Cortical Representation of the Sensory Dimension of Pain

2001 ◽  
Vol 86 (1) ◽  
pp. 402-411 ◽  
Author(s):  
Robert K. Hofbauer ◽  
Pierre Rainville ◽  
Gary H. Duncan ◽  
M. Catherine Bushnell
Keyword(s):  
Pain Intensity ◽  
Somatosensory Cortex ◽  
Insular Cortex ◽  
Anterior Cingulate ◽  
Experimental Conditions ◽  
Noxious Heat ◽  
Positron Emission ◽  
Before And After ◽  
Dimensions Of Pain ◽  
Hypnotic Suggestions

It is well accepted that pain is a multidimensional experience, but little is known of how the brain represents these dimensions. We used positron emission tomography (PET) to indirectly measure pain-evoked cerebral activity before and after hypnotic suggestions were given to modulate the perceived intensity of a painful stimulus. These techniques were similar to those of a previous study in which we gave suggestions to modulate the perceived unpleasantness of a noxious stimulus. Ten volunteers were scanned while tonic warm and noxious heat stimuli were presented to the hand during four experimental conditions: alert control, hypnosis control, hypnotic suggestions for increased-pain intensity and hypnotic suggestions for decreased-pain intensity. As shown in previous brain imaging studies, noxious thermal stimuli presented during the alert and hypnosis-control conditions reliably activated contralateral structures, including primary somatosensory cortex (S1), secondary somatosensory cortex (S2), anterior cingulate cortex, and insular cortex. Hypnotic modulation of the intensity of the pain sensation led to significant changes in pain-evoked activity within S1 in contrast to our previous study in which specific modulation of pain unpleasantness (affect), independent of pain intensity, produced specific changes within the ACC. This double dissociation of cortical modulation indicates a relative specialization of the sensory and the classical limbic cortical areas in the processing of the sensory and affective dimensions of pain.

Cerebral Mechanisms of Hypnotic Induction and Suggestion

1999 ◽  
Vol 11 (1) ◽  
pp. 110-125 ◽  
Author(s):  
Pierre Rainville ◽  
Robert K. Hofbauer ◽  
Tomáš Paus ◽  
Gary H. Duncan ◽  
M. Catherine Bushnell ◽  
...  
Keyword(s):  
Pain Perception ◽  
State Theory ◽  
Hot Water ◽  
Anterior Cingulate ◽  
Experimental Conditions ◽  
Left Hand ◽  
Positron Emission ◽  
Highly Correlated ◽  
The Right ◽  
Hypnotic Suggestions

The neural mechanisms underlying hypnotic states and responses to hypnotic suggestions remain largely unknown and, to date, have been studied only with indirect methods. Here, the effects of hypnosis and suggestions to alter pain perception were investigated in hypnotizable subjects by using positron emission tomography (PET) measures of regional cerebral blood flow (rCBF) and electroencephalographic (EEG) measures of brain electrical activity. The experimental conditions included a restful state (Baseline) followed by hypnotic relaxation alone (Hypnosis) and by hypnotic relaxation with suggestions for altered pain unpleasantness (Hypnosis-with-Suggestion). During each scan, the left hand was immersed in neutral (35°C) or painfully hot (47°C) water in the first two conditions and in painfully hot water in the last condition. Hypnosis was accompanied by significant increases in both occipital rCBF and delta EEG activity, which were highly correlated with each other (r = 0.70, p < 0.0001). Peak increases in rCBF were also observed in the caudal part of the right anterior cingulate sulcus and bilaterally in the inferior frontal gyri. Hypnosis-related decreases in rCBF were found in the right inferior parietal lobule, the left precuneus, and the posterior cingulate gyrus. Hypnosis-with-suggestions produced additional widespread increases in rCBF in the frontal cortices predominantly on the left side. Moreover, the medial and lateral posterior parietal cortices showed suggestion-related increases overlapping partly with regions of hypnosis-related decreases. Results support a state theory of hypnosis in which occipital increases in rCBF and delta activity reflect the alteration of consciousness associated with decreased arousal and possible facilitation of visual imagery. Frontal increases in rCBF associated with suggestions for altered perception might reflect the verbal mediation of the suggestions, working memory, and top-down processes involved in the reinterpretation of the perceptual experience. These results provide a new description of the neurobiological basis of hypnosis, demonstrating specific patterns of cerebral activation associated with the hypnotic state and with the processing of hypnotic suggestions.

Pain Intensity Processing Within the Human Brain: A Bilateral, Distributed Mechanism

1999 ◽  
Vol 82 (4) ◽  
pp. 1934-1943 ◽  
Author(s):  
Robert C. Coghill ◽  
Christine N. Sang ◽  
Jose Ma. Maisog ◽  
Michael J. Iadarola
Keyword(s):  
Pain Intensity ◽  
Somatosensory Cortex ◽  
Functional Organization ◽  
Human Subjects ◽  
Brain Regions ◽  
Anterior Cingulate ◽  
Pain Processing ◽  
Brain Areas ◽  
Secondary Somatosensory Cortex ◽  
Positron Emission

Functional imaging studies of human subjects have identified a diverse assortment of brain areas that are engaged in the processing of pain. Although many of these brain areas are highly interconnected and are engaged in multiple processing roles, each area has been typically considered in isolation. Accordingly, little attention has been given to the global functional organization of brain mechanisms mediating pain processing. In the present investigation, we have combined positron emission tomography with psychophysical assessment of graded painful stimuli to better characterize the multiregional organization of supraspinal pain processing mechanisms and to identify a brain mechanism subserving the processing of pain intensity. Multiple regression analysis revealed statistically reliable relationships between perceived pain intensity and activation of a functionally diverse group of brain regions, including those important in sensation, motor control, affect, and attention. Pain intensity–related activation occurred bilaterally in the cerebellum, putamen, thalamus, insula, anterior cingulate cortex, and secondary somatosensory cortex, contralaterally in the primary somatosensory cortex and supplementary motor area, and ipsilaterally in the ventral premotor area. These results confirm the existence of a highly distributed, bilateral supraspinal mechanism engaged in the processing of pain intensity. The conservation of pain intensity information across multiple, functionally distinct brain areas contrasts sharply with traditional views that sensory-discriminative processing of pain is confined within the somatosensory cortex and can account for the preservation of conscious awareness of pain intensity after extensive cerebral cortical lesions.

scholarly journals Differential Involvement of the Anterior Cingulate and Primary Sensorimotor Cortices in Sensory and Affective Functions of Pain

2009 ◽  
Vol 101 (3) ◽  
pp. 1201-1210 ◽  
Author(s):  
Chung-Chih Kuo ◽  
Ruei-Jen Chiou ◽  
Keng-Chen Liang ◽  
Chen-Tung Yen
Keyword(s):  
Electric Shock ◽  
Conditioned Fear ◽  
Anterior Cingulate ◽  
Neuronal Responses ◽  
Noxious Heat ◽  
Stimulus Response ◽  
Laser Heat ◽  
Primary Sensorimotor Cortex ◽  
Fear Potentiated Startle ◽  
Dimensions Of Pain

The present study examined the role of neurons in different pain-related functions of the anterior cingulate cortex (ACC) and primary sensorimotor cortex (SmI) by assessing their abilities to code different levels of noxious heat and activity changes evoked by classical fear conditioning involving electric shocks. Multiple single-unit activity was recorded with microwires implanted in the SmI and ACC of each rat. In the first set of experiments, the middle segment of the tail in each rat was irradiated with laser-heat pulses of various intensities. Neuronal responses in both the SmI and ACC increased with the intensity of the laser heat, although there was a significantly higher percentage of intensity-related units in the SmI. Furthermore, the stimulus–response curve of SmI ensemble activity had a steeper slope than that of the ACC. In the second set of experiments, rats were trained and tested on a conditioned fear-potentiated startle task in which a light was paired with an electric shock and, later, the startle response was elicited by a burst of noise in the presence or absence of light. A higher percentage of ACC units changed their neuronal responses to the conditioned stimulus after the light–shock pairing and the average activity change was also significantly stronger. Our results suggest that SmI neurons are better at coding laser-heat intensity than ACC neurons, whereas more ACC neurons are involved in conditioned fear associated with an electric shock than SmI neurons. These data provide evidence for differential contributions of the SmI and ACC to sensory and affective dimensions of pain.

Deficits in Selective Attention Following Bilateral Anterior Cingulotomy

1991 ◽  
Vol 3 (3) ◽  
pp. 231-241 ◽  
Author(s):  
Kevin W. Janer ◽  
José V. Pardo
Keyword(s):  
Anterior Cingulate Cortex ◽  
Cingulate Cortex ◽  
Anterior Cingulate ◽  
Neuropsychological Measures ◽  
Positron Emission ◽  
Cognitive Operations ◽  
Before And After ◽  
Attentional System ◽  
Cortical Regions ◽  
High Level

Positron emission tomographic (PET) studies of normal humans undergoing specific cognitive activation paradigms have identified a region of the anterior cingulate cortex as a component of an anterior, midline attentional system involved in high-level processing selection. However, deficits in attention have not been demonstrated in patients following bilateral anterior cingulotomy, a procedure that results in lesions of adjacent anterior cingulate cortex. Task paradigms used in PET studies that recruit the anterior cingulate cortex were applied to normal, control subjects and to a patient before and after cingulotomy to provide highly sensitive and functionally targeted reaction time measures of attentional performance. In contrast to unchanged performance in several neuropsychological measures, this patient demonstrated specific deficits in attention during the subacute postoperative period, which resolved spontaneously several months after surgery. Such impairment is consistent with the evolving view of the anterior cingulate's involvement in high-level processing selection. These data show the feasibility of using information from PET activation studies of normals in the design of novel chronometric tasks useful for probing abnormalities in specific cognitive operations associated with discrete cortical regions.

scholarly journals Interplay of spinal and vagal pathways on esophageal acid-related anterior cingulate cortex functional networks in rats

2019 ◽  
Vol 316 (5) ◽  
pp. G615-G622
Author(s):  
Patrick Sanvanson ◽  
Zhixin Li ◽  
Ling Mei ◽  
Venelin Kounev ◽  
Mark Kern ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Anterior Cingulate Cortex ◽  
Somatosensory Cortex ◽  
Cingulate Cortex ◽  
Anterior Cingulate ◽  
Acid Infusion ◽  
Spinal Nerves ◽  
Secondary Somatosensory Cortex ◽  
Before And After ◽  
Bilateral Vagotomy

Esophageal acid sensory signals are transmitted by both vagal and spinal pathways to the cerebral cortex. The influence and interplay of these pathways on esophageal acid-related functional connectivity has been elusive. Our aim was to evaluate the esophageal acid exposure-related effect on the anterior cingulate cortex (ACC) functional connectivity networks using functional MRI-guided functional connectivity MRI (fcMRI) analysis. We studied six Sprague-Dawley rats for fcMRI experiments under dexmedetomidine hydrochloride anesthesia. Each rat was scanned for 6 min before and after esophageal hydrochloric acid infusion (0.1 N, 0.2 ml/min). The protocol was repeated before and after bilateral cervical vagotomy on the same rat. Seed-based fcMRI analysis was used to examine ACC networks and acid-induced network alterations. Three-factor repeated-measures ANOVA analysis among all four subgroups revealed that the interaction of acid infusion and bilateral vagotomy was mainly detected in the hypothalamus, insula, left secondary somatosensory cortex, left parietal cortex, and right thalamus in the left ACC network. In the right ACC network, this interaction effect was detected in the caudate putamen, insula, motor, primary somatosensory cortex, secondary somatosensory cortex, and thalamic regions. These regions in the ACC networks showed decreased intranetwork connectivity due to acid infusion. However, after bilateral vagotomy, intranetwork connectivity strength inversed and became stronger following postvagotomy acid infusion. Signals transmitted through both the vagal nerve and spinal nerves play a role in esophageal acid-related functional connectivity of the ACC. The vagal signals appear to dampen the acid sensation-related functional connectivity of the ACC networks. NEW & NOTEWORTHY These studies show that esophageal acid-induced brain functional connectivity changes are vagally mediated and suggest that signals transmitted through both the vagal nerve and spinal nerves play a role in esophageal acid-related functional connectivity of the anterior cingulate cortex. This paper focuses on the development of a novel rat functional MRI model fostering improved understanding of acid-related esophageal disorders.

Temporal and Spatial Dynamics of Human Forebrain Activity During Heat Pain: Analysis by Positron Emission Tomography

2001 ◽  
Vol 85 (2) ◽  
pp. 951-959 ◽  
Author(s):  
Kenneth L. Casey ◽  
Thomas J. Morrow ◽  
Jürgen Lorenz ◽  
Satoshi Minoshima
Keyword(s):  
Premotor Cortex ◽  
Insular Cortex ◽  
Brain Activation ◽  
Brain Structures ◽  
Anterior Cingulate ◽  
Average Intensity ◽  
Heat Pain ◽  
Heat Stimulation ◽  
Perceived Intensity ◽  
Positron Emission

To learn about the sequence of brain activation patterns during heat pain, we acquired positron emission tomographic (PET) brain scans at different times during repetitive heat stimulation (40 or 50°C; 5-s contact) of each subject's left forearm. Early scans began at the onset of 60 s of stimulation; late scans began after 40 s of stimulation, which continued throughout the 60-s scan period (total stimulus duration 100 s). Each subject (14 normal, right-handed subjects; 10 male, 4 female; ages 18–42) used a visual analog scale to rate the perceived stimulus intensity (0 = no heat, 7 = pain threshold, 10 = barely tolerable pain) after each scan. The 40°C stimulation received an average intensity rating of 2.19 ± 1.22 (mean ± SD) and the 50°C an average rating of 8.93 ± 1.33. During the scan sessions, subjects did not report a difference between early and late scans. To examine the effect of the duration of stimulation specifically, 8 of these subjects rated the perceived intensity of each of 20 sequential 5-s duration contact heat stimuli (40 or 50°C; 100 s of stimulation). We used a graphical method to detect changes in perceived unpleasantness. There was no difference in perceived intensity or unpleasantness during the 40°C stimulation. However, during 50°C stimulation, perceived unpleasantness increased and subjects perceived the last five, but not the second five, stimuli as more intense than the first five stimuli. These psychophysical changes could be mediated by brain structures with increasing activity from early to late PET scans or that are active only during late scans. These structures include the contralateral M1/S1 cortex, bilateral S2 and mid-insular cortex, contralateral VP thalamus, medial ipsilateral thalamus, and the vermis and paravermis of the cerebellum. Structures that are equally active throughout stimulation (contralateral mid-anterior cingulate and premotor cortex) are less likely to mediate these psychophysical changes. Some cortical, but not subcortical, structures showed significant or borderline activation only during the early scans (ipsilateral premotor cortex, contralateral perigenual anterior cingulate, lateral prefrontal, and anterior insular cortex); they may mediate pain-related attentive or anticipatory functions. Overall, the results reveal that 1) the pattern of brain activation and the perception of heat pain both change during repetitive noxious heat stimulation, 2) cortical activity can be detected before subcortical responses appear, and 3) timing the stimulation with respect to the scan period can, together with psychophysical measurements, identify brain structures that are likely to participate in the perception of pain.

scholarly journals HF-rTMS Treatment in Medication-Resistant Melancholic Depression: Results from 18FDG-PET Brain Imaging

CNS Spectrums ◽  
2009 ◽  
Vol 14 (8) ◽  
pp. 439-448 ◽  
Author(s):  
Chris Baeken ◽  
Rudi De Raedt ◽  
Christian Van Hove ◽  
Peter Clerinx ◽  
Johan De Mey ◽  
...  
Keyword(s):  
Fdg Pet ◽  
Rating Scale ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Positive Outcome ◽  
Anterior Cingulate ◽  
18Fdg Pet ◽  
Positron Emission ◽  
Dorsolateral Prefrontal ◽  
Before And After ◽  
Brodmann Areas

ABSTRACTIntroduction: High frequency repetitive transcranial magnetic stimulation (HF-rTMS) of the left dorsolateral prefrontal cortex (DLPFC) might be a promising strategy to treat depression, but not all patients show a positive outcome.Objective: In this open study, we evaluate whether a favorable HF-rTMS treatment outcome could be predicted by baseline prefrontal brain glucose metabolism (CMRglc), measured by 18fluorodeoxyglucose positron emission tomography (18FDG-PET).Methods: A sample of 21 antidepressant-free, treatment-resistant depression (TRD) patients of the melancholic subtype received 10 sessions of HF-rTMS delivered on the left DLPFC. Patients underwent a static 18FDG-PET before and after HF-rTMS treatment.Results: Forty-three percent of the patients showed a reduction of at least 50% on their Hamilton Rating Scale for Depression scores. Higher baseline metabolic activities in the DLPFC and the anterior cingulate cortex (ACC) were associated with better clinical outcome. Successful HF-rTMS treatment was related to metabolic changes in subdivisions of the ACC (Brodmann areas 24 and 32).Conclusion: This biological impact of HF-rTMS on regional brain CMRglc explains to some extent how HF-rTMS may improve moods in TRD patients. Larger sham-controlled HF-rTMS treatment studies are needed to confirm these results.

scholarly journals Placebo-induced pain reduction is associated with inverse network coupling at rest

2019 ◽  
Author(s):  
Isabella C. Wagner ◽  
Markus Rütgen ◽  
Allan Hummer ◽  
Christian Windischberger ◽  
Claus Lamm
Keyword(s):  
Pain Intensity ◽  
Somatosensory Cortex ◽  
Resting State ◽  
Large Scale ◽  
Brain Networks ◽  
Anterior Cingulate ◽  
Control Group ◽  
List Type ◽  
Placebo Analgesia ◽  
Sensory Motor

AbstractPlacebos can reduce pain by inducing beliefs in the effectiveness of an actually inert treatment. Such top-down effects on pain typically engage lateral and medial prefrontal regions, the insula, somatosensory cortex, as well as the thalamus and brainstem during pain anticipation or perception. Considering the level of large-scale brain networks, these regions spatially align with fronto-parietal/executive control, salience, and sensory-motor networks, but it is unclear if and how placebos alter interactions between them during rest. Here, we investigated how placebo analgesia affected intrinsic network coupling. Ninety-nine human participants were randomly assigned to a placebo or control group and underwent resting-state fMRI after pain processing. Results revealed inverse coupling between sensory-motor and salience-like networks in placebo but not control participants. Specifically, networks were centered on the bilateral somatosensory cortex, as well as on the brainstem, thalamus, striatal regions, dorsal and rostral anterior cingulate cortex, and the insula, respectively. Across participants, more negative between-network coupling was associated with lower individual pain intensity as assessed during a preceding pain task, but was unrelated to expectations of medication effectiveness in the placebo group. Altogether, these findings provide initial evidence that placebo analgesia affects the intrinsic communication between large-scale brain networks, even in the absence of pain. We suggest a model where placebo analgesia increases activation within a descending pain-modulatory network, segregating it from somatosensory regions that might code for painful experiences.HighlightsPlacebo analgesia affects resting-state connectivity between networks.Salience-related and somatosensory regions are negatively coupled at rest.This coupling is negative following placebo, but not in control participants.More negative between-network coupling is related to lower pain intensity.

scholarly journals Adsorption Studies on Magnetic Nanoparticles Functionalized with Silver to Remove Nitrates from Waters

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1757
Author(s):  
Yesica Vicente-Martínez ◽  
Manuel Caravaca ◽  
Antonio Soto-Meca ◽  
Miguel Ángel Martín-Pereira ◽  
María del Carmen García-Onsurbe
Keyword(s):  
Magnetic Nanoparticles ◽  
Nitrate Content ◽  
Adsorption Efficiency ◽  
Experimental Conditions ◽  
Dependent Behavior ◽  
Before And After ◽  
Naoh Solution ◽  
High Concentrations ◽  
Interference Studies

This paper presents a novel procedure for the treatment of contaminated water with high concentrations of nitrates, which are considered as one of the main causes of the eutrophication phenomena. For this purpose, magnetic nanoparticles functionalized with silver (Fe3O4@AgNPs) were synthesized and used as an adsorbent of nitrates. Experimental conditions, including the pH, adsorbent and adsorbate dose, temperature and contact time, were analyzed to obtain the highest adsorption efficiency for different concentration of nitrates in water. A maximum removal efficiency of 100% was reached for 2, 5, 10 and 50 mg/L of nitrate at pH = 5, room temperature, and 50, 100, 250 and 500 µL of Fe3O4@AgNPs, respectively. The characterization of the adsorbent, before and after adsorption, was performed by energy dispersive X-ray spectroscopy, scanning electron microscopy, Brunauer-Emmett-Teller analysis and Fourier-transform infrared spectroscopy. Nitrates can be desorbed, and the adsorbent can be reused using 500 µL of NaOH solution 0.01 M, remaining unchanged for the first three cycles, and exhibiting 90% adsorption efficiency after three regenerations. A deep study on equilibrium isotherms reveals a pH-dependent behavior, characterized by Langmuir and Freundlich models at pH = 5 and pH = 1, respectively. Thermodynamic studies were consistent with physicochemical adsorption for all experiments but showed a change from endothermic to exothermic behavior as the temperature increases. Interference studies of other ions commonly present in water were carried out, enabling this procedure as very selective for nitrate ions. In addition, the method was applied to real samples of seawater, showing its ability to eliminate the total nitrate content in eutrophized waters.

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