image: Figure 9. (A) Diurnal rhythm control under homeostatic conditions. Initial circadian input occurs via light activating specialized retinal ganglion cells that project directly to the suprachiasmatic nucleus (SCN). The SCN is the master circadian oscillator; in turn, this regulates extra-SCN ("peripheral") rhythms via direct and indirect routes. The SCN controls peripheral clocks directly via autonomic control (sympathetic and parasympathetic innervation), whereas the SCN controls peripheral clocks indirectly through regulation of physiologic and humoral factors. Appropriately entrained clocks throughout the body (likely every cell) optimize organismal performance for time-of-day. (B) Diurnal rhythm control is disrupted by SCI. Our data suggest that SCI disrupts rhythms of key zeitgebers - including body temperature, activity, and CORT (yellow bolts) - which could disrupt peripheral clock entrainment. In addition, data from other groups suggest that SCI also disrupts additional entraining factors (e.g., feeding, melatonin, and autonomic input; grey bolts). Ultimately, prolonged SCI-elicited disruption of these entraining factors could contribute to loss of homeostasis and suboptimal repair. view more
Credit: Gaudet et al., JNeurosci (2018)
Moderate damage to the thoracic spinal cord causes widespread disruption to the timing of the body's daily activities, according to a study of male and female rats published in eNeuro. If this also occurs in humans, transitioning patients back to the normal rhythms of their daily life after a spinal cord injury could help prevent further dysregulation of essential biological processes.
Andrew Gaudet and colleagues found their rat model of spinal cord injury altered daily rhythms in body temperature and active time as well as the expression of genes and hormones that synchronize the timing of other body processes. These findings suggest efforts to restore a patient's normal routines -- for example, encouraging beneficial sleeping and eating schedules and optimizing the timing of physical rehabilitation -- could promote recovery. Future studies of spinal cord injury that incorporate circadian factors could inform the development of such "chronotherapies."
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Article: Spinal cord injury in rats disrupts the circadian system
DOI: https://doi.org/10.1523/ENEURO.0328-18.2018
Andrew Gaudet (The University of Texas at Austin, USA), andrew.gaudet@utexas.edu
About eNeuro
eNeuro, the Society for Neuroscience's open-access journal launched in 2014, publishes rigorous neuroscience research with double-blind peer review that masks the identity of both the authors and reviewers, minimizing the potential for implicit biases. eNeuro is distinguished by a broader scope and balanced perspective achieved by publishing negative results, failure to replicate or replication studies. New research, computational neuroscience, theories and methods are also published.
About The Society for Neuroscience
The Society for Neuroscience is the world's largest organization of scientists and physicians devoted to understanding the brain and nervous system. The nonprofit organization, founded in 1969, now has nearly 37,000 members in more than 90 countries and over 130 chapters worldwide.
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eNeuro