Poster No:
2473
Submission Type:
Abstract Submission
Authors:
Maximilian Kathofer1, Marie Spies2, Pedro Mediano3, Benjamin Eggerstorfer2, Gregor Dörl2, David Gomola2, Christina Bieglmayer1, Peter Stöhrmann2, Julia Payer1, Manfred Klöbl2, Simon Mehler1, Clemens Schmidt2, Hanna Scharler1, Gabriel Schlosser2, Alexandra Mayerweg2, Nina Granabetter1, Lukas Artmeier2, Benedikt Schmidt1, Elisa Briem2, Helmut Leder1, Rupert Lanzenberger2, Julia Crone1,4
Institutions:
1University Of Vienna, Vienna, Austria, 2Medical University of Vienna, Vienna, Austria, 3Imperial College London, London, United Kingdom, 4University of California Los Angeles, Los Angeles, CA
First Author:
Co-Author(s):
Marie Spies
Medical University of Vienna
Vienna, Austria
Gregor Dörl
Medical University of Vienna
Vienna, Austria
Elisa Briem
Medical University of Vienna
Vienna, Austria
Julia Crone
University Of Vienna|University of California Los Angeles
Vienna, Austria|Los Angeles, CA
Introduction:
Originally devised as a potent anesthetic, subanesthetic doses of ketamine induce an altered state of consciousness and increase complex brain network dynamics [1]. This surge in network dynamics is thought to reflect ketamine's neuroplastic properties, ultimately enabling the brain to explore a broader range of possible states, and thus, increasing the integration of new information [2,3]. Leveraging recent advancements in information theory, we employ partial information decomposition (PID) to uncover higher-order dependencies that common bivariate approaches fail to uncover. By disentangling the observed neuronal information into redundant and synergistic parts, of which the latter serves as a measure of information integration, PID enables the detection of these higher-order dependencies across brain regions [4]. The still poorly understood rapid-acting, pro-hedonic properties of ketamine might be linked to its modulation of precisely these higher-order dependencies, reflecting a breakup of engrained connections inducing increased information integration. This seems convincing, as hedonic experiences – a product of various concurrent cognitive and affective processes - are themselves states of enhanced integration [5,6].
Methods:
We use ketamine to alter hedonic experiences in response to music in 31 neurotypical subjects. The full within-subject design consists of 4 sessions; baseline, two treatment sessions (ketamine and placebo) counterbalanced across subjects, and a follow-up session. To assess the subacute state in which the beneficial effects start to emerge, participants complete a battery of standardized assessment scales (e.g., 5-Dimensional Altered States of Consciousness and Dimensional Anhedonia Rating Scale) as well as a resting-state scan and an aesthetic task using fMRI four hours after administration. The aesthetic task consists of self-selected highly moving and neutral music to examine ketamine's effect on the hedonic tone. Participants rate the induced experiences based on 3 dimensions: aesthetically moving, aesthetic chills, and valence. For the resting-state data, a linear mixed-effects model (LME) was implemented to evaluate whether ketamine increases synergistic information processing with the within-subjects factors of Treatment (ketamine & placebo) and Timepoint (treatment session 1 & 2). To probe whether altered synergistic information processing is associated with ketamine administration and peak hedonic experiences, we used the aesthetic task data and implemented a LME model with the factors of Hedonic Experience (high & low), Treatment (ketamine & placebo) and Timepoint (treatment session 1 & 2). Preliminary data of 9 participants is presented.
Results:
The preliminary results of the resting state data show a main effect of Treatment, indicating that ketamine increases synergistic information processing compared to placebo (beta = 3.89, t(14) = 2.35, p = 0.047). Furthermore, the analysis of the aesthetic task data, revealed a main effect of Hedonic Experience, indicating that low hedonic experiences are associated with decreased synergistic processing compared to high hedonic experiences (beta = -32.26, t(24) = -2.35, p = 0.027). No main effect of Treatment was observed during the aesthetic task (beta = -4.41, t(24) = -0.32, p = 0.750).
Conclusions:
In line with our hypothesis, we found an association between high hedonic experiences and increased information integration. In the resting state, ketamine – which is known to enhance neuroplasticity – also increased information integration. Interestingly, this effect was not evident during the presentation of moving and neutral music. However, in light of the limited power of this sample, we refrain from speculating about the meaning of this null result until the complete sample has been analyzed. Taken together, the present study poses an important contribution to the understanding of the intricate role of enhanced information integration for the emergence of hedonic experiences.
Emotion, Motivation and Social Neuroscience:
Reward and Punishment
Modeling and Analysis Methods:
Multivariate Approaches 2
Other Methods
Perception, Attention and Motor Behavior:
Consciousness and Awareness 1
Keywords:
Computational Neuroscience
Consciousness
Plasticity
Other - Hedonic Experiences, Ketamine
1|2Indicates the priority used for review
Provide references using author date format
[1] Schartner, M.M. (2017), 'Increased spontaneous MEG signal diversity for psychoactive doses of ketamine, LSD and psilocybin', Scientific Reports, 7(1), 46421
[2] Aleksandrova, L. R., (2021), 'Neuroplasticity as a convergent mechanism of ketamine and classical psychedelics', Trends in pharmacological sciences, 42(11), pp. 929-942
[3] Rubinov, M., (2010), 'Complex network measures of brain connectivity: uses and interpretations', Neuroimage, 52(3), pp.1059-1069
[4] Luppi, A. I., (2022), 'A synergistic core for human brain evolution and cognition', Nature Neuroscience, 25(6), pp. 771-782
[5] Kringelbach, M. L. (2005), 'The human orbitofrontal cortex: linking reward to hedonic experience', Nature Reviews Neuroscience, 6(9), pp. 691-702
[6] Brattico, E., (2013), 'Toward a neural chronometry for the aesthetic experience of music', Frontiers in Psychology, 4, 206