To everyone reading this question,

I hope you are doing well.

I have been using the Master-8, Digidata 1440A, SYS-DAM80 (amplifier), and Iso-Flex (stimulus) with an Ag/Cl electrode & stimulus (monopolar) to record fEPSP signals in the lateral habenula and hippocampus regions until last year.

However, from January to March this year, I encountered an issue where signals would appear but disappear within five minutes (as shown in the left image).

Based on advice from colleagues, I considered potential causes such as unstable slice conditions, shunting due to excessive grounding wires for noise reduction, battery depletion, poor tissue condition, and inappropriate pore size of the recording electrode for fEPSP measurement.

To address these concerns, I conducted a series of troubleshooting steps, including:

• Comparing input and output of aCSF
• Minimizing grounding by adding one wire at a time
• Replacing grounding wires
• Replacing the stimulus battery
• Changing section aCSF and applying various ECR preparation methods from literature
• Measuring and adjusting pore impedance to 1–1.5 MΩ
• Changing the headstage connecting the recording electrode

After these attempts, I resumed measurements, but I observed unusual artifacts, as shown in the right image. Even when I turned off the Iso-Flex, the same artifact persisted.

At this point, I am uncertain whether the issue stems from the amplifier or other equipment.

Has anyone encountered a similar problem, either as shown in the left image (signal disappearing) or the right image (persistent artifact)? Any advice or insights would be greatly appreciated.

Best regards,

Younsoo BYUN