Neural correlates of naming animals from their characteristic sounds

The neural correlates of naming stimuli presented through the auditory modality have scarcely been studied. Using a PET experiment in 10 normal subjects, we began to address this issue by testing the hypothesis that naming animals from their characteristic sounds will engage bilateral primary auditory and auditory association cortices, bilateral early visual association cortices, left inferotemporal (IT) cortices, and left frontal operculum. Subjects listened to characteristic animal sounds (e.g. a rooster crowing), and named the animals making the sounds. When contrasted with a baseline task that involved saying up/down to the direction of pitch change in tone sequences, the naming task produced activation in mesial occipital cortices, the left ventral IT region, and the left frontal operculum. We interpret the activation in visual association cortices to reflect the process of retrieving conceptual knowledge (e.g. physical structure) pertinent to the animals being named, as in visual images. The left IT activation is interpreted to reflect activation of a mediation system for word retrieval, that operates to link conceptual knowledge retrieval to word production, and whose triggering is independent of the sensory modality in which a stimulus is presented.