A great resource for thoroughly vetted studies and peer-reviewed papers is the m.f.network’s linktree. The m.f.network is a DID system that is high up in the research field of trauma and dissociation and has an incredible collection of resources. I highly recommend looking into the work they do for any professional in the field. 

Studies

Neuro-imaging Dissociative Identity Disorder

The leading researcher in neuro-imaging for DID is Dr. A.A.T. Simone Reinders. These are the papers that have been written based off of testing that has been completed, more are being worked on. 

Two Ph.D. students have completed their thesis and gotten their degrees under Dr. Reinders. 

Dr. Eline Vissa’s thesis.                        Dr. Sima Chalavi’s thesis.

A full list of Dr. Reinder’s publications.

Dr. Reinder’s biography.

Sleep, Trauma, Fantasy, and Cognition in DID

Link to a peer reviewed study available via King’s College London’s Research Portal.