Bio-neural gel packs are organic components containing synthetic neural tissue, used in Intrepid-class starships such as Voyager to process information faster than conventional circuitry.
Voyager's computer system incorporated gel packs that mimic the workings of living neurons, allowing faster and more flexible data processing. The design gave the ship an edge in speed, but it also meant that the computer could be affected like a living body.
The vulnerability became clear when bacteria from a cheese Neelix was making infected the gel packs, causing systems throughout the ship to fail. The Doctor and B'Elanna Torres raised the ship's temperature to induce a fever and kill the infection.