REM Sleep And Dreaming
- irenechiandetti
- Sep 30, 2025
- 2 min read
The Possible Functions Of REM Sleep And Dreaming
Dreaming in REM vs. Non-REM
Experiments waking volunteers during different stages reveal a striking difference:
REM awakenings → people recall vivid, emotional, and often bizarre dreams, filled with imagery and strong feelings.
Non-REM awakenings → fewer dreams are reported, and those are typically less vivid, more logical, and less emotional.
This sharp contrast has fueled the idea that dreams themselves may hold clues to the role of REM sleep.
Freud, Emotions, and Modern Dream Science
Sigmund Freud’s The Interpretation of Dreams (1900) famously framed dreams as windows into the unconscious. While psychoanalysis has fallen out of favor in neuroscience, the emotional content of dreams remains compelling.
Modern studies suggest:
~65% of dreams involve negative emotions like sadness, anxiety, or anger.
~20% involve happiness or excitement.
Only ~1% involve sexual content, despite popular assumptions.
The Puzzle of REM Deprivation
Here’s the twist: depriving humans of REM sleep for up to two weeks produces surprisingly few side effects.
Volunteers deprived of REM simply “rebound” later, spending more time in REM when allowed.
Patients on certain antidepressants (MAO inhibitors) have little or no REM for months or years—with no obvious ill effects.
This is in stark contrast to total sleep deprivation, which quickly causes profound cognitive and health problems.
Competing Hypotheses: Why REM And Dreams?
Scientists have proposed several intriguing theories:
Crick & Mitchison’s “Unlearning” Hypothesis: Dreams help erase useless or harmful patterns of neural activity—preventing obsession or paranoia.
Jouvet’s Rehearsal Hypothesis: Dreams let us practice responses to rare but vital situations, like danger or aggression.
Memory Consolidation: REM helps transfer memories between the hippocampus and neocortex, reinforcing learning.
Incidental By-Product: Dreaming is simply the side effect of brain activation during REM, with no deeper function.
None of these theories is universally accepted.
Why It Matters
Understanding REM sleep and dreaming isn’t just about decoding the mysteries of the night—it has direct implications for neuroscience, medicine, and daily life.
Memory and learning: If REM plays a role in consolidating memories, then improving REM quality could enhance education and skill acquisition.
Mental health: Disturbances in REM are linked to conditions such as depression, PTSD, and anxiety. Clarifying its role could open new therapeutic strategies.
Neurodegeneration: Changes in REM sleep patterns are often early markers of diseases like Parkinson’s and Alzheimer’s, offering potential for earlier diagnosis.
Everyday performance: Good REM sleep supports emotional regulation, creativity, and problem-solving—skills essential in modern life.
Conclusion: Mystery at the Heart of Sleep
The truth is, we still don’t know why we dream—or why REM exists at all.
It may be a tool for memory, learning, and emotion, or a neurological “clean-up” mechanism, or perhaps just a side effect of brain activity at rest.
What is clear is that REM and dreaming connect to the broader puzzle of consciousness—why we experience anything at all.
Until we solve that riddle, REM will remain
one of neuroscience’s most tantalizing enigmas.
Source: Crick, F. & Mitchison, G.; Jouvet, M.; Freud, S.; Hobson, J.A. – The Possible Functions of REM Sleep and Dreaming (adapted from Sinauer Associates, 2001).
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