The majority of participants were right-handed (87.5%) and allhad normal or corrected-to-normal vision and hearing. Based oninitial descriptive statistics, it was determined that two partici-pants had a single score each that exceeded the sample mean by 4standard deviation units (one each in the rare Nogo P3 amplitudeand RT IIV). Consequently these two participants were excludedfrom the analysis, leaving a total sample size of 40 (23 HC and 17SCD). Summary statistics for the resulting sample demographicsare listed in Table 3.3.1.