The terms "Antahkarana" and "Sutratma" are used to distinguish between those threads that connect the persona and Soul, and those that connect the Soul and Spirit.
However, D.K. indicates that the distinction in terminology between antahkarana and sutratma is arbitrary. Thus, in one system "Antahkarana" may refer to the "Rainbow Bridge" between the persona and the Soul, while in another it refers to the higher correspondent that links the Soul and Spirit.
In The Nature of The Soul (NS) and the related material, the term "antahkarana" is used for both, or rather, it is used for the entire line of light from the persona to the Spirit. This is an unimportant slight variation in terminology, resulting from the Synthetic approach, but should be kept in mind.
The antahkarana was "broken" by the Spiritual Hierarchy in Atlantean times, in an effort similar to, say, cutting the power to a runaway machine. This stopped worst of the destruction, but left humanity cut-off from intimate contact with its Soul.
The "break" in the antahkarana appears to be on the fourth subplane of the mental plane. This places it above the frequency of the throat center, but within that of a fully functional ajna. The antahkarana is rebuilt through aspiration to, contact and at-one-ment with the Overshadowing Spiritual Soul, and embodiment of the life of the Overshadowing Soul in the three lower worlds and world of affairs.
This creative process automatically rebuilds the antahkarana. However, in the new process of group initiation, all of this is done as part of an effort by a group unit, within the Ashramic Group Life, to reflect its Ashramic life and affairs into the three lower worlds and become, as a group, the Spiritual Soul Incarnate.
The line from the Soul to the Crown may be experienced as more "present", and as it moves downward this will enliven the lower center system, but in order to be completed, the new growth must be grounded via a service activity that reflects the life and affairs of the Overshadowing Soul.
This grounding also gives the downward moving energy a place to go, preventing it from backing up in the persona instrument (which can be quite painful). This outward movement is part of a triangular alignment (much like that of the See-La-Aum technique in NS 35) down from the overshadowing, out to the embodied group, condition, whatever, and back up from that group to the overshadowing source.
In this regard, I strongly suggest that you focus on invoking your service work as part of the Ashramic Group Life, taking up whatever inner and outer service work that offers itself as a prelude to the actual work.
For more on the See-La-Aum technique, I suggest you see the article on the “Ceremony of Life”.