Brain

Brain=

A Brain is an item in Pathologic 2. It can be harvested from corpses, is used in both trade with Var and the Fellow Traveller, and can also be used in painkiller creation.

Quotes
Half Brain=

A Half Brain is an unused item in Pathologic 2 only accessible by utilizing the console commands to place it in the player's inventory. It has no functional use, though it is likely it would be used in medicinal brewing and trade with the Fellow Traveller.

A Half Brain section can be seen in a pre-release trailer that previews the surgery mechanic, suggesting that with the use of a Trepanner, one could collect either a full brain or half brain section.

Quotes
Infected Brain=

An Infected Brain is an item in Pathologic 2. It can be harvested through infected corpses and is used in trade with the Fellow Traveler, and can also be used in antibiotics creation.