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Our group studies changes in motivation, memory and decision-making that occur in neurological disease. We combine behavioural, neuroimaging, and pharmacological experiments to apply cognitive neuroscience to clinical problems.

Manohargroup

Motivation is our ability to perform better with incentives. It allows us to exceed our natural performance limits, by

  • energising action,
  • boosting attention, and
  • improving motor and cognitive precision.

We model motivation using the idea of “costly noise-reduction”. According to this view, the signal-to-noise ratio in the brain can be increased, but this is expensive. The cost for being precise explains why we perform better when we are likely to be rewarded. The lab studies the nature of these precision costs:

  1. Do specific brain structures help control noise?
  2. Are there specific brain chemicals involved?
  3. Can these costs be increased in disease and reduced by drugs?  

We study patients with neurodegenerative disorders like Parkinson’s disease, and patients who have brain damage, for example due to stroke. By studying the effects of reward on behaviour in these groups, and whether the neurotransmitters dopamine and acetylcholine modulate these effects, we test quantitative computational and neuroeconomic models of motivation.

Selected publications

DPhil Projects

Our lab has broad interests, applying neuropsychological methods to open questions in cognitive neuroscience. We are especially interested in working memory, attention and motivation. Cognitive models of these functions generate testable neural predictions about what we should observe when neurotransmitters are modulated, and when specific brain areas are damaged. These predictions can then be tested by comparing behavioural performance of healthy volunteers and patients with neurological disease.  We collaborate with several other groups including with Prof Masud Husain, Prof Mark Stokes, and Prof Rafal Bogacz.

Major questions we wish to answer include:

  1. Is dopamine responsible for learning along multiple dimensions of outcomes?
  2. Does motivation depend on frontostriatal dopamine? (Manohar et al Current Biology 2015)
  3. Do acetylcholine and dopamine influence reward-based decision-making?
  4. Can we modulate attention through cholinergic drugs?
  5. How do neurons support attention in working memory? (Manohar et al. 2017)

Methods

To manipulate neurotransmitters, we administer dopaminergic and cholinergic drugs to healthy volunteers, and study patients with Parkinson’s disease on and off their medication. To study the effect of brain lesions, we test patients who have focal damage in the frontal lobes. We also have access to neurological patients with a number of other diseases.

 The main methods that we use for testing include eye tracking, pupillometry and decision-making tasks, combined with computational modelling, but we also have at our disposal functional MRI, EEG and MEG.

Principal Investigator: Prof Sanjay Manohar

Research experience

As part of this Master’s / DPhil project, you will gain experience in designing experiments, using an eye tracker, and pupillometry. You will also have the opportunity to work with patients, or to study the effects of dopaminergic medication. If interested, you will also have the opportunity to learn how to apply computational modelling and machine learning to data.  

You will work in a team comprising a postdoctoral researcher, a research assistant, other DPhil students and undergraduates. There will be plenty of guidance on day-to-day issues, plus a weekly meeting with the supervisor.  We hold weekly lab meetings, and you will have an opportunity to present your design and data to the group.

Current projects