Understand and Use Dreams to Learn and Forget | Huberman Lab Essentials
- Aisha Washington
- 2 hours ago
- 7 min read
Dreams have inspired centuries of interpretation, but Andrew Huberman approaches them through sleep physiology rather than symbolism. In this Huberman Lab Essentials episode, the Stanford neurobiologist examines how different stages of sleep contribute to learning, memory, and the gradual reduction of emotional intensity around difficult experiences.
His central argument is that sleep is not one uniform state. Slow-wave sleep and rapid eye movement (REM) sleep dominate different parts of the night and appear to perform different jobs. One helps stabilize detailed information and physical skills; the other may reorganize memories, establish meaning, and loosen the bond between an event and its emotional charge.
Sleep Changes as the Night Progresses
Sleep unfolds through recurring cycles that last roughly 90 minutes, although their exact duration can vary. Early cycles contain proportionally more slow-wave sleep, while REM periods generally become longer toward morning. That changing architecture matters because cutting sleep short does not simply remove more of the same kind of rest—it can disproportionately eliminate later REM-rich cycles.
Huberman distinguishes the stages by their likely contributions to learning. Slow-wave sleep is especially relevant to precise information and motor skills. REM sleep is more closely associated with emotional memories, broader relationships, and the extraction of meaning.
This division is not absolute. Both stages participate in memory, and dreaming can occur outside REM sleep. The useful principle is that a complete night gives the brain access to a sequence of complementary processes. Protecting only the first or last portion may leave some of that work unfinished.
Slow-Wave Sleep Consolidates Skills and Details
Slow-wave sleep, concentrated toward the beginning of the night, is marked by large, coordinated patterns of neural activity. Despite its quiet outward appearance, the brain remains metabolically active. The chemistry of this state also differs substantially from wakefulness.
Huberman describes acetylcholine, a neuromodulator associated with attention and focused engagement, as very low during slow-wave sleep. Norepinephrine—the chemical messenger involved in alertness and mobilization—is present at a lower level than during waking. Serotonin activity, by contrast, is relatively prominent, matching the stillness typically seen in this stage.
The body is not paralyzed during slow-wave sleep, but movement is usually limited. Sleepwalking, when it occurs, is often associated with this part of the sleep cycle.
Functionally, Huberman emphasizes two outcomes: retaining fine-grained information and consolidating motor learning. Practicing a movement during the day initiates learning, but subsequent slow-wave sleep helps stabilize that skill. Experiments that selectively interfere with deep sleep have found poorer motor-learning outcomes, supporting the idea that practice and sleep operate as parts of the same learning process.
For anyone developing a physical skill—playing an instrument, learning a sport, improving a technical procedure, or refining a repetitive movement—the lesson is straightforward: training supplies the experience, while sleep helps preserve it.
REM Sleep Replays Experience Without the Same Chemistry
REM sleep occurs throughout the night but occupies more time in later cycles. It takes its name from the rapid, irregular eye movements first systematically observed by sleep researchers in the 1950s. These movements are generated through circuits involving the brainstem, pons, and thalamus, yet they are not simply deliberate waking eye movements performed during sleep.
REM also produces a striking combination of an active brain and an immobilized body. Most skeletal muscles enter a temporary state of atonia, which prevents a sleeper from physically acting out vivid dream activity.
The neurochemical environment is equally unusual. According to Huberman, norepinephrine and epinephrine—the latter closely involved in bodily arousal, fear, and anxiety—are effectively absent during REM sleep. Serotonin levels are also extremely low. This creates a state in which a person can experience elaborate, emotionally meaningful dream imagery without the same chemical conditions that accompany waking alarm.
Huberman proposes that this separation allows memories to be reactivated while their emotional force is revised. The brain does not necessarily erase what happened. Instead, it may weaken the automatic connection between remembering an event and re-experiencing its original level of distress.
That is the sense in which sleep can support “forgetting”: not by deleting the factual memory, but by reducing an emotional response that is no longer useful.
Why Missing Late-Night REM Can Affect Mood
Because REM periods lengthen toward morning, waking very early and failing to return to sleep may remove a particularly REM-rich portion of the night. Huberman connects insufficient REM sleep with irritability, exaggerated reactions, and a tendency to interpret minor problems as major threats.
Selective REM-deprivation studies have shown that emotional regulation can deteriorate even when participants still obtain other forms of sleep. People may feel overwhelmed, form inappropriate associations, or struggle to judge the importance of events accurately.
This helps explain why sleep loss is more than an energy problem. A tired person is not merely slower or less attentive. They may also be operating with memories and emotions that have not been adequately recalibrated.
If someone wakes during the night, Huberman suggests that a non-sleep deep rest protocol—often called NSDR—may help the body settle sufficiently to return to sleep. The goal is not to replace REM sleep with guided relaxation, but to improve the chances of reaching the later sleep cycles that remain available.
Dreams Help Organize Space, Relationships, and Meaning
REM sleep appears to do more than reduce emotional intensity. Huberman points to research associated with MIT neuroscientist Matt Wilson showing that patterns of neural activity linked to navigating an environment can be replayed during sleep. Work across animal models and humans suggests that the brain revisits aspects of spatial experience after the original event.
Imagine arriving in an unfamiliar city, learning the route through a new building, or discovering how several locations connect. The initial experience produces detailed neural activity. During later sleep, elements of that activity may recur as the brain decides which relationships deserve long-term storage.
Not every detail survives. Information judged irrelevant can fade, while useful patterns become more stable. REM sleep may therefore help construct a broader model: where events occurred, how they relate, and why they matter.
Huberman extends this idea from physical space to meaning itself. Memories are valuable not as isolated records but as networks of relationships. Healthy cognition requires preserving relevant links while discarding misleading ones. When REM sleep is repeatedly disrupted, the brain may assign too much importance to coincidences, attach emotion to the wrong cues, or generate distorted associations.
What REM Sleep Does—and Does Not—Explain About EMDR
Huberman compares REM sleep with eye movement desensitization and reprocessing, or EMDR, a clinical therapy developed by psychologist Francine Shapiro. EMDR commonly asks a client to recall a troubling event while following a therapist’s side-to-side visual cue.
The intended result is not amnesia. Rather, the person may retain the factual memory while experiencing less distress when recalling it. Huberman cites evidence that lateral eye movements can reduce activity in circuits involving the amygdala, a brain structure important to threat detection and anxiety. The amygdala should not be treated as a simple “fear center,” but it contributes substantially to many fear responses.
The resemblance to REM is tempting: both involve eye movements and the processing of emotionally charged material. Huberman cautions, however, that EMDR’s movements are not copies of REM eye activity. He also rejects the popular explanation that the therapy works merely by synchronizing the brain’s two hemispheres.
The better-supported comparison is functional. REM sleep creates a chemical context in which memories can be revisited without normal epinephrine signaling, while EMDR may reduce threat-system activation during intentional recall. Each may help separate an event from an excessive emotional reaction through a different mechanism.
EMDR is a clinical intervention, not a self-guided eye exercise. Huberman notes that it appears most effective for certain specific or single-event traumas and may be less suitable for prolonged, complex trauma. Anyone considering it should work with a properly trained mental health professional.
Ketamine, Plasticity, and the Ethics of Emotional Unlearning
The episode also examines ketamine, a dissociative anesthetic used in carefully supervised medical settings. Ketamine affects NMDA receptors, which participate in neural plasticity and long-term changes in synaptic strength.
Huberman describes a clinical rationale in which ketamine may interrupt the formation or persistence of an intensely emotional association. In that limited sense, it resembles the proposed emotional uncoupling of REM sleep: the experience remains, but its relationship to fear or distress may change.
The comparison should not be mistaken for a recommendation. Ketamine has significant risks, is chemically related to PCP, and is not appropriate for everyone. Its therapeutic use requires medical evaluation and supervision.
There is also an ethical dimension. Emotions teach people what to approach, avoid, and remember. Eliminating every painful association would not be healthy or adaptive. The clinical objective is therefore not emotional blankness, but relief when an emotional response has become disproportionate, persistent, or disabling.
Practical Ways to Protect Both Major Sleep Stages
Huberman places unusual emphasis on consistency. In his account, keeping total sleep duration relatively stable may be as important as occasionally obtaining a longer night. A predictable schedule gives the brain a better chance to complete both early slow-wave-dominant cycles and later REM-dominant cycles.
Several practical considerations follow:
Avoid consuming so much fluid before bed that bladder pressure repeatedly interrupts sleep.
Treat alcohol and cannabis-induced sedation as different from normal sleep; both can disturb sleep depth and the orderly transition between stages.
Be cautious with tryptophan or 5-HTP. Although they may help some people, Huberman argues that altering serotonin can change the timing of slow-wave and REM sleep.
Consider resistance exercise as one way to support slow-wave sleep. Huberman notes that it need not occur immediately before bedtime to have an effect.
When possible, protect the final hours of sleep rather than assuming the first several hours provide every benefit.
The larger message is not to manipulate each stage obsessively. It is to create conditions in which the brain can move through its natural sequence with fewer interruptions.
Sleep as Nightly Emotional Maintenance
Huberman’s most memorable framing is that REM sleep can act as a form of overnight emotional therapy. The phrase should not imply that sleep replaces trauma treatment, medication, or professional care. It captures a narrower idea: each night, the brain may revisit experience in a physiological state that supports memory without recreating the full stress response.
Slow-wave sleep preserves skills and particulars. REM sleep helps evaluate emotional weight, connect related information, and loosen outdated reactions. Together, they allow people to remember what matters without remaining trapped in the original intensity of every experience.
The practical conclusion is modest but powerful. Consistent, sufficiently long sleep is not passive downtime. It is part of how the brain learns from the day, decides what to keep, and makes difficult memories easier to carry.
