Neural correlates of pain-related anxiety: an fMRI study

Functional neuroimaging studies have provided more insight in the understanding
of neural mechanisms of pain. However, only a few studies have investigated the
neural mechanisms by which anxiety exacerbates pain perception and the neural
substrates for anticipation on pain.

The present study aims to get more insight in the neural mechanisms of pain
modulation by anxiety. Psychometric scales acquired from two questionnaires
assessing pain-related anxiety, will be used to select two groups based on
pain-related anxiety level (low or high). In selected subjects we will use fMRI
to measure brain activity in anticipation of and during a pain stimulus. This
could provide more insight in neural mechanisms of chronic pain development.

This study is designed to investigate neural correlates of pain perception
and pain-related anxiety as determined by fMRI. Individual temperatures for
the heat stimuli will be selected in a short training session. During this
session we will determine the temperature correlating with a VASscore of 4 for
a 'mild' pain stimulus and the temperature correlating with a VASscore of 7 for
a 'moderate' pain stimulus. The study then starts with a design containing two
session, an implicit learning and a test session. In the implicit learning
session, two visual cues and two heat stimuli are used. One of the cues is
always followed by a 'mild' painful stimulus (VAS 4), another signal is
followed by either a 'mild' painful (VAS 4) or a 'moderate' painful stimulus
(VAS 7). After each heat stimulus, pain intensity is rated by the subjects,
using a visual analogue scale. In the second session the same two visual cues
are used, but both cues will be followed by the same mild painful stimulus.
Difference in anticipation of pain after the cues will be studied. During these
sessions of approximately 20 minutes each, subjects receive 20 cue-stimulus
trials. After the functional scans a short (5min) structural MRI scan will be
made to map the anatomy of the brain. Participants will be in the scanner for
aproximately 60 minutes.

heat stimuli

Risks are minimal. The burden consists of tolerating and rating pain
applications to the inner forearm within the MRI acquisition. The subjects
will receive financial compensation; they contribute to better understanding of
brain circuitry involved in the anticipation of pain, resulting from
pain-related anxiety.