Chapter 9 The effects of a prepulse on the StartReact phenomenon
Publisher Summary This chapter presents a study to investigate whether the inhibitory effects of the prepulse are different in the condition of motor preparation with respect to that of unexpectancy and whether the inhibition of the startle reaction by a prepulse is associated with the inhibition of the StartReact phenomenon. The chapter demonstrates that the procedure could help in ascertaining whether reflex and volitional components are actually combined in the StartReact phenomenon. Eight healthy volunteers, six men and two women, aged between 25 and 52 years were investigated and the startle reaction was recorded with surface electrodes over the right orbicularis oculi muscle and, in t…
Excitability of subcortical motor circuits in Go/noGo and forced choice reaction time tasks
The size of the response to a startling auditory stimulus (SAS) may reflect the excitability of the reticulospinal tract. In this study, we examined whether there was any excitability change in the reticulospinal tract during preparation for execution of two types of choice reaction time task: a forced choice reaction time task (fCRT) and a Go/no-Go task (GnG). In 13 healthy volunteers we used three types of trials: control trials in which subjects were requested to perform ballistic wrist movements during fCRT or GnG tasks; test trials in which a SAS was presented with the visual cue, and baseline trials in which SAS was presented alone. Latency and area of the responses to SAS were measur…