Researchers at the University of Michigan have found that while the brains of people with migraine generally operate in a less flexible manner, neural activity temporarily becomes more chaotic during a migraine attack. According to the authors, this process may represent a form of "reset" for the brain's neural networks. The findings were published in NeuroImage.

The study included 66 participants: healthy volunteers, patients with episodic migraine, and individuals with chronic migraine. Using functional MRI (fMRI), the researchers measured brain entropy—a metric that reflects the diversity and unpredictability of neural activity. Higher brain entropy is thought to indicate greater flexibility in information processing and adaptation to changing conditions.

The results showed that people with migraine had lower brain entropy on average than healthy participants, with the greatest reduction observed in those with chronic migraine. The longer participants had lived with migraine and the more frequent their attacks, the more rigid their neural network activity appeared to become.

However, the researchers observed the opposite pattern during an active migraine attack. Brain entropy temporarily increased in regions involved in processing visual, auditory, and other sensory information. Further analysis indicated that this was not simply random neural noise but rather a phenomenon known as chaotic dynamics—a state in which the brain becomes more sensitive to change and is able to break away from its usual patterns of activity.

The authors suggest that a migraine attack may temporarily disrupt overly stable neural network activity, allowing the brain to shift into a more flexible state. However, the study does not demonstrate that this process is beneficial, nor does it explain why such a reorganization is accompanied by the severe headache characteristic of migraine.