| |
Abstract:
Abstract: Neuropsychological and neuroimaging literature
suggests that non-identical neural/cognitive systems subserve
semantic memories of living and nonliving things. To examine the
nature of the differences between the living/non-living systems,
the present study recorded ERPs while participants classified words
into tool/animal categories. Our previous study with pictures
showed that the fronto-central negativity in the N400 time-window,
thought to reflect image-based semantic system activity, was larger
to animals than tools, suggesting that this system has special
significance for animal concepts. In contrast, the posterior
component, believed to be evoked by an amodal semantic system, was
larger to tools than animals, showing that tool knowledge may
depend more on the amodal system. The present results supported
these findings in that words elicited N400-like parietal (N380) and
fronto-central (N450) components, the former being larger to tools.
Earlier occurrence of the parietal component was consistent with
Pavioís dual-coding representation theory that words
activate imagistic representations after accessing amodal codes.
The anterior component was comparable between tools and animals,
which however could be explained by the fact that extensive
secondary activation of imagistic representations might not occur
as the participantsí task did not require deep semantic
processing. Thus, the current results supported the view that
although living objects may have more extensive representations in
the imagistic system, and non-living objects in the amodal system,
involvement of these semantic systems in object processing may
depend more on the performed task.
|
