Which change in instrumentation settings can lead to the loss of cortical spikes?

Changing the high-frequency filter (HFF) from 70 Hz to 15 Hz is significant because it directly affects the ability of the system to capture high-frequency cortical spikes. Cortical spikes, often associated with neuronal activity, typically contain frequencies that can be significantly higher than 15 Hz. When the HFF is lowered to 15 Hz, any neuronal activity that occurs above this frequency can be attenuated or completely lost in the recording. This adjustment essentially cuts off the higher frequency components that are essential for accurately capturing the rapid changes in electrical activity that occur during spike events.

In contrast, adjustments to the low-frequency filter (LFF) or moderate changes to the HFF that do not drop below the threshold of interest will not result in such a substantial loss in data quality concerning cortical spikes. For instance, shifting the LFF from 1 Hz to 0.1 Hz would generally permit more low-frequency activity to be recorded, which does not directly impact the detection of higher-frequency spikes.