Several authors described cases of dissociated impairment in naming nouns and verbs. There are four accounts of this dissociation: (i) patients may have purely lexical damage, which selectively affects verbs or nouns at a late stage of the linguistic processing (phonological or orthographic lexicons) (Rapp & Caramazza, 2002); (ii) the damage affects a lexical device, either at an ortographic-phonological modality-specific level (the lexeme; Levelt, Roelofs, & Meyer, 1999) or at a unitary lexical–syntactic level (the lemma

) (Berndt, Mitchum, Haen-diges, & Sandson, 1997); (iii) N–V dissociation is not a lexical but a semantic phenomenon (Bird, Howard, & Franklin, 2000); (iv) N–V dissociation is due to syntactic damage (Friedmann & Grodzinsky,1997).

To disentangle imageability and grammatical class effects, a new task was developed that allows to elicit nouns and verbs with identical imageability ratings in a sentence context. The results obtained will permit to address the following three questions: Does imageability

play a role in determining N–V dissociation? If so, is imageability the unique cause of dissociation? If there is additional damage, at which level of linguistic processing does it take place?