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

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8.3 Results
Chapter 8
To assess the influence of speed and accuracy, reaction times were corrected
for accuracy in each condition. This was achieved by dividing reaction time (± 3
standard deviations and all errors removed) by accuracy in each condition.
The role of rSI and rIFG in recognizing different facial expressions of emotion
Preliminary analysis confirmed that baseline performance for each expression-
type did not significantly differ across the sites stimulated [Disgust - F(2,20) = 1.4 ,
nsig; Happy – F(2,20) = .280, nsig; Neutral – F(2,20) = .913, nsig; Sad – F(2,20) =
1.01, nsig].
To assess the effects across expression-types and across sites, the difference
between the post cTBS and pre-cTBS baseline reaction times for each expression (i.e.
baseline RT corrected for accuracy minus post cTBS RT corrected for accuracy) was
compared for each site stimulated (as per Chapter 7). A 3 (TMS Site) x 4
(Expression-Type) repeated measures ANOVA showed that neither the main effect of
TMS Site [F(2,20) = 1.55, p = .237] nor the main effect of Expression-Type reached
significance [F(3,30) = 1.39, p = .265]. There was however a significant TMS Site x
Expression-Type interaction [F(6,60) = 2.82, p = .017]. This was because cTBS at rSI
resulted in a significantly different pattern of effects across expression types [F(3,30)
= 4.34, p = .012], whereby cTBS impaired performance on trials involving
expressions of happiness relative to neutral facial expressions (p = < .05), and on trials
involving sadness relative to neutral (p = < .01) and disgusted facial expressions (p =
< .05). This was not the case at rIFG [F(3,30) = .977, p = .417] or right V5 / MT
[F(1.863,18.629) = .489, p = .608], where the effects of cTBS did not significantly
differ between the expression-types (Figure 7.2).