Solution: We figured out that the new headstage for that channel was faulty and are getting it repaired. Thank you for all the helpful answers!
Question:
I recently built an extracellular field recording rig with all new micromanipulators, chambers, and stim boxes. I am recording in the Schaffer Collaterals in the hippocampus. In one of my channels I am consistently getting an upward deflection of the fEPSP and this is not present in my three other channels. If I invert the y-axis for that channel in Clampex it looks like a normal fEPSP. I am having the same issue as seen in this thread but I still haven't found a solution: https://www.researchgate.net/post/Why_can_I_no_longer_record_typical_synaptic_response_in_hippocampus
Does anyone know how to fix this issue?
I just checked on your question. I am also working on large-scale LTP recordings. Since I don't have detailed information about your technical experimental setup and software, if I see your provided signal, it appears that either you have artifact-embedded noise with the physiological signal or your response exceeds the recording limits of your acquisition system. This can occur when the recorded signals are too strong or outside the dynamic range of your equipment. To address this issue, you may need to adjust the recording settings or potentially use attenuators to bring the signal within the system's range. Further, you can use signal processing techniques like filtering, notch filtering, or common average referencing to reduce noise and artifacts. Adjust the amplification or gain settings on your acquisition system to bring the signal within the system's limits. It's essential to identify the specific sources of deflection or noise in your setup and apply appropriate methods to mitigate them. Beside everything it is also very important specifically in CA1-CA2-CA3 where you are exactly recording.
What does it look like if you change the polarity of your stim that yielded the abnormal response?
BTW your normal response looks rather unhealthy, as the presynaptic fiber volley is actually bigger than the EPSP.
Karen Parfitt When the polarity is changed the fEPSP looks the same. However, we figured out the issue was with the headstage being faulty.
Also, yes the normal response was just an example as I am still training on how to get a healthier response. Thank you!
Shahrukh Khanzada Thank you for your response! We solved the issue and figured out the new headstage we bought was faulty and are betting it repaired. Thanks again!
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