Biomedical Engineering Reference
In-Depth Information
Figure 8b
. Theoretical considerations regarding utility or relative preference. The output of this keypress
procedure was a representation of the utility function for each individual toward this set of items. The objec-
tive was to determine their relative preferences for these items compared to the default position of not expend-
ing any effort to change a set viewing time. The keypress procedure quantified both the valence and the
amount of the value that each item or face picture had relative to the default position of 8 seconds of viewing
time.
of neuroeconomics (102). Overall, this set of studies in healthy controls ob-
served that "classic" reward circuitry (including the NAc, SLEA, amygdala, VT,
and GOb) processes a continuum between rewarding and aversive stimuli, with
salient similarities and differences in regional activation (Figure 10a).
The segregation of neural systems that process aversive stimuli from those
that process rewarding stimuli might be an artificial distinction (132). Com-
prised of subcortical gray structures, the "classic reward system" is activated by
aversive stimuli such as thermal pain, expectancies of bad outcomes, and social
stimuli that are not wanted (3,19,38). Comprised of paralimbic cortical and tha-
lamic structures, "classic pain circuitry" (18,19,57,62,71,72,201,207,208,221,
247) is also activated by rewarding stimuli (18,19,57,62,71,72,201,207,208,
221,247) (Figure 10b). This commonality of activation patterns produced in
healthy humans by stimuli with positive and negative outcomes (Figure 10b)
argues that an extended set of subcortical gray matter and paralimbic cortical
regions processes both rewarding and aversive information, and could be con-
sidered a generalized system (31).
A metaanalysis or general survey of neuroimaging studies presenting
rewarding stimuli to humans suggests that an extended set of reward/aversion
regions responds across multiple categories of rewarding stimuli (3,12,23,24,
27,28,33,38,44,83,87,88,133,137,155,188,189,
239
,
250
,
257
,
270
,
272-274
,
277
,
279
,
280) (Figure 11). This observation is complemented by animal data indicating
