Infraspace

Infraspace is a region in the IDW comics portion of the Generation 1 continuity family.

They're actually both looking for characterization. Let's see what you can see... This article is in need of images. Specifics: picture of Prime in infraspace from Escalation #6

Not much is known of infraspace. A Transformer can seemingly exist there without a body, or perhaps it is where a Transformers' mind or spark exist when their bodies have been destroyed.

Fiction

IDW comics continuity

Optimus Prime had received a severe beat-down from an Ore-13-powered Megatron, and was on the verge of terminal shutdown. In a desperate ploy, he transferred his higher functions into his trailer section, giving the appearance of lifelessness.

During the transfer, Prime's consciousness drifted through infraspace. While there, he felt a sinister presence that seemed to recognize and watch him. Escalation (issue 6)

The term "intraspace" was not used in Escalation, but when Prime later related the experience to Omega Supreme, he referred to his disembodied state as being in "infraspace". Spotlight: Optimus Prime

The connection between infraspace and the Dead Universe, if any, has yet to be revealed.