TY - JOUR
T1 - Evaluation of coupling between optical intrinsic signals and neuronal activity in rat somatosensory cortex
AU - Sheth, Sameer
AU - Nemoto, Masahito
AU - Guiou, Michael
AU - Walker, Melissa
AU - Pouratian, Nader
AU - Toga, Arthur W.
N1 - Funding Information:
The authors thank Syam Lakkaraju for his help with pilot experiments. S.S. and N.P. were supported in part by the NIH Medical Scientist Training Program (GM08042). S.S. was also supported by the NIH Training Program in Neuroimaging (MH19950) and an ARCS Foundation grant, and N.P. by an NIH National Research Service Award (MH12796). Additional support was provided by an NIH research grant (MH/NS52083) to A.W.T.
PY - 2003/7/1
Y1 - 2003/7/1
N2 - We investigated the coupling between perfusion-related brain imaging signals and evoked neuronal activity using optical imaging of intrinsic signals (OIS) at 570 and 610 nm. OIS at 570 nm reflects changes in cerebral blood volume (CBV), and the 610 nm response is related to hemoglobin oxygenation changes. We assessed the degree to which these components of the hemodynamic response were coupled to neuronal activity in rat barrel, hindpaw, and forepaw somatosensory cortex by simultaneously recording extracellular evoked field potentials (EPs) and OIS while varying stimulation frequency. In all stimulation paradigms, 10 Hz stimulation evoked the largest optical and electrophysiological responses. Across all animals, the 610 late phase and 570 responses correlated linearly with ΣEP (P < 0.05) during both whisker deflection and electrical hindpaw stimulation, but the 610 early phase did not (whisker P = 0.27, hindpaw P = 0.28). The signal-to-noise ratio (SNR) of the 610 early phase (whisker 3.1, hindpaw 5.3) was much less than that for the late phase (whisker 14, hindpaw 51) and 570 response (whisker 11, hindpaw 46). During forepaw stimulation, however, the 610 early phase had a SNR (17) higher than that during hindpaw stimulation and correlated well with neuronal activity (P < 0.05). We conclude that the early deoxygenation change does not correlate consistently with neuronal activity, possibly because of its low SNR. The robust CBV-related response, however, has a high SNR and correlates well with evoked cortical activity.
AB - We investigated the coupling between perfusion-related brain imaging signals and evoked neuronal activity using optical imaging of intrinsic signals (OIS) at 570 and 610 nm. OIS at 570 nm reflects changes in cerebral blood volume (CBV), and the 610 nm response is related to hemoglobin oxygenation changes. We assessed the degree to which these components of the hemodynamic response were coupled to neuronal activity in rat barrel, hindpaw, and forepaw somatosensory cortex by simultaneously recording extracellular evoked field potentials (EPs) and OIS while varying stimulation frequency. In all stimulation paradigms, 10 Hz stimulation evoked the largest optical and electrophysiological responses. Across all animals, the 610 late phase and 570 responses correlated linearly with ΣEP (P < 0.05) during both whisker deflection and electrical hindpaw stimulation, but the 610 early phase did not (whisker P = 0.27, hindpaw P = 0.28). The signal-to-noise ratio (SNR) of the 610 early phase (whisker 3.1, hindpaw 5.3) was much less than that for the late phase (whisker 14, hindpaw 51) and 570 response (whisker 11, hindpaw 46). During forepaw stimulation, however, the 610 early phase had a SNR (17) higher than that during hindpaw stimulation and correlated well with neuronal activity (P < 0.05). We conclude that the early deoxygenation change does not correlate consistently with neuronal activity, possibly because of its low SNR. The robust CBV-related response, however, has a high SNR and correlates well with evoked cortical activity.
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U2 - 10.1016/S1053-8119(03)00086-7
DO - 10.1016/S1053-8119(03)00086-7
M3 - Article
C2 - 12880817
AN - SCOPUS:0041669355
SN - 1053-8119
VL - 19
SP - 884
EP - 894
JO - NeuroImage
JF - NeuroImage
IS - 3
ER -