History of Brain Mapping and Neurophotonics
Yu Chen, Babak Kateb in Neurophotonics and Brain Mapping, 2017
According to the Society for Brain Mapping and Therapeutics (SBMT), brain mapping is defined as the study and elucidation of the anatomy and functionality of the brain and spinal cord through the use of imaging (including intraoperative, microscopic, endoscopic, molecular, and multimodality imaging), immunohistochemistry, optogenetics, stem cell and cellular biology, engineering (material, electrical, and biomedical), advanced technologies (ultrasound, photonics, etc.), neurophysiology, and nanotechnology (Kateb and Heiss, 2013). Diverse types of brain mapping exist, encompassing anatomical, structural, cellular, functional, and metabolic. Cellular maps, for instance, may comprise nanoscale imaging and may be alternately defined via genomics. This volume will endeavor to survey and articulate the latest advances in neurophotonics. These exciting technological advances will lead to the further enhancement of the diagnoses and treatments of myriad brain conditions toward improved patient outcomes globally.
Advanced Electrophysiological Imaging Techniques for Studying Drug Effects
Edythe D. London in Imaging Drug Action in the Brain, 2017
Traditional methods of assessing the electrophysiological effects of drugs have relied upon visual inspection of up to 21 individual tracings of brain electrical activity. While such tactics capitalize on the capacity of the human eye to identify subtle aberrations or asymmetries, the observed changes are impossible to quantify numerically. In addition, such electroencephalograms often present too much data to be synthesized in a relatively short period of time. Quantitative measures of electroencephalographic activity have been used extensively to explore the nature of aberrations in central nervous system (CNS) excitability (Nuwer, 1988). Topographic brain mapping is one such method that has been developed to provide a complete view of the distribution of brain electrical activity over the scalp at any point in time. The technique employs high speed digital computing and mathematical algorithms to interpolate the activity of the area between EEG electrodes. These calculated voltages are then color-coded to provide a quantitative measure of the distribution of brain electrical activity over the entire scalp.
Pharmacological MRI as a Molecular Imaging Technique
Michel M. J. Modo, Jeff W. M. Bulte in Molecular and Cellular MR Imaging, 2007
In the case that a pharmacological ligand is used to provoke neuronal activity, the MRI-measured hemodynamic change (either BOLD or rCBV changes) can serve as an indirect index to a specific neurotransmission function and provide us with the knowledge of how the brain works from focal neuronal innervation to an extended circuitry. As we will discuss in depth later, studying D-amphetamine (AMPH; a dopamine releaser) challenge with phMRI not only allows us to investigate the neuronal response at the site of dopaminergic innervation (such as caudate/putamen and nucleus accumbens), but also allows us to follow activation along the basal ganglia feedback loop, which includes downstream structures such as the thalamus and the neocortex.6,15–17 Whole-brain mapping by imaging methods thus provides us with the opportunity to identify the responsible cerebral organs and circuits for conditions or disorders that are less understood. For other conditions or disorders that may already have a sound hypothesis regarding which circuitry is involved, phMRI can also help to deepen our understanding of when the neuroadaptation happens and what is the impact on the downstream structures. Once the active centers are identified by the imaging techniques, more fundamental mechanistic changes (how) have to be probed using a direct measurement. Take the AMPH challenge as an example again: phMRI first identifies the sites of interests to be the striatum, thalamus, and nucleus accumbens (NAc). Afterwards, the real neurotransmitter dynamics have to be assessed using well-established traditional standards, such as measuring the alteration in dopamine (DA) release using microdialysis or voltametry, measuring consequent postsynaptic changes by probing the mitogen-activated protein (MAP) kinase pathway, c-Fos and ΔfosB expression, and probing the modulation of the mRNA profile via the expression of the D1/D2 receptor. An example of such an integrated multimodal design is schematically illustrated in Figure 12.2. Combining integrated information obtained at the molecular and neurotransmitter levels with the gross neuroanatomical functional map provides a fuller picture of a complicated cerebral task.
Improved Visual Function in a Case of Ultra-low Vision following Ischemic Encephalopathy Using Transcranial Electrical Stimulation; A Brief Report
Published in Developmental Neurorehabilitation, 2021
Ali-Mohammad Kamali, Mohammad Javad Gholamzadeh, Seyedeh Zahra Mousavi, Maryam Vasaghi Gharamaleki, Mohammad Nami
In general, the application of a novel method with a proper safety profile resulting in a sustained improvement in visual function (at least over a 20 months of follow-up) was the highlight of our study. Meanwhile, more investigation is needed to assess the patient’s vision improvement in a long-term period. Most of the previous studies have articulated the effect of common neurovisual rehabilitation strategies in adults whilst such reports in the pediatric population are scant. Since CVI is an important cause of vision loss in children, it is also necessary to evaluate and recommend the rehabilitation approaches in children and young adults.25 In addition, the employment of noninvasive brain stimulation as a therapeutic approach for visual rehabilitation has not been the case in our setting yet. Other than the above, based on some recent reports, CVI can be characterized as a condition of dorsal stream dysfunction or dorsal stream vulnerability which appears to be the most common type of visual processing impairment observed in children with such a condition. This needs to be focused upon future studies which employ neuroscience imaging approaches including quantitative electroencephalography-included brain mapping26
Beyond Epilepsy: How Can Quantitative Electroencephalography Improve Conventional Electroencephalography Findings? A Systematic Review of Comparative EEG Studies
Published in The Neurodiagnostic Journal, 2018
Cassio Henrique Taques Martins, Catarina De Marchi Assunção
A systematic review was performed on the MEDLINE database using the search strategy: (Nervous System Diseases) AND (Electroencephalography[Title] OR EEG[Title]) AND (Brain Mapping[Title/Abstract] OR Quantitative[Title/Abstract]) AND (comparative study). The authors individually and carefully analyzed by title and abstract each one of the retrieved articles. Selected articles were only those categorized very clearly in their abstract that they were comparative studies between the use of conventional EEG and QEEG and written in the English language. The present review focused on the possibility of observing diagnostic differences between QEEG over traditional EEG. Hence, comparison studies between QEEG and any other imaging techniques for brain mapping, such as functional magnetic resonance imaging (fMRI), diffusion MRI (dMRI), magnetoencephalography (MEG), positron emission tomography (PET), and near-infrared spectroscopy (NIRS), were excluded. Studies older than 30 years were also excluded from the discussion. After articles were selected by the above criteria, careful analysis of each selected article’s full text was performed. When the data allowed, “exact” Clopper-Pearson confidence intervals (CIs) for sensitivity were calculated so that the EEG methods could be statistically compared.
The effects of Alzheimer's disease related striatal pathologic changes on the fractional amplitude of low-frequency fluctuations
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2020
Resting-state functional Magnetic Resonance Imaging (rs-fMRI), a non-invasive functional imaging technique, has been used extensively in brain mapping for evaluating the regional interactions which occur in a resting state when a task is not being performed. fMRI is used to measure spontaneous brain activities in vivo and is most commonly performed using blood oxygenation level dependent (BOLD) contrast to study the local changes in deoxyhemoglobin concentration in the brain. Under normal and pathological conditions such as AD which is a progressive neurodegenerative disorder, it helps to detect the intrinsic brain functional architecture (Agosta et al. 2012; Liu et al. 2014; Lindquist and Wager 2016; Ren et al. 2016; Yang et al. 2018).
Related Knowledge Centers
- Anatomy
- Cell Biology
- Molecular Genetics
- Neuroimaging
- Optogenetics
- Spinal Cord
- Stem Cell
- Brain
- Neuroscience
- Immunohistochemistry