Visual and haptic object priming have a similar effect on fMRI activation in extra-striate cortex [e-mail]

Abstract

Vision is the primary sensory modality used by humans and other primates for object recognition. Although we are capable of discriminating shape, texture and other characteristics of objects using our sense of touch (haptics), it has been suggested that our ability to process information haptically might rely on visual imagery and thus, on the activation of purely visual representations. To address the question of whether or not visual and haptic information have overlapping neural representations, we used high-field fMRI to measure the effects of cross-modal priming (haptic — visual) on brain activation. Subjects studied 3D novel clay objects either visually or haptically before entering the scanner. During scanning, subjects passively viewed visually and haptically studied objects as well as non-studied objects. After scanning, subjects completed an old/new recognition test with the same set of studied and non-studied objects. Studied objects produced more activation than non-studied objects in both the fusiform gyrus (FG) and middle occipital gyrus (MOG). In the posterior FG and MOG, there was no difference in signal between visually and haptically studied objects, but in areas of the anterior FG, there was a selective enhancement in the signal for visually studied objects. These results suggest that haptic exploration of objects can affect later processing in visual areas of the brain and that these effects are similar to those produced by visual exploration of objects.

Footnotes

 Supported by a CIHR grant to MAG and an NSERC grant to GKH (Canada).