Why is it difficult to gather a baseline measure in fMRI scanning?

The challenge in obtaining a baseline measure in fMRI scanning stems from the inherent nature of brain activity. The brain is not a static organ; it is constantly active at varying levels, even when a person is at rest or not engaging in a specific task. This persistent background activity can complicate efforts to establish a reliable baseline, as there may not be a true state of "no activity" to compare against.

When researchers attempt to measure brain activity, they often face the difficulty of distinguishing between baseline levels of activity and those induced by specific tasks or stimuli. Therefore, the brain's continuous engagement in processes, both conscious and unconscious, can produce a complex pattern of activation that makes it challenging to define a clear, stable baseline state for comparison in studies involving fMRI.