The regular brain...
Cca 60 % of the heart cells are of the NEURAL type. The heart is a center of intelligent information processing. That has been known also for many years.
Now they discovered a third brain, in the stomach:
(they call it the second, but actually it is the third)
However, the Chinese have known for centuries about the existence of these three brains:
http://www.ichikung.com/html/dantians.php
There is nothing new under the sun ? Not exactly. We know now what the Chinese have known for many centuries...but we know it in much more detail,
with explanation of biological processes and with development of new medical
drugs and procedures. This is known in dialectic as "negation of negation."
Knowledge cannot be frozen in time: it changes, and changes, and changes...