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Pain can be modulated by several cognitive techniques, typically involving increased cognitive control and decreased sensory processing. Recently, it has been demonstrated that pain can also be attenuated by mindfulness. Here, we investigate the underlying brain mechanisms by which the state of mindfulness reduces pain. Mindfulness practitioners and controls received unpleasant electric stimuli in the functional magnetic resonance imaging scanner during a mindfulness and a control condition. Mindfulness practitioners, but not controls, were able to reduce pain unpleasantness by 22% and anticipatory anxiety by 29% during a mindful state. In the brain, this reduction was associated with decreased activation in the lateral prefrontal cortex and increased activation in the right posterior insula during stimulation and increased rostral anterior cingulate cortex activation during the anticipation of pain. These findings reveal a unique mechanism of pain modulation, comprising increased sensory processing and decreased cognitive control, and are in sharp contrast to established pain modulation mechanisms.
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The majority of neuroimaging studies on affective processing have indicated that there are specific brain structures, which are selectively responsive to fear and disgust. Whereas the amygdala is assumed to be fear-related, the insular cortex is most likely involved in disgust processing. Since these findings are mainly a result of studies focusing exclusively either on fear, or on disgust, but rarely on both emotions together, the present experiment explored the neural effects of viewing disgusting and fear-inducing pictures in contrast to neutral pictures. This was done by means of functional magnetic resonance imaging (fMRI) with 19 subjects (nine males, ten females), who also gave affective ratings for the presented pictures. The fear and the disgust pictures were able to induce the target emotions and they received comparable valence and arousal ratings. The processing of both aversive picture types was associated with an increased brain activation in the occipital-temporal lobe, in the prefrontal cortex, and in the thalamus. The amygdala was significantly activated by disgusting, but not by fear-inducing, pictures. Thus, our data are in contrast with the idea of highly emotion-specific brain structures and rather suggest the existence of a common affective circuit.
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Findings from animal as well as human neuroimaging studies suggest that reward delivery is associated with the activation of subcortical limbic and prefrontal brain regions, including the thalamus, the striatum, the anterior cingulate and the prefrontal cortex. The aim of the present study was to explore if these reward-sensitive regions are also activated during the anticipation of reinforcers that vary with regard to their motivational value. A differential conditioning paradigm was performed, with the presentation of a rewarded reaction time task serving as the unconditioned stimulus (US). Depending on their reaction time, subjects were given (or not given) a monetary reward, or were presented with a verbal feedback consisting of being fast or slow. In a third control condition no task needed to be executed. Each of the three conditions was introduced by a different visual cue (CS). Brain activation of 27 subjects was recorded using event-related functional magnetic resonance imaging. The results showed significant activation of the substantia nigra, thalamic, striatal, and orbitofrontal brain regions as well as of the insula and the anterior cingulate during the presentation of a CS signalling a rewarded task. The anticipation of a monetary reward produced stronger activation in these regions than the anticipation of positive verbal feedback. The results are interpreted as reflecting the motivation-dependent reactivity of the brain reward system with highly motivating stimuli (monetary reward) leading to a stronger activation than those less motivating ones (verbal reward).
Erkunden
Eintragsart
Sprache
- Englisch (3)
Thema
- Image Processing, Computer-Assisted
- Adult (3)
- Anticipation, Psychological/physiology (1)
- Anxiety/psychology (1)
- Behavior/physiology (1)
- Brain/*physiology (1)
- Brain/physiology (1)
- Brain/*physiopathology (1)
- Cerebral Cortex/physiopathology (1)
- Cognition/*physiology (1)
- Conditioning, Operant/*physiology (1)
- Data Interpretation, Statistical (1)
- Echo-Planar Imaging (1)
- Electric Stimulation Therapy (1)
- Emotions/*physiology (1)
- Fear/*physiology (1)
- Feedback/physiology (1)
- Female (3)
- Gyrus Cinguli/physiology (1)
- Hemodynamics/*physiology (1)
- Humans (3)
- Magnetic Resonance Imaging (3)
- Male (3)
- Mental Healing/*psychology (1)
- Neostriatum/physiology (1)
- Occipital Lobe/physiology (1)
- Oxygen/blood (1)
- Pain Management/adverse effects/*methods/psychology (1)
- Pain Measurement (1)
- Pain/*physiopathology (1)
- Photic Stimulation (1)
- Prefrontal Cortex/physiology (1)
- Prefrontal Cortex/physiopathology (1)
- Psychomotor Performance/physiology (1)
- Reaction Time (1)
- *Reward (1)
- Sensation/*physiology (1)
- Sex Characteristics (1)
- Somatosensory Cortex/physiopathology (1)
- Thalamus/physiopathology (1)