Tone of Voice and Mind : The Connections between Intonation ...

14 Chapter 1
Motor cortical activation (pixels)
250
200
150
100
50
0
250
200
150
100
50
0
A
B
C
NS
I C I
***
C–I C–I
Left hemisphere Right hemisphere
Figure 1-3. Relative activation of the left and right motor cortex during a motor task
of the left or right hand. (A) shows the hemispheric activation during ipsilateral, I,
and contralateral, C, hand movements. (B) shows that, although the right hemisphere
is significantly activated during the contralateral left-hand task, the left hemisphere is
equally activated whichever hand is used (after Kim et al. 1993).
pattern of executive motor control exercised by the left hemisphere is not easily
shifted over to the right hemisphere – even when the non-dominant hand is
the actual somatic structure involved. It would appear that, instead of relying
on the unpracticed motor control skills of the right hemisphere, the brain retains
its normal mode of dominance by having the left hemisphere control the
right hemisphere – presumably using fibers that cross in the corpus callosum.
Such results are consistent with other findings in neuropsychology suggestive
of executive control and “response selection” mechanisms being located in
the left hemisphere (Rushworth et al. 1998). Together, they are indication that
theeasewithwhichwemaybeabletoswitchhandsinamotortaskisdeceptive
with regard to the actual control mechanism. If it is an even mildly skilled
motor task, the brain is probably smart enough not to hand control over to the
naïve, untrained right hemisphere, but rather maintains left hemisphere exec-