Different kinds of challenge can alter cognitive process and electroencephalographic (EEG) rhythms in humans.
This can provide an alternative paradigms to evaluate treatment effects in drug discovery. Here, we report recent
findings on the effects of challenges represented by sleep deprivation (SD), transient hypoxia, and transcranial magnetic
stimulation (TMS) in healthy volunteers on cognitive processes and EEG rhythms to build a knowledge platform for novel
research for drug discovery in AD Alzheimer's disease (AD). Sleep pressure enhanced frontal delta rhythms (< 4 Hz) during
the night, while SD increased slow rhythms in the theta range (4-7 Hz), and reduced resting state alpha rhythms (8-12
Hz) after the following day. Furthermore, SD transiently affected cognitive performance. In contrast, transient experimental
hypoxia induced abnormal posterior resting state delta and alpha rhythms in healthy volunteers that resemble the abnormal
EEG rhythms typically recorded in AD patients. However, the relationship between the cognitive and EEG effects
of such challenges is poorly understood. TMS reversibly interfered with higher brain functions during EEG recordings,
but few studies have investigated the relationship between the cognitive and EEG effects of TMS. In conclusion, SD is the
most mature challenge model for testing new drugs for AD. Future investigation is needed to better understand the
opportunities offered by TMS and hypoxia challenges.