Hi all,

I have been attempting to do field EPSP but I am not able to elicit a response. I am using a thin walled electrode for the recording electrode at 1.5mOhm resistance. I have filled the intracellular solution with ACSF and I have also tried it with saline, but no luck. I am recording from CA1 and stimulating at CA2 Schaffer collaterals. I am using a bipolar electrode. My stimulating artifact sometimes looks weird (does not go up and down) and other times it looks normal (goes up and down). This seems to be dependent on how close I am to the electrodes with my recording electrode. The stimulation length is set to 40us and I have tried stimulation levels from 0.1 to 2mA. Not sure if something is wrong with the system itself or if I am doing something wrong.

For the slice prep I cut the coronal slices in cold sucrose solution (in mM: 183 sucrose, 20 NaCl, 0.5 KCl, 1 MgCl2, 1.4 NaH2PO4, 25 NaHCO3, and 10 glucose) and transfer them to ACSF (in mM: 124 NaCl, 4.4 KCl, 2CaCl2, 2.95 MgSO4, 1 NaH2PO4, 10 glucose, 26 NaHCO3) for 30 minutes at 32C. Then I let the slices be at room temp for an hour before recording. I have verified that the cells are alive so I don't think it is an issue of the slice health.

I am using the Clampex software and for using this stimulator https://www.digitimer.com/product/life-science-research/stimulators/ds3-isolated-current-stimulator/

Any help is much appreciated.