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(309) Evoked brain response to fearful faces in pediatric complex regional pain syndrome (CRPS)
Abstracts
(308) A comparison of the BOLD and ASL temporal responses during functional imaging of pain J Ibinson, M Gach, and K Vogt; University of Pittsburgh, Pittsburgh, PA The temporal dynamics of the blood oxygen level dependent (BOLD) signal, especially for painful stimulations, is not completely understood. In prior work using a continuous painful electrical stimulation of 2 minutes, we showed that the BOLD signal contained three peaks; suggesting an early and delayed BOLD response to painful stimulation initiation that occurs within the first 30 seconds of stimulation and an additional response related to stimulus termination. Furthermore, despite the continuous stimulation, the BOLD signal returned to baseline during the two-minute task. One possible reason for this signal decay is increased regional cerebral blood volume despite continued increased blood flow during the task. Using pseudo-continuous arterial spin labeling (pCASL), we directly measured regional cerebral blood flow during the same painful stimulation, hypothesizing that the flow would remain elevated in the areas of the brain known to process pain. pCASL data was acquired in 6 healthy adults in an IRB-approved 3 T whole brain study of painful electrical nerve stimulation in the right index finger (intensity self-adjusted to 7/10). Signals from the contralateral insula, the anterior cingulate cortex, and the primary somatosensory cortex were investigated. A clear increase in blood flow was found with pCASL at the initiation of painful stimulation and the flow remained increased throughout the stimulation period. This suggests that the signal decay seen in BOLD studies of pain may be due to changes in blood volume and that continued pain causes a continued blood flow increase. Due to the temporal resolution of our pCASL sequence, we were not able to determine if the early and delayed BOLD responses are reflective of blood flow.
(309) Evoked brain response to fearful faces in pediatric complex regional pain syndrome (CRPS) J Hernandez, K Zhang, C Linnman, P Serrano, L Becerra, D Borsook, and L Simons; Boston Children’s Hospital, Boston, MA Complex regional pain syndrome is a chronic neuropathic pain disorder that effects many pediatric pain patients after injury, and pathways and causes have yet to be well understood. Fear of pain in these children has presented as a major challenge, which can vastly limit progress in treatment. We seek to better understand the neural underpinnings of fear processing in pediatric CRPS patients using functional magnetic resonance imaging (fMRI). We measured the evoked brain responses of youth, ages 9-20, at two time points (Time 1: admission to intensive pain rehabilitation; Time 2: two months post-discharge) using an unmasked emotional faces paradigm. A group of pediatric CRPS patients (Time 1: n=16; Time 2: n=8) with matched healthy controls (Time 1: n=18; Time 2: n =7) were shown two runs of unmasked images of faces representing different emotions (i.e. neutral, happy, fear). All analyses were conducted using FSL examining functional differences between patients and controls over the two time points. Using GLM in a Mixed effects model (z=1.96, corrected cluster p<.05), patients were less responsive to fearful faces in several areas including the right caudate (MNIx,y,z=18, -2, 22), right superior frontal gyrus (MNIx,y,z= 28, 2, 60), and inferior frontal gyrus (MNIx,y,z=56, 14, 30). These differences did not emerge for neutral or happy faces. At time 2, there were no significant differences between patients and matched healthy controls across conditions. Contrary to our expectations, patients showed a dampened, rather than heightened response to negative emotional stimuli in relevant emotional circuitry. It also appears that these circuits may have normalized after intensive treatment, which may be associated with recovery and brain plasticity observed in children with CRPS.
The Journal of Pain
S53
(310) Discrete region and distributed network analysis of attention and cognitive modulation of pain A Sentis, C Law, E Bagarinao, K Johnson, and S Mackey; Stanford University, Stanford, CA Complex cognitive processes have been shown to involve the coordinated activity of a distributed network of brain regions.1 We sought to understand whether the brain states of attention regulation and cognitive regulation acting on pain processing involve distributed networks or discrete brain regions. To do so, this pilot study analysis investigated the regions of interest (ROIs) generated using traditional GLM methods as well as those generated using Support Vector Machine (SVM), a widely-used multivariate pattern analysis technique. GLM has traditionally been used to identify specific isolated brain regions, while SVM searches for global patterns – a technique that may favor identification of coordinated brain network activation. We collected data from individuals with chronic low back pain. During block-design real-time fMRI scanning, participants utilized either attention regulation or cognitive regulation to modulate their endogenous pain. We used both GLM and SVM methods to generate regions of interest based on patterns of BOLD activation. In our preliminary analyses, individual GLM results for both regulation groups show activation in the premotor cortex. In addition to this activation, individual SVM results show activation in the bilateral prefrontal cortex and deactivation in the precuneus region. These preliminary results suggest that SVM is capable of identifying the coordinated activity of several brain regions, thus showing the benefits of using pattern analysis techniques. Funding: NIH NIDA (K24 DA029262 Neuroimaging and Mentoring in Translational Pain Research), NIH NCCAM (P01 AT006651 Stanford CAM Center for Chronic Back Pain). (1. Ruiz, Biological Psychology, 2014.)
(311) Optimism is associated with decreased bilateral anterior insula activity during a conditioned pain modulation paradigm V Mathur, E Boyd, and R Quiton; University of Maryland, Baltimore County, Baltimore, MD Psychophysical evidence suggests a link between optimism and increased conditioned pain modulation (CPM), however, the neural mechanism underlying this relationship is not known. Optimism is associated with greater placebo response, suggesting optimism may influence endogenous opioid function. Here we assessed the relationship between dispositional optimism and functional brain response underlying CPM. Twenty-three healthy volunteers (8 female, 25.4 6 8.2 years old) completed a CPM paradigm using a thermal heat test stimulus (TS) and pressure cuff conditioning stimulus (CS) during fMRI. Participants completed the revised Life Orientation Test (LOT-R) as a measure of dispositional optimism during a pre-testing day prior to scanning. Results revealed CPM-related deactivations in the bilateral anterior insula, such that activity within these regions was decreased in the presence of the conditioning stimulus (TS+CS) compared to conditions where the TS was presented alone. The anterior insula (aINS) is known to have a high concentration of opioid receptors and is thought to underlie the subjective and affective components of pain. Deactivations within these regions of interest were associated with greater optimism (L aINS: R = -.41, p = .05; R aINS: R = -.53, p = .009) during the conditioned stimulus (TS+CS), but not during the thermal test-stimulus alone (TS) conditions (ps >.05) suggesting that optimism may modulate CPMrelated brain response by decreasing affective pain response and may operate through increased opioid-dependent modulation mechanisms.
(308) A comparison of the BOLD and ASL temporal responses during functional imaging of pain J Ibinson, M Gach, and K Vogt; University of Pittsburgh, Pittsburgh, PA The temporal dynamics of the blood oxygen level dependent (BOLD) signal, especially for painful stimulations, is not completely understood. In prior work using a continuous painful electrical stimulation of 2 minutes, we showed that the BOLD signal contained three peaks; suggesting an early and delayed BOLD response to painful stimulation initiation that occurs within the first 30 seconds of stimulation and an additional response related to stimulus termination. Furthermore, despite the continuous stimulation, the BOLD signal returned to baseline during the two-minute task. One possible reason for this signal decay is increased regional cerebral blood volume despite continued increased blood flow during the task. Using pseudo-continuous arterial spin labeling (pCASL), we directly measured regional cerebral blood flow during the same painful stimulation, hypothesizing that the flow would remain elevated in the areas of the brain known to process pain. pCASL data was acquired in 6 healthy adults in an IRB-approved 3 T whole brain study of painful electrical nerve stimulation in the right index finger (intensity self-adjusted to 7/10). Signals from the contralateral insula, the anterior cingulate cortex, and the primary somatosensory cortex were investigated. A clear increase in blood flow was found with pCASL at the initiation of painful stimulation and the flow remained increased throughout the stimulation period. This suggests that the signal decay seen in BOLD studies of pain may be due to changes in blood volume and that continued pain causes a continued blood flow increase. Due to the temporal resolution of our pCASL sequence, we were not able to determine if the early and delayed BOLD responses are reflective of blood flow.
(309) Evoked brain response to fearful faces in pediatric complex regional pain syndrome (CRPS) J Hernandez, K Zhang, C Linnman, P Serrano, L Becerra, D Borsook, and L Simons; Boston Children’s Hospital, Boston, MA Complex regional pain syndrome is a chronic neuropathic pain disorder that effects many pediatric pain patients after injury, and pathways and causes have yet to be well understood. Fear of pain in these children has presented as a major challenge, which can vastly limit progress in treatment. We seek to better understand the neural underpinnings of fear processing in pediatric CRPS patients using functional magnetic resonance imaging (fMRI). We measured the evoked brain responses of youth, ages 9-20, at two time points (Time 1: admission to intensive pain rehabilitation; Time 2: two months post-discharge) using an unmasked emotional faces paradigm. A group of pediatric CRPS patients (Time 1: n=16; Time 2: n=8) with matched healthy controls (Time 1: n=18; Time 2: n =7) were shown two runs of unmasked images of faces representing different emotions (i.e. neutral, happy, fear). All analyses were conducted using FSL examining functional differences between patients and controls over the two time points. Using GLM in a Mixed effects model (z=1.96, corrected cluster p<.05), patients were less responsive to fearful faces in several areas including the right caudate (MNIx,y,z=18, -2, 22), right superior frontal gyrus (MNIx,y,z= 28, 2, 60), and inferior frontal gyrus (MNIx,y,z=56, 14, 30). These differences did not emerge for neutral or happy faces. At time 2, there were no significant differences between patients and matched healthy controls across conditions. Contrary to our expectations, patients showed a dampened, rather than heightened response to negative emotional stimuli in relevant emotional circuitry. It also appears that these circuits may have normalized after intensive treatment, which may be associated with recovery and brain plasticity observed in children with CRPS.
The Journal of Pain
S53
(310) Discrete region and distributed network analysis of attention and cognitive modulation of pain A Sentis, C Law, E Bagarinao, K Johnson, and S Mackey; Stanford University, Stanford, CA Complex cognitive processes have been shown to involve the coordinated activity of a distributed network of brain regions.1 We sought to understand whether the brain states of attention regulation and cognitive regulation acting on pain processing involve distributed networks or discrete brain regions. To do so, this pilot study analysis investigated the regions of interest (ROIs) generated using traditional GLM methods as well as those generated using Support Vector Machine (SVM), a widely-used multivariate pattern analysis technique. GLM has traditionally been used to identify specific isolated brain regions, while SVM searches for global patterns – a technique that may favor identification of coordinated brain network activation. We collected data from individuals with chronic low back pain. During block-design real-time fMRI scanning, participants utilized either attention regulation or cognitive regulation to modulate their endogenous pain. We used both GLM and SVM methods to generate regions of interest based on patterns of BOLD activation. In our preliminary analyses, individual GLM results for both regulation groups show activation in the premotor cortex. In addition to this activation, individual SVM results show activation in the bilateral prefrontal cortex and deactivation in the precuneus region. These preliminary results suggest that SVM is capable of identifying the coordinated activity of several brain regions, thus showing the benefits of using pattern analysis techniques. Funding: NIH NIDA (K24 DA029262 Neuroimaging and Mentoring in Translational Pain Research), NIH NCCAM (P01 AT006651 Stanford CAM Center for Chronic Back Pain). (1. Ruiz, Biological Psychology, 2014.)
(311) Optimism is associated with decreased bilateral anterior insula activity during a conditioned pain modulation paradigm V Mathur, E Boyd, and R Quiton; University of Maryland, Baltimore County, Baltimore, MD Psychophysical evidence suggests a link between optimism and increased conditioned pain modulation (CPM), however, the neural mechanism underlying this relationship is not known. Optimism is associated with greater placebo response, suggesting optimism may influence endogenous opioid function. Here we assessed the relationship between dispositional optimism and functional brain response underlying CPM. Twenty-three healthy volunteers (8 female, 25.4 6 8.2 years old) completed a CPM paradigm using a thermal heat test stimulus (TS) and pressure cuff conditioning stimulus (CS) during fMRI. Participants completed the revised Life Orientation Test (LOT-R) as a measure of dispositional optimism during a pre-testing day prior to scanning. Results revealed CPM-related deactivations in the bilateral anterior insula, such that activity within these regions was decreased in the presence of the conditioning stimulus (TS+CS) compared to conditions where the TS was presented alone. The anterior insula (aINS) is known to have a high concentration of opioid receptors and is thought to underlie the subjective and affective components of pain. Deactivations within these regions of interest were associated with greater optimism (L aINS: R = -.41, p = .05; R aINS: R = -.53, p = .009) during the conditioned stimulus (TS+CS), but not during the thermal test-stimulus alone (TS) conditions (ps >.05) suggesting that optimism may modulate CPMrelated brain response by decreasing affective pain response and may operate through increased opioid-dependent modulation mechanisms.