Contents lists available at ScienceDirect Neuroscience Letters journal homepage: www.elsevier.com/locate/neulet Research article Age effects on event-related potentials in individuals with amnestic Mild Cognitive Impairment during semantic categorization Go/NoGo tasks Hsueh-Sheng Chiang a,b , Jeffrey S. Spence a , Michael A. Kraut c , Raksha A. Mudar a,d, ⁎ a The University of Texas at Dallas, Richardson, TX, United States b University of Texas Southwestern Medical Center, Dallas, TX, United States c The Johns Hopkins School of Medicine, Baltimore, MD, United States d University of Illinois at Urbana-Champaign, Champaign, IL, United States ARTICLE INFO Keywords: MCI ERP Cognitive control Age N2 P3 ABSTRACT Both age and amnestic Mild Cognitive Impairment (aMCI), two major risk factors associated with Alzheimer’s disease, have been associated with increased latency of event-related potentials, but how these factors interact has been less extensively evaluated. We examined the effects of age as a factor in 25 individuals with aMCI and in 25 age-matched normal controls (NC) during semantic categorization Go/NoGo tasks. We found that N2 latency was prolonged with increasing age in aMCI but not in the NC, and P3 latency was prolonged with increasing age in both groups. Furthermore, aMCI individuals showed significant prolongation in N2 latency compared to NC in the older age group, whereas such group differences were not observed in the younger age group. Our findings suggest that N2 latency corresponding to cognitive control is susceptible to a combination of age and disease effects, especially in older individuals, and thus may be useful in differentiating normal from pathological aging in this age group. 1. Introduction Mild Cognitive Impairment (MCI) is often observed before dementia develops, with the amnestic subtype (aMCI) most predictive of pro- gression to Alzheimer’s disease (AD) [1]. Endogenous event-related potentials (ERPs) that measure synchronized activity among cortical neurons during controlled cognitive processes appear to be sensitive to earliest cognitive changes in the pre-dementia phase [2]. For example, prolongation in ERP latency has been linked to AD risk factors such as APOE-4 alleles and family history [3,4] and has been found to dis- criminate individuals with aMCI from normal controls or to predict later progression to AD [5,6]. In our previous study, we showed that aMCI is associated with de- layed latency in neural activity underlying cognitive control (measured by N2, a fronto-central ERP component occurring between 200 and 400 ms post-stimulus onset) [7], adding to existing literature on the sensitivity of N2 as a marker of cognitive deterioration [8]. However, we did not consider ‘age’ as an independent variable in our analyses as our aMCI and normal control groups were age-matched. However, age has been identified as a major risk factor of AD [9], suggesting its in- teraction with underlying disease processes. Papaliagkas et al. found that aMCI participants and controls showed positive correlations between N2/P3 latencies, but they did not directly explore the inter- action between age and N2/P3 latencies across aMCI and control groups [5]. Also, whether their findings are unique to auditory tasks involving simple perceptual discrimination of pure tones used in their study, or whether the N2/P3 latency findings apply to semantically laden tasks, remains unknown. To this end, we examined the effects of age on N2 and P3 latencies associated with Go/NoGo tasks during se- mantic categorization in individuals with aMCI and in cognitively normal controls. 2. Materials and methods 2.1. Participants and cognitive EEG tasks Twenty-five individuals with aMCI (16 F; 68.5 ± 8 years) and 25 age- and sex-matched normal control participants (16 F; 65.4 ± 7.1 years) performed two Go/NoGo tasks. The single car task (SiC) involved basic categorization and used single exemplars of a car (Go) and a dog (NoGo). The object animal task (ObA) involved super- ordinate categorization and used multiple exemplars of objects (Go) and animals (NoGo) across trials. Each task consisted of 200 trials: 160 (80%) ‘Go’ trials that required a response through button pressing and https://doi.org/10.1016/j.neulet.2018.01.034 Received 16 June 2017; Received in revised form 7 January 2018; Accepted 17 January 2018 ⁎ Corresponding author at: Department of Speech and Hearing Science, University of Illinois at Urbana-Champaign, 901, S. Sixth Street, Champaign, IL 61820, United States. E-mail address: raksha@illinois.edu (R.A. Mudar). Neuroscience Letters 670 (2018) 19–21 Available online 31 January 2018 0304-3940/ © 2018 Elsevier B.V. All rights reserved. T