I found out that the mind and the body are interrelated but completely different in nature. The body is physical, made of atoms; it has shape and color. The mind is formless, clear light in nature, and has the ability to perceive objects; there's no way it can come from the brain. The body starts at conception; the mind is beginningless. At conception, the consciousness, which comes from the previous life, enters the fertilized egg. Each individual's previous lives are infinite in number and it is one's own discrete stream of consciousness that passes through them all. Thus, our present mind is the result of everything we have ever been and done, and our future mind and lives depend upon what we do today. This is the same for all of us.
The good news is that all sentient beings have the potential to reach enlightenment, the highest possible state of mind, everlasting, blissful happiness, because we all have clear light nature of mind. Enlightenment is what the Buddha himself attained way back in India more than 2,500 years ago, what he shared with his disciples, and what has been taught by a succession of Indian, Tibetan and other masters in an unbroken lineage going back to the historical Buddha himself.
A sentient being is a being whose mind is ignorant; a buddha is a being who was once a sentient being but became enlightened by totally purifying his or her mind of ignorance and fully imbuing it with the qualities of compassion and wisdom. Buddhist meditation teaches us to cleanse our own minds of ignorance and the other delusions that spring from it, such as attachment, jealousy, pride and hatred - which obscure our mind's clear light nature and are the actual cause of all the suffering we experience - and to develop desirable attributes such as love, compassion, tranquility, concentration and divine intelligence, which are the cause of all happiness.