title: The Thatcher illusion reveals orientation dependence in brain regions involved in processing facial expressions.
abstract: Although the processing of facial identity is known to be sensitive to the orientation of the face, it is less clear whether orientation sensitivity extends to the processing of facial expressions. To address this issue, we used functional MRI (fMRI) to measure the neural response to the Thatcher illusion. This illusion involves a local inversion of the eyes and mouth in a smiling face-when the face is upright, the inverted features make it appear grotesque, but when the face is inverted, the inversion is no longer apparent. Using an fMRI-adaptation paradigm, we found a release from adaptation in the superior temporal sulcus-a region directly linked to the processing of facial expressions-when the images were upright and they changed from a normal to a Thatcherized configuration. However, this release from adaptation was not evident when the faces were inverted. These results show that regions involved in processing facial expressions display a pronounced orientation sensitivity.
authors.affiliation: Department of Psychology and York Neuroimaging Centre, University of York.
authors.forename: Lilia
authors.initials: L
authors.lastname: Psalta
authors.forename: Andrew W
authors.initials: AW
authors.lastname: Young
authors.forename: Peter
authors.initials: P
authors.lastname: Thompson
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Andrews
mesh_terms: D000328:Adult; D005149:Facial Expression; D005260:Female; D006801:Humans; D007088:Illusions / Q000502:physiology*; D008279:Magnetic Resonance Imaging; D008297:Male; D010364:Pattern Recognition, Visual / Q000502:physiology*; D013702:Temporal Lobe / Q000502:physiology*; D055815:Young Adult
keywords: cognitive neuroscience; face perception; facial expressions; facial features; neuroimaging