Neural Response to Naturalistic Stimuli Under Psilocybin: An fMRI Study
Poster No:
1443
Submission Type:
Abstract Submission
Authors:
Lucia Jajcay1,2,3, Petr Adámek2, David Greguš2, Jiří Horáček2,4, Jaroslav Hlinka1,2
Institutions:
1Institute of Computer Science, The Czech Academy of Sciences, Prague, Czech Republic, 2National Institute of Mental Health, Klecany, Czech Republic, 3Faculty of Electrical Engineering, Czech Technical University in Prague, Prague, Czech Republic, 4Third Faculty of Medicine, Charles University, Prague, Czech Republic
First Author:
Lucia Jajcay
Institute of Computer Science, The Czech Academy of Sciences|National Institute of Mental Health|Faculty of Electrical Engineering, Czech Technical University in Prague
Prague, Czech Republic|Klecany, Czech Republic|Prague, Czech Republic
Institute of Computer Science, The Czech Academy of Sciences|National Institute of Mental Health|Faculty of Electrical Engineering, Czech Technical University in Prague
Prague, Czech Republic|Klecany, Czech Republic|Prague, Czech Republic
Co-Author(s):
Jiří Horáček
National Institute of Mental Health|Third Faculty of Medicine, Charles University
Klecany, Czech Republic|Prague, Czech Republic
National Institute of Mental Health|Third Faculty of Medicine, Charles University
Klecany, Czech Republic|Prague, Czech Republic
Jaroslav Hlinka
Institute of Computer Science, The Czech Academy of Sciences|National Institute of Mental Health
Prague, Czech Republic|Klecany, Czech Republic
Institute of Computer Science, The Czech Academy of Sciences|National Institute of Mental Health
Prague, Czech Republic|Klecany, Czech Republic
Introduction:
Psilocybin has been studied increasingly, and shown to alter brain connectivity. Unlike traditional task-based paradigms, naturalistic stimuli such as movies provide a more ecologically valid context, engaging multiple cognitive and emotional processes simultaneously and closely resembling real-world experiences. Using naturalistic fMRI, we investigated the effects of psilocybin on brain activity while participants watched a movie, comparing connectivity patterns with a placebo condition. We aimed to examine how psilocybin influences network dynamics.
Methods:
Using a Siemens Prisma 3T MRI scanner, we measured the brain activity of 25 healthy subjects (15M, 10F, mean age ± SD: 37.84 ± 7.90 years) while they watched an uninterrupted segment from the feature film 'The Good, the Bad and the Ugly' (17:25–26:48; 9 min 23s).
The study employed a double-blind, placebo-controlled crossover design, with subjects undergoing two scanning sessions separated by 28–135 days. During each session, either psilocybin (THC Pharm GmbH, >98% purity) or a placebo was administered orally with 200 ml of water. The dosage was adjusted based on each participant's body weight, targeting an approximate dose of 0.26 mg/kg.
The movie-watching fMRI was recorded approximately 180–210 min after drug administration. Functional T2*-weighted images with BOLD contrast (GE-EPIs; TR/TE = 2500/30 ms, flip angle = 52°, voxel size = 3 × 3 × 3 mm³, FOV = 210 mm, 225 volumes, 52 slices per volume), as well as high-resolution 3D T1-weighted images (for anatomical reference), were acquired. Data preprocessing was performed using performed using fMRIPrep 23.0.0, based on Nipype 1.8.5.
Mean BOLD time series of 90 ROIs of the AAL atlas were extracted. Using these, FC matrices for each subject and each condition were computed by linear (Pearson's) correlation (Hlinka et al., 2011, Hartman et al., 2011), Fisher's r-to-z transformation was applied, and, for each pair of regions, the two conditions were compared using the Wilcoxon signed-rank test.
The study employed a double-blind, placebo-controlled crossover design, with subjects undergoing two scanning sessions separated by 28–135 days. During each session, either psilocybin (THC Pharm GmbH, >98% purity) or a placebo was administered orally with 200 ml of water. The dosage was adjusted based on each participant's body weight, targeting an approximate dose of 0.26 mg/kg.
The movie-watching fMRI was recorded approximately 180–210 min after drug administration. Functional T2*-weighted images with BOLD contrast (GE-EPIs; TR/TE = 2500/30 ms, flip angle = 52°, voxel size = 3 × 3 × 3 mm³, FOV = 210 mm, 225 volumes, 52 slices per volume), as well as high-resolution 3D T1-weighted images (for anatomical reference), were acquired. Data preprocessing was performed using performed using fMRIPrep 23.0.0, based on Nipype 1.8.5.
Mean BOLD time series of 90 ROIs of the AAL atlas were extracted. Using these, FC matrices for each subject and each condition were computed by linear (Pearson's) correlation (Hlinka et al., 2011, Hartman et al., 2011), Fisher's r-to-z transformation was applied, and, for each pair of regions, the two conditions were compared using the Wilcoxon signed-rank test.
Results:
For results – differences in functional connectivity during naturalistic stimulation between the two experimental conditions – see Figure 1.
·Significant differences (p<0.01) in FC during naturalistic stimulation. Red = higher in psilocybin; blue = higher in placebo.
Conclusions:
We found that, under psilocybin, connectivity is increased among selected regions of the frontal cortex, decreased between regions of the frontal cortex and other brain regions.
The study was supported by ERDF-Project Brain dynamics, No. CZ.02.01.01/00/22_008/0004643.
The study was supported by ERDF-Project Brain dynamics, No. CZ.02.01.01/00/22_008/0004643.
Modeling and Analysis Methods:
Connectivity (eg. functional, effective, structural)
fMRI Connectivity and Network Modeling 1
Task-Independent and Resting-State Analysis 2
Keywords:
FUNCTIONAL MRI
Other - Functional Connectivity, Naturalistic Stimuli, Movie fMRI, Psilocybin
1|2Indicates the priority used for review
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Provide references using APA citation style.
2. Hlinka, J., Paluš, M., Vejmelka, M., Mantini, D., & Corbetta, M. (2011). Functional connectivity in resting-state fMRI: Is linear correlation sufficient?. NeuroImage, 54(3), 2218–2225.