“…However, more recently, the Na + indicators Asante NaTRIUM Green‐2 (ANG‐2) (Miyazaki & Ross, 2015; Miyazaki, Lisman, & Ross, 2019) and ION NaTRIUM Green‐2 (ING‐2; commercially available from Ion Indicators) have been shown to provide a significant improvement in the signal‐to‐noise ratio (SNR) compared to SBFI. Combined with the latest technology in acquisition systems and lasers (Filipis et al., 2018), we recently measured Na + signals in the AIS at 10 kHz (Filipis & Canepari, 2020), i.e., at a temporal resolution comparable to that of optical AP recordings using voltage‐sensitive dyes (Popovic et al., 2015). Similar to the optical measurement of dendritic Ca 2+ currents (Jaafari & Canepari, 2016; Jaafari, De Waard, & Canepari, 2014; Jaafari, Marret, & Canepari, 2015), the Na + current was extracted by calculating the time derivative of the Na + transient.…”