An interspatial manifold was an advanced technology used by races such as the Sphere-Builders and the Borg.
The Delphic Expanse spheres each contained an interspatial manifold, used for gravimetrically linking all of the spheres to create the Expanse. In 2154, Enterprise NX-01 used a deflector pulse to disable the manifold on Sphere 41, setting off a chain reaction which destroyed the entire Sphere network. (ENT: "Countdown", "Zero Hour")
The Borg utilized a series of hexagonal interspatial manifold structures to support their transwarp hubs. These manifolds were protected by shielding which was regulated from the central nexus by the Borg Queen herself. In 2378, Captain Janeway's counterpart from twenty-six years in the future deliberately infected herself with a neurolytic pathogen, and subsequently allowed herself to be assimilated by the Borg Queen, as part of a plot to destroy the Borg's transwarp network. As the pathogen began to take effect, the Queen lost contact with the majority of the Collective, and the shielding protecting the interspatial manifolds supporting the network, which the Queen regulated personally, began to destabilize. This allowed the crew of the USS Voyager to fire a series of transphasic torpedoes, destroying the manifolds and causing the network to collapse. (VOY: "Endgame")