Neuroscience
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Despite the high prevalence of medicinal use and abuse of opioids, their neurobiology and mechanisms of action are not fully understood. Experimental (animal) models are critical for improving our understanding of opioid effects in vivo. ⋯ As many human brain diseases involve pain and aberrant reward, we also summarize zebrafish models relevant to opioid regulation of pain and addiction, including evidence of functional interplay between the opioid system and central dopaminergic and other neurotransmitter mechanisms. Additionally, we critically evaluate the limitations of zebrafish models for translational opioid research and emphasize their developing utility for improving our understanding of evolutionarily conserved mechanisms of pain-related, addictive, affective and other behaviors, as well as for fostering opioid-related drug discovery.
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Major depressive disorder (MDD) is a very common disease that affects more than 350 million people worldwide, representing an enormous socioeconomic burden. From a clinical perspective, MDD can be divided into different subtypes, such as melancholic or atypical MDD. Interestingly, increasing evidence points toward an involvement of the immune system in MDD pathogenesis. ⋯ Next, we examine the regional specificity of neuroinflammation, which shows striking overlaps with neural patterns activated in atypical MDD. Furthermore, we outline how inflammation may translate to subtype-specific clinical features and we suggest how this could be used for diagnostic and treatment purposes. By providing a link back to a dysregulated immune system as a contributing factor to MDD subtypes, we explain how brain regions particularly affected by certain subtypes may regulate the cortisol circuitry.
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Positron emission tomography (PET) provides spatially localized information about brain metabolism and function and innovative tracers have extended this potential to the study of neuroinflammation (NI), an important process in the pathophysiology of several neurological disorders. However, PET is limited by low spatial resolution. Conversely, Magnetic Resonance Imaging (MRI) affords high-resolution information about brain anatomy and metabolism which can complement PET-related information as well as aid in post-processing of PET data. ⋯ While, the clinical applicability and impact on diagnostic accuracy of PET/MRI in neurological disorders is still under investigation, the study of NI, a complex processes mediated by multiple metabolic pathways and hence likely characterized by different biomarkers, represents an opportunity to characterize the added value of joint MRI-PET techniques in a clinical context. This would in turn offer improved diagnostic and prognostic tools in several neurological disorders in which NI is a key mediator. This review aims at summarizing the current state as well as future potential of using hybrid PET/MRI for characterizing NI phenomena, both in terms of technical challenges and clinical relevance.
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Network science provides powerful access to essential organizational principles of the human brain. It has been applied in combination with graph theory to characterize brain connectivity patterns. In multiple sclerosis (MS), analysis of the brain networks derived from either structural or functional imaging provides new insights into pathological processes within the gray and white matter. ⋯ We further provide an outline of functional and structural connectivity patterns observed in MS, spanning from disconnection and disruption on one hand to adaptation and compensation on the other. Moreover, we link network changes and their relation to clinical disability based on the current literature. Finally, we discuss the perspective of network science in MS for future research and postulate its role in the clinical framework.
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Multiple Sclerosis (MS) is a chronic neurological disease that represents a leading cause of disability in young adults and is characterized by inflammation and degeneration of both white matter (WM) and gray matter (GM). Defining the presence or absence of inflammation on individual basis is a key point in choosing the therapy and monitoring the treatment response. Magnetic resonance imaging (MRI) represents the most sensitive non-invasive tool to monitor inflammation in the clinical practice. ⋯ New imaging techniques have been developed to study diffuse inflammation taking place outside the focal plaques. The scope of this review is to examine the various neuroimaging techniques and those biophysical quantities that can be non-invasively detected to enlighten the different aspects of neuroinflammation. Some techniques are commonly used in the clinical practice, while others are used in the research field to better understand the pathophysiological mechanisms of the disease and the role of inflammation.