Comment on "Exploring and developing the concept of the dream as a threat monitoring-alerting mechanism" by Rupert Harwood

Summary . In his citation, Harwood drew his conclusions from an analysis of 61 dreams logged during the start of an, unfortunate, chronic autoimmune condition. Such data, logged during the initial stages of an illness, could or could not necessarily have an immediate impact on the deep sleep conditions, depending on the nature of the illness: for instance, a simple cold virus could have a more direct effect on the deep sleep, than a more serious illness, like cancer at its initial stages: albeit, the latter could usually generate emotional conditions, that would be more susceptible to the deep sleep eventually. Harwood also introduced seven new hypotheses, in a few which the author’s theory was addressed. The author will only elaborate on Harwood’s relevant hypotheses, with the aim to further consolidate, and create a clear rationale for the author’s theory as the main function of dreams, and any content-interpretation is a by-product, related to wishes, desires, environmental effects and emotions that dreams draw their substance from. Harwood (2018, P.8) states...” [H]owever, during deep sleep, cerebral blood flows are at their lowest during REM sleep (e.g., Madson and Vorstrup, 1991). Further, Jurysta et al. (2003, P2146) note that...”[i]n healthy subjects, heart rate decreases during non-rapid-eye movement (NREM) sleep and increases during rapid-eye-movement (REM) sleep...”. In the author’s theory, it states that during the deep sleep, the body functions are lowered to their respective permissible levels of operation, and if therefore the cerebral blood flow (CBF) is to be at a specific required level, then the author’s theory referred to that specific level as the permissible level, and the deep sleep monitoring mechanism maintains a close surveillance over this flow; among other tasks, to ensure that blood supplies to the body organs like brain, which is automatically controlled by the Cerebral Pressure Autoregulation Process, to meet the metabolic demand. On the other hand, it is the Cerebral Perfusion Pressure (CPP) that could change. Moreover, the nocturnal blood pressure which dips during sleep by about 10% -20%, is also, under surveillance of the monitoring mechanism; in addition to any other abnormalities and discomforts experienced during the sleep. It is of interest to perceive the intricate and complex operations performed by the human organs when in deep sleep, specifically the heart must reduce its workload to minimum permissible level, yet simultaneously maintaining the (CBF) rate, and (CPP) that intends to drop with the body operations slowing down during the sleep.