Higher cognitive reserve is associated with better neural efficiency in the cognitive performance of young adults. An event-related potential study

To examine the effects of cognitive reserve (CR) and working memory (WM) load on the cognitive performance of young adults, we performed two event-related potential (ERP) experiments. The first experiment aims to show how high CR influences young adult performance as a function of two levels of working memory load (high vs. low) during a Sternberg task. For both positive and negative probes, participants with high and low CR showed larger P300 amplitudes to low WM loads than to high WM loads. Both CR groups showed a longer P300 latency to high WM loads than to low WM loads, but this difference was greater for the low CR group than for the high CR group. The high CR group displayed larger P300 amplitudes for every experimental condition compared to the low CR group. The second experiment analyzed grammatical gender agreement in sentence processing when CR and WM load were manipulated. Sentences varied according to the gender agreement of the noun and adjective, where the gender of the adjective either agreed or disagreed with that of the noun (agreement), and with regard to the number of words between the noun and the adjective in the sentence (WM load). Participants with high CR showed greater modulation of left anterior negativity (LAN) and P600a effects as WM increased than that observed in participants with low CR. The findings together suggest that higher levels of cognitive reserve improve neural efficiency, which may result in better working memory performance and sentence processing.