We are trying to do metaplasticity experiments in the scaffer collateral pathway. We record baseline for 60 min (30 min of recording followed by 15 minutes of DHPG administration and 15 minutes of washout period) and then the LTP induction using TBS. We are trying to record e-LTP for a during of 2.5 hours following TBS. However, it comes back to the baseline after about 1.5 hours following TBS. Can anyone guide us if we are doing it correctly and if we need to record e-LTP for a duration of 2.5 hours after TBS?