This Atika Kadisha, Arich Anpin, is hidden and concealed. The upper incomprehensible Chochmah is present in that head, Keter of Arich Anpin. The head alone is visible in Atika. The head is the first three Sfirot of Arich Anpin that are called head; but the seven lower Sfirot of Arich Anpin are encased in Aba and Ima, the Male and Female of Atzilut and are therefore not revealed, for it is the beginning (head) of all beginnings; all the Partzufim of Atzilut are connected to it: Aba and Ima encase its Chesed, Gvurah and Tiferet; the Male and Female encase its Netzach, Hod and Yesod.
The other Partzufim of Atzilut, however, are not encased by their lower counterpart but only by the lower three Sfirot – Netzach, Hod and Yesod; their Keter, Chochmah, Binah, Chesed, Gvurah and Tiferet are exposed. The upper Chochmah – the head, as said before – is imperceptible within the head of Arich Anpin and is called the upper brain, the concealed brain, the calm and silent brain. None can comprehend it save for itself.