TY - JOUR
T1 - Visualizing and quantifying evoked cortical activity assessed with intrinsic signal imaging
AU - Chen-Bee, Cynthia H.
AU - Polley, Daniel B.
AU - Brett-Green, Barbara
AU - Prakash, Neal
AU - Kwon, Michael C.
AU - Frostig, Ron D.
N1 - Funding Information:
This work was supported by National Institutes of Mental Health National Research Service Award MH014599-23 to D.B.P., University of California Irvine Medical Scientist Training Program to N.P. and M.C.K., National Institute of Neurological Disorder and Stroke Grant NS-34519 and NS-39760 to R.D.F., and National Science Foundation Grant IBN 9507936 to R.D.F.
PY - 2000/4/15
Y1 - 2000/4/15
N2 - Intrinsic signal imaging (ISI) measures changes in light reflectance from the illuminated cortex (intrinsic signals or IS) attributed to various vascular and metabolic sources that, when using illumination in the 600 nm range, appear to co-localize with neuronal activity. Given the multiple sources contributing to the collected IS, the common practice of averaging across an extended post-stimulus time epoch before dividing by baseline data typically visualizes evoked IS overlying both the cortical tissue and the large surface blood vessels. In rat PMBSF, the contribution from these vessels are problematic as they do not co-localize with known PMBSF function. Determining a means for quantifying the evoked IS area poses an additional challenge. Here, we describe how exploiting IS collected shortly after stimulus onset (within 1.5 s), which coincides with fast oxygen consumption of active neurons, visualizes evoked IS overlying the cortical tissue without the large surface vessels. We also describe how the use of absolute thresholds combined with a baseline determined from data collected immediately prior to stimulus onset (within 1 s) targets most precisely a specific evoked IS amplitude, a method that should be especially useful when evoked areas are expected to occupy a substantial portion of the total imaged area and/or when peak activity is expected to differ between subjects.
AB - Intrinsic signal imaging (ISI) measures changes in light reflectance from the illuminated cortex (intrinsic signals or IS) attributed to various vascular and metabolic sources that, when using illumination in the 600 nm range, appear to co-localize with neuronal activity. Given the multiple sources contributing to the collected IS, the common practice of averaging across an extended post-stimulus time epoch before dividing by baseline data typically visualizes evoked IS overlying both the cortical tissue and the large surface blood vessels. In rat PMBSF, the contribution from these vessels are problematic as they do not co-localize with known PMBSF function. Determining a means for quantifying the evoked IS area poses an additional challenge. Here, we describe how exploiting IS collected shortly after stimulus onset (within 1.5 s), which coincides with fast oxygen consumption of active neurons, visualizes evoked IS overlying the cortical tissue without the large surface vessels. We also describe how the use of absolute thresholds combined with a baseline determined from data collected immediately prior to stimulus onset (within 1 s) targets most precisely a specific evoked IS amplitude, a method that should be especially useful when evoked areas are expected to occupy a substantial portion of the total imaged area and/or when peak activity is expected to differ between subjects.
KW - Barrel
KW - Intrinsic signal
KW - Optical imaging
KW - Rat somatosensory cortex
KW - Vibrissa
KW - Whisker
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U2 - 10.1016/S0165-0270(00)00180-1
DO - 10.1016/S0165-0270(00)00180-1
M3 - Article
C2 - 10788670
AN - SCOPUS:0034656051
SN - 0165-0270
VL - 97
SP - 157
EP - 173
JO - Journal of Neuroscience Methods
JF - Journal of Neuroscience Methods
IS - 2
ER -