With Kellogg's secrets at hand, The Railroad have plans to use them to help further their goals into infiltrating the Institute and rescuing as many synths as possible.
This quest can be acquired from more than one source, with slight differences in the early stages. The Sole Survivor will need the cybernetic brain augmenter, looted from Kellogg during the course of completing an earlier quest, Reunions.
If acquired from Nick Valentine
Speaking to Valentine in Diamond City after the events of Reunions, Nick will suggest paying a visit to a neuroscientist, Doctor Amari.
If acquired from Desdemona
Desdemona will reveal that Doctor Amari, a scientist under the employment of Memory Den within Goodneighbor, is working for The Railroad, and has the equipment and means to decipher Kellogg's memories. However, in order to access her services, the Sole Survivor must agree to Desdemona's terms, in which she demands the enhancements under her personal possession afterwards. Agree with her terms, or deal with her under less conventional means.
Continuation, regardless of quest giver
At the Memory Den in Goodneighbor, Valentine and Amari will be awaiting the Sole Survivor's arrival with the cybernetic brain augmenter.
Amari will then use Valentine, being a synth, as a conduit for the Sole Survivor to use to travel across each of the still intact memory nodes. After putting both into the memory loungers, they will both be put to sleep, and the experiment will begin.
The Sole Survivor will then need to travel across each of the memory nodes in sequence (the path is linear). Interaction with a memory will reveal more and more of Kellogg's past, and how he ended up finally becoming involved with the Institute.
At the final intact memory node, it is discovered that the Institute uses teleportation technology within its courser models of synth, which must be retrieved to gain access to the Institute.
Valentine will offer advice on how to survive radiation exposure in the Glowing Sea.
Retrieve a Piece of Kellogg's Brain
Talk to Doctor Amari
There's a woman named Doctor Amari who might be able to extract the secrets of entering the Institute from Kellogg's brain.
Sit in the Memory Lounger
Explore Kellogg's memories
Talk to Doctor Amari
Doctor Amari has plugged a piece of Kellogg's brain into Nick Valentine. Now all I have to do is sit down and experience any memories we can find.
Doctor Amari's procedure is complete. I have access to Kellogg's memories. Hopefully one of them will tell me how to find the Institute... and Shaun.
Doctor Amari's procedure was a success. By exploring Kellogg's memories, I learned that the Institute uses teleportation technology, and that a top scientist named Dr. Virgil is hiding out somewhere in the Glowing Sea.