Related Experiment Videos
Activation of auditory cortex during silent lipreading
G A Calvert1, E T Bullmore, M J Brammer
1Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford OX3 7JX, UK. gemma.calvert@psychiatry.ox.ac.uk
Science (New York, N.Y.)
|April 25, 1997
Summary
Visual lip cues from speech significantly enhance speech perception, especially in noise. Functional MRI shows lipreading activates the auditory cortex even without sound, demonstrating its prelexical influence.
Area of Science:
- Neuroscience
- Auditory Perception
- Visual Speech Processing
Background:
- Lipreading during conversation improves speech perception, particularly in noisy environments.
- Previous research suggests visual speech information influences auditory processing.
Purpose of the Study:
- To investigate if visual linguistic cues from lip movements alone can activate the auditory cortex.
- To determine if this activation is specific to speech-related movements.
Main Methods:
- Functional magnetic resonance imaging (fMRI) was used to measure brain activity in normal-hearing individuals.
- Participants viewed different types of visual stimuli: silent speech, pseudospeech (meaningless speech-like movements), and nonlinguistic facial movements.
Main Results:
- Viewing lip movements associated with speech (lipreading) activated the auditory cortex in the absence of sound.
- Activation was not observed when viewing nonlinguistic facial movements.
- Silent pseudospeech also elicited activation in auditory cortical areas.
Conclusions:
- Visual speech information, including meaningless speech movements, is sufficient to activate the auditory cortex.
- This activation occurs at a prelexical stage, influencing auditory speech perception before word recognition.
- Findings support the integration of visual and auditory speech information in the brain.