Functional magnetic resonance imaging adaptation (fMRIa) is an increasingly used method of functional magnetic resonance imaging which takes advantage of the brain changes which occur in response to long exposure to some evocative stimulus. If Stimulus 1 (S1) excites a certain neuronal population, repeated exposure to S1 will result in subsequently attenuated responses. This adaptation may be due to neural fatigue or may be due to coupled hemodynamic processes. However, when S1 is followed by a unique stimulus, S2, the response amplitudes should not be attenuated as a fresh sub-population of neurons is excited. Using this technique can allow researchers to determine if the same or unique neuronal groups are involved in processing two stimuli.[1]
This technique has been used successfully in examination of the visual system, particularly orientation, motion, and face detection.[1]