A Goal Direction Signal in the Human Entorhinal/Subicular Region

Martin J Chadwick,Amy E.J Jolly,Doran P Amos,Demis Hassabis,Hugo J Spiers

doi:10.1016/j.cub.2014.11.001

Martin J Chadwick, Amy E.J Jolly + Show 3 more

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https://doi.org/10.1016/j.cub.2014.11.001

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SummaryNavigating to a safe place, such as a home or nest, is a fundamental behavior for all complex animals. Determining the direction to such goals is a crucial first step in navigation. Surprisingly, little is known about how or where in the brain this “goal direction signal” is represented. In mammals, “head-direction cells” are thought to support this process, but despite 30 years of research, no evidence for a goal direction representation has been reported [1, 2]. Here, we used fMRI to record neural activity while participants made goal direction judgments based on a previously learned virtual environment. We applied multivoxel pattern analysis [3–5] to these data and found that the human entorhinal/subicular region contains a neural representation of intended goal direction. Furthermore, the neural pattern expressed for a given goal direction matched the pattern expressed when simply facing that same direction. This suggests the existence of a shared neural representation of both goal and facing direction. We argue that this reflects a mechanism based on head-direction populations that simulate future goal directions during route planning [6]. Our data further revealed that the strength of direction information predicts performance. Finally, we found a dissociation between this geocentric information in the entorhinal/subicular region and egocentric direction information in the precuneus.

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According to this proposal, during goal direction simulation, the head-direction cell population activity would change from cells responsive to current facing direction being suppressed to cells representing the desired future heading direction becoming active
To infer the presence of this kind of general direction information, we looked for increased pattern similarity between pairs of trials where the facing direction in trial A matched the goal direction in trial B, which we refer to as a ‘‘cross match’’ (Figure 3A)
We further investigated the selectivity of these results and found that the entorhinal/subicular region shows no evidence for egocentric direction representations (t(15) = 0.94, p = 0.18), while the precuneus shows no evidence for geocentric direction representations (t(15) = 0.41, p = 0.34)