Cerebral differences in explicit and implicit emotional processing - An fMRI study

The processing of emotional facial expression is a major part of
social communication and understanding. In addition to explicit
processing, facial expressions are also processed rapidly and
automatically in the absence of explicit awareness. We investigated
12 healthy subjects by presenting them with an implicit and
explicit emotional paradigm. The subjects reacted significantly
faster in implicit than in explicit trials but did not differ in
their error ratio. For the implicit condition increased signals
were observed in particular in the thalami, the hippocampi, the
frontal inferior gyri and the right middle temporal region. The
analysis of the explicit condition showed increased
blood-oxygen-level-dependent signals especially in the caudate
nucleus, the cingulum and the right prefrontal cortex. The direct
comparison of these 2 different processes revealed increased
activity for explicit trials in the inferior, superior and middle
frontal gyri, the middle cingulum and left parietal regions.
Additional signal increases were detected in occipital regions, the
cerebellum, and the right angular and lingual gyrus. Our data
partially confirm the hypothesis of different neural substrates for
the processing of implicit and explicit emotional stimuli.
Copyright (c) 2007 S. Karger AG, Basel.