Steady state visually evoked potential (SSVEP) phase change as an index of Spatial Working Memory task performance: the influence of nootropic supplementation

Background: Spatial Working Memory (SWM) is a cognitive domain that has a high degree of sensitivity to pharmaceutical intervention and is one of the first domains to be adversely impacted by agerelated cognitive decline. Steady State Probe Topography (SST) at a frequency of 13 Hz is a novel electrophysiological technique that enables investigation into SSVEP amplitude and phase change with a precise temporal resolution of b80 ms. Methods: The following presentation will detail a program of research conducted at the Centre for Human Psychopharmacology since 2009 which has involved randomized placebo-controlled nootropic intervention studies of SSVEP changes during SWM task performance (with a combined N of 200 people). Nootropic substances that have been administered include Cocoa Polyphenols, Panax quinquefolius (American ginseng), Ginkgo biloba, Hypericum perforatum, Guarana and B-vitamins. Results: SSVEP phase lag in posterior-parietal and prefrontal brain regions during the online maintenance of spatial locations in WM has been found to be increased in response to nootropic supplementation. Conclusions: These studies provide preliminary evidence to suggest that the typical SSVEP phase advance observed under conditions of increased WM load may be ameliorated by nootropic intervention — a finding that may be explained by increases in inhibitory neural processes