Cognitive Aspects: How People Perceive, Memorize, Think and Talk About Landmarks - Landmarks: GIScience for Intelligent Services - page 61

While processing of spatial scenes involves the parahippocampus, the right hippocampus
appears particularly involved in memory for locations within an environment, with the left
hippocampus more involved in context-dependent episodic or autobiographical memory
(p. 625).
The other one is for survey-like, from-above visual imagination and manipulation
of environments. Shelton and Gabrieli [ 196 ] have observed people viewing an
environment in each of the two perspectives with fMRI. When comparing the
brain activation during route and survey encoding they found that both types of
information recruited a common network of brain areas, but while survey encoding
recruited a subset of areas recruited by route encoding, route encoding, in contrast,
recruited regions that were not activated by survey encoding.
Similarly, routine behavior in well learned environments may be stored as
schema knowledge outside the hippocampus [ 219 ] . This means, people in spatial
decision making situations may follow schemas (mental shortcuts) rather than
analysing their mental spatial representations.
In all likelihood a person will not experience every square-meter of the Earth
in their life-time. But there will be a difference between the traveling range of
the peasant in the middle ages, who rarely left the district, and a global nomad
of the twenty-first century. The global nomad at least will appreciate schema
knowledge after experiencing that all airports look alike. Relph called them even
'no-places' [ 175 ] . On the other hand, Maguire et al. found that spatial memory
shows plasticity in response to environmental demands [ 130 ] . They compared the
brains of London taxi drivers with control participants who did not drive taxis.
It turned out that the posterior hippocampi of taxi drivers were significantly larger,
and this observation correlated with the amount of their professional experience.
The involvement of the parahippocampal region in both spatial memory as well
as object or scene recognition is particularly interesting in the context of landmarks
as used for visual navigation. Janzen and Turennout [ 92 ] have investigated combi-
nations of skills:
Human adults viewed a route through a virtual museum with objects placed at intersec-
tions (decision points) or at simple turns (non-decision points). Event-related functional
magnetic resonance imaging (fMRI) data were acquired during subsequent recognition
of the objects in isolation. Neural activity in the parahippocampal gyrus reflected the
navigational relevance of an object's location in the museum. Parahippocampal responses
were selectively increased for objects that occurred at decision points, independent of
attentional demands. This increase occurred for forgotten as well as remembered objects,
showing implicit retrieval of navigational information (p. 673).
We will come back to this encoding of navigational relevance; in Sect. 3.2 we have
called it structural salience. In addition, Janzen and Turennout demonstrated later
that good navigators show even a consolidation effect in their spatial memory. Their
activity in the hippocampus increases when recognizing objects along routes learned
a while a ago, compared to routes traveled just now [ 91 ] . Furthermore, Maguire
and colleagues have investigated whether a specific human navigation system
exists [ 129 , 203 ] . Their experiment was based on fMRI while tracking participants
in virtual environments. They could identify three specific brain regions supporting