This fundamental question remains unanswered, but there are some directions in which to search for answers. One suggestion is that chaos is inevitable in so large and complex a system as the simplest brain with its many interconnections. Engineers and computer scientists already find undesired chaos emergent in their more advanced systems. If this is the source and significance of brain chaos, perhaps the study of brain dynamics can show how to function in chaos. Yet the evidence suggests that brain chaos is the result of design by evolution and is not an epiphenomenon of hypercomplexity.
Brains are intrinsically unstable.
Even when animals are at rest and immobile their brains ceaselessly generate temporally unpatterned activity reflected in their EEGs. It is a deterministic output like a complex modern symphony that is orchestrated by the system. It is not a product of the bulb or cortex alone but of these and other parts of the olfactory system in feedback interaction. One role for this mechanism might be to provide unpatterned activity as a form of exercise for neurons, which must keep active or die. This is biologically unrealistic.