Recently I learned that our noses can remember 50,000 different scents. Impressive, even more, is that memories can be recalled in detail from way back in our past.
So if you recall as a child smelling your mother’s perfume your brain waves will respond including neural networks with synchronized brain waves of 20-40 Hz. Emotions corresponding to memory will cause endorphin secretion and more. Brain waves connect smell through memories and smell is the strongest retainer