PURPOSE: To develop a high temporal resolution functional MRI (fMRI) method for tracking repeating events in the brain. METHODS: We developed a novel fMRI method using Multi-Band SWeep Imaging with Fourier Transformation (MB-SWIFT), termed EVEnt-Recurring SWIFT (EVER-SWIFT). The method is able to image similar repeating events with sub-second temporal resolution. Here, we demonstrate the use of EVER-SWIFT for detecting fMRI responses during deep brain stimulation (DBS) of the medial septal nucleus (MSN) and during spontaneous isoflurane-induced burst suppression in the rat brain at 9.4 T with 200-ms temporal resolution. RESULTS: EVER-SWIFT showed that the shapes and time-to-peak values of the response curves to DBS stimulation significantly differed between downstream brain regions connected to the MSN, resembling findings obtained with traditional 2-s temporal resolution. In contrast, EVER-SWIFT allowed for detailed temporal measurement of a spontaneous isoflurane-induced bursting activity pattern, which was not achieved with traditional temporal resolution. CONCLUSION: EVER-SWIFT enables sub-second 3-dimensional imaging of both stimulated and spontaneously recurring brain activities, and thus holds great potential for studying the mechanisms of neuromodulation and spontaneous brain activity.
