Correlation of functional and resting state connectivity of cerebral oxy-, deoxy-, and total hemoglobin concentration changes measured by near-infrared spectrophotometry

摘要

The aim is to study cerebral vascular functional connectivity during motor tasks and resting state usingnmultichannel frequency-domain near-infrared spectrophotometry. Maps of 5.7 × 10.8 cm size displaying changesnin cerebral oxyhemoglobin (O2Hb), deoxyhemoglobin (HHb), and total hemoglobin (tHb) concentrations werenmeasured in the motor cortex in 12 subjects (mean age of 28.8±12.7 yrs) during resting state and during twonpalm squeezing tasks with different timing. For each condition, phase plane plots, cross correlation functions, andnconnectivity indices were generated for O2Hb, HHb, and tHb. The amplitude of the concentration changes innO2Hb and HHb depends on the age of the subject. We found large regions of connectivity, which were similarnfor resting state and task conditions. This means the spatial relationships during resting state, when changes innO2Hb, HHb, and tHb corresponded to spontaneous oscillations, were correlated to the spatial patterns duringnthe activation tasks, when changes in O2Hb, HHb, and tHb concentration were related to the alternation ofnstimulation and rest. Thus, the vascular functional connectivity was also present during resting state. The findingsnsuggest that the vascular response to functional activation may be a nonlinear synchronization phenomenon andnthat resting state processes are more important than previously expected.