China
Africa
Explore chapters and articles related to this topic
Control of the Upper Airway during Sleep
Published in Susmita Chowdhuri, M Safwan Badr, James A Rowley, Control of Breathing during Sleep, 2022
Recordings from central respiratory neurons across sleep-wake states revealed that those that drive respiratory pump muscles show small sleep-related changes that closely follow the magnitude and pattern of the effects of non-REM and REM sleep on inspiratory activity of the diaphragm (102–104). Recordings also revealed the presence in the medulla, pons, and midbrain of the weakly respiratory-modulated cell whose activity strongly declined during sleep (105–107). Such mildly respiratory-modulated reticular formation cells were considered as a possible substrate for the concept of the “wakefulness stimulus for breathing” (108). The essence of this concept was that distinct neurons with predictable changes of activity in association with sleep are functionally connected with upper airway motoneurons. Initially, such neurons were hypothesized to be an important source of inspiratory drive to upper airway muscles, as this could explain the sleep-related loss of respiratory modulation of upper airway muscle activity. Ultimately the evidence for such neurons being responsible for sleep-related upper airway hypotonia proved to be weak due to the absence of evidence that such cells have appropriate efferent connections. Still, the concept proved important for the search for other sources of state-dependent regulation of upper airway muscle tone.
Disorders of Consciousness
Published in Philip B. Gorelick, Fernando D. Testai, Graeme J. Hankey, Joanna M. Wardlaw, Hankey's Clinical Neurology, 2020
Consciousness depends on an intact and interacting brainstem reticular formation and cerebral hemispheres. The reticular formation (from the Latin word reticulum, meaning a net) consists of a network of small and large cells and their connections throughout the brainstem from the medulla to the thalamus. All major sensory pathways project to the reticular formation where they interact before proceeding to the sensory cortex. The ascending reticular activating system (ARAS) originates in the tegmentum of the upper pons and projects through the intralaminar nuclei of the thalamus bilaterally and diffusely to the cerebral cortex. The ARAS influences arousal and maintains wakefulness. When the ARAS pathways in the brainstem and/or the bilateral cerebral hemispheres are disrupted, impaired consciousness occurs.
Brain Motor Centers and Pathways
Published in Nassir H. Sabah, Neuromuscular Fundamentals, 2020
The functions of the reticular formation include control of state of consciousness, habituation, control of eye movements, facial expressions, and some reflexes involving the mouth and face – such as swallowing, sneezing, and yawning – autonomic respiratory rhythms, and some cardiac functions and centers that coordinate somatic and autonomic motor activities such as vomiting, laughing, and crying.
The Effectiveness of a Multi-Sensory Sleep-Promotion Program on Sleep Quality among Hospitalized Older Adults of Thailand: A Quasi-Experimental Study
Published in Behavioral Sleep Medicine, 2023
Amornrat Kaewlue, Samoraphop Banharak, Ladawan Panpanit, Sutin Chanaboon
Back rubs can promote sleep quality (Cinar & Eser, 2012; Khieophung et al., 2011; Panpanit, 2019). This alternative intervention reduces muscle tension and stimulates the circulatory system. Back rub also relaxes the body and makes it free from stress. As a result, the body releases endorphins. However, catecholamines were lowered, and reticular formation functions were suppressed, reducing the body’s alertness. Finally, better sleep is promoted (Liu et al., 2015; Norman, 2015: Pornratshanee et al., 2005). Ayik and Ozden (2018) studied the mixed effects of back massage using lavender oil (aroma) in hospitalized adults and older adults. Our findings from the multi-sensory sleep promotion program were like theirs: the experimental group had fewer awakenings and reported better sleep quality than the control group.
Experts, but not novices, exhibit StartReact indicating experts use the reticulospinal system more than novices
Published in Journal of Motor Behavior, 2021
Brandon M. Bartels, Maria Jose Quezada, Vengateswaran J. Ravichandran, Claire F. Honeycutt
While several subcortical structures may be involved in the transfer from cortical to subcortical structures (cerebellum, basal ganglia, red nucleus, superior colliculus), a handful of studies indicate that the reticular formation may be an important facilitator. Evidence from humans shows that reticulospinal contributions are modulated during intense, repetitive training. Direct measurement of the reticulospinal system in humans is not feasible; thus the StartReact (SR) response is utilized to assess reticulospinal contributions. The use of SR to investigate the reticular formation in humans is predicated on animal work (Davis, Gendelman, Tischler, & Gendelman, 1982; Davis & Gendelman, 1977; Groves, Wilson, & Boyle, 1974; Hammond, 1973); however, strong evidence exists that the role of the reticular formation during SR is maintained in humans. Patients with heredity spasticity disorder (HSP) have selective corticospinal tract damage but intact reticulospinal pathways. In these patients, SR is intact and further shows no evidence of deficit or delay (Nonnekes, Geurts, et al., 2014). Additionally, SR remains intact following cortical lesion in stroke survivors (Honeycutt, Tresch, & Perreault, 2014; Honeycutt & Perreault, 2012; Marinovic, Brauer, Hayward, Carroll, & Riek, 2016) indicating that SR does not rely on the cortex or corticospinal projection for execution in humans.
Difference between injuries of the corticospinal tract and corticoreticulospinal tract in patients with diffuse axonal injury: a diffusion tensor tractography study
Published in International Journal of Neuroscience, 2020
DTI data were acquired using a six-channel head coil on a 1.5T Philips Gyroscan Intera (Philips Ltd., Best, the Netherlands) with single-shot echo-planar imaging. For each of the 32 non-collinear diffusion sensitizing gradients, 67 contiguous slices were acquired parallel to the anterior commissure-posterior commissure line. The imaging parameters were as follows: acquisition matrix = 96 × 96; reconstructed to matrix = 128 × 128; field of view = 221 × 221 mm2; TR = 10,726 ms; TE = 76 ms; parallel imaging reduction factor (SENSE factor) = 2; EPI factor = 49; b = 1000 s/mm2; NEX = 1; and a slice thickness of 2.3 mm (acquired voxel size 1.73 × 1.73 × 2.3 mm3). Removal of eddy current-induced image distortions using affine multi-scale two-dimensional registration was performed at the Oxford Centre for Functional Magnetic Resonance Imaging of Brain Software Library (FSL; www.fmrib.ox.ac.uk/fsl) [29]. DTI-Studio software (CMRM, Johns Hopkins Medical Institute, Baltimore, MD, USA) was used for reconstruction of the CRT. For reconstruction of tracts, the seed and target ROI were determined. A seed ROI was placed on the reticular formation of the medulla, and the target ROI was placed on the midbrain tegmentum. Termination criteria were fractional anisotropy <0.1 and an angle change >30° [20].