INTRODUCTION:

Developmental topographical
disorientation (DTD) is a lifelong condition in which affected
individuals are selectively impaired in navigating space. Although it
seems that DTD is widespread in the population, only a few cases have
been studied from both a behavioral and a neuroimaging point of view.
Here, we report a new case of DTD, never described previously, of a
young woman (C.F.) showing a specific deficit in translating
allocentrically coded information into egocentrically guided navigation,
in presence of spared ability of constructing such representations.

METHOD:

A series of behavioral experiments was performed together with a resting-state functional magnetic resonance imaging (fMRI).

RESULTS:

We
demonstrated that C.F. was fully effective in learning and following
routes and in building up cognitive maps as well as in recognizing
landmarks. C.F.'s navigational skills, instead, dropped drastically in
the map-following task when she was required to use a map to navigate in
a novel environment. The rs-fMRI experiment demonstrated aberrant
functional connectivity between regions within the default-mode network
(DMN), and in particular between medial prefrontal cortex and posterior
cingulate, medial parietal, and temporal cortices.

DISCUSSION:

Our
results would suggest that, at least in C.F., dysfunctional
coactivation of core DMN regions would interfere with the ability to
exploit cognitive maps for real-life navigation even when these maps can
be correctly built.

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