2.4. Electroencephalogram (EEG) recording
In order to collect EEG data in the acute and chronic stages of PTE
(Pitkänen et al., 2014), mice underwent electrode implantation prior to
seizure induction by KA. A bipolar electrode was implanted into CA3
region (AP-2.9 mm; ML-3.0 mm; V-3.0 mm) for EEG recording. After seven
days’ recovery, the baseline EEG trace was recorded 30 min before
FeCl3 injection. Subsequently, an injection tube (62204,
RWD Life Science) was inserted into the guide cannula which was placed
in the somatosensory cortex (AP-1.3 mm; ML-2.0 mm; V-1.6 mm) for
injection with 5 μl of a 50 mM solution of FeCl3 or 1
pmol Fer-1. Five minutes later, mice were subjected to 2 h EEG
monitoring session. EEG data in the acute and chronic stages of PTE were
both collected for 3 d with 2 h per day. Electrical seizures were
defined as regular spike clusters lasting more than 10 s, spike
frequency greater than 3 Hz and amplitude at least three times higher
than the baseline according to the previous investigation (Zhao et al.,
2020).