title: Imaging brain hemodynamic changes during rat forepaw electrical stimulation using functional photoacoustic microscopy.
abstract: The present study reported the development of a novel functional photoacoustic microscopy (fPAM) system for investigating hemodynamic changes in rat cortical vessels associated with electrical forepaw stimulation. Imaging of blood optical absorption by fPAM at multiple appropriately-selected and distinct wavelengths can be used to probe changes in total hemoglobin concentration (HbT, i.e., cerebral blood volume [CBV]) and hemoglobin oxygen saturation (SO(2)). Changes in CBV were measured by images acquired at a wavelength of 570nm (lambda(570)), an isosbestic point of the molar extinction spectra of oxy- and deoxy-hemoglobin, whereas SO(2) changes were sensed by pixel-wise normalization of images acquired at lambda(560) or lambda(600) to those at lambda(570). We demonstrated the capacity of the fPAM system to image and quantify significant contralateral changes in both SO(2) and CBV driven by electrical forepaw stimulation. The fPAM system complements existing imaging techniques, with the potential to serve as a favorable tool for explicitly studying brain hemodynamics in animal models.
authors.affiliation: Department of Electrical Engineering, National Chiao Tung University, No. 1001, Ta-Hsueh Rd., Hsinchu 300, Taiwan ROC.
authors.forename: Lun-De
authors.initials: LD
authors.lastname: Liao
authors.forename: Meng-Lin
authors.initials: ML
authors.lastname: Li
authors.forename: Hsin-Yi
authors.initials: HY
authors.lastname: Lai
authors.forename: Yen-Yu I
authors.initials: YY
authors.lastname: Shih
authors.forename: Yu-Chun
authors.initials: YC
authors.lastname: Lo
authors.forename: Siny
authors.initials: S
authors.lastname: Tsang
authors.forename: Paul Chang-Po
authors.initials: PC
authors.lastname: Chao
authors.forename: Chin-Teng
authors.initials: CT
authors.lastname: Lin
authors.forename: Fu-Shan
authors.initials: FS
authors.lastname: Jaw
authors.forename: You-Yin
authors.initials: YY
authors.lastname: Chen
mesh_terms: D000818:Animals; D001810:Blood Volume; D001921:Brain / Q000098:blood supply* / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D002540:Cerebral Cortex / Q000098:blood supply / Q000502:physiology; D004558:Electric Stimulation; D005528:Foot / Q000502:physiology; D005552:Forelimb / Q000502:physiology*; D007839:Functional Laterality; D006454:Hemoglobins / Q000378:metabolism; D008297:Male; D033401:Microscopy, Acoustic / Q000295:instrumentation / Q000379:methods*; D018613:Microscopy, Confocal / Q000295:instrumentation / Q000379:methods; D010100:Oxygen / Q000097:blood / Q000378:metabolism; D010465:Perception / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D012815:Signal Processing, Computer-Assisted
chemical_list: D006454:Hemoglobins; D010100:Oxygen