1.4. Freudian Psychology.
The most evident influence of Freud in Joyce's work is the interior monologue, however Freudian psychology is present in Joyce's imagery as well. In "Cliffs Notes on Joyce's Portrait..." an example of Freudian imagery is given, which refers to the moment when Stephen the child begins to imaginatively open and close the flaps of his ears, creating a Freudian-like sensation of a "train going in to a tunnel". In this book is explained that this image belonging to Freud, refers not only to the experience of childbirth, but it also is related to Stephen's separation from home.
But we find in Finnegans Wake the clearest example of Freudian imagery due to the fact that it describes a dream. Katie Wales comment in The Language of James Joyce, that in Finnegans Wake "the reader is forced into the role of a psychoanalyst, searching for the keys to interpretation"; she explains how the idea of incest through the insect imagery and puns appears in the novel.
(Section 2 in "Joyce's Use of Imagery in Different Topics")