When humans distribute their attention in space, biases or asymmetries of spatial attention exist. Healthy individuals exhibit a processing advantage favouring left space but this advantage is lost in disorders such as unilateral spatial neglect, ADHD and dyslexia. This study will develop novel electrophysiological methods to dissociate the sensory, attentional, decision-making and motoric contributions to spatial asymmetries. By interfacing electrophysiology with genetic, neurochemical and brain imaging methods, this project will comprehensively map the biology of spatial asymmetry. This knowledge is vital to developing effective treatments for disorders where atypical patterns of spatial asymmetry index neurological vulnerability.