Context-dependent Deactivation of the Amygdala during Pain

Abstract

Abstract& The amygdala has been implicated in fundamental functions for the survival of the organism, such as fear and pain. In accord with this, several studies have shown increased amygdala activity during fear conditioning and the processing of fear-relevant material in human subjects. In contrast, functional neuroimaging studies of pain have shown a decreased amygdala activity. It has previously been proposed that the observed deactivations of the amygdala in these studies indicate a cognitive strategy to adapt to a distressful but in the experimental setting unavoidable painful event. In this positron emission tomography study, we show that a simple contextual manipulation, immediately preceding a painful stimulation, that increases the anticipated duration of the painful event leads to a decrease in amygdala activity and modulates the autonomic response during the noxious stimulation. On a behavioral level, 7 of the 10 subjects reported that they used coping strategies more intensely in this context. We suggest that the altered activity in the amygdala may be part of a mechanism to attenuate pain-related stress responses in a context that is perceived as being more aversive. The study also showed an increased activity in the rostral part of anterior cingulate cortex in the same context in which the amygdala activity decreased, further supporting the idea that this part of the cingulate cortex is involved in the modulation of emotional and pain networks. &

Reduced Brainstem Inhibition during Anticipated Pelvic Visceral Pain Correlates with Enhanced Brain Response to the Visceral Stimulus in Women with Irritable Bowel Syndrome

“…Recent studies have associated BOLD decreases with decreased neural firing (Logothetis et al, 2001;Shmuel et al, 2002). Limbic downregulation during pain anticipation has been suggested as a cognitive coping strategy (Petrovic et al, 2004). The current results demonstrate that during certain expectation of experimental abdominal/pelvic discomfort, female IBS-C patients are more anxious and less able than healthy controls to downregulate activity within the CNS network activated by potentially aversive interoceptive stimuli, especially within DBS.…”

“…Inhibition of limbic brain activity during anticipation of pain has often been reported in experimental studies where healthy participants are asked to tolerate maximal pain but know they will not sustain serious damage and can terminate pain at will. The brain structures most commonly inhibited are limbic (infragenual/perigenual) portions of the ACC, often with contiguous ventromedial prefrontal cortex (Porro et al, 1998(Porro et al, , 2004Hsieh et al, 1999;Simpson et al, 2001), the functionally connected amygdala (AMYG) (Berman et al, 2002a;Bonaz et al, 2002;Petrovic et al, 1999Petrovic et al, , 2001), or both (Derbyshire et al, 1997). An important role of the right ventrolateral prefrontal cortex (vlPFC) or orbitofrontal cortex (OFC) in driving this inhibition of limbic activity has been implicated in imaging studies using experimental techniques, including distraction, hypnosis, expected control, and placebo (for review, see Mayer et al, 2006).…”

Functional Neuroimaging of Anxiety: A Meta-Analysis of Emotional Processing in PTSD, Social Anxiety Disorder, and Specific Phobia

“…Specifically, amygdala activity strongly habituates to repeated presentation of emotional (48,82,83), which may result in below-baseline levels of activity (48,82). Although such habituation favors elimination of patient-comparison subject differences rather than hypoactivity (84), it suggests that greater attention should be paid to the time course of amygdala effects.…”

Inhibitory control and emotional stress regulation: Neuroimaging evidence for frontal–limbic dysfunction in psycho-stimulant addiction

“…Affect dysregulation as a result of altered medial frontal activation may result in greater susceptibility of these patients to emotionally threatening stimuli, which elicited greater activation in the amygdala. A similar functional coupling between rostral ACC and amygdala may also be involved in pain regulation and the placebo effect (Petrovic et al, 2004;Petrovic et al, 2005).…”

“…Affect dysregulation as a result of altered medial frontal activation may result in greater susceptibility of these patients to emotionally threatening stimuli, which elicited greater activation in the amygdala. A similar functional coupling between rostral ACC and amygdala may also be involved in pain regulation and the placebo effect (Petrovic et al, 2004;Petrovic et al, 2005).Cingulate cortex has long been recognized as an important structure in cognitive and emotional control. In contrast to a more dorsal sub-region in the ACC that activates in response to maintenance of working memory, conflict monitoring, error processing and other cognitive manipulations, the subcallosal and/or perigenual cingulate has been associated with processing of emotional experiences ((Bush et al, 2000).…”