Cognitive enhancement (CE) is the pursuit of enhancing and increasing the core mental capacity above the normal level. With the advancement of science and technology, many different approaches to carry out enhancement are available. The use of psychostimulants as the choice of cognitive enhancer is rapidly growing. Although anecdotal and subjective evidences claim that these drugs work however, empirical evidences from studies in healthy adults show inconclusive evidences. One reason could be that these studies did not consider sleep as an important factor mediating the effect of stimulants on brain activities. My study 1 investigates the role of sleep in stimulant mediated CE. Along with sleep, there are other factors which are important when investigating the stimulants’ effect of CE such as dosage, type of cognitive tasks, individual variability and bias of stimulant drugs toward certain cognitive domain. My study 2 investigates the evidences of bias by stimulants towards specific cognitive domain/s. Stimulants are addictive and comes with many side effects that may cause long term health issues. In my study 3, I investigated CE through targeted memory reactivation (TMR) which exploits the natural process of memory formation and strengthening during sleep with sensory stimulation to manipulate the memory strength. Specifically, in study 3 I developed a homebased- TMR protocol to selectively bias the weak and strong memories. This protocol was designed to carry out the study amidst the COVID pandemic lockdown. I developed a brand-new spatial memory cognitive task for remote online participation. The TMR intervention protocol is suitable for real world and naturalist setting without the participants having to come to the lab. This new homebased-TMR protocol shows some promising results. With future improvement and refinement, it could be turned into fully automated unsupervised TMR system.