Auditory-Visual Speech Processing (AVSP'99)
August 7-10, 1999
Which brain networks support simple silent speechreading (identifying spoken numbers by eye alone)? We summarize recent fMRI findings that show auditory cortex is reliably activated by seen speech. Activation of these regions is robust under numerous testing conditions, and parts of the network are specific to speechreading rather than viewing faces performing rhythmic lower face movements that cannot be construed as speech (facial gurning). In one adult with a longstanding malfunction of auditory cortex, speechreading was both functionally impaired and cortically anomalous. Areas traditionally described as auditory cortex are probably specialized for the perception of natural segmented language, rather than for the perception of heard signals.
Bibliographic reference. Campbell, Ruth / Calvert, G. / Brammer, M. / MacSweeney, M. / Surguladze, S. / McGuire, P. / Woll, B. / Williams, S. / Amaro, E. / David, A.S. (1999): "Activation in auditory cortex by speechreading in hearing people: fMRI studies", In AVSP-1999, paper #7.