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letter
. 2013 Jun 5;33(8):1148–1152. doi: 10.1038/jcbfm.2013.89

Figure 1.

Figure 1

A 5-minute common carotid artery occlusion (CCAO) diminishes the amplitude of the electromyography (EMG) and electroencephalography (EEG) maps evoked by cortical channelrhodopsin-2 (ChR2) stimulation, with rapid recovery after reperfusion. (A, B) An overview of experimental setup and design. (A) Anesthetized, head-fixed mice are placed on a scanning stage and an array of cortical points (insert) is stimulated by a 473 nm collimated laser beam directed through a video microscope objective. Motor output is detected by EMG electrodes in the forelimb muscles. Surface temperature (a—temperature probe) and cortical EEG signal (b—electrode) are collected. Scale bar is 500 μm. (B) Experimental design. Two groups of mice are used to conduct either motor mapping or motor output (repetitive center stimulation in the motor map) assessment during baseline, 5-minute CCAO and reperfusion. (C) Laser speckle contrast imaging confirms >80% decrease in blood flow in the forelimb motor representation during CCAO, which recovers to >80% of pre-CCAO value within 2 minutes after reperfusion. (i) Representative laser speckle contrast images at pre-CCAO, 1 minute after ischemia, 1 and 2 minutes after reperfusion. The region surrounded by white dash line indicates the forelimb motor representation obtained by laser-based motor mapping (threshold at 0%). (ii) Quantitative summary of blood flow in the motor representation after CCAO and reperfusion. (n=4, **P<0.01, compared with pre-CCAO value, one-way analysis of variance (ANOVA). (D) A 5-minute CCAO depresses both EEG and EMG maps (integration of signals) evoked by the cortical ChR2 stimulation. Reperfusion recovers both maps within 1 hour. Representative EMG maps (i) and EEG maps (ii) evoked by the cortical ChR2 stimulation after 5-minute CCAO and reperfusion. Only the center of motor map (3 × 3 pixels indicated by black dash line) is used to calculate the ChR2-evoked EEG signal. (E) Quantitative summaries of EMG maps and EEG maps after CCAO and reperfusion (n=5, ***P<0.001, ##P<0.01, ###P<0.001, compared with the pre-CCAO values, one-way ANOVA; $P<0.05, EMG map versus EEG map, Student's t-test). All data are shown as mean±s.e.m.