Doubts about Transcendental Bliss

I'm interested in hearing if someone could contribute input into this topic that has troubled me for a while. I understand from the Bhagavad Gita that Krishna explains the difference between Purusha and Prakriti. Krishna seems to make it clear that the nervous system is part of Prakriti. In our modern era with neuroscience, even something as small as a wikipedia article, tends to show that brain chemicals and receptors are involved in emotions like happiness, euphoria, contentment. In fact, I have read some studies from Andrew Newberg on Neurotheology who even goes as far to explain fmri scans show reduced activity in the parietal lobe in meditating buddhists that experience a blissful formlessness during deep meditation.

How do you integrate current science on mood with your faith? This seems a bit concerning because obviously all of us as humans want to be happy but we face many difficulties in our lives and it makes one think about how their brain chemicals and receptors fluctuate and for those of us who tend to get stressed easily, we certainly know a bit more than just an intellectual understanding of the transitory aspect of life, let alone many dharma traditions speak of transitory pleasure and pain and then speak of bliss.