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

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Chapter 7
2000; Pitcher et al., 2008) to suggest that activity in rSI is central to the perception of
emotion across different modalities. Further, in recent years a number of functional
brain imaging studies have documented the role of premotor cortex activity in the
mirroring of actions and emotions of others (Dapretto et al., 2006; Hennenlotter et al.,
2005; Leslie, Johnsen-Frey, and Grafton, 2004; Montgomery and Haxby, 2008; van
der Gaag, Minderaa, and Keysers, 2007; Warren et al., 2006). Using stimuli adapted
from one such study (Warren et al., 2006), the findings show that neural activity in
rPM plays a central role in non-verbal auditory emotion discrimination in healthy
adults. These findings are consistent with simulation-based accounts of emotion
processing, which contend that perceived emotions are mapped onto an individual’s
own somatosensory and motor representations to facilitate emotion recognition
(Adolphs, 2002; Adolphs, 2003; Damasio, 1990; Gallese, Keysers, and Rizzolatti,
2004; Goldman and Sripada, 2005; Keysers and Gazzola, 2006).
The task specific nature of the findings further supports the role of rSI and
rPM activity as a substrate for a mechanism that facilitates emotion processing.
Under equivalent conditions to experiment 1, cTBS targeted at rSI and rPM did not
impair participants’ ability to discriminate another’s identity, indicating that the
changes in reaction time are not simply due to a general reduction in reaction times
following cTBS stimulation of these regions or more widespread suppression of
neural activity. In contrast to a disruption in emotion discrimination abilities, there
was a trend for facilitation when participants were asked to discriminate the identity
of others. This facilitation is non-specific because it is seen over all sites stimulated in
the identity task, and does not differ significantly between sites. The nature of the
effect may reflect practice in the post-cTBS blocks or intersensory facilitation
following cTBS (Marzi et al., 1998; Walsh and Pascual-Leone, 2003).