While dreaming, the brain connects new information with already-stored memories

Researchers believe the brain consolidates memories, processes emotions, and plans for the future during dream states

The brain consolidates memories during sleep

During sleep, the brain appears to process memories from the day and encode them into long-term storage. At the same time, the brain prunes old memories out of the brain that are no longer useful. Understanding this process also sheds light a various neurodegenerative diseases.

How dreams affect your memory

In 1999, scientists conducted a study in which participants were asked to recall images flashed before them for milliseconds. They found that participants who slept before recalling the information performed better than those who had been asked to recall the same information that same day. This was some of the earliest convincing evidence of how crucial sleep is for learning and memory, findings that current research continues to strengthen.

Dreams largely occur during REM sleep (but not entirely)

Modern imaging tools have enabled scientists to carry out in-depth studies of brain activity during sleep. Researchers know dreams arise largely during REM, blending emotion-driven visual imagery, memory consolidation, and weak associations to help us make sense of experiences, regulate emotions, and prepare for future situations.

The dreaming brain, as understood by scientists

Technology has advanced to where the seemingly separate fields of psychology and neuroscience are asking the same questions about dreams, such as whether they're more closely related to perception or visualization. Some field-intersecting findings include research that shows people with impaired face perception don't dream of faces, those with brain legion-related cognition difficulties deal with similar issues in dreams, and children's dreams change in parallel to their cognitive development.

The hippocampus plays a central role in dreaming

It's theorized that the hippocampus—a brain structure involved with memory formation and the simulation of imagined and novel scenarios using those memories—plays a major role in dreaming. Studies of people with damaged hippocampi show that they still dream, but their dreams lack the richness of detail described by others.

Why don’t you remember all your dreams?

Despite being a near-nightly occurrence, we remember very few of our dreams. Researchers believe reduced activity in regions where memories are stored, a different neurochemical environment during sleep, and rapid transition during waking contribute to this phenomenon.

Sharp wave ripples in the brain tag experiences for long-term memory storage

These ripples were known to quickly replay neuronal sequences during sleep for consolidation. While awake, they help the brain prioritize memories to remember, and their disruption can impair memory formation.

Why do dreamers twitch?

This thought-provoking piece highlights newer research suggesting sleep twitches may not be random dream leftovers, but instead a crucial way our brains map and understand our bodies. From sleeping rat pups to dreaming octopi, this biological mapping system appears universal across animal species.

What is the brain up to when the mind wanders?

As you stare into the distance while washing your home's seemingly never-ending pile of dishes, the brain activates its default mode network. This collection of "task-negative" brain regions associated with memory, reward, action consideration, and prediction alight with activity when humans mentally turn inward, possibly giving rise to the brain's ability to wander and humans' ability to construct internal narratives about the world.

Memories are formed through attention, repetition, and emotional significance

Our brains create memories by taking in sensory input, filtering it through short-term memory, and storing it in long-term memory. Emotional events are more likely to become vivid, lasting memories because they activate stronger neural connections.

Lucid dreaming: the ability to control or influence your dream environment

Every night, most of us dream, but about 20% of people experience lucid dreaming at least once a month. In these rare moments, dreamers are aware they're dreaming, and can even control their actions. Though linked to increased frontal lobe activity, why this state occurs remains a mystery.

For most of recorded history dreams were considered divine in origin

The first venture into modern dream interpretation may have been when ancient Greek philosopher Heracleitus proposed dreams were created within the mind. In the late 1800s, the rise of psychoanalysis theorized that dreams content revealed truths about one's psyche, while the invention of the electroencephalogram linked dreams to brain functions.

The brain will attempt to rest itself in periods of chronic sleep deprivation

Skimping on sleep lengthens reaction times and blunts decision-making skills. At a certain point, the brain will try to sneak sleep where it can, shifting sections offline even as you remain awake. Going without sleep raises blood pressure, undermines the immune system, and increases one's risk of dementia.

Understanding the stages of sleep

Do you have trouble keeping the different stages of sleep straight and organized in your mind? Us too. Sometimes it helps to have a straightforward listing of what each stage is and why it’s important. Look no further than this resource from Lumen. It is a basic outline of the four stages of the sleep cycle, along with the brainwaves and attributes that characterize each. If you’re brave enough, test yourself on the built-in quiz!

Psychedelics set off a flurry of brain activity that may permanently alter it

The brain seems to experience a sharp increase in communication between areas that generally don't interact. New research suggests a thin, sheet-like gray matter structure tucked deep within the brain, between the insular cortex and striatum, may be the key to this change. The area is centrally located and home to many of the receptors that psychedelics target, potentially rewiring the brain and rewriting thought patterns.

Research suggests the brain maintains connections to lost limbs

Decades-old research suggested brain reorganization after amputations, but brain scans show unchanged limb representations. Phantom limb pain may result from such unchanged brain maps, which may enhance prosthetic limb control in brain-computer interface technology.

Déjà vu is a memory illusion involving brain regions correcting inaccurate memories

Neuroscientists suggest the phenomenon is your brain recognizing that this feeling of familiarity is incorrect, showing off the brain's internal fact-checking system. Younger people experience déjà vu more often because their brains have higher excitatory activity and stronger memory monitoring systems.

'Those who dream by day are cognizant of many things which escape those who dream only by night.'

- Edgar Allan Poe (1809-1849) in "Elenora"

Nightmares are unpredictable, but are linked to stress, anxiety, trauma, and more

Nightmare comes from the terms "night" and "mare," an Old English word for evil, suffocating spirits. Nightmares are parasomnias, meaning they are undesirable events experienced during sleep, and may stem from building tensions in one's unconscious.

How brain cells carry information

At any moment, there is an electrical storm coursing through your body. Discover how chemical reactions create an electric current that drives our responses to everything from hot pans to a mother’s caress.

Short-term memory is a temporary space for limited, newly learned information

Short-term memory stores info for 15 to 30 seconds and is managed by the prefrontal cortex. Though they're often confused, short-term memory stores information, while working memory actively uses it to help you reason, learn, and solve problems, such as a math equation.

Studies suggest when you sleep is as important as how much you get, and syncing with your circadian rhythms may lead to less fatigue and improved long-term health outcomes

How alcohol rewires your brain

Alcohol doesn't just make you tipsy—it rewires your brain chemistry in real time. It slows your brain with GABA, spikes dopamine to make you feel unstoppable, and blocks glutamate so you can't form memories. That mix explains everything from slurred speech to blackouts … and brutal hangovers.

What happens in a dying brain?

Near-death experiences usually happen during death or on the border of life and death when a person isn't understood to be conscious. This article details the science of what's going on with the brain during NDEs.

Sleep paralysis occurs when the body fails to 'unfreeze' in sync with waking

When the body falls into a deep enough phase of sleep, it paralyzes certain parts of itself so the brain can't force it to physically act out dreams. This well-known but little-understood phenomenon happens when the brain awakens early and typically results in haunting hallucinations and reports of supernatural terrors.

How the brain processes a calendar year

When most of us picture a calendar year, we have a foggy image in our minds of the months, in rough, calendar-like grids. But for some folks, that picture is a whole lot more clear. Around 1 percent of the population has a strange ability known as "calendar synaesthesia," which means they're able to visualize in crisp detail an elaborate calendar of the months of the year. Learn how it works here.

Recent research found that the brain doesn't seem to massively rewire following amputation—upending earlier beliefs about the cause of phantom limb pain.

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The Dracula character, now seen as the vampire archetype, was inspired by a seafood-induced nightmare its creator experienced.

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