Heart, mind, brain domination

What is effect of heart on mind in reality? Is it the effect due to coziness felt across the walls of heart (similar to the one felt by a child sitting in the parent's lap) leading to the change in perception, can be bad (ill hearted), can be good(emotional), can be right(compassion). Or Is that effect due to the oxygen interchanged blood? Blood having usedup O2 usually accompanied with various deep rooted sankharas/emotions/pictures/previous-deeds and blood which got injected by fresh O2 has very low quanties of them. This 2nd one seems little clearer and unveils some concepts like,"how come compassion around an arhat's body is so strong" at physical level. Any Buddha's teaching/sutta in this meditation context.