03 Sep Temperature modulation of Dream sleep
An interesting article was recently published on the ScienceDaily website discussing research about lengthening our dream phase of sleep:
Every night while sleeping, we cycle between two very different states of sleep. Upon falling asleep, we enter non-rapid eye movement (non-REM) sleep where our breathing is slow and regular and movement of our limbs or eyes are minimal. Approximately 90 minutes later, however, we enter rapid eye movement (REM) sleep. This is a paradoxical state where our breathing becomes fast and irregular, our limbs twitch, our eyes move rapidly and we dream. In REM sleep, our brain is highly active, but we also become paralysed and we lose the ability to thermoregulate or maintain our constant body temperature.
It has been a mystery why our REM sleep, or dream sleep, increases when room temperature is ‘just right’, however neuroscientists from the University of Bern have found that an explanation lies with a specific group of neurons in the brain.
The researchers discovered that a small population of neurons within the hypothalamus, called melanin-concentrating hormone (MCH) neurons, play a critical role in how we modulate REM sleep expression as a function of ambient (or room) temperature.
Mark Schmidt, senior author of the study, suggested that REM sleep is a behavioural strategy that shifts energy resources away from costly thermoregulatory defence toward, instead, the brain to enhance many brain functions. Their research confirmed this hypothesis and found that MCH neurons specifically increase REM sleep when the room temperature is ‘just right’ and the need for body temperature defence is minimized. Increasing REM sleep can be of great importance as it is known to play an important role in many brain functions such as memory consolidation.