Functional MRI measurement for the visual target stimulus in oddball paradigm

In late years, many researchers have been studying about activated regions in the brain by using fMRI to investigate a source of brain activity for various sensory stimulus. However, previous reports are not necessarily consistent. We examined the activation for target task in oddball paradigm as a first step to investigating sources associated with the function of decision and recognition. In our analysis, we examined the activated area in the brain by three kinds of time sections for analysis, from stimulus onset to 5 seconds after the stimulus (time section A), from 2 to 7 seconds (time section B) and from 4 to 9 seconds (time section C). On the temporal change, in time section A, the occipital area including visual cortex, the parietal area including motor area and occipitotemporal regions (BA19, BA37) were activated. In time section B and C, anterior cingulated gyrus, dorsolateral prefrontal cortex (BA9, BA10), premotor area (BA6) and cuneus (BA17) showed the prominent activation. We could see the activations at SMA, BA40 and cerebellum in some subjects. It is considered that various areas are involved in the visual target response from our results.