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Month: November 2020

Parkinson’s medication has opposite effects on two kinds of motivation

November 29, 2020 admin Leave a comment

Patients with Parkinson’s disease lack the brain chemical dopamine. Dopamine is thought to signal upcoming rewards, and this might explain…

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Recent Posts

  • Hunger increases reinforcement learning rate May 26, 2021
  • Frontal brain damage makes decisions less biased February 13, 2021
  • Drugs affect subtypes of Parkinson’s disease differently December 26, 2020
  • Parkinson’s medication has opposite effects on two kinds of motivation November 29, 2020
  • Are working memory and visual search windows into the same neural process? October 1, 2020
  • Pupil size betrays contents of working memory October 25, 2019
  • Dopamine can make our working memory more or less flexible September 19, 2019
  • Neural model of working memory July 29, 2019
  • Why does it feel effortful to be precise? April 2, 2019

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    Recent work

    • Hunger increases reinforcement learning rate
      Sometimes we plan ahead, thinking about future consequences of our actions. Other times, we select actions based only on their immediate reward associations. Planning ahead is crucial to staying healthy, but might be affected by motivation. We asked whether hunger affects planned vs directly reinforced action (van Swieten, Bogacz & Manohar Cortex 2021). We found that people learned quicker about action values when they were hungry. Hunger didn’t affect planning. Overall, hunger may […]
    • Frontal brain damage makes decisions less biased
      Learning from reinforcement is a classic way to study how brain areas contribute to adaptive behaviour. The most frontal parts of the brain probably contribute at a very high, abstract level. In this study (Manohar et al. Cortex 2021), we asked how confident people are in what they have learned. Underside of a human brain showing a part of the ventromedial prefrontal cortex. Healthy people are biased by previous choices, and by competing information, when making these […]
    • Drugs affect subtypes of Parkinson’s disease differently
      In this commentary, I discuss the implications of new work from Hanneke Den Ouden’s lab. The authors subdivided Parkinson’s disease patients into those with and without tremor, and found that learning was affected by dopamine in opposite directions in the two groups! […]
    • Parkinson’s medication has opposite effects on two kinds of motivation
      Patients with Parkinson’s disease lack the brain chemical dopamine. Dopamine is thought to signal upcoming rewards, and this might explain why patients on treatment can develop impulse control disorders. My lab is studying two different ways to motivate people. One way is to reward or punish them based on how well they do — like performance-related pay. The other way is to promise a guaranteed reward, which also tends to keep people motivated (even though they don’t have to). […]
    • Are working memory and visual search windows into the same neural process?
      When you recall an item from memory, a prompt usually brings associated parts of that item into mind. Could this process be the same thing that occurs when you search for a visual target? We tested a neural model designed to perform working memory tasks, to see if it could also perform visual search. The model retrieves information when a partial cue re-activates a pattern of neurons by associative pattern completion. This same process could occur when we look for an item that we have in mind: […]
    • Pupil size betrays contents of working memory
      When we hold several things in short-term memory, we can shift our attention internally between different features in memory. For example we might hold two visual objects in memory, and choose to think about one of them. We show that pupils shrink when we are currently thinking of a bright object, in our recent study published in PNAS with Nahid Zokaei and Kia Nobre. […]
    • Dopamine can make our working memory more or less flexible
      Dopamine drugs are used to treat Parkinson’s disease, and alter a wide range of brain functions. One role of dopamine might be to make information we are currently holding in mind more stable — we are less likely to get distracted. We showed that this effect is crucially dependent on our initial memory capacity. People with worse memory actually showed the opposite effect of dopamine: it made them more distractible — in a new paper in J Psychopharm with Sean Fallon, Kinan […]