That Lucio Fulci sure loved kitty cats, so much so that he made a film of Edgar Alan Poe's THE BLACK CAT in 1981. That was not enough, however; cats also feature in DEMONIA (a rather ridiculous puppet) and in this 1990 flick, as seen below.
I've never managed to track down a copy of this particular film, but I understand that the plot involves Fulci playing himself undergoing a nervous breakdown, which includes flashbacks to his past films. He goes to a shrink for help, but the psychiatrist turns out to be insane, killing people and blaming it on Fulci. If I've heard correctly, there is a scene that justifies the title by showing a cat literally eating a brain, but I'll believe that when I see it (although I don't know why I should doubt Fulci was capable of presenting such an image).
Keith Brown, the expert on this kind of thing, opines:
Watching Cat in the Brain, you get the sense of acquiring an insight into Fulci the man. All he really wanted in his old age, it would seem, was to be recognised as a serious, intelligent artist and loved as a human being.
Commercial constraints thus dictated that Fulci's 8 1/2 [...] had to be bloody. Indeed, taken purely on a count of such incidents, it's perhaps his goriest and nastiest film. Unfortunately, however, the majority of the splatter effects are poorly realised and unconvincing. Admittedly, Fulci's criticism of some effects in the film-within-the-film that he is working on do provide for a self-critical reading, but one suspects the typical gorehound would neither be interested in or willing to accept such.
Worse, they are just about the only other thing the film has going for it. Where Fulci's earlier gialli – even the much reviled New York Ripper – had atmosphere, style and mystery to keep the viewer interested, here the fact that we know the killer's identity, even if 'Fulci' doesn't – seriously undermines things, along with the difficulty of creating satisfactory matches between material culled from the various sources. (The relationship between psychoanalyst and prospective killer was better handled in Lizard in a Woman's Skin as well.)
Nevertheless, any film in which the director-protagonist writes himself a happy ending wherein he and the starlet old enough to be his daughter sail off into the sunset on a boat named "Perversion" – remembering that the alternative title of Fulci's1969 One on Top of the Other was Perversion Story – has to be saying something, consciously or not…