Cognition

A single 14-gram dose of creatine helped preserve cognitive performance after a sleepless night. doi.org

Cognition Creatine Sleep

High doses of creatine have recently been shown to help preserve cognitive performance during acute sleep deprivation, but it is less clear whether a lower dose can provide similar benefits.

A new study included 29 healthy adults aged 20 to 40 in a crossover trial. Each participant completed two separate sleepless nights in random order, receiving a single dose of 0.2 grams of creatine monohydrate per kilogram of body weight (0.2 g/kg; about 14 grams on average) on one night and a placebo on the other. Participants stayed awake from about 7 a.m. until around 4:30 a.m. the next morning. Cognitive testing was performed several times throughout the sleep-deprivation period, with creatine or placebo given after about 14 hours of wakefulness.

The clearest benefit was on reasoning questions. Across the three overnight tests, participants scored 6.1% higher with creatine than with placebo after accounting for their starting scores. On the placebo night, reasoning performance fell by 6.8%.
A few other measures also leaned in favor of creatine compared with placebo, but the evidence was statistically less robust. Participants scored 6.2% higher on numerical reasoning questions, answered verbal questions 12.3% faster, and had 9.2% less variation in their reaction times, while average reaction speed changed little.
Creatine did not clearly reduce sleepiness or fatigue compared with placebo. By 4 a.m., sleepiness had risen 155% from the 6 p.m. baseline measure with creatine and 173% with placebo. Fatigue also rose in both conditions, by 148% with creatine and 115% with placebo.
Not every measure improved with creatine: word memory, memory for number sequences, the ability to briefly hold visual information in mind, and language accuracy were not clearly better than with placebo.

Creatine supports cellular energy through the creatine kinase and phosphocreatine system, which helps regenerate ATP, the main energy molecule used by cells. Sleep deprivation is a stress condition that may strain energy reserves and make creatine uptake more relevant than it would be after a restful night, especially during demanding cognitive tasks. This could explain why creatine modestly helped preserve performance during the sleepless night, even though participants still felt increasingly sleepy and fatigued.

This was a small, one-night study in healthy young adults, so it is unclear how well the findings would apply outside this controlled setting. Still, the results suggest that creatine may help preserve some aspects of cognition during sleep loss even at 0.2 g/kg, although the effects appeared less pronounced than in earlier work from the same group using 0.35 g/kg. In this clip, I explain why I increased my creatine intake and how creatine may support brain energy during sleep loss and mid-afternoon dips.

Vitamin D supplementation during pregnancy may be linked to better verbal and visual memory in children. doi.org

Cognition Pregnancy Vitamin D

Vitamin D plays a role in fetal brain development, but it remains unclear whether higher intake during pregnancy leads to measurable cognitive differences years later. A new study examined whether children's cognitive performance differed depending on their mothers' vitamin D dose during late pregnancy.

The analysis used data from a Danish randomized trial in which 623 pregnant women had been assigned to different vitamin D doses. The researchers focused on 498 children whose mothers had received either the routine pregnancy dose recommended in Denmark of 400 IU of vitamin D3 per day or a higher dose of 2,800 IU of vitamin D3 per day, from pregnancy week 24 until one week after birth. At about age 10, the children took a series of cognitive tests that included measures of memory, attention, processing speed (how quickly they handled simple mental tasks), working memory (holding and using information briefly), executive function (skills such as planning and switching between tasks), and estimated intelligence. In their comparisons between the two groups, the researchers also accounted for the mothers' blood vitamin D levels before supplementation.

Before supplementation, the typical blood 25-hydroxyvitamin D (25(OH)D) level was 30.3 ng/mL, and 15% of mothers had levels below 20 ng/mL. One week after birth, mothers had a typical 25(OH)D level of 27.5 ng/mL in the routine-dose group compared with 41.9 ng/mL in the higher-dose group.
Children in the higher-dose group had modestly higher verbal and visual memory function scores than those in the routine-dose group.
One executive function test initially looked better in the higher-dose group, but the difference was less convincing after more rigorous statistical testing.
The findings did not suggest a broad cognitive advantage. Eight of the 11 cognitive functions tested were not clearly different between the two groups.
Estimated intelligence was nearly identical: 107.6 in the higher-dose group versus 107.8 in the routine-dose group.

Vitamin D may influence how the developing brain builds and maintains neural circuits. It is thought to support the growth and maturation of nerve cells, chemical signaling between them, immune regulation, and protection from oxidative stress. Because different brain systems mature on different timelines, vitamin D exposure in late pregnancy may be more relevant to memory-related abilities than to broader cognitive functions. That could help explain why the clearest pattern appeared in memory rather than in estimated intelligence, attention, or processing speed.

A key limitation is that this was a later analysis of a trial originally designed for asthma, not cognition, so the memory findings should be treated as suggestive. Still, the results raise the possibility that prenatal vitamin D could influence specific aspects of later cognitive performance. In Aliquot #100, I discuss factors that influence child development before conception, during pregnancy and infancy, and into the toddler and early childhood years.

Better cardiorespiratory fitness may help the brain work more efficiently after intense exercise. doi.org

BDNF Cognition Exercise

Exercise is known to support brain health, but the biological link between fitness and brain function is still being clarified. A new study tested whether improving cardiorespiratory fitness changes the brain-derived neurotrophic factor (BDNF, a protein involved in brain signaling) response to hard exercise and alters brain activity during cognitive tasks.

In this randomized study, 49 sedentary adults aged 18 to 55 were enrolled, but the final analyses included only 20 to 23 participants due to dropouts and missing data. They were assigned to either a 12-week cycling program or to a control group that kept their usual activity habits. The cycling group trained four times per week, with the program becoming more intense over time. Both groups visited the lab at the start of the study, week 6, and week 12 to complete a VO₂max test (a hard cycling test used to measure cardiorespiratory fitness) and cognitive tasks. Before and about 30 minutes after each test, blood samples were taken. At weeks 6 and 12, the researchers also estimated prefrontal brain activity (activity in the front part of the brain involved in attention, self-control, and other executive thinking skills) during the cognitive tasks using fNIRS, a wearable imaging method that tracks blood-oxygen changes near the surface of the brain.

Fitness improved in the cycling group, but not the control group: VO₂max increased from 28.8 to 32.2 ml/kg/min after 12 weeks of cycling, while it changed from 29.8 to 27.7 ml/kg/min in the control group.
Resting BDNF levels did not clearly rise in either group.
After 12 weeks, only the cycling group showed clearly higher serum BDNF levels 30 minutes after the VO₂max test. In the control group, serum BDNF levels changed little.
Participants in the cycling group who improved their VO₂max more tended to show a larger serum BDNF increase after the VO₂max test at week 12.
Participants were faster on some thinking tasks after the VO₂max test, but BDNF changes were not clearly linked to better cognitive performance, and the cycling program did not clearly improve cognitive performance overall.
BDNF was linked to an estimated brain-activity pattern that may reflect greater efficiency: In the cycling group, people with higher BDNF measures showed a larger drop in estimated prefrontal brain activity after the VO₂max test than before it during attention and self-control tasks, without a clear link to worse performance. The same overall pattern was not seen in the control group.

The study results suggest that becoming fitter may change how the brain responds to a demanding workout. Higher cardiorespiratory fitness may make the body more capable of initiating a BDNF response when exercise creates a strong physiological challenge. This matters because BDNF is involved in several processes relevant to brain health, including brain-cell signaling, blood-vessel function, metabolism, and the ability of connections between brain cells to adapt. Supporting these processes may help the brain maintain efficient function during cognitive tasks.

The study was small, and the brain-imaging correlations were exploratory, so the findings need replication in larger groups. The blood sample was collected about 30 minutes after exercise, which may have missed each participant's peak BDNF response. Even so, the study suggests that cardiorespiratory fitness may shape the BDNF response to intense exercise and how it relates to short-term brain function. My BDNF protocol includes additional lifestyle strategies that may improve cognitive performance and support brain health with aging.

A movement program that also challenges thinking skills improved self-control and memory in children with ADHD. doi.org

ADHD Cognition Exercise

Children with attention-deficit/hyperactivity disorder (ADHD) often struggle not only with attention and impulsive behavior, but also with the mental skills that help them stay focused and regulate their actions. In a randomized clinical trial, researchers tested whether exercise combined with cognitive tasks could support these skills better than aerobic exercise alone.

The study included 107 children aged 6 to 10 with ADHD. For 12 weeks, the children were assigned to one of three groups: an integrated cognitive-motor exercise program, a moderate-intensity aerobic exercise program, or a control group that received a short session on the benefits of physical activity, but no structured training. Both exercise groups trained three times a week for 45 minutes. The integrated program combined movement drills, ball skills, balance tasks, and hand-skill activities with built-in thinking challenges such as following signals, stopping or starting on cue, doing the opposite of an instruction, remembering a series of movements, and switching between rules.

Both exercise programs reduced parent-rated core symptoms of ADHD compared with the control group, including inattention and hyperactivity-impulsivity, with similar improvements in both exercise groups.
The integrated program produced a stronger improvement in a test of inhibitory control, which is the ability to hold back an automatic response (e.g., naming the color of a word instead of reading the word itself).
Children in the integrated program showed the greatest improvement in remembering visual information right after viewing it (e.g., looking at a complex picture and then drawing it from memory), suggesting a stronger effect on working memory.
Memory after a delay improved in both exercise groups, suggesting that physical activity itself may support some forms of memory in ADHD even without added mental challenges.
Both exercise programs improved cognitive flexibility, the ability to shift between rules or tasks, compared with the control group.
Parents also reported greater satisfaction with the integrated program than with aerobic exercise alone, and no exercise-related adverse events were reported.

If future, longer-term studies show that these benefits last and can be reproduced in other settings, structured exercise that combines movement with cognitive tasks could become a practical non-drug option for children with ADHD in schools, clinics, and community programs. In this clip, Dr. Andrew Huberman discusses whether behavioral modifications can replace the need for ADHD medications.

A short afternoon nap may help restore the brain's flexibility to take in and respond to new information after hours of wakefulness. doi.org

Cognition Memory Sleep

As we learn, the connections between brain cells that are being used become stronger. But after many hours without rest, this overall buildup can leave the brain with less room to make new, specific changes. Scientists have long suggested that sleep helps the brain stay flexible by easing back this buildup, but it has not been clear whether a short daytime nap is enough to do the same.

Researchers brought 20 healthy young adults into a sleep lab for two experimental sessions. In one session, they were given a one-hour afternoon sleep opportunity. In the other, they stayed awake for the same amount of time. After each session, scientists used transcranial magnetic stimulation, which sends brief magnetic pulses through the scalp, to see how strongly the motor cortex (movement area of the brain) could trigger a small electrical response in a hand muscle. They also recorded brain activity with electroencephalography (EEG), focusing on theta waves, a signal that rises the longer we stay awake and is used as an indirect sign that overall communication between brain cells has become stronger. Finally, they delivered a mild electrical pulse to a nerve at the wrist while also stimulating the motor cortex. When carefully timed together, this pairing can temporarily make communication between brain cells stronger. The change in response after stimulation serves as a lab measure of how easily that brain area can strengthen its connections.

Participants slept about 43 minutes on average during the nap, almost all of it in non-rapid eye movement (non-REM) sleep and mainly in the deeper N2 and N3 stages.
Before any training-like stimulation, the brain needed a slightly stronger magnetic pulse to activate the hand muscle after the nap. This suggests that the overall strength of communication between brain cells was lower after the nap than after staying awake.
Theta brain waves increased after staying awake but not after the nap, suggesting that time awake builds up overall communication between brain cells, while a nap is associated with lower levels of that buildup.
Researchers then tried to strengthen specific connections using the paired stimulation. After this training-like procedure, the muscle response increased after the nap but not after staying awake, suggesting that the tested brain area was better able to strengthen its connections after the nap.
Seventy-five minutes later, 80% of those who napped showed a strengthening response, compared with 55% of those who stayed awake.

Together, the findings suggest that napping helps prevent the brain's connections from becoming so built up during the day that they lose flexibility. As we stay awake, connections between nerve cells gradually grow stronger, and if that buildup continues, the brain may become less able to make further changes. A nap appears to ease this buildup, restoring the brain's readiness to respond to new stimulation.

The study included a small group of participants and did not use a placebo-style stimulation condition, making it harder to tell whether the differences were truly caused by the nap or by natural differences in how individuals respond to this type of stimulation. Still, the results suggest that a short daytime nap can recalibrate measures of plasticity in the brain. In this clip, Dr. Matthew Walker describes how napping facilitates and reinforces learning in infants.

Meta-analysis finds no reliable cognitive benefit from conventional lithium salts in mild cognitive impairment or Alzheimer's disease. doi.org

Cognition Dementia Lithium

Laboratory and animal studies suggest lithium could protect the brain from cognitive decline and Alzheimer's disease, but results from human trials have been mixed. To clarify the picture, researchers combined data from multiple clinical trials to test whether pharmaceutical lithium salts have meaningful benefits for brain health.

The authors systematically reviewed and meta-analyzed six randomized, placebo-controlled trials (435 participants) that compared lithium supplementation with placebo in studies lasting roughly 10 weeks to 24 months. All participants had either mild cognitive impairment, a stage of measurable decline that can precede dementia, or Alzheimer's disease. The main outcome was change in cognition, and the tested lithium salts were: lithium carbonate, lithium sulfate, and lithium gluconate.

When results from all six trials were combined, lithium was similar to placebo for cognitive outcomes.
In the primary analysis, which prioritized the Alzheimer's Disease Assessment Scale–Cognitive Subscale (ADAS-Cog), the average difference between lithium and placebo was small and could not be confidently attributed to the treatment rather than chance.
Follow-up analyses that relied on different cognitive measures or prioritized different tests reached the same conclusion and showed no consistent cognitive benefit from lithium.
Measures of behavioral and psychological symptoms of dementia, such as agitation and related behavioral problems, were similar between lithium and placebo groups.
Subgroup analyses found no differences based on diagnosis (mild cognitive impairment vs. Alzheimer's disease), study duration, lithium dose, or lithium salt type.
One study suggested a stronger effect from lithium, but it was judged to be at high risk of bias, making its result unreliable.

Lithium's biological effects may depend strongly on its chemical form and how it behaves in the brain. Studies in animals show that lithium can stick to amyloid-β, the protein that forms plaques in Alzheimer's disease. When this happens, lithium becomes trapped inside plaques instead of remaining available to brain cells, where it could help regulate inflammation, communication between neurons, and limit harmful changes to tau, a structural protein that helps stabilize neurons. Commonly tested lithium forms, especially lithium carbonate, appear more likely to bind to amyloid plaques in this way. By contrast, laboratory and animal studies suggest that lithium orotate, a different chemical form, may enter brain cells more easily and avoid plaque binding.

Importantly, the clinical trials analyzed here did not test lithium orotate, only carbonate, sulfate, and gluconate. As a result, the study supports the conclusion that standard lithium supplements do not slow cognitive decline in people with mild cognitive impairment or Alzheimer's disease, while leaving open the possibility that other lithium formulations could be more effective. In Q&A #69, I discuss the benefits and risks of low-dose lithium supplementation.

Early screen exposure in infancy may steer brain development in ways linked to higher anxiety later in life. doi.org

Anxiety Cognition Development Mental Health

Screen use has become common, even in infancy, yet little is known about how it might influence brain development years later. To address this gap, researchers conducted a longitudinal study to explore how early screen exposure shapes later aspects of mental health.

The study followed 168 children in Singapore from infancy into their teenage years. Parents reported how much time their children typically spent using screens at ages 1 and 2. As the children grew, researchers tracked their brain development using diffusion MRI, a type of brain scan that estimates structural connections between brain regions, at ages 4.5, 6.0, and 7.5. At age 8.5, the children completed a computer-based task that measures several aspects of decision-making, including how people respond to risk and how long they take before making a choice.

More screen time in infancy aligned with a specific pattern of brain development that was linked to slower decision timing, which in turn was associated with higher anxiety symptoms in adolescence.
Although the researchers examined multiple brain networks, the association with infant screen time emerged only for the connection between the visual network (involved in processing visual information) and the cognitive control network (involved in things like planning, attention, and self-control).
Higher infant screen time was associated with a faster drop in "integration" between these two networks from ages 4.5 to 7.5. Higher integration means that these two brain systems tend to work more closely together, while a drop in integration reflects the brain gradually separating their roles as it matures.
This faster decline in integration appeared to bridge the link between early screen exposure and longer decision times, helping explain why some children took longer before making a choice. Other aspects of their decision-making, such as how accurate or risk-taking they were, did not show the same relationship.

In early childhood, brain networks are still maturing and becoming more specialized in how they interact with one another. Heavy screen exposure early in life may overwhelm developing sensory systems, potentially influencing how visual information is processed as the brain matures. Altered sensory processing may be one pathway linking these brain changes to slower decision-making and higher anxiety later on. Some effects of screen exposure may also operate indirectly, for example by reducing opportunities for parent–child interaction during early development.

The observational design limits causal conclusions. Screen use was parent-reported without detail on content or context, and factors such as sleep, family history, and parent–child interaction were not fully captured. While not definitive, the results underscore early childhood as a sensitive window during which everyday experiences, including screen use, can have lasting developmental effects. In Aliquot #125, Dr. Andrew Huberman and I examine digital engagement, share strategies for managing technology use, and highlight the importance of boundaries for mental health and personal growth.

The breathing cycle coordinates neural processes in the brain underlying memory retrieval. doi.org

Breathing Technique Cognition Memory

Memory retrieval often begins with a brief cue—a single word, a smell, or a sound—but receptivity to such cues may fluctuate from moment to moment due to natural rhythms in the body. To explore this, a research team reexamined previously collected data to see whether the natural breathing rhythm is a factor that shapes how cues lead to successful recall.

The study involved 18 healthy young adults who learned verb–image pairs (verbs linked to either objects or scenes) across two sessions. During later memory tests, participants first judged whether a verb was old or new, then, for recognized verbs, tried to recall the associated image. The team recorded electroencephalography (EEG, a method for measuring brain electrical activity) and airflow-based respiration, then examined how recall outcomes related to specific points in the breathing cycle.

Associative recall was more likely when the cue verb appeared near the inhalation peak, and accuracy rose again later around the exhalation trough.
When people successfully recalled the image, brain activity reflected whether the image was an object or a scene, and this distinction was clearest just before the end of an exhale.
Recall was better when the breathing sequence followed an inhale-then-exhale pattern during retrieval, compared with the reverse order (about 70% vs. 65% recall out of recognized items).
When recall was successful, alpha and beta brain waves dropped shortly after the cue, a pattern often interpreted as reflecting information processing. These brain waves were also rhythmically modulated by breathing, with additional drops occurring at specific phases of the breathing cycle.
Simple recognition (old versus new decisions) did not show the same respiratory-phase dependence, suggesting the effect is stronger when retrieval requires reconstructing a specific association.

Breathing in (inhalation) may support the early stage, when the brain takes in and interprets a cue, while breathing out (exhalation) may offer a favorable window for rebuilding the stored memory itself. Together, this indicates that remembering is partly shaped by natural body rhythms and adds to growing evidence that cognitive processes are influenced not only by our senses and activity inside the brain, but also by signals from the rest of the body.

The study was small, correlational, and did not manipulate breathing, so it cannot establish causality. Future work that aligns recall attempts with specific moments in the breathing cycle could test whether breathing directly supports memory retrieval or merely tracks internal state changes. In this clip, Dr. Matthew Walker describes how sound and smell cues played during learning and subsequent sleep can enhance memory formation and retrieval.

Volunteering and everyday helping are linked to better cognitive health in older adults. doi.org

Brain Cognition Dementia

Cognitive abilities such as memory and attention often decline with age, and finding practical ways to slow this process remains a major public health challenge. Many strategies focus on medical risk factors, but less is known about whether social activities can make a difference.

Researchers analyzed more than 20 years of data from the U.S. Health and Retirement Study, which follows a nationally representative group of adults aged 51 and older. Participants repeatedly completed cognitive tests and reported their helping activities. The study focused on two common forms of helping: formal volunteering (unpaid work through organizations) and informal helping (unpaid help given directly to friends, neighbors, or relatives who do not live with the participant).

Moderate formal volunteering (about 2–4 hours/week) showed the largest short-term improvement. Higher levels also supported cognition, with benefits that appeared to build particularly when volunteering was sustained. The biggest drops occurred when high time commitments to volunteering stopped.
Informal helping showed a similar overall pattern. Low to moderate time commitments were linked to a slower rate of cognitive decline, and moving to high levels did not add clear long-term benefit beyond moderate involvement, while stopping informal helping was linked to worse cognitive outcomes and faster decline.

These patterns fit with the concept of cognitive reserve, the idea that repeated mental and social demands can help the brain keep functioning as it ages, even as underlying changes occur. Helping others may contribute by regularly engaging attention, decision-making, and social interaction. Helping behavior has also been linked to changes in stress regulation systems and immune functioning.

Although the study cannot prove cause and effect, its focus on within-person changes, timing, and dose strengthens the case that helping itself could contribute to better cognitive aging. In this clip from my appearance on the Modern Wisdom podcast, I detail seven science-based methods for improving cognition.

Heavy short-form video use is linked to weaker attention and poorer mental health. doi.org

Mental Health Cognition Social Media

Arguments about "brain rot" from TikTok and similar apps often involve anecdotes rather than data. To address this, a new meta-analysis examined whether short-form video use is linked with changes in cognition and mental health.

The researchers combined 71 studies with 98,299 adolescents and adults whose engagement with TikTok or general short-form video use was assessed. The studies assessed how much people engaged with short-form videos and examined how this related to measures of cognition and mental health.

Here are the key results:

Across all studies, heavier use was moderately associated with poorer cognition overall, with the clearest links for attention and for inhibitory control, the mental ability to suppress impulses and stay on tasks, and weaker links for memory, language, and working memory, while reasoning showed no reliable association.
On mental health scales, heavier use tracked with small but consistent signs of worse well-being (especially more anxiety and stress), and with weaker links to depression, loneliness, negative mood, and poorer sleep, while self-esteem and body image scores showed no clear pattern.
Measures that framed use as a behavioral addiction showed stronger associations with both cognitive and mental health problems than metrics that only counted minutes or distinguished users from non-users.
Correlations were similar in youth and adult samples, and results changed little when studies adjusted for background factors such as age, gender, or other social media use.

Fast, highly stimulating clips may teach the brain to expect constant novelty, which can make slower, effortful tasks and ordinary rewards feel flat. Altered reward circuits, repeated exposure to mental health-themed content, and late-night viewing that disrupts sleep are plausible pathways linking heavier use with difficulties in attention and mood, while the overwhelmingly cross-sectional evidence cannot establish cause and effect.

Taken together, the review suggests that short-form videos appear most concerning when use reflects addictive patterns that interfere with sleep, offline relationships, or tasks requiring sustained attention. Studies that follow users over time and that distinguish types of content and user motivations are needed, so that public debates about "brain rot" can shift from slogans to concrete guidance. In this clip, I discuss concerns about early smartphone and tablet access among kids and its effects on mental health later in life.

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