The representation of tools in left parietal cortex is independent of visual experience.

Tool use depends on processes represented in distinct regions of left parietal cortex. We studied the role of visual experience in shaping neural specificity for tools in parietal cortex by using functional magnetic resonance imaging with sighted, late-blind, and congenitally blind participants. Using a region-of-interest approach in which tool-specific areas of parietal cortex were identified in sighted participants viewing pictures, we found that specificity in blood-oxygen-level-dependent responses for tools in the left inferior parietal lobule and the left anterior intraparietal sulcus is independent of visual experience. These findings indicate that motor- and somatosensory-based processes are sufficient to drive specificity for representations of tools in regions of parietal cortex. More generally, some aspects of the organization of the dorsal object-processing stream develop independently of the visual information that forms the major sensory input to that pathway in sighted individuals.