title: Left ventral occipitotemporal activation during orthographic and semantic processing of auditory words.
abstract: The present fMRI study investigated the hypothesis that activation of the left ventral occipitotemporal cortex (vOT) in response to auditory words can be attributed to lexical orthographic rather than lexico-semantic processing. To this end, we presented auditory words in both an orthographic ("three or four letter word?") and a semantic ("living or nonliving?") task. In addition, a auditory control condition presented tones in a pitch evaluation task. The results showed that the left vOT exhibited higher activation for orthographic relative to semantic processing of auditory words with a peak in the posterior part of vOT. Comparisons to the auditory control condition revealed that orthographic processing of auditory words elicited activation in a large vOT cluster. In contrast, activation for semantic processing was only weak and restricted to the middle part vOT. We interpret our findings as speaking for orthographic processing in left vOT. In particular, we suggest that activation in left middle vOT can be attributed to accessing orthographic whole-word representations. While activation of such representations was experimentally ascertained in the orthographic task, it might have also occurred automatically in the semantic task. Activation in the more posterior vOT region, on the other hand, may reflect the generation of explicit images of word-specific letter sequences required by the orthographic but not the semantic task. In addition, based on cross-modal suppression, the finding of marked deactivations in response to the auditory tones is taken to reflect the visual nature of representations and processes in left vOT.
authors.affiliation: Centre for Cognitive Neuroscience, University of Salzburg, Austria. Electronic address: philipp.ludersdorfer@sbg.ac.at.
authors.forename: Philipp
authors.initials: P
authors.lastname: Ludersdorfer
authors.affiliation: Centre for Cognitive Neuroscience, University of Salzburg, Austria.
authors.forename: Heinz
authors.initials: H
authors.lastname: Wimmer
authors.affiliation: Centre for Cognitive Neuroscience, University of Salzburg, Austria.
authors.forename: Fabio
authors.initials: F
authors.lastname: Richlan
authors.affiliation: Centre for Cognitive Neuroscience, University of Salzburg, Austria.
authors.forename: Matthias
authors.initials: M
authors.lastname: Schurz
authors.affiliation: Centre for Cognitive Neuroscience, University of Salzburg, Austria.
authors.forename: Florian
authors.initials: F
authors.lastname: Hutzler
authors.affiliation: Centre for Cognitive Neuroscience, University of Salzburg, Austria; Neuroscience Institute, Christian-Doppler-Clinic, Paracelsus Medical University, Salzburg, Austria.
authors.forename: Martin
authors.initials: M
authors.lastname: Kronbichler
mesh_terms: D000161:Acoustic Stimulation; D000293:Adolescent; D000328:Adult; D001307:Auditory Perception / Q000502:physiology*; D001931:Brain Mapping; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D059906:Neuroimaging; D009778:Occipital Lobe / Q000502:physiology*; D010897:Pitch Discrimination / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology; D012660:Semantics; D013067:Speech Perception; D013702:Temporal Lobe / Q000502:physiology*; D055815:Young Adult
keywords: Neuroimaging; Orthography; Semantics; VWFA; Ventral occipitotemporal cortex; fMRI