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Abstract:
Damasio has proposed that when choosing between options that
differ in relative risk, a somatic marker (e.g. a gut feeling)
feeds back to the brain and influences cognitive appraisal the
somatic marker hypothesis. In the present study patients who had
suffered a complete tetraplegia at the level of the 6th cervical
vertebra were compared with matched healthy control subjects. As
the spinal injury group have reduced somatic/peripheral feedback
via the spinal cord, it was predicted that they may demonstrate
riskier behaviour than controls. All subjects completed the Iowa
Gambling Task, a computerised card playing game where the player is
instructed to try and win as much money as possible over 100
selections from one of four decks. The rules are not disclosed in
advance, and the player gradually learns that two of the decks are
high risk and lead to significant financial losses. In the present
study there were no significant differences between the spinal
sectioned and healthy control groups in either card selection
strategy or net financial outcome. This result suggests that in
terms of the somatic marker hypothesis, feedback to the brain from
the periphery via the cranial nerves and the hormonal route may be
equally or more influential than afferent feedback transmitted via
the spinal cord.
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