CLOSE
iStock
iStock

Does LSD Induce Synesthesia?

iStock
iStock

Since Albert Hoffman discovered LSD (lysergic acid diethylamide) in 1938 and hippie culture made it a popular social drug in the 1960s, its psychedelic effects on the brain have been a source of scientific investigation. Anecdotally it’s known to cause visual and auditory hallucinations as well as reports of an individual’s sense of self dissolving and merging with a larger consciousness.

Recent research done at Imperial College London discovered through brain imaging that there is indeed a great deal of activity in the visual cortex of the brain when on LSD, and that it seems to interrupt connections between other brain networks, leading to that ephemeral state of oneness reported by users.

Yet these overlapping sensory experiences also share a lot in common with the brain condition synesthesia, in which an individual’s senses overlap or trigger each other in a way that is atypical. The disorder is rare. Estimates range, but most agree on approximately 1 percent of the population.

A group of researchers at the University of London (UoL) recently set out to study whether the effects of LSD qualified as true synesthesia. Their results, published in Neuropsychologia, suggest that what LSD-users are experiencing is not genuine synesthesia. The researchers say their findings open the door to a better understanding of how we process sensory perceptions.

“Synesthesia is basically understood as … a kind of condition in which a stimulant, known as an inducer, will consistently elicit a secondary experience that is atypical—not something generally experienced in the general population,” Devin Terhune, cognitive neuroscientist at UoL, tells mental_floss.

While every synesthete’s experience is unique, Terhune says there are some commonalities. For instance, many report seeing the letter B as blue, zero as white, and one as black. The most common instances of synesthesia are sound/color pairings (where the sound of a doorbell may evoke a green aura, for example) and color/grapheme pairings (where a particular letter or part of a word may appear in a specific color and even shape, like a blob or spiny edges).

To be considered congenital synesthesia, however, the response must be confirmed by consistency and specificity—that is, the same inducer must produce the same reaction every time.

For the placebo-controlled study, 10 physically and psychologically healthy participants were injected with saline solution for their first session, then they completed psychological tests to measure synesthesia-like experiences: a grapheme-color association test and a sound-color association test. After five to seven days, they were injected with 40-80 micrograms of LSD, and the tests were repeated.

While the participants said they had spontaneous synesthesia-like experiences while on LSD, they didn't report specific color experiences with graphemes and sounds, and sounds and colors were no more consistent on LSD than with the placebos. These results suggest that whatever is happening while under the influence of LSD, it isn't “true” synesthesia.

Given such anecdotal associations of color hallucinations in the existing literature about LSD, Terhune says he was surprised to find that “the color experiences effect was not even statistically significant.”

Terhune says the small sample size of 10 participants may have something to do with the weakness of the results. Another factor may have been the laboratory setting itself. Most people who take LSD aren't experiencing the drug's effects in a lab environment. “Factors like novelty and exposure to stimuli may be more critical,” he says. “Congenital synesthesia is really known as a stimulant-specific phenomenon—that something in your environment triggers your experience, reliably and automatically.”

He suggests future studies could be designed that would follow people taking LSD “out in the field” and ask them at various times, using an app, to report what they’ve been experiencing. This could yield a wider range of data.

Another question for future researchers is whether there is a “fundamental distinction between spontaneous forms of synesthesia and the inducer-specific experiences that congenital synesthetes’ experience,” Terhune says.

There may be genetic underpinnings to the disorder, which seems to be inherited in families. There are several working theories on its origins. One is the immune hypothesis, which considers that the genes responsible for normal cortical development are also involved in the development of synesthesia. The hyperconnectivity theory suggests that synesthetes, whose brains have been shown to have extra-developed myelin along sensory pathways, may experience a collaboration of senses resulting in synesthesia. Other theories consider the influence of the childhood environment or potentially higher levels of serotonin in the brains of synesthetes.

While the results of this study may not appear to have immediate implications—and no researcher is out to “cure” synesthesia—Terhune says that one motivation for his work is to understand the neurochemicals involved in the phenomenon. Plus, there is research to suggest that synesthetes with grapheme-color synesthesia have enhanced recognition memory compared to the average person, which could be of benefit to cognitive research.

“I don’t think synesthesia is going to reveal the really deep insights into different psychological phenomena,” Terhune concludes, “but it can provide us with some useful insights and potentially interesting models for things such as memory, imagery, and other cognitive functions.”

nextArticle.image_alt|e
iStock
arrow
science
New Patient Test Could Suggest Whether Therapy or Meds Will Work Better for Anxiety
iStock
iStock

Like many psychological disorders, there's no one-size-fits-all treatment for patients with anxiety. Some might benefit from taking antidepressants, which boost mood-affecting brain chemicals called neurotransmitters. Others might respond better to therapy, and particularly a form called cognitive behavioral therapy, or CBT.

Figuring out which form of treatment works best often requires months of trial and error. But experts may have developed a quick clinical test to expedite this process, suggests a new study published in the journal Neuropsychopharmacology.

Researchers at the University of Illinois at Chicago have noted that patients with higher levels of anxiety exhibit more electrical activity in their brains when they make a mistake. They call this phenomenon error-related negativity, or ERN, and measure it using electroencephalography (EEG), a test that records the brain's electric signals.

“People with anxiety disorders tend to show an exaggerated neural response to their own mistakes,” the paper’s lead author, UIC psychiatrist Stephanie Gorka, said in a news release. “This is a biological internal alarm that tells you that you've made a mistake and that you should modify your behavior to prevent making the same mistake again. It is useful in helping people adapt, but for those with anxiety, this alarm is much, much louder.”

Gorka and her colleagues wanted to know whether individual differences in ERN could predict treatment outcomes, so they recruited 60 adult volunteers with various types of anxiety disorders. Also involved was a control group of 26 participants with no history of psychological disorders.

Psychiatrists gauged subjects’ baseline ERN levels by having them wear an EEG cap while performing tricky computer tasks. Ultimately, they all made mistakes thanks to the game's challenging nature. Then, randomized subjects with anxiety disorders were instructed to take an SSRI antidepressant every day for three months, or receive weekly cognitive behavioral therapy for the same duration. (Cognitive behavioral therapy is a type of evidence-based talk therapy that forces patients to challenge maladaptive thoughts and develop coping mechanisms to modify their emotions and behavior.)

After three months, the study's patients took the same computer test while wearing EEG caps. Researchers found that those who'd exhibited higher ERN levels at the study's beginning had reduced anxiety levels if they'd been treated with CBT compared to those treated with medication. This might be because the structured form of therapy is all about changing behavior: Those with enhanced ERN might be more receptive to CBT than other patients, as they're already preoccupied with the way they act.

EEG equipment sounds high-tech, but it's relatively cheap and easy to access. Thanks to its availability, UIC psychiatrists think their anxiety test could easily be used in doctors’ offices to measure ERN before determining a course of treatment.

nextArticle.image_alt|e
Hulton Archive//Getty Images
arrow
science
Newly Discovered 350-Year-Old Graffiti Shows Sir Isaac Newton's Obsession With Motion Started Early
Hulton Archive//Getty Images
Hulton Archive//Getty Images

Long before he gained fame as a mathematician and scientist, Sir Isaac Newton was a young artist who lacked a proper canvas. Now, a 350-year-old sketch on a wall, discovered at Newton’s childhood home in England, is shedding new light on the budding genius and his early fascination with motion, according to Live Science.

While surveying Woolsthorpe Manor, the Lincolnshire home where Newton was born and conducted many of his most famous experiments, conservators discovered a tiny etching of a windmill next to a fireplace in the downstairs hall. It’s believed that Newton made the drawing as a boy, and may have been inspired by the building of a nearby mill.

A windmill sketch, believed to have been made by a young Sir Isaac Newton at his childhood home in Lincolnshire, England.
A windmill sketch, believed to have been made by a young Sir Isaac Newton at his childhood home in Lincolnshire, England.
National Trust

Newton was born at Woolsthorpe Manor in 1642, and he returned for two years after a bubonic plague outbreak forced Cambridge University, where he was studying mechanical philosophy, to close temporarily in 1665. It was in this rural setting that Newton conducted his prism experiments with white light, worked on his theory of “fluxions,” or calculus, and famously watched an apple fall from a tree, a singular moment that’s said to have led to his theory of gravity.

Paper was a scarce commodity in 17th century England, so Newton often sketched and scrawled notes on the manor’s walls and ceilings. While removing old wallpaper in the 1920s and '30s, tenants discovered several sketches that may have been made by the scientist. But the windmill sketch remained undetected for centuries, until conservators used a light imaging technique called Reflectance Transformation Imaging (RTI) to survey the manor’s walls.

Conservators using light technology to survey the walls of Woolsthorpe Manor,  the childhood home of Sir Isaac Newton.
A conservator uses light technology to survey the walls of Woolsthorpe Manor, the childhood home of Sir Isaac Newton.
National Trust

RTI uses various light conditions to highlight shapes and colors that aren’t immediately visible to the naked eye. “It’s amazing to be using light, which Newton understood better than anyone before him, to discover more about his time at Woolsthorpe,” conservator Chris Pickup said in a press release.

The windmill sketch suggests that young Newton “was fascinated by mechanical objects and the forces that made them work,” added Jim Grevatte, a program manager at Woolsthorpe Manor. “Paper was expensive, and the walls of the house would have been repainted regularly, so using them as a sketchpad as he explored the world around him would have made sense," he said.

The newly discovered graffiti might be one of many hidden sketches drawn by Newton, so conservators plan to use thermal imaging to detect miniscule variations in the thickness of wall plaster and paint. This technique could reveal even more mini-drawings.

[h/t Live Science]

SECTIONS

arrow
LIVE SMARTER
More from mental floss studios