“Phosphatidylserine (abbreviated Ptd-L-Ser or PS) is an important phospholipid membrane component (i.e. component of the cell membrane) which plays a key role in cell cycle signaling, specifically in relationship to apoptosis.” – Wikipedia
Phosphatidylserine seems to be a very important component to brain and cellular health.
There seems to be conflicting claims regarding PS and Hypothalamus-Pituitary-Adrenal dysfunction. Some say that it reduces cortisol output while others say that it can increase it.