HABITUATION-LIKE EFFECTS CAUSE A SIGNIFICANT DECREASE IN RESPONSE IN MRI NEUROACTIVATION DURING VISUAL-STIMULATION

A wide range of rest/stimulus cycle durations (40-360 sec) is reported to have been used by various groups for MRI neuroactivation studies o f the visual cortex. In this paper we demonstrate a clear habituation- like response for longer cycle durations which results in a halving of apparent activation between cycle durations of 138 and 276 sec. This has important implications, not only in terms of optimizing the techni que, but also in providing an insight into the underlying physiologica l mechanisms. (C) 1997 Elsevier Science Ltd.