The laterality of stop and go processes of the motor response in left-handed and right-handed individuals.

The objective of the present study was to investigate whether the stop and go processes of the motor response are asymmetrical and whether the asymmetries are dependent on handedness and the response selection process that is engaged. Both right-handed and left-handed participants abducted either the left or right index finger in response to an imperative cue in the choice reaction time (choice RT) or the simple RT task. A stop cue was presented after the imperative cue with a probability of .25. When the stop cue was presented, the participants withheld the prepared response. On the choice RT task, left-handed participants had significantly shorter RT and stop signal reaction time (SSRT) with the left versus the right hand, whereas right-handers showed no difference between hands on either measure. In the simple RT task, the RT and SSRT were not significantly different between the groups or the response sides. These results indicate that both the stop and go processes of the prepared left-hand response are completed earlier than those of the right-hand response in left-handed individuals when the stimulus-response process involves a response selection process.

[Detectability of High Intensity Areas in FLAIR and Multi Shot EPI-FLAIR: Phantom Study].

In magnetic resonance imaging (MRI) of brain, fast spin echo-fluid attenuated inversion recovery (FSE-FLAIR) is widely used to detect high intensity areas (HIAs). The way of getting FLAIR contrast at high speed includes echo planar imaging-FLAIR (EPI-FLAIR), and in EPI-FLAIR there are single shot EPI-FLAIR (SS-EPI-FLAIR) and multi shot EPI-FLAIR (MS-EPI-FLAIR). There were negative opinions for the reports of SS-EPI-FLAIR, and it is reported that SS-EPI-FLAIR is able to acquire image quality that is equal to FSE-FLAIR in a shorter time, recently. But there are few reports that utilized contrast of MS-EPI-FLAIR. Our object was to compare HIA detectability in FSE-FLAIR and MS-EPI-FLAIR in equal imaging time, and to evaluate a basic characteristic. We dissolved indigestive dextrin in the aqua destillata and created a 0-46 wt% phantom. The concentration that correspond to T1, T2 value of brain white matter was 42 wt%. We calculated contrast by using signal intensities of each phantom, and compared contrast by signal intensities of each phantom, and compared the contrast of MS-EPI-FLAIR and FSE-FLAIR. In the range of 18-46 wt%, the contrast of MS-EPI-FLAIR was positive value, and that of FSE-FLAIR was 26-42 wt%. By the statistical test, contrast of MS-EPI-FLAIR in 18-26% was significantly different for FSE-FLAIR. In conclusion, it was suggestive that MS-EPI-FLAIR is able to detect HIA equally or sharply.