Before revision:  Nevertheless, training spiking neural networks with sparse activity on hardware devices remains a major challenge . Primarily this is due to the lack of suitable training methods that take into account device-specific imperfections and operate at the level of individual spikes instead of firing rates.
After revision:  Nevertheless, emulating high-performing spiking networks on such hardware remains a significant challenge due to device-mismatch and the lack of suitable training methods that take into account device-specific imperfections and operate at the level of individual spikes instead of firing rates.