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yn iversit 2006 2004), subsequent classification of event boundaries (Zacks et al., activity with measures such as navigational accuracy, typically previous studies. Accompanying this, we were able to pinpoint the transient and highly specific engagement and disengagement of particular brain regions, such as the hippocampus, revealing the YNIMG-03765; No. of pages: 15; 4C: DTD 5 * Corresponding author. Fax +44 207 813 1420complex inputs from the external world to produce a seamless reality and an integrated sense of who and where we are remains a fundamental mystery in neuroscience. Whilst controlled experi-ments can give snapshots of neuronal responses to simplified stimuli, they cannot hope to mirror the challenges faced by the brain in the real world (Burgess et al., 2002; Hasson et al., 2004). Thus, several recent functional magnetic resonance imaging (fMRI) studies have examined brain activity elicited by viewing more naturalistic stimuli, such as Hollywood movies (Bartels and Zeki, 2004; Hasson et al., 2004; Zacks et al., 2001). Analyses using subsequent ratings of various attribute intensities (Bartels and Zeki, averaged over epochs of 30–60 s (Hartley et al., 2003; Maguire et al., 1998). However, even in these experiments with more naturalistic interactive settings, unitary temporally gross measures fail to capture the multi-faceted and highly dynamic operation of the human navigation system. We set out to extend the previous passive, and the temporally insensitive studies by integrating three factors (see below) in a novel way in the context of fMRI. We chose to focus on navigation, a prime example of the human brain operating in a real-world context. Our approach permitted a remarkably detailed characterisation of the unfolding navigation process that has eludedThoughts, behaviour, and brain d in the real worl