Ignacio Cifre

Disrupted Functional Connectivity of the Pain Network in Fibromyalgia

Objective To investigate the impact of chronic pain on brain dynamics at rest. Methods Functional connectivity was examined in patients with fibromyalgia (FM) (n = 9) and healthy controls (n = 11) by calculating partial correlations between low-frequency blood oxygen level–dependent fluctuations extracted from 15 brain regions. Results Patients with FM had more positive and negative correlations within the pain network than healthy controls. Patients with FM displayed enhanced functional connectivity of the anterior cingulate cortex (ACC) with the insula (INS) and basal ganglia (p values between .01 and .05), the secondary somatosensory area with the caudate (CAU) (p = .012), the primary motor cortex with the supplementary motor area (p = .007), the globus pallidus with the amygdala and superior temporal sulcus (both p values < .05), and the medial prefrontal cortex with the posterior cingulate cortex (PCC) and CAU (both p values < .05). Functional connectivity of the ACC with the amygdala and periaqueductal gray (PAG) matter (p values between .001 and .05), the thalamus with the INS and PAG (both p values < .01), the INS with the putamen (p = .038), the PAG with the CAU (p = .038), the secondary somatosensory area with the motor cortex and PCC (both p values < .05), and the PCC with the superior temporal sulcus (p = .002) was also reduced in FM. In addition, significant negative correlations were observed between depression and PAG connectivity strength with the thalamus (r = −0.64, p = .003) and ACC (r = −0.60, p = .004). Conclusions These findings demonstrate that patients with FM display a substantial imbalance of the connectivity within the pain network during rest, suggesting that chronic pain may also lead to changes in brain activity during internally generated thought processes such as occur at rest. Abbreviations BOLD = blood oxygen level–dependent; FM = fibromyalgia; HC = healthy control; WHYMPI = West Haven-Yale Multidimensional Pain Inventory; fMRI = functional magnetic resonance imaging; ACC = anterior cingulate cortex; PCC = posterior cingulate cortex; AMYG = amygdala; CAU = caudate; PUT = putamen; INS = insula; M1 = primary motor area; SMA = supplementary motor area; SI = primary somatosensory area; SII = secondary somatosensory area; mPFC = medial prefrontal cortex; PAG = periaqueductal gray; STS = superior temporal sulcus; THA = thalamus

Modular Organization of Brain Resting State Networks in Chronic Back Pain Patients

Recent work on functional magnetic resonance imaging large-scale brain networks under resting conditions demonstrated its potential to evaluate the integrity of brain function under normal and pathological conditions. A similar approach is used in this work to study a group of chronic back pain patients and healthy controls to determine the impact of long enduring pain over brain dynamics. Correlation networks were constructed from the mutual partial correlations of brain activitys time series selected from ninety regions using a well validated brain parcellation atlas. The study of the resulting networks revealed an organization of up to six communities with similar modularity in both groups, but with important differences in the membership of key communities of frontal and temporal regions. The bulk of these findings were confirmed by a surprisingly naive analysis based on the pairwise correlations of the strongest and weakest correlated healthy regions. Beside confirming the brain effects of long enduring pain, these results provide a framework to study the effect of other chronic conditions over cortical function.

Somatosensory activity modulation during observation of other's pain and touch

We examined whether somatosensory activity could be modulated by the observation of bodily experiences. For this purpose, somatosensory-evoked potentials elicited by non-painful stimulation were recorded when subjects were viewing a hand penetrated by a needle, touched by a cotton swab or at resting without stimulation. Participants were instructed to adopt an egocentric perspective when viewing the videos and to rate pain intensity and unpleasantness supposedly experienced by the model, as well as the unpleasantness induced by the video clips. Results indicated that pain videos were rated as more unpleasant than touch videos, and that observation of both pain and touch video clips led to a significant enhancement of P50 amplitudes as compared to viewing a hand without stimulation. Moreover, enhanced P50 amplitudes during observation of both pain and touch in others were associated with increased unpleasant ratings induced by the video clips, as well as with high scores in a perspective taking scale (IRI). These findings provide support for the involvement of an attentional bottom-up mechanism which could be responsible to enhance sensory processing of somatic information when observing bodily experiences in others irrespective of whether they are painful or not.

Age-Related Changes of Pain Experience in Cerebral Palsy and Healthy Individuals

OBJECTIVE   Pain is a serious problem for many individuals with cerebral palsy (CP). Pain and injury in early life may cause long-term changes in somatosensory and pain processing. Nevertheless, no information exists regarding the influence of age on pain reports and touch sensitivity among persons with CP or the influence of age on the quality of life in individuals with CP. DESIGN The present cross-sectional study investigated pain characteristics, touch sensitivity, and quality of life in 86 individuals with CP and 115 healthy volunteers. Participants were grouped by age in children (6-10 years), adolescents (11-17 years), and young adults (18-30 years). Touch sensitivity at different body locations were tested by using von Frey monofilaments. Data about pain and quality of life were obtained from a semi-structured interview and questionnaires. RESULTS Participants with CP reported more pain as well as more reduced touch sensitivity and quality of life than healthy controls. Neither pain reports nor touch sensitivity or quality of life were influenced by age in CP, whereas significant age-related changes were observed in healthy participants. Multiple regression analyses also showed that age was the best predictor of current pain intensity in healthy controls but not in individuals with CP. CONCLUSION These findings emphasize the importance of considering the presence of pain at very early ages in CP. Furthermore, these results provide clinicians and researchers with a new age-related psychosocial and psychophysiological perspective to investigate the mechanisms that could be involved in the presence and maintenance of pain in this population.

Insula‐based networks in professional musicians: Evidence for increased functional connectivity during resting state fMRI

Despite considerable research on experience‐dependent neuroplasticity in professional musicians, detailed understanding of an involvement of the insula is only now beginning to emerge. We investigated the effects of musical training on intrinsic insula‐based connectivity in professional classical musicians relative to nonmusicians using resting‐state functional MRI. Following a tripartite scheme of insula subdivisions, coactivation profiles were analyzed for the posterior, ventral anterior, and dorsal anterior insula in both hemispheres. While whole‐brain connectivity across all participants confirmed previously reported patterns, between‐group comparisons revealed increased insular connectivity in musicians relative to nonmusicians. Coactivated regions encompassed constituents of large‐scale networks involved in salience detection (e.g., anterior and middle cingulate cortex), affective processing (e.g., orbitofrontal cortex and temporal pole), and higher order cognition (e.g., dorsolateral prefrontal cortex and the temporoparietal junction), whereas no differences were found for the reversed group contrast. Importantly, these connectivity patterns were stronger in musicians who experienced more years of musical practice, including also sensorimotor regions involved in music performance (M1 hand area, S1, A1, and SMA). We conclude that musical training triggers significant reorganization in insula‐based networks, potentially facilitating high‐level cognitive and affective functions associated with the fast integration of multisensory information in the context of music performance. Hum Brain Mapp 38:4834–4849, 2017.

Are physiotherapists reliable proxies for the recognition of pain in individuals with cerebral palsy? A cross sectional study

BACKGROUND Pain is an important problem for individuals with cerebral palsy (CP). In addition to pain associated to the pathology, individuals with CP are often exposed to physiotherapy procedures which may cause or relieve pain. OBJECTIVE The major aim of this study was to compare pain ratings self-reported by individuals with cerebral palsy and ratings about pain in others provided by their physiotherapists. METHOD Cross-sectional study. Children and young adults with cerebral palsy (n = 50) and their physiotherapists (n = 18) completed semi-structured interviews about clinical pain, as well as about procedural pain and pain relief elicited by standardized health procedures. Moreover, pain ratings were obtained during the application of hamstring stretching and passive joint mobilization. RESULTS Moderate-to-high agreement was observed between individuals with cerebral palsy and their physiotherapists on presence and intensity of pain, pain interference with physical activities and current and retrospective pain ratings elicited by physiotherapy procedures. By contrast, agreement regarding pain relief elicited by physiotherapy techniques was low. CONCLUSIONS Our data suggest that although physiotherapists may be reliable proxies for the recognition of pain in individuals with cerebral palsy, further research should be done to improve the communication between health professionals and individuals with cerebral palsy around pain.

Altered corticomuscular coherence elicited by paced isotonic contractions in individuals with cerebral palsy: A case-control study

The purpose of the study was to analyze corticomuscular coherence during planning and execution of simple hand movements in individuals with cerebral palsy (CP) and healthy controls (HC). Fourteen individuals with CP and 15 HC performed voluntary paced movements (opening and closing the fist) in response to a warning signal. Simultaneous scalp EEG and surface EMG of extensor carpi radialis brevis were recorded during 15 isotonic contractions. Time-frequency corticomuscular coherence (EMG-C3/C4) before and during muscular contraction, as well as EMG intensity, onset latency and duration were analyzed. Although EMG intensity was similar in both groups, individuals with CP exhibited longer onset latency and increased duration of the muscular contraction than HC. CP also showed higher corticomuscular coherence in beta EEG band during both planning and execution of muscular contraction, as well as lower corticomuscular coherence in gamma EEG band at the beginning of the contraction as compared with HC. In conclusion, our results suggest that individuals with CP are characterized by an altered functional coupling between primary motor cortex and effector muscles during planning and execution of isotonic contractions. In addition, the usefulness of corticomuscular coherence as a research tool for exploring deficits in motor central processing in persons with early brain damage is discussed.

Mindfulness and Neuroimaging

The scientific community has recently begun to unveil the numerous changes that occur while one is meditating. The ability to measure functional activity in the brain by the signal produced by changes of blood oxygenation levels has become a useful tool in cognitive neuroscience. With functional magnetic resonance imaging, researchers are able to identify associations between activation and/or deactivation of brain areas and different stimuli or responses during the performance of specific cognitive tasks or even at rest (default mode network). Structural magnetic resonance images reveal how much grey or white matter is present in different parts of the brain. Magnetic resonance spectroscopy of the brain may provide a window into the biochemical changes associated with neuronal integrity. Although these techniques are commonly known, in this chapter we will try to better explain the results provided by these neuroimaging techniques in relation to the effects produced in the brain by the practice of mindfulness.