Shape conveyed by visual-to-auditory sensory substitution activates the lateral occipital complex

Area of Science:

• Neuroscience
• Sensory Perception
• Cognitive Science

Background:

• The lateral-occipital tactile-visual area (LOtv) is known to be involved in object recognition using visual or tactile input.
• Previous research has not explored the role of LOtv in object recognition through auditory sensory substitution.

Purpose of the Study:

• To investigate whether the LOtv is activated when individuals recognize objects using shape information derived from visual-to-auditory sensory substitution soundscapes.
• To determine if LOtv activation is dependent on the presence of shape information versus other auditory cues.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used to measure brain activity in sighted and blind participants.
• Participants engaged in object recognition tasks using soundscapes generated from visual information.
• Control conditions included recognizing objects by their typical sounds and learning arbitrary soundscape-object associations.

Main Results:

• The LOtv showed significant activation when participants recognized objects by extracting shape information from auditory soundscapes.
• Activation in LOtv was not observed when recognizing objects by their inherent sounds or through learned associations.
• This pattern held true for both sighted and blind individuals.

Conclusions:

• The lateral-occipital tactile-visual area (LOtv) is sensitive to shape information, regardless of the sensory modality through which it is perceived.
• LOtv's role in object recognition extends beyond vision and touch to include auditory sensory substitution, highlighting its function in abstract shape processing.
• The findings suggest that LOtv is a cross-modal region primarily driven by the extraction of shape information.