A Right Perisylvian Neural Network for Human Spatial Orienting

Abstract

Homologous neural networks seem to exist in the human left and right hemispheres tightly linking cortical regions straddling the sylvian fissure. White matter fiber bundles connect the inferior parietal lobule with the ventrolateral frontal cortex, ventrolateral frontal cortex with superior/middle temporal cortex, and superior/middle temporal cortex with the inferior parietal lobule. It is argued that these perisylvian networks serve different cognitive functions, a representation for language and praxis in the left hemisphere and a representation for processes involved in spatial orienting in the right. The tight perisylvian anatomical connectivity between superior/middle temporal, inferior parietal, and ventrolateral frontal cortices might explain why lesions at these distant cortical sites around the sylvian fissure in the human right hemisphere can lead to the same disturbance of orienting behavior, namely, to spatial neglect.