Before revision: The brain can display self-sustained activity (SSA), which is the persistent firing of neurons in the absence of external stimuli . This spontaneous activity shows low neuronal firing rates and is observed in diverse in vitro and in vivo situations .
After revision: The brain can display self-sustained activity (SSA), which is the persistent firing of neurons in the absence of external stimuli and contributes to signal propagation, neural coding, and dynamic stability. It also plays an important role in cognitive processes .