FUNCTIONAL MRI OF BRAIN ACTIVATION-INDUCED BY SCANNER ACOUSTIC NOISE

A method is introduced by which brain activation caused by the acousti c noise associated with echo planar imaging (EPI) is mapped. Two types of time series were compared. The first time series, considered the ' 'task,'' involved applying only EPI gradients for 20 a without the app lication of RF pulses, then, without pause, starting image collection. The second, considered the ''control,'' involved typical sequential i mage acquisition without the prior gradient pulses. Subfraction of the first 5 s of the two time series revealed signal enhancement mainly i n the primary auditory cortex. The technique was validated using a mot or cortex task that mimicked the hypothesized scanner noise induced ac tivation.