Doctoral Thesis / Dissertation from the year 2013 in the subject Medicine - Neurology, Psychiatry, Addiction, grade: pass (in GB keine Benotung), University College London (Institute of Cognitive Neuroscience), course: Neurowissenschaften, language: English, abstract: Traditionally, the focus in cognitive neuroscience has been on so-called evoked neural activity in response to certain stimuli or experiences. However, most of the brain's activity is actually spontaneous and therefore not ascribed to the processing of a certain task or stimulus – or in other words, uncoupled to overt stimuli or motor outputs. In this thesis I investigated the functional role of spontaneous activity with a focus on its role in contextual changes ranging from recent experiences of individuals to trial-by-trial variability in a certain task. I studied the nature of ongoing activity from two perspectives: One looking at changes in the ongoing activity due to learning, and the other one looking at the predictive role of prestimulus activity using different methodologies, i.e. EEG and fMRI. Finally, I ventured into the realm of inter-individual differences and mind-wandering to investigate the relationship between ongoing activity, certain behavioural traits and neuronal connectivity.