Sharing pain and relief: neural correlates of physicians during treatment of patients

Abstract

Patient-physician interactions significantly contribute to placebo effects and clinical outcomes. While the neural correlates of placebo responses have been studied in patients, the neurobiology of the clinician during treatment is unknown. This study investigated physicians' brain activations during patient-physician interaction while the patient was experiencing pain, including a 'treatment', 'no-treatment' and 'control' condition. Here, we demonstrate that physicians activated brain regions previously implicated in expectancy for pain-relief and increased attention during treatment of patients, including the right ventrolateral and dorsolateral prefrontal cortices. The physician's ability to take the patients' perspective correlated with increased brain activations in the rostral anterior cingulate cortex, a region that has been associated with processing of reward and subjective value. We suggest that physician treatment involves neural representations of treatment expectation, reward processing and empathy, paired with increased activation in attention-related structures. Our findings further the understanding of the neural representations associated with reciprocal interactions between clinicians and patients; a hallmark for successful treatment outcomes.

Figure 1

Experimental setup and physicians’ satisfaction ratings during the three experimental conditions. (A) Illustration of the setup for the fMRI experiment. The physician is lying down in the scanner and the patient is placed opposite the physician, sitting on a chair. A heat pain stimulator is strapped onto the patient’s arm and a sham analgesic device is attached adjacent to the heat stimulator. The physician holds a button box that allows for pressing a ‘pain relief button’, a ‘control button’ and performing self-ratings on a visual analogue scale. The physician and the patient are positioned so that they can have constant eye contact and the physician can see the patient from the waistline and up. Treatment instructions for the physician are displayed on a screen. (B) Results from physicians’ self-ratings during fMRI scanning. After each experimental task, physicians were prompted to answer the question “How do you feel?”. The physicians responded by moving a cursor on a horizontal visual analogue scale anchored by −10 “completely dissatisfied” and +10 “completely satisfied”. A within-subject statistical analysis of the physicians’ ratings (ANOVA) validated that the three conditions ‘treatment’, ‘no-treatment’ and ‘control’ were associated with significantly different feelings.

Figure 2

Physician brain activations during treatment of a patient. The ‘treatment’ condition, compared to the ‘control’ condition, was associated with significantly increased brain activity in four clusters: right DLPFC ([48, 20, 28]), VLPFC ([48, 29, 1]), TPJ/pSTS ([63, −46, 10]) and the cerebellum ([−15, −76, −38]), as illustrated by the rendered brain in this figure. The initial statistical image threshold was p<.005 with 30 contiguous voxels and all results were FWE-corrected at the cluster level. The contrast ‘treatment’ versus ‘control’ was balanced since the physicians got identical visual inputs during both conditions; the patient was not in pain and kept a neutral face during both conditions. The only difference was the physicians’ knowledge that he/she had relieved the patient’s pain during ‘treatment’ whereas the ‘control’ condition did not include any pain application in the first place. The extracted parameter estimates from the peak activations (3 mm sphere) during ‘treatment’ and ‘control’ are represented in the three bar-plots (± 1 Standard Error). A complete list of the significant areas can be found in table 2.

Figure 3

Activation of the ventral striatum during patient-physician interaction. The activity of the reward-related circuitry was significantly increased during the ‘treatment’ condition compared to ‘control’, represented in the right ventral striatum. The same effect was found for the ‘control’ versus ‘no treatment’ contrast, represented in the bilateral ventral striatum, shown here. The extraction of the parameter estimates from the peak coordinate (3 mm sphere) in the right ventral striatum ([9, 26, 1]) indicate a dose effect of the physicians’ positive feelings during patient-physician interaction, i.e. the ‘no-treatment’ condition was associated with little or no activation of the ventral striatum, whereas the ‘treatment’ condition was associated with most robust increased activations in this region. The parameter estimates are represented in the bar-plot (± 1 Standard Error). The initial statistical image threshold was p<.005 with 30 contiguous voxels.

Figure 4

Perspective-taking skills during patient-physician interaction. Perspective-taking skills were associated with the physician’s satisfaction during treatment and increased activation of the rACC. (A) The physicians’ perspective-taking scores (IRI) correlated significantly to ratings of satisfaction during the ‘treatment’ condition. With higher perspective-taking skills, physicians felt more treatment-related satisfaction (r=.69, p=.003, two-tailed). (B) A regression analysis for the contrast ‘treatment’ versus ‘control’, using the physicians perspective-taking scores as covariate, demonstrated a significant increase of rACC activity with increased perspective-taking scores ([−12, 56, −2]). The initial statistical threshold was p<.005 with 30 contiguous voxels. (C) Illustration of the data points from the perspective-taking regression analysis (shown in panel B). A scatterplot of the extracted rACC parameter estimates and the physicians’ perspective-taking scores was performed for illustrative reasons but should not be used for statistical inference since it would infer circularity.