The mind (mana) and the energy spirit (prana, chi or life force) have always had an affinity for each other, being merely the two sides of the same coin. Whatever the mind engages upon is soon infused with life energy, and conversely, whatever the soul hungers for instantly engages our attention. As a result, certain aspects of each are present in the other.
Out of the two, the mind is the finer and more sophisticated version of the cruder life force or prana—it has a storehouse of its own energy and vitality. Some aspects of it naturally spills over, flooding the spirit with thought and intelligence (buddhi). But it is the vital force, which is inherently a conscious power, finding its expression in the mind, which is inherently the active force.
Both prana and mana (mind) are vata (vital force) humoral types, composed of air and ether. But being composed more of the air element rather than the ether, the prana is more active and energetic—like the wind! On the other hand, since the degree of ether is more in the composition of the mind, its nature is receptive and passive—like the wide open spaces.