We use neuroimaging to ask:
- How do we know where we are?
- How do we plan a route to a goal destination in a familiar environment?
- How do we deal with detours when our normal route is blocked?
- How do we learn the layout of a new environment?
- What are the different components of navigation (e.g. landmarks, routes) and how do they combine to help us navigate?
- What are the mechanisms by which networks of neurons represent our location relative to our environment and guide navigation to remembered places?
- Why are some people better at navigation than others?
- How does the navigation system fail in the context of brain injury and disease?
Our goal is to provide:
A detailed understanding of how the brain supports navigation so that we can help those who experience problems with finding their way.
We have all experienced how frustrating and anxiety-inducing it is to be lost when trying to reach a destination. The ability to navigate is central to many of our behaviours, and is one we share with most other species. Navigation is multi-faceted, and distinct brain areas seem to contribute to different features of navigation.
Conducting detailed neuroscientific studies of navigation to understand how we learn landmarks, how they link together to form routes, and how we are able to flexibly use our spatial representation of environments, means that we will be in a better position to intervene as early as possible when navigation ability starts to decline in the context of brain injury or disease. Indeed, problems with navigation are often among the earliest signs of dementia.
Our research into the neural mechanisms that support navigation aims to benefit patients with:
- Epilepsy, to minimise damage to navigation-relevant brain areas during surgery
- Alzheimer’s disease and other forms of dementia, as problems with navigation are often an early sign that something is awry
- Limbic encephalitis, and conditions affecting oxygen supply to the brain (e.g. stroke, respiratory arrest, heart attacks), to understand the nature of the navigation loss and devise means to used preserved aspects of navigation ability to offset some of the deficits
- Our work also has implications beyond patients. For example, by understanding how the brain supports navigation, we can inform architects and urban planners about how to best design buildings and other spaces so they are more easily navigable
- We discovered that licensed London taxi drivers have bigger hippocampi than control volunteers (e.g. Maguire et al., 2000; Woollett and Maguire, 2011). This work engaged not only scientists, but also the public and media world-wide. It emphasised the capacity of the adult human brain for plasticity and life-long learning, and the key role the human hippocampus plays in spatial navigation
- We pioneered the use of virtual reality in neuroimaging studies (e.g. Maguire et al., 1998; Spiers and Maguire, 2006) enabling us to examine the navigating brain in its natural context, and simulate the sorts of real-world navigation challenges that people encounter
- By conducting an in-depth study into a unique patient who had been a licensed London taxi driver for 40 years before his focal bilateral hippocampal damage occurred, we could identify the specific contribution the hippocampus makes to navigation (Maguire et al., 2006)
- We have discovered that another brain region known as the retrosplenial cortex codes for landmarks in the environment that never move (Auger et al., 2015). These key fixed landmarks may lay the foundation for our mental map of an environment
- We have found a number of parallels between the brain areas involved in supporting navigation in rodents and humans. One example is grid cells, found the entorhinal cortex, which are thought to form the metric for space.
- We found evidence for grid cells in the human episodic memory system using virtual reality and fMRI during both virtual (Doeller et al., 2010) and imagined (Horner et al., 2015) navigation
- We found a functional role for theta rhythmicity (ubiquitous in rodent hippocampus during navigation) in human navigation. Using MEG we found increases in theta power preceding navigational movements coincident with hippocampal fMRI increases (Kaplan et al., 2012), and medial prefrontal – medial temporal theta coherence during both spatial planning (Kaplan et al., 2014 and dynamic imagery (Kaplan et al., 2017). Complementary use of intra-cranial recording in epilepsy patients showed hippocampal theta power increases precede navigational trajectories and predict their length (Bush et al., 2018)
- We showed that hippocampal navigation reflects the use of extended boundaries whereas striatal navigation reflects the use of discrete landmarks (Doeller, King and Burgess, 2008), that the two systems respectively use incidental versus reinforcement learning rules (Doeller and Burgess, 2008) and support wayfinding versus route following (Hartley et al., 2003). Individual differences in hippocampal boundary-related navigation predicts people’s strategy in non-spatial decision making, an effect that disappears after temporal lobectomy (Vikbladh et al., 2019), strongly implicating the hippocampus in model-based reasoning
- The spatial world is three-dimensional (3D), and we move both horizontally and vertically within it. Despite this, we know very little about how 3D spatial information is represented in the brain. We have pioneered the study of navigation within, for example, multi-level buildings, again by combining virtual reality and neuroimaging (Kim and Maguire, 2018)
Click here to find out more about MEMO, our big study into the origin of individual differences in navigation.
Click here if you are an A-Level student and want to find resources relating to our London taxi driver work.
Click here to find detailed anatomical images relating to our tutorial on how to segment human hippocampal subfields from MR images.