This single-blind placebo-controlled study (n=10) investigated the effects of LSD (40-80μg) on lexical retrieval in a picture-naming task and found an increase in the rate at which subjects substituted items with similar words within the same semantic category. These results are consistent with the notion that LSD increases the spread of activation within semantic networks.

Abstract of Semantic activation in LSD

“Introduction: Lysergic acid diethylamide (LSD) is a classic psychedelic drug that alters cognition in a characteristic way. It has been suggested that psychedelics expand the breadth of cognition via actions on the central nervous system. Previous work has shown changes in semantic processing under psilocybin (a related psychedelic to LSD) that are consistent with an increased spread of semantic activation.

Methods: The present study investigates this further using a picture-naming task and the psychedelic, LSD. Ten participants completed the task under placebo and LSD.

Results: revealed significant effects of LSD on accuracy and error correction that were consistent with an increased spread of semantic activation under LSD.

Discussion: These results are consistent with a generalised “entropic” effect on the mind. We suggest incorporating direct neuroimaging measures in future studies, and to employ more naturalistic measures of semantic processing that may enhance ecological validity.”

Authors: Neiloufar Family, David Vinson, Gabriella Vigliocco, Mendel Kaelen, Mark Bolstridge, David J. Nutt & Robin L. Carhart-Harris

Summary of Semantic activation in LSD

This study used picture naming and priming paradigms to explore the effects of lysergic acid diethylamide, a serotonergic hallucinogen, on semantic processing and more specifically, lexical retrieval.

Lysergic Acid Diethylamide

Research on LSD and related serotonergic “psychedelics” has focused on mechanisms of action, pharmacokinetics, therapeutics, and their ability to model psychosis. Evidence suggests that the 5-HT2A receptor is involved in language production, associative learning, working memory, visual processing, and emotion regulation.

Neurochemistry and Language

While most studies focus on impairment in patient populations, a few studies have looked at pharmacological modulation of semantic network activation. These studies suggest that dopamine plays a regulatory role in semantic activation. Spitzer et al. (1996) demonstrated that psilocybin, a closely related molecule to LSD, enhances indirect semantic priming. This finding is in line with reports from the 60s that serotonergic hallucinogens render speech less predictable and enhance free-association. Spitzer et al. (1996) argued that psilocybin had semantic effects that were time-sensitive, appearing 50 minutes after ingestion. However, Gouzoulis-Mayfrank et al. (1998) found only a trend for increased indirect semantic priming, suggesting that psilocybin has a generic defocusing, hyper-associative effect.

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Find this paper

Semantic activation in LSD: evidence from picture naming

https://doi.org/10.1080/23273798.2016.1217030

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Cite this paper (APA)

Family, N., Vinson, D., Vigliocco, G., Kaelen, M., Bolstridge, M., Nutt, D. J., & Carhart-Harris, R. L. (2016). Semantic activation in LSD: evidence from picture naming. Language, Cognition and Neuroscience, 31(10), 1320-1327.

Study details

Compounds studied
LSD

Topics studied
Neuroscience

Study characteristics
Placebo-Controlled Single-Blind

Participants
10 Humans

Authors

Authors associated with this publication with profiles on Blossom

Mendel Kaelen
Mendel Kaelen is a neuroscientist and entrepreneur, researching and developing a new category of psychotherapeutic tools for care-seekers and care-providers. Mendel has researched the incomparable effects of music on the brain during LSD-assisted psychotherapy. His work has determined how LSD increases enhanced eyes-closed visual imagery, including imagery of an autobiographical nature. This gives light to how music can be used as another dimension in helping psychotherapists create the ideal setting for their patients.

David Nutt
David John Nutt is a great advocate for looking at drugs and their harm objectively and scientifically. This got him dismissed as ACMD (Advisory Council on the Misuse of Drugs) chairman.

Robin Carhart-Harris
Dr. Robin Carhart-Harris is the Founding Director of the Neuroscape Psychedelics Division at UCSF. Previously he led the Psychedelic group at Imperial College London.