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Subtle Alterations in Brain Anatomy May Change an Individual’s Personality in Chronic Pain

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  • Ref Subtle Alterations in Brain Anatomy May Change an Individual’s Personality in Chronic Pain

    http://www.plosone.org/article/info%...l.pone.0109664
    Abstract

    It is well established that gross prefrontal cortex damage can affect an individual’s personality. It is also possible that subtle prefrontal cortex changes associated with conditions such as chronic pain, and not detectable until recent advances in human brain imaging, may also result in subtle changes in an individual’s personality. In an animal model of chronic neuropathic pain, subtle prefrontal cortex changes including altered basal dendritic length, resulted in altered decision making ability. Using multiple magnetic resonance imaging techniques, we found in humans, although gray matter volume and on-going activity were unaltered, chronic neuropathic pain was associated with reduced free and bound proton movement, indicators of subtle anatomical changes, in the medial prefrontal cortex, anterior cingulate cortex and mediodorsal thalamus. Furthermore, proton spectroscopy revealed an increase in neural integrity in the medial prefrontal cortex in neuropathic pain patients, the degree of which was significantly correlated to the personality temperament of novelty seeking. These data reveal that even subtle changes in prefrontal cortex anatomy may result in a significant change in an individual’s personality.
    From the discussion:
    It is becoming increasingly clear that chronic pain is characterized not only by an ongoing sensory and emotional experience, but also significant changes in an individual’s cognitive ability. For example, it has been reported that chronic pain subjects display impaired decision making in the Iowa Gambling Task, making disadvantageous choices that gained high immediate monetary returns at the risk of higher future losses, i.e., they were less sensitive to future consequences and poor performance on the Iowa Gambling Task [7], [8], [33]. Our chronic pain subjects had reduced novelty seeking and increased harm avoidance temperaments,

    The reduced novelty seeking in our chronic pain subjects implies that they are less likely to actively avoid monotony and potential punishment, which is consistent with being less sensitive to future consequences. Novelty seeking temperaments are thought to reflect the brain’s “behavioural activation” system [35] which depends on the integrity of the mesolimbic dopaminergic pathway, of which the mPFC and ACC are integral parts [36], [37].

    Interestingly, evidence is arising that chronic pain patients also have low Self-Directedness [6], [42]. Indeed, a low value in self-directedness can predict the presence of a personality disorder [20]. Future research should examine the interaction of Novelty Seeking and Self-Directedness on brain biochemistry, structure and function, particularly within the mPFC.

    Although our data cannot implicate causality, it may provide an indication that even subtle brain alterations can change an individual’s personality. Interestingly, in healthy individuals the temperament Persistence has been shown to be associated with an overlapping circuit including the ACC, ventral striatum and the lateral orbital and mPFC [43], [44]. As this association is lacking in pain patients, this may show that the reduction in Novelty Seeking involving reduced active avoidance may be an adaptive process generated by subtle brain alterations after the development of neuropathic pain.
    Jo Bowyer
    Chartered Physiotherapist Registered Osteopath.
    "Out beyond ideas of wrongdoing and rightdoing,there is a field. I'll meet you there." Rumi

  • #2
    thanks Jo

    interesting stuff indeed.

    ANdy
    "Here is Edward Bear coming downstairs now, bump, bump, bump, on the back of his head behind Christopher Robin. It is, as far as he knows, the only way of coming downstairs, but sometimes he feels that there is another way, if only he could stop bumping for a moment and think of it." A.A. Milne

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    • #3
      Critical role for the mediodorsal thalamus in permitting rapid reward-guided updating in stochastic reward environments

      https://elifesciences.org/content/5/e13588

      Abstract
      Adaptive decision-making uses information gained when exploring alternative options to decide whether to update the current choice strategy. Magnocellular mediodorsal thalamus (MDmc) supports adaptive decision-making, but its causal contribution is not well understood. Monkeys with excitotoxic MDmc damage were tested on probabilistic three-choice decision-making tasks. They could learn and track the changing values in object-reward associations, but they were severely impaired at updating choices after reversals in reward contingencies or when there were multiple options associated with reward. These deficits were not caused by perseveration or insensitivity to negative feedback though. Instead, monkeys with MDmc lesions exhibited an inability to use reward to promote choice repetition after switching to an alternative option due to a diminished influence of recent past choices and the last outcome to guide future behavior. Together, these data suggest MDmc allows for the rapid discovery and persistence with rewarding options, particularly in uncertain or changing environments.
      Jo Bowyer
      Chartered Physiotherapist Registered Osteopath.
      "Out beyond ideas of wrongdoing and rightdoing,there is a field. I'll meet you there." Rumi

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      • #4
        Learning to produce movement that although still painful feels good, provides scope for learning. Encouraging them to give a running commentary and find new adjectives for what they are feeling can take them down previously unexplored movement and cognitive pathways. Many of my complex pain patients are not embodied, they are sitting in the command module behind their eyes and waiting for the rescue services to arrive.
        Jo Bowyer
        Chartered Physiotherapist Registered Osteopath.
        "Out beyond ideas of wrongdoing and rightdoing,there is a field. I'll meet you there." Rumi

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