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Activations due to anticipatory reactions to pain depends on paradigm
ABSTRACTS
Activations due to anticipatory reactions to pain depends on paradigm. Jen.Chuen Hsieh, MD, PhD1, 2, Sharon Stone-Elander 1, PhD Martin Ingvar, MD, PhDk 1Cognitive Neurophysiology, Dept. Clinical Neuroscience, 17176 Stockholm, Karolinska Hospital, Sweden.2Neuroanesthesia & Pain Unit, Dept. Anesthesiology, Veterans General Hospital-Taipei, 11217 Taipei, Taiwan, R.O.C.
inta~roduction: It is well known that the anticipatory response before an aversive event depends on the expectation of the individual. It has been suggested that the anticipation of a harmful event engages a cognitive appraisal, which pertains to the options for coping, which in turn are conductive to anticipatory coping with the upcoming distress (Lazarus 1991). Thus the anticipation, or expectation, of pain can be regarded as an antecedent causal factor in the emotional response. Understanding the mechanisms by which the brain adapts to the situational demands of different psychological dispositions is crucial in understanding the human adaptive behavior to emotional distress. By imaging the pre-pain cerebral activity during anticipation of a painful encounter with PET, we studied a neurophysiological modulating process between painful distress and attention. We aimed at investigating how the known pain-structures (anterior cingulate cortex-ACC and medial prefrontal cortex-MPFC) in the brain participate in an anticipatory coping mechanism with two paradigms.
rials and Methods: Experiment 1. Anticipation of an impending unknownpain. 3 scans with reassured pain free subcutaneous injection of saline in the right upper arm were first performed. Then, the subjects were informed that during the subsequent scans they would receive a painful stimulus during the scans without prior information. To maintain the anticipation, a minute amount of ethanol (actual pain) was injected intracutaneously (3*) and was intermixed with injection of saline (3*).Experiment 2. Anticipation of an inevitable known pain stimulus. Reproducible thresholds of perception and pain tolerance over the right dorsal wrist were established individually by transcutaneous electrical stimulation (5 Hz, 200 ~tsek). The 5 subjects were studied at assured rest (*3) and during warned anticipation (*3). The subjects were instructed that a similar electric stimulation would come during the scan within their established limit of tolerance. A brief stimulation was given following completion of the scan. Analysis was made with pertinent image subtractions and statistical determination of significant differences. Anatomical designation was made according to the Computerized Brain Atlas (Ingvar et el., 1994). Maet_
Results: In experiment 1 anticipation of pain led to significant activations in the caudal ACC, the MPFC and the periaqueductal gray. In the second experiment, rCBF decreased as compared to control in the caudal ACC and MPFC. The anxiety ratings using 100mm-VAS were 4.3+5.6 and 5.8+7.6 (mean_+sd) for the experiment 1 and 2, respectively. The mean Spiebergel's state anxiety score and the mean heart rate were unchanged during anticipation as compared to the control state. Subjects self-reported either promptly attended to (exp. 1) or intentionally alienated attention from (exp.2) the source of distress upon questioning. Conclusions: Having a warning of an upcoming harm is a powerful adaptational tool, especially in humans, who are able to think in terms of past, present, and future, and to cognitively engage in anticipatory coping in response to distress of various content. Understanding the mechanisms by which the brain instigates a germane central process congruent to the situational demand of different psychological disposition is crucial in understanding the human adaptive behavior to emotional distress and will shed light on the transactional differences among chronic pain populations. The activation and deactivation of the ACC and MPFC can be viewed as a neurophysiological modulation imposed by the cognitive appraisal and congruently reflects two facets of "emotion-oriented" anticipatory coping strategy: vigilance (directing attention to the encounter in exp. 1) and mollified attention (alienating attention from the source of distress in exp.2), respectively (Hsieh, 1995; Lazarus, 1991). Ref..___erences: Hsieh, J.-C. (1995) Central processing of pain: Functional brain imaging studies with PET. Karolinska Institute, Sweden. Ingvar, M., Eriksson, L., Greitz, T., Stone-Elander, S., Dahlbom, M., Rosenqvist, G., Trampe, P.a. and Euler, C.v., Methodological aspects of brain activation studies: cerebral blood flow determined with [ 150]butanol and positron emission tomography, J. Cereb. Blood Flow Metab., 14 (1994) 628-638. Lazarus, R.S., Emotion and adaptation, Oxford, New York, 1991.
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Activations due to anticipatory reactions to pain depends on paradigm. Jen.Chuen Hsieh, MD, PhD1, 2, Sharon Stone-Elander 1, PhD Martin Ingvar, MD, PhDk 1Cognitive Neurophysiology, Dept. Clinical Neuroscience, 17176 Stockholm, Karolinska Hospital, Sweden.2Neuroanesthesia & Pain Unit, Dept. Anesthesiology, Veterans General Hospital-Taipei, 11217 Taipei, Taiwan, R.O.C.
inta~roduction: It is well known that the anticipatory response before an aversive event depends on the expectation of the individual. It has been suggested that the anticipation of a harmful event engages a cognitive appraisal, which pertains to the options for coping, which in turn are conductive to anticipatory coping with the upcoming distress (Lazarus 1991). Thus the anticipation, or expectation, of pain can be regarded as an antecedent causal factor in the emotional response. Understanding the mechanisms by which the brain adapts to the situational demands of different psychological dispositions is crucial in understanding the human adaptive behavior to emotional distress. By imaging the pre-pain cerebral activity during anticipation of a painful encounter with PET, we studied a neurophysiological modulating process between painful distress and attention. We aimed at investigating how the known pain-structures (anterior cingulate cortex-ACC and medial prefrontal cortex-MPFC) in the brain participate in an anticipatory coping mechanism with two paradigms.
rials and Methods: Experiment 1. Anticipation of an impending unknownpain. 3 scans with reassured pain free subcutaneous injection of saline in the right upper arm were first performed. Then, the subjects were informed that during the subsequent scans they would receive a painful stimulus during the scans without prior information. To maintain the anticipation, a minute amount of ethanol (actual pain) was injected intracutaneously (3*) and was intermixed with injection of saline (3*).Experiment 2. Anticipation of an inevitable known pain stimulus. Reproducible thresholds of perception and pain tolerance over the right dorsal wrist were established individually by transcutaneous electrical stimulation (5 Hz, 200 ~tsek). The 5 subjects were studied at assured rest (*3) and during warned anticipation (*3). The subjects were instructed that a similar electric stimulation would come during the scan within their established limit of tolerance. A brief stimulation was given following completion of the scan. Analysis was made with pertinent image subtractions and statistical determination of significant differences. Anatomical designation was made according to the Computerized Brain Atlas (Ingvar et el., 1994). Maet_
Results: In experiment 1 anticipation of pain led to significant activations in the caudal ACC, the MPFC and the periaqueductal gray. In the second experiment, rCBF decreased as compared to control in the caudal ACC and MPFC. The anxiety ratings using 100mm-VAS were 4.3+5.6 and 5.8+7.6 (mean_+sd) for the experiment 1 and 2, respectively. The mean Spiebergel's state anxiety score and the mean heart rate were unchanged during anticipation as compared to the control state. Subjects self-reported either promptly attended to (exp. 1) or intentionally alienated attention from (exp.2) the source of distress upon questioning. Conclusions: Having a warning of an upcoming harm is a powerful adaptational tool, especially in humans, who are able to think in terms of past, present, and future, and to cognitively engage in anticipatory coping in response to distress of various content. Understanding the mechanisms by which the brain instigates a germane central process congruent to the situational demand of different psychological disposition is crucial in understanding the human adaptive behavior to emotional distress and will shed light on the transactional differences among chronic pain populations. The activation and deactivation of the ACC and MPFC can be viewed as a neurophysiological modulation imposed by the cognitive appraisal and congruently reflects two facets of "emotion-oriented" anticipatory coping strategy: vigilance (directing attention to the encounter in exp. 1) and mollified attention (alienating attention from the source of distress in exp.2), respectively (Hsieh, 1995; Lazarus, 1991). Ref..___erences: Hsieh, J.-C. (1995) Central processing of pain: Functional brain imaging studies with PET. Karolinska Institute, Sweden. Ingvar, M., Eriksson, L., Greitz, T., Stone-Elander, S., Dahlbom, M., Rosenqvist, G., Trampe, P.a. and Euler, C.v., Methodological aspects of brain activation studies: cerebral blood flow determined with [ 150]butanol and positron emission tomography, J. Cereb. Blood Flow Metab., 14 (1994) 628-638. Lazarus, R.S., Emotion and adaptation, Oxford, New York, 1991.
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