weird sine-wave oscillations?

 Hello,

I was recording some ligand-gated ionic currents with a voltage step protocol, and I got puzzled, why are all these sine wave-like oscillations appearing at the negative potentials that seemingly do not carry any channel currents? Are they normal, or are they just instrumental noise? coz I think I definitely have some channel-mediated current at some more positive potentials on the left one.



Just wonder if I can get any help?
Thanks
And

I would check, wether the frequency of this oscillations is constant, and what the frequency is. Maybe your amplifier is not properly set up (i.e. Gain too high or Compensation too high). Especially Series-Resistance Compensation can be quite unstable.

As this only ocurrs at negative potentials, I would exclude noise pick up or power line hum.