Addressing skepticism of the critical brain hypothesis

Area of Science:

• Computational Neuroscience
• Complex Systems Theory
• Statistical Physics

Background:

• The criticality hypothesis posits that living neural networks function optimally near a critical phase transition point.
• Optimal information processing and neural health are theoretically and experimentally linked to operation near this critical point.
• Recent critiques by Touboul and Destexhe challenge the universality and interpretation of criticality in neural systems.

Purpose of the Study:

• To address and refute recent objections to the criticality hypothesis concerning neural networks.
• To clarify the conditions under which neural network models exhibit signatures of criticality.
• To differentiate true emergent criticality in neural networks from artifacts of simpler random processes.

Main Methods:

• Analysis of the Brunel model for cortical networks to assess mutual information near phase transitions.
• Comparison of criticality signatures in neural network models versus random walk models.
• Evaluation of collective interactions, information processing capabilities, and temporal correlations in different models.

Main Results:

• The Brunel model does exhibit a peak in mutual information near its phase transition when not excessively driven by random inputs.
• While random walk models can mimic some criticality signatures, they lack emergent collective interactions, robust information processing, and long-range temporal correlations.
• These absent features in random walk models are consistently observed in living neural networks.

Conclusions:

• The objections raised have been addressed, refining the understanding of criticality in neural networks.
• True criticality in neural networks, characterized by collective interactions and information processing, is distinct from simple thresholded random walks.
• The criticality hypothesis remains a valuable framework for understanding neural function, with ongoing research benefiting from critical scientific discourse.