This is a summary of one of my works I did in a course of Chicago University about
Neurobiology of sleep and his important relationship between health and the sleep function. The fundamental tool for know about this is thank you of the neuroimaging technique is used to describe what's happening inside the brain while we sleep at night time. This is an experimental setup in which there is a bedroom and you have an individual that is sleeping comfortably in their bed. Although
"the brain's control of sleep and wakefulness is not entirely understood, scientists have pinpointed many areas of the brain involved in regulating these processes and have learned a great deal about how these areas function". (https://www.coursera.org/learn/neurobiology/lecture/3Lp0m/wrap-up-homeostasis Mason. 2017)
For example, we now know that several areas in
"the brainstem and hypothalamus promote wakefulness by sending arousal signals to the cerebral cortex, the brain’s largest region". (https://www.coursera.org/learn/neurobiology/lecture/D91Vt/sleep-mechanisms Mason, 2017)
These signals come in the form of chemicals called neurotransmitters. When neurons in the arousal areas are active, the cortex remains activated and we stay awake.
The areas of the brain implicates are in the frontal cortex, parietal cortex and the temporal lobe where there are dramatic reductions in metabolic activity during deep sleep. So when we're conscious and awake, our executive brain function is activating at a very high-level. And when we're asleep in contrast, these are the areas of the brain, if you will go offline or have large reductions in metabolic activity and that constitutes the restful sleep state.
The thalamus is also an area of the brain where there's a significant reduction in metabolic activity. This is because
"the levels of metabolic activity seen during rapid eye movement sleep are very comparable to those during wakefulness. So the brain is in an activated state, if you will during rapid eye movement sleep". (https://www.coursera.org/learn/neurobiology/lecture/4L0sX/sleep-phenomenology Mason, 2017)
The rapid eye movement sleep is the period of sleep that we most associate with dreaming at nighttime. The major difference then between REM sleep and wakefulness is that the person is unconscious or not aware of brain activity that's happening to them.
The relation between the mechanism of the sleep and the psychiatric disorders. If there are any alterations in non-REM sleep in specific psychiatric disorders, it may reflect an abnormality in function of these regions of the brain, heteromodal association as well as executive cortex.
"So we've identified the areas of the brain that are involved in non-REM sleep. If non-REM sleep is disturbed in a particular psychiatric disorder, it may be a reflection of an alteration and function in this circuitry in that specific specific group of individuals". (Circadian Rhythms. Retrieved July 6, 2020, from https://www.nigms.nih.gov/education/fact-sheets/Pages/circadian-rhythms.aspx )
This aspect of sleep are synchronized with a master clock in the brain. This master clock is directly influenced by environmental cues, especially light, which is why circadian rhythms are tied to the cycle of day and night. The term circadian comes from the Latin circa, meaning "around" (or "approximately"), and diem, meaning "day". Processes with 24-hour cycles are more generally called diurnal rhythms:
"Diurnal rhythms should not be called circadian rhythms unless they can be confirmed as endogenous, and not environmental". (Vitaterna MH, Takahashi JS, Turek FW, 2001.)
For understand more and to be called circadian, a biological rhythm must meet these three general criteria:
"The rhythm has an endogenous free-running period that lasts approximately 24 hours. The rhythm persists in constant conditions, (i.e., constant darkness) with a period of about 24 hours. The period of the rhythm in constant conditions is called the free-running period and is denoted by the Greek letter τ (tau). The rationale for this criterion is to distinguish circadian rhythms from simple responses to daily external cues. A rhythm cannot be said to be endogenous unless it has been tested and persists in conditions without external periodic input. In diurnal animals (active during daylight hours), in general τ is slightly greater than 24 hours, whereas, in nocturnal animals (active at night), in general τ is shorter than 24 hours". (Johnson C. 2004).
The rhythms are entrainable. The rhythm can be reset by exposure to external stimuli (such as light and heat), a process called entrainment. The external stimulus used to entrain a rhythm is called the Zeitgeber, or "time giver". Travel across time zones illustrates the ability of the human biological clock to adjust to the local time; a person will usually experience jet lag before entrainment of their circadian clock has brought it into sync with local time.
The rhythms exhibit temperature compensation. In other words, they maintain circadian periodicity over a range of physiological temperatures. Many organisms live at a broad range of temperatures, and differences in thermal energy will affect the kinetics of all molecular processes in their cell(s). In order to keep track of time, the organism's circadian clock must maintain roughly a 24-hour periodicity despite the changing kinetics, a property known as temperature compensation.
The rhythms exhibit temperature compensation. In other words, they maintain circadian periodicity over a range of physiological temperatures. Many organisms live at a broad range of temperatures, and differences in thermal energy will affect the kinetics of all molecular processes in their cell(s). In order to keep track of time, the organism's circadian clock must maintain roughly a 24-hour periodicity despite the changing kinetics, a property known as temperature compensation.
"Circadian rhythms influence mental health as well, including the risk of psychiatric illnesses like depression and bipolar disorder as well as the potential for neurodegenerative diseases like dementia". (Sollars, P. J., & Pickard, G. E. 2015)
So when people don’t get enough sleep, their health risks rise. So that’s important to receive a diagnosis and treatment right away if you suspect you might have a sleep disorder. When left untreated,
"the negative effects of sleep disorders can lead to further health consequences". (Retrieved July 7, 2020, from http://healthysleep.med.harvard.edu/healthy/science/how/neurophysiology.)
The importance of functional neuroanatomical changes in sleep. Must be treat in an integral form about our habits, our form to eat and his influence in the metabolism food and by last the sleep cycle I´ve introduced in brief mode. This is only some ideas about the importance and care we must have in our live every day. I hope it is useful.
Bibliography
Division of Sleep Medicine at Harvard Medical School. (2007, December 18). Under the Brain’s Control | Healthy Sleep. Retrieved July 7, 2020, from https://healthysleep.med.harvard.edu/healthy/science/how/neurophysiology
Johnson C. (2004). Chronobiology: Biological Timekeeping. Sunderland, Massachusetts, USA: Sinauer Associates, Inc. pp. 67–105.
National Institute of General Medical Sciences. (2020, March 4). Circadian Rhythms. Retrieved July 6, 2020, from https://www.nigms.nih.gov/education/fact-sheets/Pages/circadian-rhythms.aspx
Mason, Peggy (2017) Medical Neurobiology. Second edition. Oxford University Press. P. 329-455-448.
https://www.coursera.org/learn/neurobiology/lecture/3Lp0m/wrap-up-homeostasis / https://www.coursera.org/learn/neurobiology/lecture/D91Vt/sleep-mechanisms / https://www.coursera.org/learn/neurobiology/lecture/4L0sX/sleep-phenomenology
Sollars, P. J., & Pickard, G. E. (2015). The Neurobiology of Circadian Rhythms. The Psychiatric clinics of North America, 38(4), 645–665. https://doi.org/10.1016/j.psc.2015.07.003
Vitaterna MH, Takahashi JS, Turek FW (2001). "Overview of circadian rhythms". Alcohol Research & Health. 25 (2): 85–93.
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