Affiliations: [a] Department of Speech and Hearing Science, University of Illinois at Urbana-Champaign, Champaign, IL, USA | [b] Neuroscience Program, University of Illinois at Urbana-Champaign, Champaign, IL, USA | [c] Center for BrainHealth, The University of Texas at Dallas, Dallas, TX, USA | [d] Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
Correspondence:
[*]
Correspondence to: Raksha A. Mudar, Department of Speech and Hearing Science, University of Illinois at Urbana-Champaign, 901, S. Sixth Street, Champaign, IL 61820, USA. Tel.: +1 217 333 4718; Fax: +1 217 244 2235; E-mail: raksha@illinois.edu.
Abstract: We examined the effects of amnestic mild cognitive impairment (aMCI) on behavioral (response times and error rates) and scalp-recorded event-related potential (ERP) measures of response execution and inhibition, using Go/NoGo tasks involving basic and superordinate semantic categorization. Twenty-five aMCI (16 F; 68.5±8 years) and 25 age- and gender-matched normal control subjects (16 F; 65.4±7.1 years) completed two visual Go/NoGo tasks. In the single car task, responses were made based on single exemplars of a car (Go) and a dog (NoGo) (basic). In the object animal task, responses were based on multiple exemplars of objects (Go) and animals (NoGo) (superordinate). The aMCI subjects had higher commission errors on the NoGo trials compared to the control subjects, whereas both groups had comparable omission errors and reaction times during the Go trials. The aMCI subjects had significantly prolonged N2 ERP latency during Go and NoGo trials across tasks compared to the controls. Both groups showed similar categorization effects and response type effects in N2/P3 ERP latencies and P3 amplitude. Our findings indicate that altered early neural processing indexed by N2 latency distinguishes subjects with aMCI from controls during the Go/NoGo task. Prolonged Go-N2 latency in aMCI appears to precede behavioral changes in response execution, whereas prolonged NoGo-N2 latency underlies behavioral deterioration in response inhibition.
