL-P and ApoB remained associated with CHD after additionally adjusting for total cholesterol, HDL-C, and triglycerides (hazard ratios for top vs bottom quintile: 2.03 [95% CI 1.27–3.24] for LDL-P, and 3.08 [95% CI 1.92– 4.93] for ApoB) overall, and similarly in women with LDL-C<100 mg/dL (2.77 [95%CI 1.05–7.29] for LDL-P and 2.62 [95%CI 0.97–7.05] for ApoB). Conclusions In this large-scale prospective cohort, elevations in NMR-measured LDL particle number were significantly associated with incident CHD, with a magnitude of risk not substantially different from ApoB, non HDL-C, or total:HDL-C ratio. Among women with LDL-C <100mg/dL, elevations in LDL-P, ApoB, non HDL-C, and total:HDL-C ratio all carried higher CHD risk. Risk Factor-Adjusted Hazard Ratios for Incident CHD

scholarly journals Gray matter volume covariance networks are associated with altered emotional processing in bipolar disorder: a source-based morphometry study

2021 ◽  
Author(s):  
Alessandro Miola ◽  
Nicolò Trevisan ◽  
Arcangelo Merola ◽  
Francesco Folena Comini ◽  
Daniele Olivo ◽  
...  
Keyword(s):  
Bipolar Disorder ◽  
Gray Matter ◽  
Emotional Processing ◽  
Gray Matter Volume ◽  
Occipital Cortex ◽  
Type I ◽  
Matter Volume ◽  
Visuospatial Processing ◽  
Neural Signature ◽  
Structural Networks

AbstractWidespread regional gray matter volume (GMV) alterations have been reported in bipolar disorder (BD). Structural networks, which are thought to better reflect the complex multivariate organization of the brain, and their clinical and psychological function have not been investigated yet in BD. 24 patients with BD type-I (BD-I), and 30 with BD type-II (BD-II), and 45 controls underwent MRI scan. Voxel-based morphometry and source-based morphometry (SBM) were performed to extract structural covariation patterns of GMV. SBM components associated with morphometric differences were compared among diagnoses. Executive function and emotional processing correlated with morphometric characteristics. Compared to controls, BD-I showed reduced GMV in the temporo-insular-parieto-occipital cortex and in the culmen. An SBM component spanning the prefrontal-temporal-occipital network exhibited significantly lower GMV in BD-I compared to controls, but not between the other groups. The structural network covariance in BD-I was associated with the number of previous manic episodes and with worse executive performance. Compared to BD-II, BD-I showed a loss of GMV in the temporal-occipital regions, and this was correlated with impaired emotional processing. Altered prefrontal-temporal-occipital network structure could reflect a neural signature associated with visuospatial processing and problem-solving impairments as well as emotional processing and illness severity in BD-I.

scholarly journals Evidence against altered excitatory/inhibitory balance in the posteromedial cortex of young adult APOE E4 carriers: a resting state 1H-MRS study

2021 ◽  
Author(s):  
Alison G Costigan ◽  
Katja Umla-Runge ◽  
C John Evans ◽  
Rachel Raybould ◽  
Kim S Graham ◽  
...  
Keyword(s):  
Resting State ◽  
Genetic Risk ◽  
Occipital Cortex ◽  
Network Activity ◽  
Resonance Spectroscopy ◽  
1H Mrs ◽  
Gaba A ◽  
Spatio Temporal ◽  
E4 Allele

A strategy to gain insight into early changes that may predispose people to Alzheimer's disease is to study the brains of younger cognitively healthy people that are at increased genetic risk of AD. The Apolipoprotein (APOE) E4 allele is the strongest genetic risk factor for AD, and several neuroimaging studies comparing APOE E4 carriers with non-carriers at age ~20-30 have detected hyperactivity (or reduced deactivation) in posteromedial cortex (PMC), a key hub of the default network (DN) which has a high susceptibility to early amyloid deposition in AD. Transgenic mouse models suggest such early network activity alterations may result from altered excitatory/inhibitory (E/I) balance, but this is yet to be examined in humans. Here we test the hypothesis that PMC fMRI hyperactivity could be underpinned by altered levels of excitatory (glutamate) and/or inhibitory (GABA) neurotransmitters in this brain region. Forty-seven participants (20 APOE E4 carriers and 27 non-carriers) aged 18-25 underwent resting-state proton magnetic resonance spectroscopy (1H-MRS), a non-invasive neuroimaging technique to measure glutamate and GABA in vivo. Metabolites were measured in a PMC voxel of interest and in a comparison voxel in the occipital cortex (OCC). There was no difference in either glutamate or GABA between the E4 carriers and non-carriers in either MRS voxel, nor in the ratio of glutamate to GABA, a measure of E/I balance. Default Bayesian t-tests revealed evidence in support of this null finding. Results suggest that PMC hyperactivity in APOE E4 carriers is unlikely to be associated with, or indeed may precede, alterations in local resting-state PMC neurotransmitters, thus informing the spatio-temporal order and the cause/effect dynamic of neuroimaging differences in APOE E4 carriers.

scholarly journals Characterizing cerebral metabolite profiles in anorexia and bulimia nervosa and their associations with habitual behavior

2021 ◽  
Author(s):  
Margaret L. Westwater ◽  
Alexander G. Murley ◽  
Kelly M.J. Diederen ◽  
T. Adrian Carpenter ◽  
Hisham Ziauddeen ◽  
...  
Keyword(s):  
Eating Disorders ◽  
Bulimia Nervosa ◽  
Binge Eating ◽  
Instrumental Learning ◽  
Learning Task ◽  
Resonance Spectroscopy ◽  
Binge Eating Disorders ◽  
Habitual Behavior ◽  
Neurochemical Changes ◽  
The Right

AbstractBackgroundAnorexia nervosa (AN) and bulimia nervosa (BN) are associated with altered brain structure and function, as well as increased habitual behavior. This neurobehavioral profile may implicate neurochemical changes in the pathogenesis of these illnesses. Altered glutamate, myo-inositol and N-acetyl aspartate (NAA) concentrations are reported in restrictive AN, yet whether these extend to binge-eating disorders, or relate to habitual traits in affected individuals, remains unknown.MethodsUsing single-voxel proton magnetic resonance spectroscopy, we measured glutamate, myo-inositol and NAA in 85 women [n=22 AN (binge-eating/purging subtype; AN-BP), n=33 BN, n=30 controls]. Spectra were acquired from the right inferior lateral prefrontal cortex and the right occipital cortex. To index habitual behavior, participants performed an instrumental learning task and completed the Creature of Habit Scale. Exploratory analyses examined associations between metabolites and habitual behavior.ResultsWomen with AN-BP, but not BN, had reduced myo-inositol and NAA concentrations relative to controls in both voxels. Patient groups had intact performance on the instrumental learning task; however, both groups reported increased routine behaviors compared to controls. Women with BN also reported greater automatic behaviors, and automaticity was related to reduced prefrontal glutamate and NAA in the AN-BP group.DiscussionFindings extend previous reports of reduced myo-inositol and NAA levels in AN to AN-BP, which may reflect disrupted axonal-glial signaling. Although we found inconsistent support for increased habitual behavior in AN-BP and BN, we identified preliminary associations between prefrontal metabolites and automaticity in AN-BP. These results provide further evidence of unique neurobiological profiles across binge-eating disorders.

scholarly journals Simultaneous Measurement of the BOLD Effect and Metabolic Changes in Response to Visual Stimulation Using the MEGA-PRESS Sequence at 3 T

2021 ◽  
Vol 15 ◽  
Author(s):  
Gerard Eric Dwyer ◽  
Alexander R. Craven ◽  
Justyna Bereśniewicz ◽  
Katarzyna Kazimierczak ◽  
Lars Ersland ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Visual Stimulation ◽  
Occipital Cortex ◽  
Blood Oxygen Level Dependent ◽  
Metabolic Changes ◽  
Water Suppression ◽  
Resonance Spectroscopy ◽  
Indirect Measure ◽  
Bold Effect ◽  
Water Signal

The blood oxygen level dependent (BOLD) effect that provides the contrast in functional magnetic resonance imaging (fMRI) has been demonstrated to affect the linewidth of spectral peaks as measured with magnetic resonance spectroscopy (MRS) and through this, may be used as an indirect measure of cerebral blood flow related to neural activity. By acquiring MR-spectra interleaved with frames without water suppression, it may be possible to image the BOLD effect and associated metabolic changes simultaneously through changes in the linewidth of the unsuppressed water peak. The purpose of this study was to implement this approach with the MEGA-PRESS sequence, widely considered to be the standard sequence for quantitative measurement of GABA at field strengths of 3 T and lower, to observe how changes in both glutamate (measured as Glx) and GABA levels may relate to changes due to the BOLD effect. MR-spectra and fMRI were acquired from the occipital cortex (OCC) of 20 healthy participants whilst undergoing intrascanner visual stimulation in the form of a red and black radial checkerboard, alternating at 8 Hz, in 90 s blocks comprising 30 s of visual stimulation followed by 60 s of rest. Results show very strong agreement between the changes in the linewidth of the unsuppressed water signal and the canonical haemodynamic response function as well as a strong, negative, but not statistically significant, correlation with the Glx signal as measured from the OFF spectra in MEGA-PRESS pairs. Findings from this experiment suggest that the unsuppressed water signal provides a reliable measure of the BOLD effect and that correlations with associated changes in GABA and Glx levels may also be measured. However, discrepancies between metabolite levels as measured from the difference and OFF spectra raise questions regarding the reliability of the respective methods.

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