Beyond the Help of Google Maps

If you travel with me long enough, you’ll find out I’m amazing at U-turns. This random talent has been continually cultivated by my terrible sense of direction, a condition that, whether walking, driving, or exploring, is beyond the help of Google Maps. Naturally, I was wary of coming to Europe out of anxiety of getting lost. Sure enough, during this Paris program and my cliché Euro-backpacking trip, getting lost down strange streets and roads was inevitable. However, all things considered I’ve been impressed how easily I can navigate my way to class or tourist attractions. I’ve even found myself guiding my friends when going to particular destinations. What about Europe makes my sense of direction sharper? This question motivated my investigation into the neurobiological pathways that modulate spatial navigation.

Taken from http://favim.com/road+sign/.

In the 1970’s a groundbreaking discovery in rats started detailed neurobiology research on how we know where we are. Neurons in the hippocampus and parahippocampus (brain location shown below) increase their firing rates when rats moves through specific regions of their environment, therefore creating a mental map (Ekstrom et al., 2003).

Taken from http://www.bristol.ac.uk/synaptic/pathways/

Figure from Ekstrom et al. (2003) showing images from the virtual reality participants navigated

Human experiments have found that neurons known as parahippocampal place cells fire when recognizing landmarks and passively exploring environments (Maguire, Burgess, and O’Keefe, 1999). Many navigational studies of recent decades image brains via fMRI or record neuron firings while participants move in virtual environments. For example, in a 2003 study participants drove a virtual taxi, picking up and dropping off customers at various locations around the virtual town. Both brain regions possessed “goal cells” that fired more if the participant succeeded in one of the experiment’s tasks. They found the hippocampus primarily activated to specific spatial locations while the parahippocampus fired when viewing a landmarks (Ekstrom et al., 2003). Tourism centers obviously understand the importance of landmark recognition when getting around, as most maps for Paris contain pronounced images of popular landmarks beside the street name. Our dependence on landmarks, however, can vary. One review referenced a study stating women rely more on landmarks than men as men also incorporate more global views into their mental maps (Maguire, Burgess, and O’Keefe, 1999).

Map of Paris with landmarks emphasized. Taken from http://parismap360.com/paris-tourist-map#.WT241KtLlSU

What does this navigational model mean when I’m trying to find the Eiffel Tower? My parahippocampus registers coarse spatial features, such as the metro station sign or the Eiffel Tower itself, while my hippocampus combines contextual visual and spatial features to form a mental map. Should I make the trek back to that location the next day with my friends, the same cells that encoded those features will fire again, reinforcing my overall sense of direction.

Taken from https://www.linkparis.com/paris-metro-map.htm

As I discussed my improved sense of direction with a friend, she posited that maybe this change was simply due to increased attention to my surroundings. A 2004 paper particularly backed her claim. Spatial tasks with mice found that long term firing stability of parahippocampal place cells was significantly increased with enhanced attention and context relevance (Kentros et al., 2004). Attention’s influences on navigation probably modulate neuron firing by promoting long term information encoding instead of short-term storage. Therefore, because I’m motivated to get back to my dormitory after exploring, I pay more attention, which in turn encodes landmarks along my walking route as memory traces. According to this mouse model, several hours can go by and I can still make it back to Cité Universitaire without getting lost.

In contrast to this idea, a human experiment published this year found innate sense of direction is unaffected by conscious attention (Burte and Montello, 2017). Participants who had various levels of self-assessed sense of direction navigated an unfamiliar neighborhood under a condition of intentional attention or incidental learning. The results found intentional attention participants did not learn the route any better than those of incidental learning, concluding sense of direction is applied without internal application. However, this study recognized their experimental design did not exactly follow models of other human studies that have promoted attention modulation when navigating.

While enhanced attention is a likely candidate for my newly gained sense of direction, more research is necessary before I have a sound explanation. In the meantime, however, I plan to enjoy exploring Paris with my friends using faster routes and, hopefully, fewer U-turns.

NBB 2017 Summer Program at the Eiffel Tower!

Bibliography:

Burte H, Montello DR (2017) How sense-of-direction and learning intentionality relate to spatial knowledge acquisition in the environment. Cog. Research: Principles and Implications 2:18.

Ekstrom AD, Kahana MJ, Caplan JB, Fields TA, Isham EA, Newman EL, Itzhak F (2003) Cellular networks underlying human navigation. Nature 425:184-187.

Kentros CG, Agnihotri NT, Streater S, Hawkins RD, Kandel ER (2004) Increased attention to spatial context increases both place field stability and spatial memory. Cell 42:283-295.

Maguire EA, Burgess N, O’Keefe J (1999) Human spatial navigation: cognitive maps, sexual dimorphism, and neural substrates. Current Opinion in Neurobiology 9:2:171-177.