Functional Advantages of Critical Brain Dynamics

The brain is the organ that connects us with the outer world. Through our brain we experience, learn, progress, adapt, and create memories that make each of us unique. In fact, although we all share the same brain architecture, each of us develops his own representation of objects and surrounding environments. Why is it so? How does our brain elaborate sensory inputs to produce responses and ultimately create our own representation of the world? Questions of this sort puzzled philosophers and scientists for centuries, and still represent a major challenge for modern science. Recent studies suggest that our sensory experience is crucially shaped by the ongoing activity of the brain, which is thought to represent the brains internal state. However, such a state remains, to a large extent, an abstract entity, difficult to capture and quantify. A number of empirical evidence collected in the last two decades support the hypothesis that ongoing brain activity is consistent with a physical state named criticality. Criticality is supposed to provide neural networks with optimal computational capabilities, which would translate into the ability of the brain to promptly and adequately respond to external stimuli by generating a rich variety of coordinated collective behaviors. The hypothesis that the brain operates close to criticality was proposed more than thirty years ago. However, its role in brain functions lacks direct, in vivo empirical evidence. This project aims to directly test this hypothesis by investigating in vivo the role of brain criticality in learning and memory. By quantifying the functional benefits of brain criticality in learning and memory in vivo, the project will ultimately develop a measure of computational performance in relation to distance from a baseline, normal internal state, namely closer or further away from criticality. Providing a measure of the internal state that could be used to assess its functional role in behavioral and cognitive performance will be a major step forward in understanding how our brain interacts with the world around us.