Design and test of an optical headpiece for functional brain imaging

This study involved the design and development of a new optical headpiece for the collection of near-infrared optical data from frontal lobe, parietal lobe, and temporal lobe of human brain. The developed whole-head, near-infrared spectroscopy (NIRS) headpiece features 14 detection and 28 illumination locations to measure 56 distinct areas on the three brain lobes. The optical headpiece was applied to three healthy subjects to test for technical feasibility and to maintain optical signals associated with heartbeat-induced arterial oscillations. A commercial non-infrared tissue spectrometer was used to optically probe the tissue using two wavelengths of light, 690 and 830 nm. The optical signals at that two strong wavelengths allows one to calculate the relative changes of oxy- and deoxy-hemoglobin concentration ([Hb] and [HbO]) in brain tissue. Tests for headpiece comfort and applicability of customized branched optical fiber bundles took place before human subjects' trials. We found that this new optical headpiece can successfully detect Delta[Hb] and Delta[HbO] associated with systolic-diastolic pressure variations, indicating its applicability to the study of cerebral hemodynamics and functional brain activity.