Calcium Spikes (IMAGE) University of California - San Diego Caption This is in vivo imaging of calcium spikes. Left: Graphene electrode array placed on the surface of the cortex. Center: Two-photon microscope image (zoomed in on four electrodes A, B, C and D) of cell bodies located 250 micrometers below the cortical surface. Right: Image of individual cells directly under electrode B. Credit Yichen Lu/<i>Advanced Functional Materials</i> Usage Restrictions Please credit: Yichen Lu/Advanced Functional Materials License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.