RecruitingEarly Phase 1Drug trialAttentional Mechanisms in SCDThis study will use an anticholinergic pharmacological probe to examine attention network function in SCD using EEG. The overall hypothesis is that in older adults with SCD, normal cognitive performance is maintained by compensatory attention network activity, supported by enhanced cholinergic function. The investigators anticipate that SCD will be associated with greater compensatory attention network activity and that disrupting this compensatory process through anticholinergic challenge will result in a greater negative effect on attentional performance (Attention Network Test, ANT) and attention network functioning (EEG) in older adults with greater subjective cognitive concern.