Effective Connectivity of Beta Oscillations in Endometriosis-Related Chronic Pain During rest and Pain-Related Mental Imagery.

Using the EEG recordings of patients with endometriosis-related chronic pelvic pain, we have examined the effective connectivity within the cortical pain-related network during rest and during pain-related imagery. During rest, an altered connectivity was hypothesized between cortical somatosensory pain areas and regions involved in emotional and cognitive modulation of pain. During pain-related imagery, alterations in prefrontal-temporal connectivity were expected. The effective connectivity was estimated using the Directed Transfer Function method. Differences between endometriosis patients and controls were found in the beta band (14-25 Hz). During rest, endometriosis was associated with an increased connectivity from the left dorsolateral prefrontal cortex to the left somatosensory cortex and also from the left somatosensory cortex to the orbitofrontal cortex and the right temporal cortex. These results might be related to sustained activation of the somatosensory pain system caused by the ongoing pain. During pain-related imagery, endometriosis patients showed an increased connectivity from the left dorsolateral prefrontal cortex to the right temporal cortex. This finding might point to impaired emotional regulation when processing pain-related stimuli, or it might be related to altered memorization of pain experiences. Results of this study open up new directions in chronic pain research aimed at exploring the beta band connectivity alterations. PERSPECTIVE: This study examined the pain system's dynamics in endometriosis patients with chronic pelvic pain during resting-state and pain-related mental imagery. The results could contribute to the development of new therapies using guided mental imagery.

Pain catastrophizing is associated with altered EEG effective connectivity during pain­related mental imagery.

Pain catastrophizing - defined as a tendency to exaggerate the threat value or seriousness of experienced pain ­ has been shown to be a risk factor for pain chronification. However, the neural basis of pain catastrophizing remains unclear and requires thorough investigation. This study aimed to explore the relationship between pain catastrophizing and effective connectivity of the pain systems in healthy participants. EEG data were collected during an induced state of pain­related negative, depressive, positive and neutral mental imagery conditions, and pain catastrophizing tendencies were measured by the Pain Catastrophizing Scale. The Directed Transfer Function, a method based on Granger causality principles, was used to assess the effective connectivity. Linear mixed effects analyses revealed a negative relationship between pain catastrophizing and beta information flow from the right temporal cortex to the frontal regions and a positive relationship between pain catastrophizing and increased beta information flow from the right somatosensory cortices to the right temporal cortices when thinking about pain. These patterns were not found in other imagery conditions. Taken together, this study suggests that individual differences in pain catastrophizing might be related to an altered frontotemporal regulatory loop and increased connectivity between pain and affective systems. Our study reveals connectivity patterns related to pain catastrophizing tendencies that are detectable even in pain­free, healthy individuals.

Pain cognition versus pain intensity in patients with endometriosis: toward personalized treatment.

OBJECTIVE: To explore how pain intensity and pain cognition are related to health-related quality of life (HRQoL) in women with endometriosis. DESIGN: Cross-sectional questionnaire-based survey. SETTING: Multidisciplinary referral center. PATIENT(S): Women with laparoscopically and/or magnetic resonance imaging-proven endometriosis (n = 50) and healthy control women (n = 42). INTERVENTION(S): For HRQoL, two questionnaires: the generic Short Form Health Survey (SF-36) and the Endometriosis Health Profile 30 (EHP-30). For pain cognition, three questionnaires: the Pain Catastrophizing Scale (PCS), the Pain Vigilance and Awareness Questionnaire (PVAQ), and the Pain Anxiety Symptoms Scale (PASS). For pain intensity, the verbal Numeric Rating Scale (NRS). MAIN OUTCOME MEASURE(S): Association between pain intensity and pain cognition with HRQoL in women with endometriosis, and the differences in HRQoL and pain cognition between women with endometriosis and healthy controls. RESULT(S): Health-related quality of life was statistically significantly impaired in women with endometriosis as compared with healthy control women. The variables of pain intensity and pain cognition were independent factors influencing the HRQoL of women with endometriosis. Patients with endometriosis had statistically significantly more negative pain cognition as compared with controls. They reported more pain anxiety and catastrophizing, and they were hypervigilant toward pain. CONCLUSION(S): Pain cognition is independently associated with the HRQoL in endometriosis patients. Clinicians should be aware of this phenomenon and may consider treating pain symptoms in a multidimensional, individualized way in which the psychological aspects are taken into account. In international guidelines on management of women with endometriosis more attention should be paid to the psychological aspects of care.

Depressive rumination and the emotional control circuit: An EEG localization and effective connectivity study.

Ruminations are repetitive thoughts associated with symptoms, causes, and consequences of one's negative feelings. The objective of this study was to explore the neuronal basis of depressive rumination in a non-clinical population within the context of emotional control. Participants scoring high or low on the tendency to ruminate scale took part in the EEG experiment. Their EEG data were collected during a state of induced depressive ruminations and compared with positive and neutral conditions. We hypothesized that both groups would differ according to the level of activation and effective connectivity among the structures involved in the emotional control circuit. Clustering of independent components, together with effective connectivity (Directed Transfer Function), was performed using the EEG signal. The main findings involved decreased activation of the left dorsolateral prefrontal cortex (DLPFC) and increased activation of the left temporal lobe structures in the highly ruminating group. The latter result was most pronounced during the ruminative condition. Decreased information from the left DLPFC to the left temporal lobe structures was also found, leading to the conclusion that hypoactivation of the left DLPFC and its inability to modulate the activation of the left temporal lobe structures is crucial for the ruminative tendencies.

Cortical functional connectivity is associated with the valence of affective states.

The study investigates the relationships between the valence of affective states and the cortical patterns of functional connectivity. The information flow rate and direction were estimated by means of Directed Transfer Function (DTF), a multivariate method based on Granger causality. It was calculated on EEG activity recorded during mental imagery tasks. As a result, three regions were revealed as main network hubs, where the information outflow changed specifically with valence: the anterior orbitofrontal cortex, and the right posterior and right temporal area. The role of these structures in synchronizing the cortical affective network as well as in mediating different aspects of emotional state is discussed.