Control over brain activation and pain learned by using real-time functional MRI
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Transcript of Control over brain activation and pain learned by using real-time functional MRI
Control over brain activation and pain learned by using real-time
functional MRI
R.C. deCharms, F. Maeda, G.H. Glover, D. Ludlow, J.M. Pauly, D. Soneji, J.D.E. Gabrieli, and S.C. Mackey
By Jennifer Wong
Introduction
Can learn control of autonomic measures – heart rate, skin conductance- and EEG rhythms
Pain perception affected by placebo effects, anticipation, attention
Subregions within rostral anterior cingulate cortex (rACC) are involved in pain perception
Hypnosis and placebos alter rACC and reduce pain perception
Broodman Area: 32/24
Introduction
Real-time fMRI measures localized processes as they occur
Research Question
Can subjects learn to control the brain's system, and whether learned control over rACC activation would alter pain perception in healthy subjects and patients with chronic pain?
Hypothesis
Learned manipulation of rACC using real-time fMRI leads to decreased effects of pain perception
Methods
healthy community volunteers-20 Males, 16 Females
Chronic pain- 8 Males, 4 Females
peltier thermode on left palm
Individually selected temperatures with 7/10 pain rating
Strategy instructions1. Attention. Attend toward perceived stimulus vs. away from it.
2. Stimulus Quality. Perception as neutral experience vs. tissue damaging , overwhelming
3. Stimulus Severity. Perceive stimulus as low or high intensity
4. Control. Attempt to control painful experience.
Methods
Localizer scan, 3 training runs, post-test run Chronic pain patients chose when to end scanning
Training/ post-test runs Training rates stimulus after scan completed Post-test rates stimulus immediately after receiving
pain
Methods
Experimental: continuous video depicting activation, and scrolling line chart -% BOLD signal change over time (s)
• Control:1. Pain only- effects of repeated practice2. Behavioural training, 2x longer, overt
attention on pain 3. Shown a different region of the brain 4. rtfMRI of previously tested subject's rACC
• Patient control: autonomic biofeedback – told to control skin conductance, Heart rate, respiration
Results
A: change in activation comparing last to first training session
B: post-test compared with first training session
Results
Control over fMRI bold activation in rACC increased significantly
Control over Pain increased significantly
Results
MPQ: Mcgill pain questionaire VAS visual analogue scale 1-10:
Discussion
• rACC: important for pain perception and regulation • Associated with cognitive processes: attention, emotion, task
difficulty, motor control
• Chronic pain patients need to be able to see functions of brain to control
• Stronger pain control -> greater likelihood of successful recovery
Discussion
Limitations: subjects engaged brain regions associated with rACC
o placebo effects are mediated in part by brains control system
o Pain matrix involved with processing: ACC, somatosensory cortices, insula, thalamus
o Pain anticipation
Future Studies
- Long term pain treatment
- Type of patients show greatest response
Take Home Message
• real-time fMRI was used to guide training to control rACC
• rACC: subregions involved with mediating conscious pain perception
• Increased Activation of rACC decreases pain perception
• Experimental subjects (rtfMRI) decreased pain significantly more compared to control subjects
My Opinion
Strengths Weaknesses
• Easy to follow instructions in procedure
• Good use of images and graphs
• Interesting topic
• Hard to understand the details in the statistical analysis and results
• Small sample size of chronic pain patients