How did the Espansor Bands change their brains?

The Espansor Bands have figured prominently in Rome's Revolution since the beginning. They were an important part of the original VIRUS 5, the long-form version of Rome's Revolution and the modern version.

The bands themselves are purely electromagnetic in nature and just extremely sensitive versions of an EEG plus a pulsed magnetic driver. They sense brain waves and stimulate portions of the brain with a positive feedback loop. They are intended to be nothing more than walkie-talkies inside the head. They were helpful to the Vuduri, especially the ones who could not speak, to communicate with the mandasurte. They also allowed the Vuduri to learn to communicate with animals.

However, they were never supposed to be anything more than that. So why did they have such an incredible effect on Rei and Rome and Binoda and Fridone before that? And what did they do to them? Rome tried to explain:

     “What about Aason, though? Is he part of this?” Rei asked.
     “Yes and no,” Rome said, rubbing her tummy lightly. “You were very kind to never ask me, even once, how it was that I let myself get pregnant.”
     “Well, you told me that Vuduri women control when they ovulate. So I just figured it was your decision.”
     “No, it was not my plan,” Rome said. “I have been changed. You have changed me, my physiology.”
     “How?”
     “The bands, they are not…read-only, as you say. They are interactive.”
     “I know that,” Rei said. “I get to live in your memories. I know everything there is to know about you.”
     “It is more than that,” said Rome. “For us, the bands do more. How it happened for us is not their normal function. They have altered our neural pathways. We are…imprinted on each other. We are bound in a way that others never get to experience. It can only be for Asborodi Cimponeti.”

But the effects of the bands go even deeper than Rome realized. Rei's mind became more alert, more active, and reminiscent of the movie Charlie or Phenomenon. It also made Rome more intuitive since many of Rei's cultural ideas were planted deep within her psyche even when she didn't fully realize it.

In the end, their experiences with the bands made Rei and Rome a system which was more capable of solving problems that any person or any couple in the history of mankind.