Final answer:
Single cell recording has the best spatial resolution for measuring activity of individual neurons, while MEG offers good spatial resolution due to advanced SQUID sensors used to detect weak magnetic signals in the brain.
Step-by-step explanation:
The technique among single cell recording, EEG, ERP, and MEG that has the best spatial resolution is single cell recording. Single cell recording offers the ability to measure the exact activity of individual neurons, which provides extremely precise spatial information. However, for the options given, MEG (magnetoencephalography) also has good spatial resolution due to its ability to detect weak magnetic signals associated with brain activity. MEG utilizes advanced instrumentation such as SQUID sensors that operate at liquid helium temperatures to measure minute magnetic fields, offering greater spatial resolution than EEG (electroencephalography) and ERP (event-related potentials). The versatility of MEG has been demonstrated in research on neurological conditions like Alzheimer's disease and epilepsy.