Is negative feedback involved in Parkinson's Disease, if so why?

Parkinson's outputs, so it must be negative?

2 Answers

  • Mags
    Lv 7
    10 years ago
    Favorite Answer

    When asking for help with homework, it is important to fully understand the question. It might even help to provide the course name so that we will appreciate the direction of the question and consequently the answers.

    The most common use of the term negative feedback relates to the system of rewards and negative feedback as they apply to the learning experience. In Parkinson's disease there are a few good examples although they appear on the surface to be contradictory. And how are they connected to learning or are they? Do is connect to punishment learning? Does it stem from dopamine chemical imbalance and/or the attempt to restore that homeostasis?

    I am not going to do your homework but rather provide some links which discuss this very subject. Of course the issue of PD depression raises its head but the real issue is to isolate one of the functions of dopamine.

    Begin by reading this article: Parkinsons disease and effect on behavior

    The next article is "New findings on Parkinson's disease and effect on patient behavior"

    "What we are seeing in recently diagnosed patients is that prior to being put on any medications, they exhibit a selective impairment in their ability to learn from positive (rewarding) outcomes while their sensitivity to learning from negative (or punishing) outcomes is normal...

    This selective deficit in learning from reward is not surprising because scientists have long known that dopamine is used to carry reward information throughout the brain. Parkinson's patients, however, have lost most of their dopamine-producing cells by the time they are first diagnosed with the disease.

    This decrease in their ability to process rewarding outcomes could be one reason why many Parkinson's patients experience depression It's not just that they have an awful disease, but they have lost the ability to process the rewarding aspects of life." according to Dr Mark Gluck, director of the Rutgers' Center for Collaborative Research on Cognition and Parkinson's Disease.

    You might find the explanation in the Science Daily article easier to understand:

    Ok, so the patient is diagnosed, suffers negative feedback and begins taking medications which address Parkinson's symptom reduction. And with certain medications the trend seems to be reversed in an overly dramatic way leading to compulsive gambling, compulsive spending, hyper-sexuality. Is this actually positive feedback? And why is it occurring?

    "One lesson that could be drawn from this research is that dopamine does not appear to be all-important for learning, says Alain Dagher, a McGill University researcher. “Parkinson’s patients still do learn and are not severely impaired.” He adds that mice engineered to be dopamine-deficient also seem able to learn normally. “If dopamine is a learning signal, then how can an animal with no dopamine learn?

    He suggests that there may be redundant networks for learning and cites evidence that background levels of dopamine stimulation can serve to amplify the reward signal, motivating behavior toward already learned rewards. If that’s true, then the higher background stimulation produced by a dopamine agonist in a person with Parkinson’s could promote an excessive wanting of already-learned pleasurable behaviors such as gambling. At the same time, the ability to learn from behavioral choices and to know which ones are better would remain somewhat intact."

    You should be able to take it from here.

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  • Anonymous
    4 years ago

    The Parkinson's Reversing Breakthrough?

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