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Though most of the neuroimaging methods have been developed for decades, their application has some limitations. One of the most critical considerations for all imaging methods is the spatial and temporal resolution of imaging. For both structural and functional neuroimaging methods, a poor spatial resolution renders it hard to localize the precise position of a specific brain region. The problem of low spatial resolution is significant in PET, which investigates the brain by a voxel sized between 5 and 10 mm³ (Gazzaniga et al. 2019). Therefore, it provides spatial information at the scale of gross anatomy. However, by using different radioactive neurochemical agents, PET can detect the part of the brain which specifically engages with the agents. The problem of lower spatial resolution is also significant in magnetic resonance spectroscopy (MRS). Because MRS signals are relatively weak, to increase the signals obtained in a voxel, a larger voxel will be required for an MRS scan (Gazzaniga et al. 2019). Due to the limitation of spatial resolution, neuroimaging methods provide less information about brain features at the cellular level.

Temporal resolution is a critical factor for functional neuroimaging. For functional studies, the fundamental question would be ‘do we have a fine resolution to capture the mental functions we desire to see?’. Some mental processes may last for minutes, such as the feeling of a bad mood. In contrast, some mental processes may arise transiently, such as shifting one's attention from one thing to another. Therefore, selecting a tool that is also fast enough to capture the different mental experiences is very crucial. MRI is limited at its temporal resolution due to the longer scanning interval (i.e. a lower sampling rate, such as two seconds for a scan) and the ‘sluggish’ hemodynamic response. In contrast to MRI, EEG and MEG are more sensitive to a quick mental process, with a temporal resolution in milliseconds (Gazzaniga et al. 2019). Further considerations of the pros and cons of MRI are outlined in Section.