Acute LSD effects on response inhibition neural networks

Area of Science:

• Neuroscience
• Psychopharmacology

Background:

• The serotonin 2A receptor (5-HT2AR) is implicated in visual hallucinations and cognitive impairments.
• The precise interaction between 5-HT2AR activation, cognitive deficits, and visual hallucinations remains unclear.

Purpose of the Study:

• To investigate the impact of 5-HT2AR activation on response inhibition neural networks using LSD in healthy individuals.
• To determine if brain activity during response inhibition under LSD correlates with LSD-induced visual hallucinations.

Main Methods:

• A double-blind, randomized, placebo-controlled, cross-over study involving 18 healthy subjects.
• Functional magnetic resonance imaging (fMRI) Go/No-Go task to assess response inhibition.
• The 5 Dimensions of Altered States of Consciousness (5D-ASC) questionnaire to measure visual hallucinations.

Main Results:

• LSD impaired inhibitory performance and altered brain activation in frontal and cerebellar regions compared to placebo.
• Parahippocampal activation patterns during response inhibition differed between placebo and LSD conditions.
• Left superior frontal gyrus activation under LSD was negatively associated with cognitive impairments and visual imagery.

Conclusions:

• 5-HT2AR activation by LSD disrupts hippocampal-prefrontal cortex networks, impairing inhibitory processing.
• This disruption may underlie the formation of visual imagery and hallucinations in LSD-induced states.
• Findings enhance understanding of the neuropsychopharmacological basis of visual hallucinations in various conditions.