Macaque amygdala, claustrum and pulvinar support the cross-modal
association of social audio-visual stimuli based on meaning
Abstract
Social communication draws on several cognitive functions such as
perception, emotion recognition and attention. In a previous study, we
demonstrated that macaques associate audio-visual information when
processing their species-specific communicative signals. Specifically,
cortical activation is inhibited when there is a mismatch between
vocalisations and social visual information whereas activation is
enhanced in the lateral sulcus, superior temporal sulcus as well as a
larger network composed of early visual and prefrontal areas when
vocalisations and social visual information match. Here, we use a
similar task and functional magnetic resonance imaging to assess the
role of subcortical structures. We identify three subcortical regions
involved in audio-visual processing of species-specific communicative
signal: the amygdala, the claustrum and the pulvinar. Like the cortex,
these subcortical structures are not activated when there is a mismatch
between visual and acoustic information. In contrast, the amygdala and
claustrum are activated by visual, auditory congruent and audio-visual
stimulations. The pulvinar responds in a task-dependent manner, along a
specific spatial sensory gradient. Anterior pulvinar responds to
auditory stimuli, medial pulvinar is activated by auditory, audio-visual
and visual stimuli and the dorsal lateral pulvinar only responds to
visual stimuli in a pure visual task. The medial pulvinar and the
amygdala are the only subcortical structures integrating audio-visual
social stimuli. We propose that these three structures belong to a
multisensory network that modulates the perception of visual
socioemotional information and vocalizations as a function of the
relevance of the stimuli in the social context.