Different developmental trajectories of critical dynamics in prefrontal cortex–amygdala circuitry

Abstract Neuronal avalanches, a hallmark of self-organized criticality, represent cascading activity among interconnected neurons. Despite their hypothesized role in neuronal maturation, developmental patterns of neuronal avalanches across interconnected brain regions in vivo remain unelucidated. We applied avalanche analysis to investigate the emergent features of functional connectivity in the developing medial prefrontal cortex–basolateral amygdala (mPFC–BLA) circuitry, using simultaneous electrophysiological recordings from the BLA and mPFC in juvenile and young adult anaesthetized rats. The avalanches were mainly confined to either mPFC or BLA, a small number spanned both regions. Prefrontal avalanches exhibited scale-free behavior with branching ratio close to one and decreasing over development; amygdaloid avalanche size distributions displayed a sharp peak at the maximum size, more pronounced in adulthood, which together with branching ratios over one suggests a deviation from criticality toward a supercritical state. Different dynamical regimes in the BLA and mPFC fit distinct functional demands of these regions.