Imagine waking up at 3 a.m to find a shadowy figure standing in the corner of your bedroom. You try to scream, but nothing comes out. You try to move, but your body refuses to cooperate. At this moment, you might be thinking that you need an exorcist. However, before jumping to conclusions, you might want to see a neurologist instead. What just happened was likely sleep paralysis.
This eerie experience known as sleep paralysis, is something most children fear. However, that daunting figure may be more of a neurological phenomenon than a supernatural one.
To understand why our brains turn bedtime into a horror movie, we first need to look at what happens while we sleep.
Every night, your body cycles through three stages of non-REM sleep. After returning to stage one, your body enters a period of REM sleep (Denis 2015). During this stage, brain activity increases and you begin to experience your most vivid dreams. While the brain generates these dreams, the body enters a state of REM atonia, a temporary paralysis affecting most voluntary skeletal muscles. This process is regulated by two inhibitory neurotransmitters in the central nervous system: GABA and glycine, which reduce the activity of motor neurons. This prevents you from physically acting out most of your dreams (Jalal 2018). When you begin to wake up, the body gradually regains awareness and movement, however, when awareness is gained before voluntary movement that is when sleep paralysis occurs.
So where might this mysterious presence come from? One possible explanation involves the body schema, an internal representation of your body’s position and movement. This system relies on brain regions such as the superior parietal lobule and the temporoparietal junction. These regions help integrate sensory information to construct the brain’s representation of your body (Taylor 2026).
However, during sleep paralysis, the usual relationship between movement and sensory feedback may be disrupted. Your central nervous system sends efferent signals to your limbs, but due to the temporary paralysis, your brain does not receive the expected afferent signals back. According to one hypothesis proposed by Jalal and Ramachandran, this mismatch may distort the brain’s representation of the body. This causes it to project its internal body map, known as the homunculus, into the surrounding environment (Jalal and Ramachandran 2017).
The amygdala, a brain region involved in processing fear, may then amplify the threat created by this mysterious presence. The fear of being unable to move, combined with your cultural beliefs and expectations may shape this presence into something frightening, such as a demon or shadowy figure (John Fakoya et al. 2018).
However, this is one of many proposed explanations for these hallucinations, and the exact mechanisms remain a mystery. So, the next time you spot a shadowy figure in your room, it may just be your brain. But then again, I don’t recommend tossing that exorcist’s number just yet.
References
Baugh, Sue. n.d. “Homunculus | Description, History, Models, & Importance | Britannica.” Www.Britannica.Com. Accessed October 18, 2026. https://www.britannica.com/science/homunculus-biology.
Denis, Dan. 2015. “Understanding Sleep Paralysis: A Terrifying but Unique State of Consciousness.” The Conversation, October 5. https://theconversation.com/understanding-sleep-paralysis-a-terrifying-but-unique-state-of-consciousness-48509.
Jalal, Baland. 2018. “The Neuropharmacology of Sleep Paralysis Hallucinations: Serotonin 2A Activation and a Novel Therapeutic Drug.” Psychopharmacology 235 (11): 3083–91. https://doi.org/10.1007/s00213-018-5042-1.
Jalal, Baland, and Vilayanur S. Ramachandran. 2017. “Sleep Paralysis, ‘The Ghostly Bedroom Intruder’ and Out-of-Body Experiences: The Role of Mirror Neurons.” Frontiers in Human Neuroscience 11 (February). https://doi.org/10.3389/fnhum.2017.00092.
John Fakoya, AdegbenroOmotuyi, Esther Olunu, Ruth Kimo, et al. 2018. “Sleep Paralysis, a Medical Condition With a Diverse Cultural Interpretation.” International Journal of Applied and Basic Medical Research 8 (3): 137. https://doi.org/10.4103/ijabmr.ijabmr_19_18.
Taylor, Kenji. 2026. “Sleep Paralysis Hallucinations Aren’t Random—Here’s What Triggers Them. | Ubie Doctor’s Note.” Ubiehealth.Com, Ubie, Inc., January 16. https://ubiehealth.com/doctors-note/sleep-paralysis-hallucination-trigger-cause-37-why122e3.
Leave a Reply
You must be logged in to post a comment.