The critical point is crucial for information processing in the healthy brain. Thus, studies show the presence of a critical state with power-law distributed neuronal avalanches and other scaling properties, breaking the separation between an inactive state and a synchronized epileptic-like state, relating epileptic state and synchronization transition [1].
In our study using the KTH model (three-variable map-based neuron), a synchronization phase transition with a power-law dependence of the time for the decay of post-stimulus activity was described, interpreted as a second-order critical phase transition[2].
In addition, the critical point presents an ideal reverberation of inputs due to the characteristics of ” critical slowing down ” (critical delay), which means that the system slowly approaches the steady state when perturbed near the phase transition.
Epilepsy is a complex phenomenon that depends on multiple factors[3] For characterization purposes, we also propose a homeostatic mechanism that adjusts synaptic strength to keep the system close to the critical synchronization point, avoiding complete synchronization, which is associated with pathological states such as epileptic seizures. We can be expanded by incorporating chemical synapses and considering populations of excitatory and inhibitory neurons. Furthermore, we have open questions about how to regulate homeostatic hyperparameters.
1.SHEW, Woodrow L.; PLENZ, Dietmar. The functional benefits of criticality in the cortex. The neuroscientist, v. 19, n. 1, p. 88-100, 2013.
2.RHAMIDDA, S. L., Girardi-Schappo, M., & Kinouchi, O. (2024). Optimal input reverberation and homeostatic self-organization toward the edge of synchronization. Chaos: An Interdisciplinary Journal of Nonlinear Science, 34(5).
3.JIRUSKA, Premysl et al. Synchronization and desynchronization in epilepsy: controversies and hypotheses. The Journal of physiology, v. 591, n. 4, p. 787-797, 2013.
Contact: Sue Lam, suebioensino@gmail.com
University of São Paulo, São Paulo, Brazil
Additional Authors:
2Mauricio Girardi-Schappo, Universidade Federal de Santa Catarina, Florianópolis, SC, 88040-900, Brazil. 3-Osame Kinouchi, Universidade de São Paulo, Ribeirão Preto, SP, 14040-901, Brazil