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Self-organized criticality & maximization of Φ
Psychedelics near a critical point
Links self-organized criticality (SOC) and the maximization of Φ (IIT): the hypothesis that psychedelics push the brain toward a critical point where integrated information peaks. SOC is fairly established; IIT is major but heavily contested, and Φ is not measurable in vivo.
La Honda plate.
La Honda notes
No La Honda note on this concept yet.
This plate brings together two distinct frameworks: self-organized criticality (SOC) and Tononi's integrated information theory (IIT), whose central measure is denoted Phi. The proposed thesis is that psychedelics would bring the brain closer to a critical point where Phi would be maximised. The plate states at the outset the very unequal status of the two frameworks: SOC is relatively established in physics and in the neuroscience of complex systems, whereas IIT is a major but heavily contested theory, which in 2023 prompted an open letter signed by 124 researchers.
Self-organized criticality (SOC)
According to this first framework, the brain would operate in the vicinity of a critical point, at the boundary between order and disorder. Three regimes are distinguished: sub-critical (order), critical (optimal zone) and super-critical (disorder). The critical balance would offer efficient propagation of information, maximal sensitivity and adaptive flexibility. The hypothesis is that psychedelics would shift the brain from the sub-critical regime toward criticality.
Observed signatures
The plate gathers several signatures measured in humans, compatible with this shift. Increased complexity (Toker and collaborators, 2021) is read in Lempel-Ziv complexity and an increased diversity of explored neuronal states. The diversity of neuronal states (Atasoy and collaborators 2017; Schartner and collaborators, 2017) corresponds to the exploration of a broader and less redundant repertoire. Flexible connectivity (Atasoy and collaborators 2018; Gollo and collaborators, 2015) translates into more frequent transitions between configurations and an increased global functional flexibility.
IIT reading and maximisation of Phi
The second framework links criticality and consciousness. According to the proposed IIT reading, integrated information Phi would be maximised precisely at criticality: the curve of Phi as a function of an order parameter would show a peak at the critical point. Psychedelic states would then correspond to a local maximum of Phi, hence to a maximum of integrated information. Within a strict IIT, an increase in Phi would imply an increase in consciousness: more integration of information would amount to more conscious experience. The plate mentions a public position of Christof Koch, who explicitly committed to 5-MeO-DMT as a candidate for maximal Phi, citing his experience as the strongest candidate for a state of maximal Phi (The Feeling of Life Itself, 2019, and podcast interviews).
Epistemic status and debates
The plate presents itself not as an endorsement, but as a critical mapping of the state of research. It recalls that correlation is not causation: the observed signatures are compatible with the theory without validating it. The methodological limits are emphasised: Phi is not computable for complex in vivo systems, and the available evidence (PCI, Lempel-Ziv complexity, entropy) consists only of correlates, not Phi itself. IIT is explicitly described as highly controversial. Many grey areas remain: what level of Phi psychedelics actually reach, how Phi interacts with other cognitive functions (attention, memory, learning), whether there are biophysical limits to a maximal Phi (metabolic constraints, heat, thermal noise, dissipation), why different molecules produce distinct qualitative effects although they would converge toward criticality, and whether the maximum of Phi always corresponds to the deepest or most disintegrative experience. The implication, if the theory holds, would be that psychedelics do not merely reveal consciousness: they would transiently bring the brain closer to an optimal point of information integration. The plate finally points to several major alternatives (Dehaene's global workspace, an IIT without SOC, predictive and regulatory models, maximal entropy, other emerging theories), and recalls that it has only an informative value.
Sources
- Bak, Tang and Wiesenfeld (1987), self-organized criticality.
- Beggs and Plenz (2003), neuronal avalanches and criticality.
- Chialvo (2010), criticality in brain systems.
- Toker and collaborators (2022), complexity and criticality under psychedelics.
- Atasoy and collaborators (2017, 2018), connectome harmonics and diversity of brain states.
- Schartner and collaborators (2017), complexity and diversity under psychedelics.
- Gollo and collaborators (2015), criticality and connectivity flexibility.
- Tononi, integrated information theory (IIT): 2004, 2008, 2014 (IIT 3.0).
- Koch, The Feeling of Life Itself (2019), 5-MeO-DMT and maximal Phi.
- Open letter (2023) on the scientific status of IIT.