Mark Fenske, Ph.D.
(MGH)
Top-down influences on visual recognition and affective response
Previous research has established a network of cortical regions that are
sensitive to environmental regularities, such as associations between
visual objects that tend to appear together in familiar contexts. I will
discuss a series of behavioral and neuroimaging (fMRI) experiments
examining the top-down influence of these contextual associations on
visual recognition. Specifically, we found that upon recognition of a
strongly contextual object, the retrosplenial complex, the
parahippocampal cortex, and the ventro-medial prefrontal cortex have
largely dissociable roles in facilitating the recognition of other
contextually related objects when they are subsequently encountered.
Furthermore, the influence of top-down context-based predictions extends
to early object-processing regions, and fMRI measures of the magnitude
of this influence correlate strongly with behavioral measures of
contextual facilitation of recognition. Other evidence suggests that
when a strongly contextual object is encountered, processing of its
contextual associations proceeds almost immediately, based on early
'initial guesses' about its identity. Behavioral results suggest that
the contextual analysis occurring before recognition of an object is
even complete is nevertheless sufficient to prime recognition of objects
that are contextually related to these 'initial guesses'. Finally, I will
review evidence that the same brain regions responsible for analyzing
contextual associations are also involved in the analysis of affective
associations, and summarize the results of a series of experiments
examining the impact of top-down influences on affective response.
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