Biphasic changes in tissue partial pressure of oxygen closely related to localized neural activity in guinea pig auditory cortex

Kazuto Masamoto*, Tetsuro Omura, Naosada Takizawa, Hirosuke Kobayashi, Takusige Katura, Atsushi Maki, Hideo Kawaguchi, Kazuo Tanishita

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

30 Citations (Scopus)


An understanding of the local changes in cerebral oxygen content accompanying functional brain activation is critical for making a valid signal interpretation of hemodynamic-based functional brain imaging. However, spatiotemporal relations between changes in tissue partial pressure of oxygen (PO2) and induced neural activity remain incompletely understood. To characterize the local PO2 response to the given neural activity, the authors simultaneously measured tissue PO2 and neural activity in the identical region of guinea pig auditory cortex with an oxygen microelectrode (tip < 10 μm) and optical recording with voltage-sensitive dye (RH 795). In addition, a laser displacement gauge and a laser-Doppler flowmeter were used to monitor the spatial displacement and regional cerebral blood flow, respectively, in the PO2 measurement region. In the activated region, tissue PO2 initially decreased during the ∼3-seconds after the onset of acoustic stimuli, and then increased during the next ∼5 seconds. Such biphasic changes are consistently found in cortical layers I to IV. In addition, amplitude of the biphasic change was closely related to detected peak height of the optical signal changes. The results suggest that the initial decrease in tissue PO2 is coupled to the induced neural activity and depends on response time of local increase in cerebral blood flow.

Original languageEnglish
Pages (from-to)1075-1084
Number of pages10
JournalJournal of Cerebral Blood Flow and Metabolism
Issue number9
Publication statusPublished - 2003 Sept 1
Externally publishedYes


  • Functional brain imaging
  • Neural activity
  • Oxygen microelectrode
  • Tissue pO

ASJC Scopus subject areas

  • Endocrinology
  • Neuroscience(all)
  • Endocrinology, Diabetes and Metabolism


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