11/29/2023 0 Comments A brain scan of narcolepsy cataplexy![]() Finally, with magnetic resonance spectroscopy (MRS), one can measure metabolites or neurotransmitter concentration in a specific brain region. Functional connectivity looks at coactivated brain regions, ie, how different brain regions or networks may communicate with each other. Brain activity can be measured when subjects perform a cognitive task, during sleep, or during resting wakefulness (ie, in the absence of any particular task or sleep). fMRI can also be used to assess brain activity patterns and functional connectivity. Regional brain activity is indirectly measured by measuring the increase of oxygen consumption and, therefore, blood flow resulting from neuronal activity. Functional MRI (fMRI) measures changes in cerebral blood flow through a blood-oxygen-level-dependent contrast. MRI is used in clinical practice to investigate brain anatomy, but structural MRI can also provide measures of cortical thickness, regional gray or white matter volume, white matter integrity, and structural connectivity by looking at how water molecules diffuse in the brain. The understanding of sleep physiology and sleep disorders may, therefore, be improved by investigating structural and functional brain alterations during resting wakefulness, sleep, or while performing a task using these neuroimaging techniques. Important advances in the understanding of sleep and its disorders have been made using neuroimaging techniques, such as magnetic resonance imaging (MRI), positron emission tomography (PET), or single-photon emission computed tomography (SPECT), as they bring complementary information to electroencephalography (EEG). Both structural and functional alterations may be partially reversible with continuous positive airway pressure treatment. However, the pattern of structural alterations is less consistent. In obstructive sleep apnea, cognitive deficits might stem from lower resting state activity and functional connectivity in the frontoparietal, sensorimotor, and salience networks, which are involved in numerous cognitive processes.Specifically, the basal ganglia and sensorimotor network show altered functional connectivity, which might be a predictor of disease progression from REM sleep behavior disorder to Parkinson disease. In REM sleep behavior disorder, functional alterations are widespread across the cortex and involve the limbic network, pons, and thalamus.On the other hand, functional alterations are observed in the hypothalamus, which shows altered activation and regional blood flow during both resting wakefulness and while performing cognitive tasks, such as emotion regulation during positive emotions or cataplexy attacks. In narcolepsy with cataplexy, structural alterations, such as smaller gray matter volume and altered white matter integrity, are widespread and encompass the hypothalamus and its projections, which is in line with the evidence for loss of hypocretin neurons in the hypothalamus.In contrast, structural brain alterations are inconsistent, perhaps reflecting the complexity and heterogeneity of insomnia and suggesting that sleep-related symptoms in insomnia are reflected in functional rather than structural brain alterations. They generally point to a hyperactivation in response to sleep-related and negative emotional stimuli and a hypoactivation in response to other types of stimuli, such as tasks involving executive control. In insomnia, a variety of cognitive and emotional tasks have been used to evaluate functional brain alterations.There is a wide range of sleep disorders, and the following sleep disorders are discussed in this article: insomnia, narcolepsy and idiopathic hypersomnia, REM sleep behavior disorder, and obstructive sleep apnea. Therefore, neuroimaging may assist us in uncovering the physiological underpinnings of these conditions and the targets for the development or monitoring of sleep-related interventions. Structural and functional alterations can inform us of the neural mechanisms underlying the nighttime and daytime manifestations of sleep disorders, including their impact on cognitive function. However, neuroimaging studies on specific aspects of several sleep disorders have shown that functional as well as structural brain alterations can be identified. Sleep and its disorders are complex, and their mechanisms remain only partially understood.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |