Mirror-touch synaesthesia: the role of shared ... - UCL Discovery

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Chapter 7
CHAPTER 7: THE ROLE OF SENSORIMOTOR SIMULATION
IN AUDITORY EMOTION DISCRIMINATION
Functional neuroimaging studies indicate that activity in primary somatosensory and
premotor cortex is evoked during the perception of emotion. In the visual domain,
right somatosensory cortex activity has been shown to be critical for facial emotion
recognition. However, the importance of these representations in modalities outside
of vision remains unknown. This study used continuous theta-burst transcranial
magnetic stimulation (cTBS) to investigate whether neural activity in the right
primary somatosensory cortex (rSI) and right lateral premotor cortex (rPM) is
central to non-verbal auditory emotion recognition. Two groups of participants
completed same-different tasks on auditory stimuli, discriminating between either the
emotion expressed or the speakers’ identities, prior to and following cTBS targeted at
rSI, rPM or the vertex (control site). A task-selective deficit in auditory emotion
discrimination was observed. Stimulation to rSI and rPM resulted in a disruption of
participants’ abilities to discriminate emotion, but not identity, from vocal signals.
7.1 Introduction
Our ability to recognise the emotions of others is a crucial feature of human
social cognition. The neurocognitive processes which underpin this have recently
been described as being achieved through simulation processes (Adolphs, 2002;
Adolphs, 2003; Damasio, 1990; Gallese, Keysers, and Rizzolatti, 2004; Goldman and
Sripada, 2005; Keysers and Gazzola, 2006). These models suggest that understanding
another’s emotions requires individuals to map the observed state onto their own
representations which are active during the experience of the perceived emotion. The
discovery of mirror neurons in the primate brain (Gallese, Fadiga, Fogassi, and
Rizzolatti, 1996), and evidence of not only a ‘classical’ action mirror system (Buccino
et al., 2001; Fadiga, Fogassi, Pavesi, and Rizzolatti, 1996; Gazzola, Aziz-Zadeh, and
Keysers, 2006), but also ‘extended’ mirror systems in the human brain (involved in
mirroring sensation and emotion; Avenanti, Bueti, Galati, and Aglioti, 2005;
Blakemore, Bristow, Bird, Frith, and Ward, 2005; Carr, Iacoboni, Dubeau, Mazziotta,
and Lenzi, 2003; Keysers, Wicker, Gazzola, Anton, Fogassi, and Gallese, 2004;