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

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Chapter 7
right hemisphere somatosensory-related cortices (Adolphs, Damasio, Tranel, Cooper,
and Damasio, 2000) and transcranial magnetic stimulation (TMS) findings in healthy
adults are consistent with this (Pitcher, Garrido, Walsh and Duchaine, 2008). In the
study by Pitcher and colleagues (2008), rTMS targeted at right primary
somatosensory cortex resulted in a disruption of participants’ abilities to discriminate
the facial expressions, but not facial identities, of others. It remains unclear if neural
activity within these systems is necessary for the recognition of affect from alternative
modalities. Moreover, if sensorimotor resources are vital for global processing of
emotion then these resources should also be central for emotion recognition abilities
of healthy adults in modalities outside of visual perception. An example of this would
be in the auditory domain. Primates are highly sensitive to vocal cues and the
affective contents of vocal signals are reliably recognised by humans (Bryant and
Barett, 2007; Sauter and Scott, 2007; Schröder, 2003). An fMRI study indicates that
adult human listeners activate the sensorimotor cortices when listening to emotional
vocalisations of others (Warren et al., 2006), however whether this activity is
necessary for affect recognition remains unknown. To address this, the studies
presented in this chapter use continuous theta burst TMS (cTBS; Di Lazzaro et al.,
2005; Huang, Edwards, Rounis, Bhatia, and Rothwell, 2005; Vallesi, Shallice, and
Walsh, 2007; Kalla, Muggleton, Cowey, and Walsh, 2009), an offline (i.e. conducted
while the participant is at rest) TMS paradigm following which neural activity may be
suppressed for several minutes (Di Lazzaro et al., 2005; Huang et al., 2005), to
examine whether neural activity in the right lateral premotor (rPM) and right primary
somatosensory cortex (rSI) is involved in discriminating affect from vocal signals.
Right hemisphere representations were selected based on previous fMRI,
neuropsychological and TMS findings demonstrating the importance of right