Crossmodal interactions of haptic and visual texture information in early sensory cortex

• Published in: NeuroImage (Orlando, Fla.) Fla.), 2013-07, Vol.75, p.123-135
• Main Authors: Eck, Judith, Kaas, Amanda L., Goebel, Rainer
• Format: Article
• Language: English
• Subjects: Adult; Biological and medical sciences; Brain; Brain Mapping; Cognitive ability; Crossmodal interaction; Eye and associated structures. Visual pathways and centers. Vision; Female; Fundamental and applied biological sciences. Psychology; Haptic; Humans; Image Interpretation, Computer-Assisted; Magnetic Resonance Imaging; Male; Somatosensory cortex; Somatosensory Cortex - physiology; Somesthesis and somesthetic pathways (proprioception, exteroception, nociception); interoception; electrolocation. Sensory receptors; Studies; Texture processing; Touch Perception - physiology; Vertebrates: nervous system and sense organs; Visual; Visual cortex; Visual Cortex - physiology; Visual Perception - physiology
• ISSN: 1053-8119; 1095-9572
• DOI: 10.1016/j.neuroimage.2013.02.075

Both visual and haptic information add to the perception of surface texture. While prior studies have reported crossmodal interactions of both sensory modalities at the behavioral level, neuroimaging studies primarily investigated texture perception in separate visual and haptic paradigms. These experimental designs, however, only allowed to identify overlap in both sensory processing streams but no interaction of visual and haptic texture processing. By varying texture characteristics in a bimodal task, the current study investigated how these crossmodal interactions are reflected at the cortical level. We used fMRI to compare cortical activation in response to matching versus non-matching visual–haptic texture information. We expected that passive simultaneous presentation of matching visual–haptic input would be sufficient to induce BOLD responses graded with varying texture characteristics. Since no cognitive evaluation of the stimuli was required, we expected to find changes primarily at a rather early processing stage. Our results confirmed our assumptions by showing crossmodal interactions of visual–haptic texture information in early somatosensory and visual cortex. However, the nature of the crossmodal effects was slightly different in both sensory cortices. In early visual cortex, matching visual–haptic information increased the average activation level and induced parametric BOLD signal variations with varying texture characteristics. In early somatosensory cortex only the latter was true. These results challenge the notion that visual and haptic texture information is processed independently and indicate a crossmodal interaction of sensory information already at an early cortical processing stage. •Neural correlates of matching versus non-matching visual–haptic texture exploration•Parametric variation of texture characteristics (inter-dot spacing)•Matching visual–haptic information increased BOLD response in early visual cortex.•Parametric variation of matching visual–haptic textures induced BOLD modulation.•These crossmodal interactions occurred primarily in early sensory cortices.