“Eventually, Deleuze concluded that “subjectification, events and brains are more or less the same thing.” So the brain was fundamental to Deleuze’smaterialist philosophy. Nevertheless, he wanted to allow for a metaphysics within this materialism,and here the brain was to become crucial.
The problems involved are outlined in The Logic of Sense,
precisely when discussing the relations between the corporeal (bodies, actions) and the incorporeal (events, sense, meaning “as an encounter of force fields”). Deleuze writes of the confusion (in the mouth) of speech, language, and eating, or: “The struggle between the mouth and brain . . . eating, on the one hand, and thinking, on the other, where the second always risks disappearing into the first, and the first, on the contrary, risks being projected onto the second.”
http://www.academia.edu/1992988/Deleuze_Guattari_and_Neuroscience