title: The 170ms Response to Faces as Measured by MEG (M170) Is Consistently Altered in Congenital Prosopagnosia.
abstract: Modularity of face processing is still a controversial issue. Congenital prosopagnosia (cPA), a selective and lifelong impairment in familiar face recognition without evidence of an acquired cerebral lesion, offers a unique opportunity to support this fundamental hypothesis. However, in spite of the pronounced behavioural impairment, identification of a functionally relevant neural alteration in congenital prosopagnosia by electrophysiogical methods has not been achieved so far. Here we show that persons with congenital prosopagnosia can be distinguished as a group from unimpaired persons using magnetoencephalography. Early face-selective MEG-responses in the range of 140 to 200ms (the M170) showed prolonged latency and decreased amplitude whereas responses to another category (houses) were indistinguishable between subjects with congenital prosopagnosia and unimpaired controls. Latency and amplitude of face-selective EEG responses (the N170) which were simultaneously recorded were statistically indistinguishable between subjects with cPA and healthy controls which resolves heterogeneous and partly conflicting results from existing studies. The complementary analysis of categorical differences (evoked activity to faces minus evoked activity to houses) revealed that the early part of the 170ms response to faces is altered in subjects with cPA. This finding can be adequately explained in a common framework of holistic and part-based face processing. Whereas a significant brain-behaviour correlation of face recognition performance and the size of the M170 amplitude is found in controls a corresponding correlation is not seen in subjects with cPA. This indicates functional relevance of the alteration found for the 170ms response to faces in cPA and pinpoints the impairment of face processing to early perceptual stages.
authors.affiliation: Dept. of Neurology, Campus Benjamin Franklin, Charité - University Medicine Berlin, Berlin, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Lueschow
authors.affiliation: Dept. of Neurology, Campus Benjamin Franklin, Charité - University Medicine Berlin, Berlin, Germany.
authors.forename: Joachim E
authors.initials: JE
authors.lastname: Weber
authors.affiliation: Department of General Psychology and Methodology, University of Bamberg, Bamberg, Germany.
authors.forename: Claus-Christian
authors.initials: CC
authors.lastname: Carbon
authors.affiliation: Dept. of Neurology, Campus Benjamin Franklin, Charité - University Medicine Berlin, Berlin, Germany.
authors.forename: Iris
authors.initials: I
authors.lastname: Deffke
authors.affiliation: Physikalisch-Technische Bundesanstalt, Berlin, Germany.
authors.forename: Tilmann
authors.initials: T
authors.lastname: Sander
authors.affiliation: Department of General Psychology and Methodology, University of Bamberg, Bamberg, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Grüter
authors.affiliation: Department of General Psychology and Methodology, University of Bamberg, Bamberg, Germany.
authors.forename: Martina
authors.initials: M
authors.lastname: Grüter
authors.affiliation: Physikalisch-Technische Bundesanstalt, Berlin, Germany.
authors.forename: Lutz
authors.initials: L
authors.lastname: Trahms
authors.affiliation: Dept. of Neurology, Campus Benjamin Franklin, Charité - University Medicine Berlin, Berlin, Germany.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Curio
mesh_terms: D000328:Adult; D001921:Brain / Q000503:physiopathology; D004569:Electroencephalography; D005074:Evoked Potentials, Visual; D005145:Face; D005260:Female; D006801:Humans; D007407:Interviews as Topic; D015225:Magnetoencephalography; D008297:Male; D008875:Middle Aged; D020238:Prosopagnosia / Q000151:congenital* / Q000503:physiopathology; D021641:Recognition, Psychology / Q000502:physiology; D013997:Time Factors; D014796:Visual Perception; D055815:Young Adult