0124 Dextroamphetamine biases the brain towards enhanced spatial selective attention compared over working memory

Abstract

Abstract Introduction There is a growing trend in the non-medical use of prescription psychostimulant (PStim) in healthy adults One of the main reasons of increased usage of PStim is due to their perceived benefits on the cognitive capacity. However, evidences from empirical studies on healthy adults point to an inconclusive answer. There are various factors which could have contributed to these overall mixed findings. These factors range from differences in drug dosages, individual baseline variability and use of different tasks. However, one of the important factors that previous studies have not considered is the presence possible selective bias of PStim towards a specific cognitive domain over others which may lead to its selective enhancement at the cost of others’ degradation. Methods To study this, we carried out a double blind, placebo-controlled study, with repeated measures design to investigate the differential influence of a stimulant drug (DEX vs PBO) on the cognitive skills of working memory (WM) and spatial selective attentive in the form multiple object tracking (MOT) across a period of a day. We compared the change in the performance of WM and MOT in DEX vs PBO conditions at 1) pre-drug baseline, 2) 75 minutes post-drug (peak concentration), 3) 12 hours post-drug intake (washout). Results First, we found that DEX did not have any overall significant effect on WM performance across a period of day compared to the placebo condition. We also found that MOT performance was rescued by DEX, unlike the placebo condition in which the MOT performance degraded over different testing periods across a wake day period. Importantly, we found that during the peak concentration of DEX in the body MOT performance was significantly superior to that of the WM performance. This superiority of MOT over WM was not present before the drug administration (baseline) and also returned to a level similar to baseline after a gap of 12hours. Conclusion Overall, our study findings suggest that DEX has a favorable bias towards MOT compared to WM and selectively enhances its performance when the brain is required to support both of these two cognitive domains concurrently. Support (If Any)