How Does LSD Impact the Brain? – Your Brain on LSD

The impact of LSD on the brain has been a subject of some debate over the years. Opinions can vary from extreme to extreme, with some naysayers proclaiming that LSD causes irreversible damage to the brain whereas advocates say that, if LSD does produce any changes, they’re most definitely positive changes associated with neural growth.

As the world begins to shift its perspective on the use and application of psychedelics, more and more researchers are being given grants to study these fascinating substances. As such, LSD researchers can now actually figure out what sort of impact LSD has on the brain.

That’s what this article is here to explain.

Effects of LSD on Human Beings

LSD causes a number of powerful and profound changes in anybody who consumes it. These changes are not altogether that much different than those produced by other psychedelics, but LSD has become something of a flagship for representing the range of psychedelic effects.

These effects are fascinating and interesting for numerous reasons, not the least of which being the fact that we don’t really understand how they work. Thanks to the brain scans described in this article, we know a little bit more – but we’re still far from completely understanding how LSD actually goes about producing these myriad effects.

Many of the effects produced by LSD would likely target areas of the brain that are seldom researched in any relevant context. Perhaps the most relevant studies would be those done on monks and disciplined meditators who can will themselves into a trance state. These studies have revealed activation of certain areas of the brain and decreased activity in others.

However, even if an acid trip may, at times, share some similarities with a meditative mind state, there’s a heck of a lot more going on. LSD produces visual and auditory hallucinations (which are not unheard of with extremely focused and consistent meditation pursued over a number of years), drastic changes in thinking and perception, and an increase in appreciation and awareness for the spiritual and metaphysical.

We haven’t yet mapped which part of the brain is related to these types of changes. Part of the reason for this is the highly subjective nature of some of these experiences. How, for example, can you evaluate or quantify the level of spiritual insight or awareness that an individual is feeling? Even if that were possible, we wouldn’t know what part of the brain is responsible for engaging with this type of activity.

Now you understand some of the difficulties facing people interested in researching LSD. Add to that the fact the most modern MRI brain scans involve laying people on a gurney and feeding them into a massive, gaping cylindrical tube filled with futuristic technology and people in white lab coats? This sounds like the recipe for a Kafkaesque nightmare.

vPolarity on the Issue of LSD and the Brain

When LSD first gained popularity in the 1960s, advocates of the substances were extremely inspired by its potential as a creative and spiritual tool. They suggested that LSD could do everything from healing the human soul and the planet itself as well as help to facilitate personal and spiritual growth at the level of the individual and the community.

Those who were opposed to LSD, however, held entirely different views. They believed that LSD was the work of the devil or, if they held a less religious standpoint, at least the work of a medical chemist that should not be abused by youngsters looking to see funny colors and shapes.

These individuals based their beliefs on the well-described experience of an LSD trip, which include extreme alterations of color, sound, and texture. It was believed that these changes could only occur by damaging the brain’s circuitry, with many making comparisons between LSD and schizophrenia or other mental disorders.

schizophrenia drawn
Artist suffering from schizophrenia would draw what she saw on the walls.

While the parallels between LSD and mental disorders are still worth looking at (which we will discuss during this article, below) it seems that LSD itself doesn’t cause these conditions. Actually, it seems that the hippies and LSD enthusiasts of the 1960s were closer to hitting the mark than those who dismissed LSD as a dangerous and impractical illegal substance.

This article will explore how and why the hippies of 1960 America, who praised LSD for its ability to activate human potential, were… Well, actually, sort of right.

Your Brain On LSD

The science of LSD in the brain is a very complicated matter requiring a great deal of precision. Knowledgeable professionals capable of operating top-of-the-line equipment must be present to make observations regarding the brains of people under the influence of LSD.

And how do you even manage to take a look at the brain of someone on LSD? You can’t just cut someone’s head open and take a peek. (Well, actually, you can – many brain surgeries are performed with the patient remaining conscious since the brain itself doesn’t actually sense pain). Instead, you’ll want to rely on advanced equipment to perform a brain scan.

What Is a Brain Scan?

Brain scans are used to produce detailed pictures of the brain for doctors and other medical professionals. These pictures provide information that allows doctors to diagnose health problems or, such as in the case of psychedelic study, observe which areas of the brain are more or less active when influenced by certain substances.

brain scan

There are different types of brain scans that can be used. Among the most common are magnetic resonance imaging (MRI) and computed tomography (CAT) scans.

  • A CAT scan involves the use of special x-rays to produce images of the brain. These images can be captured on any number of different axes: vertical, horizontal, axial, etc. This allows researchers to observe different sections of brain tissue. Sometimes doctors will inject a contrast substance into the brain that will illuminate or darken certain areas so that the focus areas will be more readily visible.
  • An MRI involves the use of a large and powerful magnet combined with radiofrequency. The combination allows researchers to acquire detailed images of various organs in the body, including the brain. MRI machines are basically large tubes that patients are slid into. The machine generates a strong magnetic field which influences the natural arrangement of hydrogen atoms in the human body by forcing the nuclei of the atoms out of their normal positions. When they return to their standard position they produce radio signals which are interpreted by the computer and used to produce a visible image. Sounds healthy, right?

LSD Impact on the Brain – The First Brain Scans of 2016

In 2016, a group of volunteers agreed to undergo a psychedelic trip and have their brains scanned, most likely due to the promise of free LSD without the risk of legal repercussions.

This free LSD was delivered by intravenous injection rather than by the typical paper blotter, and the setting was much different than most psychonauts are used to: rather than tripping in a familiar setting, they were confined to a medical laboratory and surrounded by machines and professionals in white suits.

The results of their abnormal psychedelic experience, however, are nothing short of profound. Researchers say that the brain scans have provided significant evidence that may help them understand why users develop such a profound sense of connection with the universe.

brain scan on lsd users
Increase in the brain connectivity after LSD (right), compared to placebo (left). Credit: Imperial College London

There were many things revealed by these scans that caused scientists and psychonauts alike to reconsider their understanding of how and why LSD causes hallucinations.

How the Study Worked

The setup of a study is nearly as important as the actual results of the study. This particular study involved 20 volunteers, each of them deemed to be physically and mentally fit. They were made to attend the study clinic on two separate days, receiving on one day an injection of 75 mcg of LSD (about half of the dose contained on a standard, modern tab of acid) and on the other day they received a placebo.

The scientists then used a number of different techniques to observe and evaluate various physiological functions. Of particular importance were techniques known as arterial spin labeling, resting state MRI, and magnetoencephalography.

Without going into too much detail, suffice to say that these techniques allow for the accurate evaluation of blood flow, neural connections, and brainwave production and function. The volunteers were given both a placebo and a dose of LSD without knowing which was which helped to ensure that the results were unbiased and that the volunteers would produce an equal amount of psychosomatic changes in their brain and body.

Robin Carhart-Harris was the other leading researcher spearheading the study with Nutt. He pointed out that the scans indicated that the volunteers high on acid were “seeing with their eyes shut.” The brain could not easily differentiate the visual experiences that were perceived, even with the volunteer’s eyes shut, from those of an ordinary, open-eyed visual experience.

In fact, even though the LSD-influenced volunteers had their eyes shut, the scans showed that far more areas in the brain were active and contributing to visual processing.

There are some doubts about how effective the study can be given the small sample size, at least according to an interviewer working for They also expressed concern about some of the study subjects moving around too much in the brain scanner and how this might influence results.

Nutt says that he believes the results are accurate. They are very similar to the results achieved when studying volunteers under the influence of psilocybin, he says, only much stronger.

Unification & Separation of Brain Regions

The administration of LSD to subjects led to a whole host of changes in the brain. These changes were extremely varied and it would take an immense amount of time to determine how each of these changes contribute to the complex interplay of LSD’s effects.

The visual cortex, for example, is generally the part of the brain responsible for processing visual information like images . Carhart-Harris pointed out that dropping LSD led to changes in visual processing that seemed to indicate a “more unified brain.” Neural networks that normally processed vision, attention, movement, and hearing were now working in tandem with one another.

With eyes closed, much more of the brain contributes to the visual experience under LSD than under placebo, as shown in this image. Participants’ reports of complex, dreamlike visions were related to the magnitude of this effect. Credit: Imperial College London

This accounts for some of the hallucinatory experiences that people report when using LSD, as well as the significant increase in imaginative capabilities. However, the opposite is also true: some areas of the brain become disjointed and disconnected.

The parahippocampal and the retrosplenial cortex are the two most significant regions affected by this phenomenon. This segregation led to a loss of identification with the self or personal identity which psychonauts often refer to as ‘ego loss.’

This loss of individuality may sound scary, and at first, many report that it is. However, the result of this experience is often that the individual merges their identity with that of the world around them.

Much like a child, filled with wonder, has not learned how to separate itself from its environment by erecting boundaries between the Self and the Other, LSD allows people to temporarily experience unity consciousness. This is generally followed by feelings of love and acceptance of other living beings and of life itself.

Nutt thinks along similar lines. He believes that LSD helps to dissolve some of the restrictions that are placed upon the thinking mind as humans are fed through the school system and spat out into society. We must place strict limits on the expression and formation of thoughts if we are to succeed in a capitalist society and adhere to the law.

In essence, science has succeeded in its reductionist approach to reducing a transcendent and spiritual experience into nothing more than the rearrangement of neural networks. Does this defy the notion that there is, in fact, a spiritual experience happening? As the ancient adage says, as above, so below. Perhaps these neural changes are only the gross, physical shadow of the effects produced by LSD in subtle realms of consciousness that remain elusive to the probing dissection of reductionism.

Potential for Therapeutic Usage of LSD

In either case, neuroscientists are ecstatic about this discovery. David Nutt, the leader of the previous study, is particularly excited, saying that this discovery “is to neuroscience what the Higgs boson was to particle physics,” referencing the neurological understanding of spiritual experiences of unity. “We didn’t know how these profound effects were produced. It was too difficult. Scientists were either scared or couldn’t be bothered to overcome the enormous hurdles to get this done.”

It’s taken nearly a century since the first synthesis of LSD in 1938 for researchers to get a grasp on how it produces some of its more transcendental experiences. Part of this is largely due to the criminalization of LSD that occurred towards the end of the 1960s. This effectively put an immediate end to scientific research on the substance.

Nowadays, however, as a more liberal approach is being taken in regard to psychedelics, researchers are picking up the pace. Nutt continues to explain how LSD’s ability to eliminate restrictive thinking could help people overcome psychiatric disorders.

For example, depressed patients or people struggling with addictions often find themselves operating, or living out, unhealthy thought patterns. These thought patterns form beliefs which then manifest as actions and keep the person trapped in a negative cycle. Nutt believes that LSD can help people pull themselves out of such toxic thought cycles and potentially, with the help of psychotherapy, replace them with healthier ones.

Further Study – Does LSD Really Cause Hallucinations, or Does It Show Us the Real World?

The above subheading might sound ridiculous to someone who hasn’t done many studies on LSD, but, those who are familiar with psychedelics will see that it’s not so improbable. For more than a decade, a consistent hypothesis has suggested that LSD doesn’t actually cause hallucinations, at least not in the traditional sense. Rather, what we see when we are under the influence of LSD is closer to what the universe actually looks like.

During our everyday life, a part of the brain known as the thalamus generally acts as a filter. It helps to remove ‘excess’ sensory input from the world so that we don’t get overwhelmed. Without the thalamus, we would constantly be bombarded with so much stimuli that it would feel like… well, – as this study seems to suggest – an acid trip.

That’s because the running theory suggests that LSD causes the thalamus to stop filtering out excess information, thereby allowing us to perceive the universe in its unadulterated form.

Recent discoveries in quantum physics as well as a long-standing knowledge gained through the study of particle physics are what paved the way for this theory as well as many other, less viable theories surrounding the use of acid.

Quantum physics has revealed that reality exists only when there is a conscious observer present to collapse the probability function into solid reality. We also understand that, at an even deeper level, there is no solid reality. There’s not even any matter present at all. There’s just energy, undulating at different frequencies to produce the illusion of varying densities.

In other words, the universe consists only of energy in motion – which is, well, sort of what it looks like to somebody high on acid.

When someone takes LSD, not only does the thalamus allow a greater amount of information to enter the conscious mind. This information is also translated deeper into the brain into regions like the cortex.

There are some interesting theories as to how this might influence the effects of LSD. For example, the posterior cingulate cortex is known to help shape one’s sense of self. It’s thought that overloading this region might contribute to a sense of self-dissolution.

Written by Nigel Ford – research author, outreach worker and owner of Hermetic Herbals.


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