The Impact of Circadian Rhythms on Sleep, Wakefulness, and Insomnia

Abstract

A circadian rhythm is the rhythm about a day in length. Typically, we function on a 24-hour cycle that goes along with the sun/moon cycle. The suprachiasmatic nucleus (SCN) is responsible for for the biological clock (Garrett & Hough, 2018). The SCN is located in the hypothalamus. If the SCN were to have a lesion, it would not be able to keep time and regulate the activity of other cells. This would impact many things including sleep, activity, body temperature, and so on (Garrett & Hough, 2018).  Waking controls consists of two pathways: the brainstem arousal centers and the basal forebrain. In the brainstem arousal centers are two branches contain the pedunculopontine and laterodorsal tegmental nuclei and the second contains locus coeruleus, raphe nuclei, tuberomammillary nucleus, and parabrachial nucleus (Garrett & Hough, 2018). These are responsible for sending projections to the prefrontal cortex, basal forebrain, and lateral hypothalamus. Orexin-releasing hormones are responsible to sustain wakefulness and suppress the REM sleep (Garrett & Hough, 2018). Insomnia is the inability to sleep or get adequate and quality sleep. This is true for individuals that feel that they are not well rested. Not only is insomnia difficult for a person feeling not well-rested, but it can have a lasting impact on health (Garrett & Hough, 2018). Factors that can result in insomnia include but are not limited to stress, loss of gray matter in the orbitofrontal cortex and the parietal cortex, and psychological problems (such as affective disorders). Sleep medications that are often used to treat insomnia can lead to more sleep difficulties as they tend to be highly addictive (Garrett & Hough, 2018). An interesting snippet from the text discusses the difficulties of sleep cycles for individuals who do shift work. Their constant changing in shifts and trying to adapt to 'regular'...