Christoph Mathys

2 papers in the library · 82 citations · publishing 2020-2023

Papers

Ketamine Affects Prediction Errors about Statistical Regularities: A Computational Single-Trial Analysis of the Mismatch Negativity

Journal of Neuroscience June 19, 2020 Lilian Weber, Andreea O. Diaconescu, Christoph Mathys et al. 82 citations

The auditory mismatch negativity (MMN) is reduced in schizophrenia and can also be reduced by NMDA receptor (NMDAR) antagonists, suggesting impaired predictive coding. This study tested the theory that perceptual inference depends on NMDAR-dependent hierarchical precision-weighted prediction errors (PEs). Using a hierarchical Bayesian model on single-trial EEG data from healthy volunteers given the NMDAR antagonist S-ketamine in a placebo-controlled, double-blind, within-subject design, the analysis showed that low-level PEs (about stimulus transitions) appear early (102-207 ms), while high-level PEs (about transition probability) appear later (152-199 and 215-277 ms). Ketamine significantly diminished high-level PE responses, indicating NMDAR antagonism disrupts inference on abstract statistical regularities and impairs hierarchical Bayesian inference about the world's statistical structure.

DOI: 10.1523/jneurosci.3069-19.2020 Full text Ketamine Mismatch negativity Negativity effect Computer science +3

Phi fluctuates with surprisal: An empirical pre-study for the synthesis of the free energy principle and integrated information theory.

PLoS Computational Biology October 1, 2023 Christoffer Lundbak Olesen, Peter Thestrup Waade, Larissa Albantakis et al.

Two major theoretical frameworks—the Free Energy Principle, which describes how self-organizing systems maintain order, and Integrated Information Theory, which aims to mathematically characterize conscious experience—are brought together. Analyzing data from an earlier evolutionary simulation, the authors show that agents' surprisal (a measure from the Free Energy Principle) decreases as their fitness and neural integration increase over evolutionary time. Furthermore, surprisal fluctuates in tandem with IIT-based measures of consciousness within individual trials. This suggests that IIT's consciousness measures are partly shaped by the agent's interaction with its environment, making a formal link between the two theories possible.

DOI: 10.1371/journal.pcbi.1011346 Full text