Imaging Usual Addictions: Tobacco, Canabis and Alcohol

2009 ◽  
Vol 24 (S1) ◽  
pp. 1-1
Author(s):  
C. Leroy ◽  
S. Chanraud ◽  
E. Artiges ◽  
C. Martelli ◽  
A. Cachia ◽  
...  
Keyword(s):  
White Matter ◽  
Psychosocial Functioning ◽  
Grey Matter ◽  
Diffusion Imaging ◽  
Temporal Cortex ◽  
List Type ◽  
Dopamine Level ◽  
Type Number ◽  
Positron Emission ◽  
Brain Microstructure

Background:Brain models of drug addiction are being tackled in humans, using PET and MRI.Results:1.Whereas tobacco and cannabis do not interact directly with dopamine sites, positron emission tomography detected lower availability in sites regulating the catecholamines homeostasis, notably in dopamine transporter sites in striatal and in extrastriatal regions. This further supports repeated and long term substance use progress towards an adaptative diminished basal dopamine level that would contribute to the switch to an addicted brain.2.Alcohol: abnormalities in brain macro- and micro- structure were searched in detoxified alcohol-dependents with preserved psychosocial functioning:-Brain function (fMRI): fronto-cerebellar overactivation detected during an auditory language task in alcohol-dependents may reflect the compensatory effort required for patients to maintain the same level of performance as controls.-Brain macrostructure (MRI). Widespread lower white matter volumes, and lower grey matter volumes in the frontal lobe, insula, hippocampus, thalami and cerebellum, were detected. Poorer neuropsychological performance correlated with smaller grey matter volumes in these regions and with lower white matter volume in the brainstem.-Brain microstructure (DTI): tractography of white matter fiber bundles revealed that brainstem bundles alteration may contribute to cognitive flexibility impairment. Regression analyses showed memory scores were related to brain microstructure in parahippocampal areas, frontal cortex, and left temporal cortex. This suggest diffusion imaging (DTI) is a useful probe to early alcohol-induced brain alterations.Conclusion:While indices of dopamine down-regulation are consistency detected in several drug addictions, even “socially-adapted” alcohol dependence may induce change in brain structure.Psychol Med. 1998 28:1039-48.Neuropsychopharmacology. 2007 32:429-38.IEEE Trans Med Imaging. 2007 26:553-65J Nucl Med. 2007 48:538-46.Neuropsychopharmacology (Chanraud S et al., 2008 Jul 9. [Epub ahead of print]).J Clin Psychopharmacol (Leroy C et al, in press).

Diffusion imaging perspectives on brain development in childhood and adolescence

2021 ◽  
Author(s):  
Bryce L. Geeraert ◽  
Jess E. Reynolds ◽  
Catherine Lebel
Keyword(s):  
White Matter ◽  
Brain Development ◽  
Diffusion Imaging ◽  
Childhood And Adolescence ◽  
Tissue Properties ◽  
Versatile Tool ◽  
P Diffusion ◽  
White Matter Development ◽  
Brain Microstructure ◽  
Development Trajectories

Diffusion magnetic resonance imaging (dMRI) is a versatile tool which can be applied to investigate brain microstructure. This chapter outlines brain development trajectories from infancy to adulthood as described by dMRI. The chapter focuses on white matter development, as dMRI is particularly well suited to describing white matter tissue properties. The chapter also discusses sources of individual variation which are simultaneously fascinating and confounding to research efforts. Next, the chapter discusses links between white matter development and cognition, with specific examples drawn from reading research. Additional techniques which may complement future diffusion-based research are introduced in the chapter’s final section.

scholarly journals Perivascular space fluid contributes to diffusion tensor imaging changes in white matter

2018 ◽  
Author(s):  
Farshid Sepehrband ◽  
Ryan P Cabeen ◽  
Jeiran Choupan ◽  
Giuseppe Barisano ◽  
Meng Law ◽  
...  
Keyword(s):  
Diffusion Tensor Imaging ◽  
White Matter ◽  
Fractional Anisotropy ◽  
Diffusion Mri ◽  
Diffusion Tensor ◽  
Diffusion Imaging ◽  
Mean Diffusivity ◽  
Brain Parenchyma ◽  
Perivascular Space ◽  
List Type

AbstractDiffusion tensor imaging (DTI) has been extensively used to map changes in brain tissue related to neurological disorders. Among the most widespread DTI findings are increased mean diffusivity and decreased fractional anisotropy of white matter tissue in neurodegenerative diseases. Here we utilize multi-shell diffusion imaging to separate diffusion signal of the brain parenchyma from fluid within the white matter. We show that unincorporated anisotropic water in perivascular space (PVS) significantly, and systematically, biases DTI measures, casting new light on the biological validity of many previously reported findings. Despite the challenge this poses for interpreting these past findings, our results suggest that multi-shell diffusion MRI provides a new opportunity for incorporating the PVS contribution, ultimately strengthening the clinical and scientific value of diffusion MRI.HighlightsPerivascular space (PVS) fluid significantly contributes to diffusion tensor imaging metricsIncreased PVS fluid results in increased mean diffusivity and decreased fractional anisotropyPVS contribution to diffusion signal is overlooked and demands further investigation

scholarly journals Musical hallucinations in elderly patients with visuospatial impairment: two case reports

2017 ◽  
Vol 2 (3) ◽  
Author(s):  
Chiara Luppi ◽  
Francesca Santagata ◽  
Margherita Marchetti ◽  
Giuliana Bottignole ◽  
Pasqualina Sapone ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
White Matter ◽  
Case Reports ◽  
Temporal Cortex ◽  
Pharmacological Therapy ◽  
Auditory Hallucinations ◽  
Emission Tomography ◽  
Inferior Temporal Cortex ◽  
Vascular Events ◽  
Positron Emission

Musical hallucinations are an uncommon type of auditory hallucinations, they widely occur in elderly. Our group analyzed medical history, pharmacological therapy, neuropsychological pattern, audiometric testing, electroencephalogram, cerebral magnetic resonance and cerebral fludeoxyglucose-positron emission tomography (FDG-PET) of two patients. FDGPET showed in both patients hypometabolism pronounced in posterior regions. In particular the medial-inferior temporal cortex and the occipital associative areas were affected. Moreover, neuropsychological pattern suggested a visuospatial-executive deficit, conformed to the occipital involvement. Our reported cases might suggest that musical hallucinations have been arisen from a combination of peripheral and central dysfunction. A further explanation might be that musical hallucinations result from multiple white matter lacunar lesions due to small vascular events. A question is whether musical hallucinations might be primarily associated with occipital areas hypometabolism and visuospatial alterations typically associated with Levy body dementia (LBD).

Structural and metabolic cerebral alterations between elderly bipolar disorder and behavioural variant frontotemporal dementia: A combined MRI-PET study

2018 ◽  
Vol 53 (5) ◽  
pp. 413-423 ◽  
Author(s):  
Giuseppe Delvecchio ◽  
Gian Mario Mandolini ◽  
Andrea Arighi ◽  
Cecilia Prunas ◽  
Carlo Massimo Mauri ◽  
...  
Keyword(s):  
Bipolar Disorder ◽  
Prefrontal Cortex ◽  
Frontotemporal Dementia ◽  
Grey Matter ◽  
Temporal Cortex ◽  
Positron Emission ◽  
Dorsolateral Prefrontal ◽  
Magnetic Resonance Imaging Mri ◽  
Subcortical Regions ◽  
First Time

Background: Elderly bipolar disorder (BD) and behavioural variant of frontotemporal dementia (bvFTD) may exhibit similar symptoms and both disorders are characterized by selective abnormalities in cortical and subcortical regions that are associated with cognitive and emotional impairments. We aimed to investigate common and distinct neural substrates of BD and bvFTD by coupling, for the first time, magnetic resonance imaging (MRI) and positron emission tomography (PET) techniques. Methods: 3-Tesla MRI and 18 fluorodeoxyglucose–PET scans were acquired for 16 elderly BD patients, 23 bvFTD patients with mild cognitive impairments and 68 healthy controls (48 for PET and 20 for MRI analyses). Results: BD and bvFTD patients exhibit a different localization of grey matter reductions in the lateral prefrontal cortex, with the first group showing grey matter decrease in the ventrolateral prefrontal cortex and the latter group showing grey matter reductions in the dorsolateral prefrontal cortex as well as unique grey matter and metabolic alterations within the orbitofrontal cortex. The bvFTD group also displayed unique volumetric shrinkage in regions within the temporo-parietal network together with greater metabolic impairments within the temporal cortex and more extensive volumetric and metabolic abnormalities within the limbic lobe. Finally, while the BD group showed greater grey matter volumes in caudate nucleus, bvFTD subjects displayed lower metabolism. Conclusion: This MRI-PET study explored, for the first time to the best of our knowledge, structural and functional abnormalities in bvFTD and elderly BD patients, with the final aim of identifying the specific biological signature of these disorders, which might have important implications not only in prevention but also in differential diagnosis and treatment.

scholarly journals Test-retest reliability and long-term stability of 3-tissue constrained spherical deconvolution methods for analyzing diffusion MRI data

2019 ◽  
Author(s):  
Benjamin T. Newman ◽  
Thijs Dhollander ◽  
Kristen A. Reynier ◽  
Matthew B. Panzer ◽  
T. Jason Druzgal
Keyword(s):  
White Matter ◽  
Grey Matter ◽  
Tissue Microstructure ◽  
Term Stability ◽  
Long Term Stability ◽  
Constrained Spherical Deconvolution ◽  
Spherical Deconvolution ◽  
Brain Microstructure ◽  
Tissue Compartments

AbstractPurposeSeveral recent studies have utilized a 3-tissue constrained spherical deconvolution pipeline to obtain quantitative metrics of brain tissue microstructure from diffusion-weighted MRI data. The three tissue compartments, comprising white matter-, grey matter-, and CSF-like (free water) signals, are potentially useful in the evaluation of brain microstructure in a range of pathologies. However, the reliability and long-term stability of these metrics has not yet been evaluated.MethodsThis study examined estimates of whole brain microstructure for the three tissue compartments, in three separate test-retest cohorts. Each cohort has different lengths of time between baseline and retest, ranging from within the same scanning session in the shortest interval to three months in the longest interval. Each cohort was also collected with different acquisition parameters.ResultsThe CSF-like compartment displayed the greatest reliability across all cohorts, with intraclass correlation coefficient (ICC) values being above 0.95 in each cohort. White matter-like and grey matter-like compartments both demonstrated very high reliability in the immediate cohort (both ICC>0.90), however this declined in the 3 month interval cohort to both compartments having ICC>0.80. Regional CSF-like signal fraction was examined in bilateral hippocampus and had an ICC>0.80 in each cohort.ConclusionThe 3-tissue CSD techniques provide reliable and stable estimates of tissue microstructure composition, up to 3 months longitudinally in a control population. This forms an important basis for further investigations utilizing 3-tissue CSD techniques to track changes in microstructure across a variety of brain pathologies.

scholarly journals Compensatory reconfiguration of functional networks between white matter and grey matter in Alzheimer’s disease

2021 ◽  
Author(s):  
Xingxing Zhang ◽  
Qing Guan ◽  
Debo Dong ◽  
Fuyong Chen ◽  
Jing Yi ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
White Matter ◽  
Euclidean Distance ◽  
Grey Matter ◽  
Temporal Cortex ◽  
Resting State Fmri ◽  
Functional Networks ◽  
Compensatory Mechanisms ◽  
The Brain

AbstractThe temporal synchronization of BOLD signals within white matter (WM) and between WM and grey matter (GM) exhibited intrinsic architecture and cognitive relevance. However, few studies examined the network property within- and between-tissue in Alzheimer’s disease (AD). The hub regions with high weighted degree (WD) were prone to the neuropathological damage of AD. To systematically investigate the changes of hubs within- and between-tissue functional networks in AD patients, we used the resting-state fMRI data of 30 AD patients and 37 normal older adults (NC) from the ADNI open database, and obtained four types of voxel-based WD metrics and four types of distant-dependent WD metrics (ddWD) based on a series of Euclidean distance ranges with a 20mm increment. We found that AD patients showed decreased within-tissue ddWD in the thalamic nucleus and increased between-tissue ddWD in the occipito-temporal cortex, posterior thalamic radiation, and sagittal stratum, compared to NC. We also found that AD patients showed the increased between-tissue FCs between the posterior thalamic radiation and occipito-temporal cortex, and between the sagittal stratum and the salience and executive networks. The dichotomy of decreased and increased ddWD metrics and their locations were consistent with previous studies on the neurodegnerative and compensatory mechanisms of AD, indicating that despite the disruptions, the brain still strived to compensate for the neural inefficiency by reorganizing functional circuits. Our findings also suggested the short-to-medium ranged ddWD metrics between WM and GM as useful biomarker to detect the compensatory changes of functional networks in AD.

scholarly journals Effects of unilateral cortical resection of the visual cortex on bilateral human white matter

2019 ◽  
Author(s):  
Anne Margarette S. Maallo ◽  
Erez Freud ◽  
Tina Tong Liu ◽  
Christina Patterson ◽  
Marlene Behrmann
Keyword(s):  
White Matter ◽  
Right Hemisphere ◽  
Temporal Cortex ◽  
Pediatric Epilepsy ◽  
Single Subject ◽  
List Type ◽  
Network Efficiency ◽  
White Matter Microstructure ◽  
Network Properties ◽  
Tractography Data

AbstractChildren with unilateral resections of ventral occipito-temporal cortex (VOTC) typically do not evince visual perceptual impairments, even when relatively large swathes of VOTC are resected. In search of possible explanations for this behavioral competence, we evaluated white matter microstructure and connectivity in eight pediatric epilepsy patients following unilateral cortical resection and 15 age-matched controls. To uncover both local and broader resection-induced effects, we analyzed tractography data using two complementary approaches. First, the microstructural properties were measured in the inferior longitudinal and the inferior fronto-occipital fasciculi, the major VOTC association tracts. Group differences were only evident in the ipsilesional, and not in the contralesional, hemisphere, and single-subject analyses revealed that these differences were limited to the site of the resection. Second, graph theory was used to characterize the connectivity of the contralesional occipito-temporal regions. There were no changes to the network properties in patients with left VOTC resections nor in patients with resections outside the VOTC, but altered network efficiency was observed in two cases with right VOTC resections. These results suggest that, in many, although perhaps not all, cases of unilateral VOTC resections in childhood, the white matter integrity in the preserved contralesional hemisphere along with residual neural activity might be sufficient for normal visual perception.HighlightsThere is well-circumscribed white matter damage in pediatric epilepsy after surgeryWhite matter pathways are normal distal as well as contralesional to the resectionContralesional network properties differ after left or right hemisphere resectionPreserved cortex and white matter may be sufficient for normal perception

Solar Corona Investigation by the Coronal Line Photometer at Lomnický Peak

1994 ◽  
Vol 144 ◽  
pp. 431-434
Author(s):  
M. Minarovjech ◽  
M. Rybanský
Keyword(s):  
Solar Corona ◽  
Time Resolution ◽  
Active Regions ◽  
High Time ◽  
High Time Resolution ◽  
List Type ◽  
Type Number ◽  
Coronal Line ◽  
Global Cycle

AbstractThis paper deals with a possibility to use the ground-based method of observation in order to solve basic problems connected with the solar corona research. Namely:1.heating of the solar corona2.course of the global cycle in the corona3.rotation of the solar corona and development of active regions.There is stressed a possibility of high-time resolution of the coronal line photometer at Lomnický Peak coronal station, and use of the latter to obtain crucial observations.

The LDE-Type Flare Occurrence (1969-1993)

1994 ◽  
Vol 144 ◽  
pp. 279-282
Author(s):  
A. Antalová
Keyword(s):  
Time Series ◽  
Fourier Analysis ◽  
Sunspot Cycle ◽  
List Type ◽  
Type Number ◽  
Solar Cycles ◽  
Type Iv ◽  
Long Duration ◽  
Cycle Maximum ◽  
Flare Index

AbstractThe occurrence of LDE-type flares in the last three cycles has been investigated. The Fourier analysis spectrum was calculated for the time series of the LDE-type flare occurrence during the 20-th, the 21-st and the rising part of the 22-nd cycle. LDE-type flares (Long Duration Events in SXR) are associated with the interplanetary protons (SEP and STIP as well), energized coronal archs and radio type IV emission. Generally, in all the cycles considered, LDE-type flares mainly originated during a 6-year interval of the respective cycle (2 years before and 4 years after the sunspot cycle maximum). The following significant periodicities were found:• in the 20-th cycle: 1.4, 2.1, 2.9, 4.0, 10.7 and 54.2 of month,• in the 21-st cycle: 1.2, 1.6, 2.8, 4.9, 7.8 and 44.5 of month,• in the 22-nd cycle, till March 1992: 1.4, 1.8, 2.4, 7.2, 8.7, 11.8 and 29.1 of month,• in all interval (1969-1992):a)the longer periodicities: 232.1, 121.1 (the dominant at 10.1 of year), 80.7, 61.9 and 25.6 of month,b)the shorter periodicities: 4.7, 5.0, 6.8, 7.9, 9.1, 15.8 and 20.4 of month.Fourier analysis of the LDE-type flare index (FI) yields significant peaks at 2.3 - 2.9 months and 4.2 - 4.9 months. These short periodicities correspond remarkably in the all three last solar cycles. The larger periodicities are different in respective cycles.

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