Abstract
The human perceptual system enables us to extract visual properties of an object’s material from auditory information. In monkeys, the neural basis underlying such multisensory association develops through experience of exposure to a material; material information could be processed in the posterior inferior temporal cortex, progressively from the high-order visual areas. In humans, however, the development of this neural representation remains poorly understood. Here, we demonstrated for the first time the presence of a mapping of the auditory material property with visual material (“Metal” and “Wood”) in the right temporal region in preverbal 4- to 8-month-old infants, using near-infrared spectroscopy (NIRS). Furthermore, we found that infants acquired the audio-visual mapping for a property of the “Metal” material later than for the “Wood” material, since infants form the visual property of “Metal” material after approximately 6 months of age. These findings indicate that multisensory processing of material information induces the activation of brain areas related to sound symbolism. Our findings also indicate that the material’s familiarity might facilitate the development of multisensory processing during the first year of life.
Highlights
Material properties of objects1–5 consist of multisensory information such as color, texture, light field, and hardness
The superior temporal region is involved in relatively high-order processing, the mapping of a specific material sound with a visual material property possibly occurs in the superior temporal sulcus (STS) if material information is processed progressively
The results of the present study suggested that the mapping of the auditory material property with visual material in the right temporal region occurs in infants, indicating that audiovisual material information is involved in the relatively high-order processing that envelopes the sound symbolism
Summary
We measured the brain activity in infants using an NIRS system (ERG-4000; Hitachi Medical). In the Wood-sound condition, increased concentrations of oxy-Hb in the right temporal regions during the match trials, but not during the mismatch trials, were observed in both age groups. Condition, at a marginally significant level (match trials: t [7] = 2.32, p = 0.054, d = 0.82; mismatch trials: t [7] = 0.31, p = 0.77, d = 0.11) The responses from this channel (ch 20) could be assumed to be associated with the activation of the right superior temporal sulcus, which is related to the processing of sound symbolism. The individual channel analysis indicated significant differences in oxy-Hb responses in the temporal regions between trials, which suggests that audiovisual material matching is represented in the right superior temporal area in infants already at the age of 6 to 8 months. Our results indicate that such development might depend on a material’s familiarity
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
