“I have read many books but forgot most of them. What remains is a kind of mood, a vague memory of the feeling rather than the facts.” George Orwell #quote
Summary: While recent research has suggested potential neuroprotective benefits for older adults, a new study, the largest brain imaging study of its kind, highlights a significant downside for young adults. Examining over 1,000 participants aged 22 to 36, researchers found that heavy cannabis use (defined as 1,000+ lifetime uses) is linked to reduced brain activity in regions critical for decision-making and attention.
Specifically, 63% of heavy lifetime users and 68% of recent users showed diminished neural response during working memory tasks.These findings suggest that while cannabis effects may vary across a lifespan, frequent use during early adulthood can impair the “mental workspace” needed to retain and manipulate information for everyday problem-solving.
Key Facts
The Study Scope: This is the largest study to use functional MRI (fMRI) to examine how cannabis specifically impacts the neural networks involved in working memory.
Working Memory Deficit: Working memory—the ability to hold and use information (like following multi-step directions)—was the only cognitive domain out of seven tested to show a statistically significant decline.
Brain Activity Reduction: Heavy users showed lower activity in the dorsolateral prefrontal cortex and the anterior insula, hubs responsible for executive control and emotional processing.
The 1,000-Use Threshold: The most pronounced impairments were observed in “heavy users” who had consumed cannabis more than 1,000 times in their lifetime.
Reversibility Potential: Preliminary data suggest that abstaining from use before a cognitive task could help improve performance, offering hope for recovery through behavioral changes.
Source: University of Colorado
A new study published today in JAMA Network Open explores the effects of both recent and lifetime cannabis use on brain function during cognitive tasks.
The study, the largest of its kind ever to be completed, examined the effects of cannabis use on over 1,000 young adults aged 22 to 36 using brain imaging technology. The researchers found that 63% of heavy lifetime cannabis users exhibited reduced brain activity during a working memory task, while 68% of recent users also demonstrated a similar impact.
This decline in brain activity was associated with worse performance on working memory – the ability to retain and use information to perform tasks. For example, working memory allows a person to follow instructions they’ve just been given or to mentally visualize and manipulate information, like solving a math problem.
‘Make informed decisions’
“As cannabis use continues to grow globally, studying its effects on human health has become increasingly important. By doing so, we can provide a well-rounded understanding of both the benefits and risks of cannabis use, empowering people to make informed decisions and fully comprehend the potential consequences,” said the study’s first author Joshua Gowin, PhD, assistant professor of radiology at the University of Colorado School of Medicine on the University of Colorado Anschutz Medical Campus.
In the study, heavy users are considered young adults who’ve used cannabis more than 1000 times over their lifetime. Whereas, using 10 to 999 times was considered a moderate user and less than 10 times was considered a nonuser.
The researchers then studied the neural response of participants during a magnetic resonance imaging (MRI) session and gave them seven cognitive tasks to complete. The tasks tested working memory, reward, emotion, language, motor skills – such as tapping a finger to map brain control, relational assessment and theory of mind.
Statistically significant effect on brain function
The researchers found that cannabis had a statistically significant effect on brain function during working memory tasks, meaning the observed impact is very unlikely to be due to random chance. This effect was seen in both recent and lifetime cannabis users. The impact was less significant for the other tasks.
“We applied the highest standards to our research, setting rigorous thresholds for statistical significance across all seven cognitive function tests. To minimize the risk of false positives, we employed false discovery rate (FDR) correction. While some of the other tasks indicated potential cognitive impairment, only the working memory task showed a statistically significant impact,” adds Gowin.
During working memory tasks, the researchers found heavy cannabis use appeared to reduce brain activity in certain areas of the brain (dorsolateral prefrontal cortex, dorsomedial prefrontal cortex and anterior insula). These regions of the brain are involved in important cognitive functions such as decision-making, memory, attention and emotional processing.
However, Gowin mentions their research also suggests that abstaining from using cannabis before doing a cognitive task could help to improve performance. “People need to be aware of their relationship with cannabis since abstaining cold turkey could disrupt their cognition as well. For example, heavy users may need to be more cautious,” Gowin says.
He adds, “There are a lot of questions we still need answers to regarding how cannabis impacts the brain. Large, long-term studies are needed next to understand whether cannabis use directly changes brain function, how long these effects last and the impact on different age groups.”
Key Questions Answered:
Q: What exactly is “working memory”?
A: Think of it as your brain’s “sticky note.” It’s the ability to hold a thought while you’re doing something else—like remembering the first half of a sentence while you finish reading the second, or keeping a phone number in your head while you look for a pen.
Q: Why is this study different from the one about older adults?
A: Context is everything. This study focused on young adults (22–36). The brain is still highly plastic in this age range, and frequent use may “blunt” the activity of executive networks. In older adults, the same substance might interact differently with a brain that is already facing age-related decline.
Q: Is the damage permanent?
A: The study noted that abstaining before tasks might improve performance, which suggests the impact is functional (how the brain works) rather than purely structural (the brain’s physical shape). More long-term research is needed to see how long it takes for the brain to “re-calibrate” after quitting.
Editorial Notes:
This article was edited by a Neuroscience News editor.
Journal paper reviewed in full.
Additional context added by our staff.
About this memory and cannabis research news
Author: Julia Milzer Source: University of Colorado Contact: Julia Milzer – University of Colorado Image: The image is credited to Neuroscience News
Original Research: Open access. “Brain Function Outcomes of Recent and Lifetime Cannabis Use” by Joshua L. Gowin, Jarrod M. Ellingson, Hollis C. Karoly, Peter Manza, J. Megan Ross, Matthew E. Sloan, Jody L. Tanabe, and Nora D. Volkow. JAMA Network Open DOI:10.1001/jamanetworkopen.2024.57069
Abstract
Brain Function Outcomes of Recent and Lifetime Cannabis Use
Importance
Cannabis use has increased globally, but its effects on brain function are not fully known, highlighting the need to better determine recent and long-term brain activation outcomes of cannabis use.
Objective
To examine the association of lifetime history of heavy cannabis use and recent cannabis use with brain activation across a range of brain functions in a large sample of young adults in the US.
Design, Setting, and Participants
This cross-sectional study used data (2017 release) from the Human Connectome Project (collected between August 2012 and 2015). Young adults (aged 22-36 years) with magnetic resonance imaging (MRI), urine toxicology, and cannabis use data were included in the analysis. Data were analyzed from January 31 to July 30, 2024.
Exposures
History of heavy cannabis use was assessed using the Semi-Structured Assessment for the Genetics of Alcoholism, with variables for lifetime history and diagnosis of cannabis dependence. Individuals were grouped as heavy lifetime cannabis users if they had greater than 1000 uses, as moderate users if they had 10 to 999 uses, and as nonusers if they had fewer than 10 uses.
Participants provided urine samples on the day of scanning to assess recent use. Diagnosis of cannabis dependence (per Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria) was also included.
Main Outcomes and Measures
Brain activation was assessed during each of the 7 tasks administered during the functional MRI session (working memory, reward, emotion, language, motor, relational assessment, and theory of mind). Mean activation from regions associated with the primary contrast for each task was used.
The primary analysis was a linear mixed-effects regression model (one model per task) examining the association of lifetime cannabis and recent cannabis use on the mean brain activation value.
Results
The sample comprised 1003 adults (mean [SD] age, 28.7 [3.7] years; 470 men [46.9%] and 533 women [53.1%]). A total of 63 participants were Asian (6.3%), 137 were Black (13.7%), and 762 were White (76.0%). For lifetime history criteria, 88 participants (8.8%) were classified as heavy cannabis users, 179 (17.8%) as moderate users, and 736 (73.4%) as nonusers. Heavy lifetime use (Cohen d = −0.28 [95% CI, −0.50 to −0.06]; false discovery rate corrected P = .02) was associated with lower activation on the working memory task.
Regions associated with a history of heavy use included the anterior insula, medial prefrontal cortex, and dorsolateral prefrontal cortex. Recent cannabis use was associated with poorer performance and lower brain activation in the working memory and motor tasks, but the associations between recent use and brain activation did not survive false discovery rate correction. No other tasks were associated with lifetime history of heavy use, recent use, or dependence diagnosis.
Conclusions and Relevance
In this study of young adults, lifetime history of heavy cannabis use was associated with lower brain activation during a working memory task. These findings identify negative outcomes associated with heavy lifetime cannabis use and working memory in healthy young adults that may be long lasting.
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Starting in 2026, the European Union has significantly restricted Chinese entities from participating in Horizon Europe, the EU’s €93.5 billion research and innovation programme, citing security concerns and the protection of intellectual property.
Key details regarding the restriction:
Excluded Areas: Chinese organizations are barred from participation in Health (Cluster 1), Civil Security (Cluster 3), and Digitalization, Industry, and Space (Cluster 4).
Specific Exclusions:“Seven Sons of National Defence” universities are completely excluded from all Horizon Europe projects.
Strategic Shift: The move aims to prevent unwanted technology transfer and protect European strategic assets in AI, semiconductors, and quantum technologies.
Continued Collaboration: Cooperation remains in specific areas, including climate, energy, and mobility (Cluster 5), and some, but not all, collaborative research projects, according to sciencebusiness.net.
Scope: The restrictions apply to the second pillar of the program—“Global Challenges and European Industrial Competitiveness”.
These measures are part of a broader strategy to prioritize European technological sovereignty and follow the inability to reach an agreement with China on research and innovation, as noted by research-and-innovation.ec.europa.eu and reported by Table.Briefings.
Starmer’s Censorship Hits the Wall as US Tech Giants Intervene!
The emergency legal injunction from No. 10 didn’t just fail—it backfired on a global scale. As Keir Starmer’s team worked through the night to “scrub” the Katie Hopkins video from UK servers, a massive response came from across the ocean.
Late last night, a major US tech platform (X) officially declined to comply with the British “D-Notice,” citing First Amendment protections. Within hours, the banned footage was “pinned” to the top of every feed, rendering the UK censorship order completely useless.
Katie Hopkins appeared on a massive US news broadcast, laughing at the attempt to silence her: “Keir, you forgot one thing—the internet doesn’t have a border, and freedom of speech is a global currency.” While Starmer faces a diplomatic nightmare with Washington over “Digital Sovereignty,” Nigel Farage has landed in Parliament Square, welcoming the first wave of protesters.
The “Digital Iron Curtain” that Starmer tried to build has been torn down by a single click from Silicon Valley. The rally isn’t just about Katie anymore—it’s now a global movement for the right to speak. The “Unfiltered US Interview” and the list of Silicon Valley CEOs backing Katie.
You cannot remember being a toddler primarily due to childhood amnesia, a phenomenon driven by rapid brain development and neurogenesis, where the hippocampus is too immature to store long-term memories. Although infants can form short-term memories, the high rate of new neuron creation in the hippocampus disrupts memory stability, acting as a “soft reset” that clears early experiences, usually lasting until about age seven.
Key Reasons for Childhood Amnesia:
Rapid Brain Growth & Neurogenesis: In the first years, the brain creates neurons at a high rate. While this fuels learning, it disrupts existing circuits in the hippocampus (responsible for forming long-term memories), causing early, fragile memories to be lost.
Immature Hippocampus: The brain region necessary for storing episodic memory (specific events) is underdeveloped in infants.
Language Development: Early memories are often stored as feelings or sensations rather than language-based narratives. As language skills develop around age 2–4, the way the brain encodes memories changes, making early pre-verbal memories inaccessible.
Synaptic Pruning:Around age 7, the brain begins to prune and reorganize connections to become more efficient, which further clears away early, unencoded memories.
Surprising Truths About Early Memory:
Memories Aren’t Gone, Just Inaccessible: Research suggests these early memories might still exist in the brain but are inaccessible to conscious recall.
Emotional Memory Remains: While you cannot recall the facts of early life (where you were, what happened), early memories are often stored as emotional, implicit memories in the amygdala, shaping attachment styles and stress responses.
Purposeful Forgetting:This “forgetting” is not a flaw, but a necessary process that allows the brain to restructure and build a more stable sense of self.
Data: J.P. Morgan Asset Management. (Royal Dutch Shell and Shell Oil operated as two legal entities before they were integrated in 2005.) Table: Kavya Beheraj/Axios
Only four of the top 10 biggest companies in America by market cap last year were on the list a decade before: Apple, Microsoft, Berkshire Hathaway and JPMorgan Chase.
Why it matters: Big tech, particularly the Magnificent Seven, might seem like an enduring force, but life comes at you fast. The biggest companies change over time, Axios Markets author Emily Peck writes.
Stunning stat:The top 10’s total market cap in 2025 was an astonishing $19.4 trillion.
The Rev. Jesse Jackson speaks to the Democratic National Convention in L.A. in 2000. Photo: Paul J. Richards/AFP via Getty Images
The Rev. Jesse Jackson, a civil rights icon who spent his career fighting racial inequality and injustice, and who made two historic runs for the presidency, died today, his family said in a statement. He was 84. Jackson leaves behind an expansive legacy, starting with his time alongside Rev. Martin Luther King Jr. to founding Operation Rainbow PUSH on the South Side of Chicago,Axios’ Justin Kaufmann, Delano Massey and Russell Contreras write.
“Part of what makes America great is the right to fight for your rights,” Jackson told Axios’ Justin Kaufmann on WGN Radio in 2015. “You can change America. It’s like putty. You can reshape it.”Jesse Jackson (left) with the Rev. Dr. Martin Luther King Jr. in 1966. Photo: Universal History Archive/Universal Images Group via Getty Images
The civil rights pioneer grew up in Greenville, S.C., and after college joined King’s Southern Christian Leadership Conference.
Jackson ran for presidentin 1984 and 1988, becoming the first major Black candidate to mount a nationwide campaign, finishing second to Michael Dukakis in the 1988 Democratic primary.
Jackson also played a pivotal role in Barack Obama’s presidential campaign in 2008.
“The night when President Obama was declared the winner,” Jackson reflected in 2015, “I stood there and cried, in part because we’d won the big one, but also because it was the movement that made it possible.”Full obituary … Jackson’s life in photos.
President Trump had just won reelection and was basking in the parade of congratulatory pilgrimages to Mar-a-Lago. On this day in November 2024, an old friend and a first-time visitor were meeting privately with Trump. They wanted something, and they brought something.
Charlie Kirk — a beloved Trump confidant who had just led a smashingly successful turnout drive among young voters — was shepherding TikTok CEO Shou Zi Chew. A law banning the Chinese-owned TikTok in the U.S. was scheduled to kick in the same week Trump was inaugurated. They wanted him to stall the ban and eventually kill it.
Knowing Trumpresponds best to visual stimuli, Kirk had coached the company to spin up four pages of infographics, “Trump on TikTok,” showing his campaign’s tens of billions of views on the now-threatened app.
A chart (shown above) on the first page jumped out at Trump, who had backed a TikTok ban in his first term. “I’m more popular than Taylor Swift,” he crowed. Many in Trumpworld heard he quickly called Barron, his youngest son, to savor the stat.On Day 1 of his second term, Trump signed an executive order to punt the TikTok ban.
Why it matters: The Mar-a-Lago meeting was a pivotal victory in a campaign by several Trump insiders to overcome furious opposition to TikTok from China hawks on the Hill and in his political orbit who had national-security concerns.
These insiders helped convince Trump’s campaign to launch a TikTok account in June 2024, when he was looking for ways around traditional media.
Then the insiders patiently engineered a complex deal, which closed last month, to sell TikTok’s U.S. operations to a joint venture controlled by American investors — the death of the ban.
How it happened: The campaign was born in early 2024, according to sources familiar with the internal deliberations. Tony Sayegh, a Treasury and White House official in Trump’s first term, became a key man in the TikTok triumph. Sayegh was on a ski vacation when he saw President Biden declare in March 2024 that he’d sign a TikTok ban if Congress passed one.
Sayegh — dubbed “TikTok’s Trump Whisperer” by a Wall Street Journal article shortly after Trump’s election — phoned a TikTok executive and suggested the very solution that eventually came to pass: If Trump won, he could sign an executive order thwarting the ban.
“Impossible,” the TikTok official said. “Can’t happen.”
But it did, thanks to an aggressive political and legal strategy, paired with some lucky breaks. Some TikTok executives were skittish about going all-in with Trump, but Sayegh often told the company’s D.C. team that Trump was the only person who could save TikTok in America. Chew warmed to the strategy.
Jason Miller— a senior adviser to Trump during the campaign, who remains in close touch with him — told me that Trump “always recognized the power of TikTok, because he saw the impact it had with younger voters.”
“He’d say all the time: ‘You guys are missing it! These young people, they love TikTok. They’re on it all day long.’ And he’d recount stories of Barron talking about it, and also younger people who work with him and for him.”
Behind the scenes: To counter fears among some top Republicans about China’s control of TikTok, Sayegh, Miller and others amped up outside allies — including Kirk, Tucker Carlson and Kellyanne Conway — to give Trump cover to take the plunge.
'They keep saying we sent an aircraft carrier towards Iran. Well, an aircraft carrier is certainly a dangerous tool, but more dangerous than the aircraft carrier is the weapon that can send this warship to the bottom of the sea' pic.twitter.com/5p91KM1TfT
Data: J.P. Morgan Asset Management. (Royal Dutch Shell and Shell Oil operated as two legal entities before they were integrated in 2005.) Table: Kavya Beheraj/Axios
The Rev. Jesse Jackson speaks to the Democratic National Convention in L.A. in 2000. Photo: Paul J. Richards/AFP via Getty Images
Jesse Jackson (left) with the Rev. Dr. Martin Luther King Jr. in 1966. Photo: Universal History Archive/Universal Images Group via Getty Images
Obtained by Axios
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