scholarly journals Same Brain, Different Look?—The Impact of Scanner, Sequence and Preprocessing on Diffusion Imaging Outcome Parameters

2021 ◽  
Vol 10 (21) ◽  
pp. 4987
Author(s):  
Ronja Thieleking ◽  
Rui Zhang ◽  
Maria Paerisch ◽  
Kerstin Wirkner ◽  
Alfred Anwander ◽  
...  
Keyword(s):  
Data Acquisition ◽  
Diffusion Imaging ◽  
Mean Diffusivity ◽  
Brain Regions ◽  
Clinical Diagnostics ◽  
Neuroimaging Data ◽  
Age Range ◽  
The Impact ◽  
The Brain ◽  
Healthy Participants

In clinical diagnostics and longitudinal studies, the reproducibility of MRI assessments is of high importance in order to detect pathological changes, but developments in MRI hard- and software often outrun extended periods of data acquisition and analysis. This could potentially introduce artefactual changes or mask pathological alterations. However, if and how changes of MRI hardware, scanning protocols or preprocessing software affect complex neuroimaging outcomes from, e.g., diffusion weighted imaging (DWI) remains largely understudied. We therefore compared DWI outcomes and artefact severity of 121 healthy participants (age range 19–54 years) who underwent two matched DWI protocols (Siemens product and Center for Magnetic Resonance Research sequence) at two sites (Siemens 3T Magnetom Verio and Skyrafit). After different preprocessing steps, fractional anisotropy (FA) and mean diffusivity (MD) maps, obtained by tensor fitting, were processed with tract-based spatial statistics (TBSS). Inter-scanner and inter-sequence variability of skeletonised FA values reached up to 5% and differed largely in magnitude and direction across the brain. Skeletonised MD values differed up to 14% between scanners. We here demonstrate that DTI outcome measures strongly depend on imaging site and software, and that these biases vary between brain regions. These regionally inhomogeneous biases may exceed and considerably confound physiological effects such as ageing, highlighting the need to harmonise data acquisition and analysis. Future studies thus need to implement novel strategies to augment neuroimaging data reliability and replicability.

scholarly journals Same Brain, Different Look? – the Impact of Scanner, Sequence and Preprocessing on Diffusion Imaging Outcome Parameters

2021 ◽  
Author(s):  
Ronja Thieleking ◽  
Rui Zhang ◽  
Maria Paerisch ◽  
Kerstin Wirkner ◽  
Alfred Anwander ◽  
...  
Keyword(s):  
Data Acquisition ◽  
Diffusion Imaging ◽  
Mean Diffusivity ◽  
Brain Regions ◽  
Clinical Diagnostics ◽  
Neuroimaging Data ◽  
Age Range ◽  
The Impact ◽  
The Brain ◽  
Healthy Participants

In clinical diagnostics and longitudinal studies, the reproducibility of MRI assessments is of high importance in order to detect pathological changes, but developments in MRI hard- and software often outrun extended periods of data acquisition and analysis. This could potentially introduce artefactual changes or mask pathological alterations. However, if and how changes of MRI hardware, scanning protocols or preprocessing software affect complex neuroimaging outcomes from e.g. diffusion weighted imaging (DWI) remains largely understudied. We therefore compared DWI outcomes and artefact severity of 121 healthy participants (age range 19-54 years) who underwent two matched DWI protocols (Siemens product and Center for Magnetic Resonance Research sequence) at two sites (Siemens 3T Magnetom Verio and Skyrafit). After different preprocessing steps, fractional anisotropy (FA) and mean diffusivity (MD) maps,obtained by tensor fitting, were processed with tract-based spatial statistics (TBSS). Inter-scanner and inter-sequence variability of skeletonised FA values reached up to 5% and differed largely in magnitude and direction across the brain. Skeletonised MD values differed up to 14% between scanners. We here demonstrate that DTI outcome measures strongly depend on imaging site and software, and that these biases vary between brain regions. These regionally inhomogeneous biases may exceed and considerably confound physiological effects such as ageing, highlighting the need to harmonise data acquisition and analysis. Future studies thus need to implement novel strategies to augment neuroimaging data reliability and replicability.

scholarly journals Same Brain, Different Look? – the Impact of Scanner, Sequence and Preprocessing on Diffusion Imaging Outcome Parameters

2021 ◽  
Author(s):  
Ronja Thieleking ◽  
Rui Zhang ◽  
Maria Paerisch ◽  
Kerstin Wirkner ◽  
Alfred Anwander ◽  
...  
Keyword(s):  
Data Acquisition ◽  
Diffusion Imaging ◽  
Brain Regions ◽  
Clinical Diagnostics ◽  
Future Studies ◽  
Neuroimaging Data ◽  
Age Range ◽  
The Impact ◽  
The Brain ◽  
Healthy Participants

In clinical diagnostics and longitudinal studies, the reproducibility of MRI assessments is of high importance in order to detect pathological changes, but developments in MRI hard- and software often outrun extended periods of data acquisition and analysis. This could potentially introduce artefactual changes or masking pathological alterations. However, if and how changes of MRI hardware, scanning protocols or preprocessing software affect complex neuroimaging outcomes from e.g. diffusion weighted imaging (DWI) remains largely understudied. We therefore compared DWI outcomes and artefact severity of 121 healthy participants (age range 19-54 years) who underwent two matched DWI protocols (Siemens product and Center for Magnetic Resonance Research sequence) at two sites (Siemens 3T Magnetom Verio and Skyrafit). After differing preprocessing steps, 3D-fractional anisotropy (FA) maps obtained by tensor fitting were processed with tract-based spatial statistics (TBSS). Inter-scanner and inter-sequence variability of skeletonised FA values reached up to 5% and differed largely in magnitude and direction across the brain. Preprocessing including unringing reduced the Gibbs ringing artefact, and head motion estimates were significantly lower at Skyra. We here demonstrate that DTI outcome measures strongly depend on imaging site and software, and that these biases vary between brain regions. These regionally inhomogeneous biases may exceed and considerably confound physiological effects such as ageing, highlighting the need to harmonise data acquisition and analysis. Future studies thus need to implement novel strategies to augment neuroimaging data reliability and replicability.

scholarly journals Developmental cannabidiol exposure increases anxiety and modifies genome-wide brain DNA methylation in adult female mice

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Nicole M. Wanner ◽  
Mathia Colwell ◽  
Chelsea Drown ◽  
Christopher Faulk
Keyword(s):  
Dna Methylation ◽  
Molecular Mechanisms ◽  
Coat Color ◽  
Brain Regions ◽  
Functional Enrichment ◽  
Positive Effects ◽  
Genome Wide ◽  
Nulliparous Female ◽  
The Impact ◽  
The Brain

Abstract Background Use of cannabidiol (CBD), the primary non-psychoactive compound found in cannabis, has recently risen dramatically, while relatively little is known about the underlying molecular mechanisms of its effects. Previous work indicates that direct CBD exposure strongly impacts the brain, with anxiolytic, antidepressant, antipsychotic, and other effects being observed in animal and human studies. The epigenome, particularly DNA methylation, is responsive to environmental input and can direct persistent patterns of gene regulation impacting phenotype. Epigenetic perturbation is particularly impactful during embryogenesis, when exogenous exposures can disrupt critical resetting of epigenetic marks and impart phenotypic effects lasting into adulthood. The impact of prenatal CBD exposure has not been evaluated; however, studies using the psychomimetic cannabinoid Δ9-tetrahydrocannabinol (THC) have identified detrimental effects on psychological outcomes in developmentally exposed adult offspring. We hypothesized that developmental CBD exposure would have similar negative effects on behavior mediated in part by the epigenome. Nulliparous female wild-type Agouti viable yellow (Avy) mice were exposed to 20 mg/kg CBD or vehicle daily from two weeks prior to mating through gestation and lactation. Coat color shifts, a readout of DNA methylation at the Agouti locus in this strain, were measured in F1 Avy/a offspring. Young adult F1 a/a offspring were then subjected to tests of working spatial memory and anxiety/compulsive behavior. Reduced-representation bisulfite sequencing was performed on both F0 and F1 cerebral cortex and F1 hippocampus to identify genome-wide changes in DNA methylation for direct and developmental exposure, respectively. Results F1 offspring exposed to CBD during development exhibited increased anxiety and improved memory behavior in a sex-specific manner. Further, while no significant coat color shift was observed in Avy/a offspring, thousands of differentially methylated loci (DMLs) were identified in both brain regions with functional enrichment for neurogenesis, substance use phenotypes, and other psychologically relevant terms. Conclusions These findings demonstrate for the first time that despite positive effects of direct exposure, developmental CBD is associated with mixed behavioral outcomes and perturbation of the brain epigenome.

Structural magnetic resonance imaging markers of susceptibility and transition to schizophrenia: A review of familial and clinical high risk population studies

2014 ◽  
Vol 29 (2) ◽  
pp. 144-154 ◽  
Author(s):  
C Bois ◽  
HC Whalley ◽  
AM McIntosh ◽  
SM Lawrie
Keyword(s):  
High Risk ◽  
Grey Matter ◽  
Brain Regions ◽  
High Risk Population ◽  
Clinical High Risk ◽  
Cross Sectional ◽  
Structural Abnormalities ◽  
Neuroimaging Data ◽  
Imaging Markers ◽  
The Brain

There is a growing consensus that a symptomatology as complex and heterogeneous as schizophrenia is likely to be produced by widespread perturbations of brain structure, as opposed to isolated deficits in specific brain regions. Structural brain-imaging studies have shown that several features of the brain, such as grey matter, white matter integrity and the morphology of the cortex differ in individuals at high risk of the disorder compared to controls, but to a lesser extent than in patients, suggesting that structural abnormalities may form markers of vulnerability to the disorder. Research has had some success in delineating abnormalities specific to those individuals that transition to psychosis, compared to those at high risk that do not, suggesting that a general risk for the disorder can be distinguished from alterations specific to frank psychosis. In this paper, we review cross-sectional and longitudinal studies of individuals at familial or clinical high risk of the disorder. We conclude that the search for reliable markers of schizophrenia is likely to be enhanced by methods which amalgamate structural neuroimaging data into a coherent framework that takes into account the widespread distribution of brain alterations, and relates this to leading hypotheses of schizophrenia.

scholarly journals Neurorehabilitation in Multiple Sclerosis – Resilience in Practice

2017 ◽  
Vol 12 (01) ◽  
pp. 31 ◽  
Author(s):  
Jürg Kesselring ◽  
Keyword(s):  
Multiple Sclerosis ◽  
Best Practice ◽  
Healthcare Providers ◽  
Brain Regions ◽  
Standards Of Care ◽  
Key Factors ◽  
Disease Modifying Drugs ◽  
Randomised Controlled ◽  
The Impact ◽  
The Brain

In recent years, enormous strides have been made in increasing the range and efficacy of disease-modifying drugs available for the treatment of multiple sclerosis (MS) in its early and remitting stages, and more continue to emerge. Another equally important concept of successful treatment of MS is neurorehabilitation, which must be pursued alongside these medications. Key factors that contribute to the impact of neurorehabilitation include resilience and neuroplasticity. In the former, components such as nutrition, self-belief and physical activity provide a stronger response to the disease and improved responses to treatment. Neuroplasticity is the capacity of the brain to establish new neuronal networks after lesion damage has occurred and distant brain regions assume control of lost functions. In MS, it is vital that each patient is treated by a coordinated multidisciplinary team. This enables all aspects of the disease including problems with mobility, gait, bladder/bowel disturbances, fatigue and depression to be effectively treated. It is also important that the treating team adopts current best practice and provides internationally agreed standards of care. A further vital aspect of MS management is patient engagement, in which individuals are fully involved and are encouraged to strive and put effort into meeting treatment goals. In this approach, healthcare providers become motivators and patients need less intervention and consume fewer resources. Numerous interventions that promote neurorehabilitation are available, though evidence to support their use is limited by a lack of data from large randomised controlled trials. Combining interventions that promote neurorehabilitation with newer, more effective treatments creates a promising potential to substantially improve the outlook for patients at all stages of MS.

The Brain in a Physician’s Life

2017 ◽  
Author(s):  
Peggy Mason
Keyword(s):  
Nervous System ◽  
Brain Regions ◽  
Altered State ◽  
Compassionate Care ◽  
Clinical Impairment ◽  
Altered State Of Consciousness ◽  
Individual Nature ◽  
The Impact ◽  
The Brain

With the knowledge acquired from this book, the brain regions responsible for each of the symptoms suffered by Jean-Dominique Bauby can be identified. It is also possible to understand why thought, language, and memory were unaffected in Bauby. Bauby’s narrative is used to launch a consideration of the role of embodiment in affective experience. The experience of Clive Wearing who, after a bout of encephalitis, was left without the ability to make new declarative memories is introduced to illustrate the highly personal and individual nature of people’s reactions to disease or clinical impairment. The impact of disease does not stop with the patient but extends to the patient’s loved ones and caregivers. This is particularly true of patients with dementia or those in an altered state of consciousness. Finally the reader is encouraged to use their understanding of the nervous system to provide compassionate care for patients.

scholarly journals Connectome Analysis of Brain Functional Network Alterations in Depressive Patients with Suicidal Attempt

2019 ◽  
Vol 8 (11) ◽  
pp. 1966 ◽  
Author(s):  
Jun-Cheng Weng ◽  
Yu-Syuan Chou ◽  
Yuan-Hsiung Tsai ◽  
Chun-Te Lee ◽  
Ming-Hong Hsieh ◽  
...  
Keyword(s):  
Suicide Attempt ◽  
Depressive Disorders ◽  
Rating Scale ◽  
Suicide Attempts ◽  
Imaging System ◽  
Brain Regions ◽  
Healthy Controls ◽  
Depressed Patients ◽  
The Brain ◽  
Healthy Participants

Our study aimed to clarify the neuroimaging correlates of suicide attempt by comparing differences in functional magnetic resonance imaging (fMRI) among depressed suicide attempters, depressed patients without suicide attempt history, and healthy controls through comprehensive and novel fMRI analyses and methods in the same study population. The association between depression severity and aspects of the brain imaging was also discussed. Our study recruited 109 participants who were assigned to three groups: 33 depressed patients with suicide attempt (SA), 32 depressed patients without suicide attempt (NS), and 44 healthy controls (HC). All participants were scanned using a 3 T MRI imaging system to obtain resting-state functional images. In seed-based correlation analysis, we found altered functional connectivity in some brain regions of the SA compared with the NS or HC, especially in the hippocampus and thalamus. In the voxel-based analysis, our results showed differential activation and regional homogeneity of the temporal lobe and several brain regions in the SA compared with the NS and HC. We also found that some brain areas correlated with the Hamilton Depression Rating Scale (HAM-D), anxiety, and depression scores, especially in the frontal and temporal lobes. Graph theoretical analysis (GTA) and network-based statistical (NBS) analyses revealed different topological organization as well as slightly better global integration and worse local segregation of the brain network (i.e., more like a random network) in depressed participants compared with healthy participants. We concluded that the brain function of major depressive disorders with and without suicide attempts changed compared with healthy participants.

Chemical targeting of voltage sensitive dyes to specific cells and molecules in the brain

2020 ◽  
Author(s):  
Tomas Fiala ◽  
Jihang Wang ◽  
Matthew Dunn ◽  
Peter Šebej ◽  
Se Joon Choi ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Brain Tissue ◽  
Fluorescent Dyes ◽  
Brain Slices ◽  
Brain Regions ◽  
Expression Levels ◽  
Specific Targeting ◽  
The Impact ◽  
Voltage Sensitive Dyes ◽  
The Brain

Voltage sensitive fluorescent dyes (VSDs) are important tools for probing signal transduction in neurons and other excitable cells. These sensors, rendered highly lipophilic to anchor the conjugated pi-wire molecular framework in the membrane, offer several favorable functional parameters including fast response kinetics and high sensitivity to membrane potential changes. The impact of VSDs has, however, been limited due to the lack of cell-specific targeting methods in brain tissue or living animals. We address this key challenge by introducing a non-genetic molecular platform for cell- and molecule-specific targeting of synthetic voltage sensitive dyes in the brain. We employ a dextran polymer particle to overcome the inherent lipophilicity of voltage sensitive dyes by dynamic encapsulation, and high-affinity ligands to target the construct to specific neuronal cells utilizing only native components of the neurotransmission machinery at physiological expression levels. Dichloropane, a monoamine transporter ligand, enables targeting of dense dopaminergic axons in the mouse striatum and sparse noradrenergic axons in the mouse cortex in acute brain slices. PFQX in conjunction with ligand-directed acyl imidazole chemistry enables covalent labeling of AMPA-type glutamate receptors in the same brain regions. Probe variants bearing either a classical electrochromic ANEP dye or state-of-the-art VoltageFluor-type dye respond to membrane potential changes in a similar manner to the parent dyes, as shown by whole-cell patch recording. We demonstrate the feasibility of optical voltage recording with our probes in brain tissue with one-photon and two-photon fluorescence microscopy and define the signal limits of optical voltage imaging with synthetic sensors under a low photon budget determined by the native expression levels of the target proteins. We envision that modularity of our platform will enable its application to a variety of molecular targets and sensors, as well as lipophilic drugs and signaling modulators. This work demonstrates the feasibility of a chemical targeting approach and expands the possibilities of cell-specific imaging and pharmacology.

Neuron–glia synapses in the brain: properties, diversity and functions of NG2 glia

e-Neuroforum ◽  
2015 ◽  
Vol 21 (3) ◽  
Author(s):  
Christian Steinhäuser ◽  
Dirk Dietrich
Keyword(s):  
White Matter ◽  
Glial Cells ◽  
Temporal Integration ◽  
Brain Regions ◽  
Gabaergic Neurons ◽  
Cell Type ◽  
Transmitter Receptors ◽  
Ng2 Proteoglycan ◽  
The Impact ◽  
The Brain

AbstractAlthough NG2 glial cells represent a frequent glial cell type in the brain, characterized by expression of the NG2 proteoglycan, the functional impact of these cells is still enigmatic. A large proportion of NG2 glia are proliferatively active throughout life. These cells express a plethora of ion channels and transmitter receptors, which enable them to detect neuronal activity. Intriguingly, NG2 glial cells receive synaptic input from glutamatergic and GABAergic neurons. Since these postsynaptic glial currents are very small, their spatial and temporal integration might play an important role. In white matter, most NG2 glial cells differentiate into oligodendrocytes and this process might be influenced through the activity of the aforementioned neuron-glia synapses. Increasing evidence suggests that the properties of NG2 glia vary across brain regions; however, the impact of this variability is not understood yet.

scholarly journals A systematic review of neuroimaging and acute cannabis exposure in age-of-risk for psychosis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lani Cupo ◽  
Eric Plitman ◽  
Elisa Guma ◽  
M. Mallar Chakravarty
Keyword(s):  
Chronic Exposure ◽  
Brain Regions ◽  
Acute Exposure ◽  
Psychotic Symptoms ◽  
Long Term Effects ◽  
Symptom Dimensions ◽  
Increased Risk ◽  
The Impact ◽  
The Brain

AbstractAcute exposure to cannabis has been associated with an array of cognitive alterations, increased risk for neuropsychiatric illness, and other neuropsychiatric sequelae including the emergence of acute psychotic symptoms. However, the brain alterations associating cannabis use and these behavioral and clinical phenotypes remains disputed. To this end, neuroimaging can be a powerful technique to non-invasively study the impact of cannabis exposure on brain structure and function in both humans and animal models. While chronic exposure studies provide insight into how use may be related to long-term outcomes, acute exposure may reveal interesting information regarding the immediate impact of use and abuse on brain circuits. Understanding these alterations could reveal the connection with symptom dimensions in neuropsychiatric disorders and, more specifically with psychosis. The purpose of the present review is to: 1) provide an update on the findings of pharmacological neuroimaging studies examining the effects of administered cannabinoids and 2) focus the discussion on studies that examine the sensitive window for the emergence of psychosis. Current literature indicates that cannabis exposure has varied effects on the brain, with the principal compounds in cannabis (delta-9-tetrahydrocannabinol and cannabidiol) altering activity across different brain regions. Importantly, we also discovered critical gaps in the literature, particularly regarding sex-dependent responses and long-term effects of chronic exposure. Certain networks often characterized as dysregulated in psychosis, like the default mode network and limbic system, were also impacted by THC exposure, identifying areas of particular interest for future work investigating the potential relationship between the two.

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