I came upon another site the other day and read this . . .
Neuroscientists have discovered that the heart has it’s own independent nervous system, a complex system referred to as the “brain in the heart”. There are at least 40,000 neurons (nerve cells) in the heart, this can be as many neurons as are found in some parts of the brain. And this “brain in the heart” has the ability to relay information back to the brain creating a two-way communication system between the heart and brain. Physiologists John and Beatrice Lacy discovered that when the heart sends messages to the brain the brain not only understands the messages but also obeys them. ~ Mind Body Solutions
which caused me to search a little more where I found these -