"The purpose of splitting reaction time into these two components," explained Simmons, "is that it allows us to measure the time required for information processing, called central activity, without the influence of the time required to convey the action plan from the brain to the muscles, called peripheral activity."
The children with prenatal exposure to alcohol had slower premotor RTs during the CRT task. This means they were not able to process information as quickly as the control children when they had to respond to more than one signal. During SRT and CRT tasks, the alcohol-exposed children also had slower motor RTs. This indicates that prenatal alcohol exposure also had a negative impact on the peripheral processes involved in conveying the action plan from the brain to the muscles.
"Young children typically respond with less accuracy or speed than older children or adults on a variety of motor skills," said Simmons. "Our study confirmed this for both groups using the premotor and motor components of reaction time. The younger children were unable to process information at the same speed as the older children, and were also slower in conveying the action plan from the brain to the muscle. However, these differences were more acute within the alcohol group. Furthermore, the performance of the older alcohol-exposed children was often very similar to the performance of the younger, nonexposed children. Collectively, these results indicate a lack of development in both central and peripheral structures to the extent that it significantly affects both premotor and motor reaction time. We believe that ex
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16-Sep-2002