Silent fMRI acquisition methods for large acoustic noise during scan.

Functional magnetic resonance imaging (fMRI) is now the method of choice for studying neural correlates of various tasks in normal subjects as well as patients. This method, however, is inevitably coupled with the acoustic noise produced during the image acquisition process. This is a problem not only in auditory experiments but also in other cognitive tasks in general. The problems caused by such noise are modulation of auditory activation, impaired perception of auditory stimuli, and deterioration of task performance possibly due to stress from the abnormal circumstances. While both hardware and software solutions have been reported, several methods are introduced here that focus on software solutions that can be implemented in scanners already installed. Their advantages and disadvantages differ depending on the kinds of tasks involved, i.e. whether block design or event-related design, and they are discussed with a view to better utilization.