SciTech

LSD destabilizes the brain’s “sense of self” neural network

This is your brain on drugs! But more importantly this is also your brain not on drugs. In a series of brightly colored collages of “lit-up” brains, neuroscientists Robin Carhart-Harris, David Nutt, et al. released their findings on the first modern imaging studies of human participants on Lysergic Acid Diethylamide (LSD). While there has been previous work done on the effects of psychedelics and the brain, many of these studies are limited by methodological concerns, legal issues, and their lack of scope. Like many secondary reports on psychopharmacological research, these reports ignore the fact that these brains are still a product of their previous experiences and environments. These drugs don’t create new neural networks, they work with and augment systems that exist in the default brain, which can vary drastically. The limitations of prior research have led to a multitude of current research on these substances, including a study published by Carhart-Harris and Nutt.

LSD was first synthesized in 1938 by Alfred Hoffman.It is derived from ergotamine, a component of ergot fungus, which is a type of mold that grows on rye bread. Soon after its psychoactive (brain-altering) properties were discovered in 1943, it became a part of psychological “research,” which ranged from psychoanalysis sessions, to marriage counseling, to the infamous CIA trials to put soldiers through “living hell,” to getting dolphins to trip. This, and the rise in the recreational use, led to governments around the world prohibiting the drug and keeping it under strict control. Until recently, this conversation around LSD has remained stuck in the world of the 1950’s. Even now, as research is expanding in the field of psychedelic neuroscience, studies are often fettered by the drug’s complicated past.

LSD is an organic molecule that is able to cross the blood-brain-barrier, meaning it can interact with neurons and receptors in the brain. From there, LSD is able to interact with many different receptors. On some receptors, it acts as an agonist, activating specific cellular pathways in neural circuits. On others, it is an antagonist, blocking these receptors and preventing the activation of these neural circuit pathways. While we know a little about how these molecules bind to receptors at a biochemical level, there is still uncertainty about how this affects larger sections of the brain. Existing research regarding systems related to LSD functionality centered around the medial

temporal lobes, which are involved in processing vision, language, and emotion. Patients with part of their medial temporal lobes removed showed diminished LSD effects, and electrical stimulation of these regions is known to produce dreamlike “visions” and distortions to visual perception similar to those associated with LSD. However, the effect of this substance on the brain cannot be isolated to a singular brain area or receptor type. In order to understand the effect of any molecule in the brain, we must consider how that substance interacts with the brain as a whole. The aforementioned study, led by Carhart-Harris and Nutt, not only sheds light on how LSD interacts with larger scale neural systems, but also clarifies how certain parts of the brain interact.

Carhart-Harris and Nutt’s study provides evidence that LSD promotes interaction between regions of the brain that are normally thought to have discrete psychological functions such as emotion, sound, or cognition. This increased interaction between traditionally separated parts of the brain helps explain some of the common traits associated with LSD such as geometric visual patterns, impaired motion perception, and auditory synesthesia (hearing sounds when other senses, such as vision, are stimulated).

Carhart-Harris and Nutt also found a correlation between LSD and decreased connection in the Default Mode Network, a network thought to be the foundation for a person’s understanding of “self.” The breakdown of these connections mirrors the loss of self-identity that is a part of the LSD experience.

Carhart-Harris and Nutt explain that these findings could have important implications in a variety of fields of study, saying “in the same way the neurobiology of psychedelic induced visual hallucinations can inform on the neurobiology of visual processing, so the neurobiology of psychedelic-induced ego dissolution can inform on the neurobiology of the ‘self’ or ‘ego.’” While this study made significant headway in uncovering correlations between states of consciousness and brain activity in the presence of LSD, it is still uncertain how this can be applied to normal brain function. Further studies are needed to really understand how distinct brain regions are connected. LSD has been used in trials to help treat anxiety disorders and cluster headaches and has had astoundingly positive results. LSD has also been fruitful in studying other disease states, since some of the same regions and neurotransmitter receptor systems are implicated in forms of depression and schizophrenia. By focusing on what these LSD studies can tell us about brain connectivity and normal brain function, LSD studies could become an important part of neuroscience research. While headlines of “Your Brain on LSD” grab attention, they provide only a cursory glance at the complex and intricate relation between your brain and the world around it. Hopefully, with further studies of this type, we can continue to unravel the enigma that is the phenomenology of human brain, be it on drugs or not.