Intraoperative optical imaging of human cortex

Optical imaging of the human brain can be performed during neurosurgical operations. In spite of large sources of noise it is possible to obtain maps of somatosensory, motor and language cortices. These changes in intrinsic light reflectance tend to overestimate the area of cortex essential for these functions, representing hemodynamic alterations associated with neuronal activity. Imaging of abnormal cortical activity such as afterdischarges or seizures can also be performed intraoperatively and the larger magnitude of the signal improves the singal-to-noise ratio. The utility of intrinsic signal imaging during neurosurgical operations and as a tool for human brain mapping is still evolving but certainly holds great promise based on the success of the preliminary experiments to date.