Jai Sai Master, Babu garu..
Jai Sai Master, Sai Bandhus..
Jai Sai Master, Srusti..
Sai Bandhus, I don't mean to be funny but here it is.
Brain: Physical part of our body.
Mind: Thinking process that happens in the Brain.
Heart: Although a body part, in this particular context, it is an unseen sense perception, something like "thinking with the heart", which again is amost like Mind. So, in this particular context, Mind and heart are similar processes, only they take 2 different roads, one logical and one illogical, materialistically speaking.
Babu garu, Srusti has asked a very good question. It is my inability to give crisp answers that I don't even want to attempt an answer to this budding mind of Srusti. But at the same time I just wanted to share my thoughts on the following.
In the meanwhile, I would like to give this link to Srusti to go through which you have typed. Please delete it if you think that it is beyond the scope of this discussion, because what you have typed there should last several years to even understand them.
http://www.brchaitanya.org/saimasterforums/index.php?topic=47.165 Also Babu garu, these are some of the things that I read.
Thought is an electrical impulse that happens in the brain. With the latest technology, the scientific community has gone to the extent of video recording the nerves to get the electrical impulses that are happening whenever a person is thinking. Science is giving particular importance to this process probably because they want some groundbreaking knowledge on treating Alzeimers disease.
So, just like you said, Science is able to successfully see that the sparks are there in the brain, whenever a thought occurs, but we are still not able to see the source of that firing process. One example that I can readily see is this.......
We have 2 wires in each hand and when we touch one with the other, we see some sparks. That's exactly what is happening in the brain, and so we can (can we??) equate the process of touching wires to thinking. I am just trying to see how we can relate Spirituality to science in this context.
Everytime, I observe this point, it just stops dead in its track. When you THINK (or see or observe) where a particular thought is coming from, it gets blank. COMPLETELY BLANK. It's like you in a room with a bright light, suddenly the light is gone, and it is completely pitch dark, you cannot see anything in front, you will feel like you are blind. The same blindness happens to the mind when we try to investigate where a thought is coming from. At this point, I am sure Sai Bandhus are thinking I am Weird.

Regards to all,
Jai Sai Master!
Ananth