Tamam, Sofina
(2016)
fMRI study of pain threshold in the presence and absence of the loved one.
Masters thesis, Pusat Pengajian Sains Perubatan.
Abstract
Laser-induced heat pain and functional magnetic resonance imaging (fMRI)
techniques were used to investigate the modulation of pain response under two
different conditions. One condition was when the participants were not accompanied
by their loved ones (Alone condition) and the other condition was when the
participants were accompanied by their loved ones (Support condition) during pain
stimulus delivery inside the MRI gantry. Th:YAG laser was used as pain stimuli with
its light beam targeted onto the dorsum of the right hand. An experimental paradigm
utilizing block design was first developed for the fMRI scan. 17 female subjects
participated (mean age 20.59; SD 2.85 years) and the pain threshold was determined
prior to scanning. The Experience Closed Relationship - Relationship Structure
(ECR - RS) test and USM personality inventory questionnaires (USMaP-i) were
given prior to fMRI scanning. Statistical Parametric Mapping (SPM) version 8 with
Dynamic Causal Modelling (DCM) approach was used to investigate the
connectivity between activated regions and one optimum connectivity model was
identified finally. It was found that individual responses to pain may be divided into
two categories. The group accompanied by a family member as the loved one have
lower pain threshold in Support condition, representing Love Hurts; while the group
accompanied by a partner have higher pain threshold in the same condition,
representing Love Heals. Extraversion personality was found to reduce the response
to pain stimulation when accompanied by the loved one. All participants showed
activations in areas associated with pain processing. In Alone condition, ACC, MCC,INS, AMY, VLPFC and HIP were activated, while in Support condition, INS,
VLPFC, SII, THA and supramarginal gyrus were activated. DCM analysis revealed
that Love Hurts involved activations in THA, PHG and HIP while Love Heals
involved activations in all parts of cingulate cortex. BMS showed that Love Heals
could be represented by a cortical network involving the intrinsic connectivity of
ACC → PCC → MCC and ACC → MCC. In conclusion, the present study revealed
that having a loved one nearby modulates pain differently depending on the
personality of the individual and the type of relationship with the loved one. More
interestingly, this study discovers a new possible cortical network for Love Heals
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