Spatiotemporal characteristics of low-frequency functional activation measured by laser speckle imaging

William Lau, Shanbao Tong, Nitish V. Thakor

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Changes in neuronal activity have been shown to be accompanied by alteration in regional cerebral blood flow. In the present study, laser speckle imaging (LSI) was employed to measure stimulus-evoked neuronal activities in rat barrel cortex. The spatiotemporal characteristics of hemodynamic response to mechanical stimuli from 1 to 3 Hz were examined. Tune to peak amplitude reduced from 4.5 to 3.5 s with increasing frequencies. Spatially, the response was confined to a small circular region at the beginning and then spread out asymmetrically to the surrounding regions. The maximal area of activation ranged from 2.2 to 3.5 mm2, while the time to reach maximal area occurred between 5.5 and 6 s. Moreover, there was a high correlation between LSI and laser-Doppler flowmetry in terms of peak response magnitude and the time to reach peak. These two values were linearly dependent on stimulus frequency whereas area of activation and time to maximal area appeared to be independent of this parameter. LSI's high sensitivity, low cost of the equipment, and size and complexity make this a suitable technique for fundamental neurophysiological investigations.

Original languageEnglish (US)
Pages (from-to)179-185
Number of pages7
JournalIEEE Transactions on Neural Systems and Rehabilitation Engineering
Issue number2
StatePublished - Jun 2005


  • Cerebral blood flow (CBF)
  • Functional imaging
  • Laser speckle imaging (LSI)
  • Neuronal activity
  • Whisker barrel field
  • Whisker stimulation

ASJC Scopus subject areas

  • Internal Medicine
  • Neuroscience(all)
  • Biomedical Engineering


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