An Interesting Paper

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

Amir Amedi 1,2, William Stern 1, Joan A. Camprodon 1, Felix Bermpohl 1,3, Lotfi Merabet 1, Stephen Rotman 1, Christopher Hemond 1, Peter Meijer 4 and Alvaro Pascual-Leone

This paper reports some functional characteristics of a part of brain known as the lateral-occipital tactile-visual (LOtv) area. Traditionally, this part is known to be activated when a person observes the shape of an object through vision or touch. In this paper, it is claimed that this part of brain is responsible for analyzing shape of an object regardless of the modality of the incoming signal. This assertion has been made based on an experiment where the authors analyzed the functional characteristics of the LOtv area in response to sensory substitution soundscape.

VOICE is a computer program that converts the raw pixel intensities of a picture into a soundscape. There are some blind and sighted expert users who can perceive the shapes of objects by listening to the soundscapes. Neural images of these people’s brain reveal that when they try to perceive the shape of an object from the soundscape, their LOtv area activates. Moreover, this happened only to the people who were trained to interpret the soundscape and can extract shape information from it. People, who associate a particular soundscape to a particular shape of an object, do not display any activity in this area.

The authors have proposed a hypothesis based on this observation. They claimed that, the LOtv processes the shape information regardless the modality of sensory signal.