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Abstract:
Affective cues provided simultaneously by a face expression
and a tone of voice are combined in the course of perception(1).
The integration of the two sensory inputs is mandatory and not
under attentional control. Recent studies have provided evidence
for non-conscious processing of emotions involving predominantly
subcortical structures. Purpose. To find evidence of processing of
the emotional valence of faces in a blindsight patient by
presenting emotional stimuli to lesioned field and establish
thereby that facial expressions can be processed in the absence of
intact V1. Methods. Four experiments tested recognition of facial
expressions in a subject with unilateral damage to the primary
visual cortex (GY). Materials consisted of short video clips of
facial expressions and short sentences. Design. In the uni-modal
experiments only the facial expressions were presented. In the
bi-modal ones the facial expressions were combined and presented
simultaneously with the voice expression creating either a
congruent of an incongruent bimodal stimulus. Procedure. For
presentations in a single modality a direct testing method was
used. The bimodal task relied on an indirect testing method and
required a judgement of the voice used the impact of the unseen
face expression on the voice as a measure of covert recognition of
the facial expression. Stimuli were presented to either the RVF or
the LVF. Conclusions. GY reliably perceives facial expressions in
the blind field. In the uni-modal condition discrimination of the
facial expression was well above chance. In the bimodal task the
face projected to the blind field systematically influenced his
report of voice expression. (1) de Gelder, Bocker, Tuomainen,
Hensen and Vroomen(in press). Neuroscience Letters
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