Many congratulations to Matthew Rushworth, Watts Chair and Professor of Neuroscience, for receiving new major funding from the Wellcome Trust to investigate the distributed brain systems for motivation and action. The overarching aim of this five-year research project is to understand the neural mechanisms of learning, decision-making, and motivation in humans. He will examine how they emerge from distributed patterns of activity across networks of subcortical nuclei such as the basal forebrain and dorsal raphe nucleus.
Although there have been animal studies regarding such subcortical areas, they have been under-investigated in humans. New imaging and uni- and multivariate analysis methods now make it possible to examine the distributed patterns of activity that arise in these areas. It has recently been found that we can record from these areas of the human brain using ultra high-field magnetic resonance imaging. In addition, it is known that these nuclei interact with cortical areas, especially in orbitofrontal, anterior cingulate, and insula cortex (regions that are especially prominent in humans and other primates).
The project aims to record from both cortical and subcortical areas and to understand how they interact during learning, decision making, and motivation. It also seeks to assess whether new ultrasound stimulation tools – that make it possible to alter neural activity in a minimally invasive manner even in brain areas far from the surface – can be used to manipulate brain activity in these circuits in humans.
Professor Rushworth said,
The brain is important for learning and deciding what it is good to do, such as when we decide whether we want to go to a restaurant or museum, or not even bother to leave the house at all. These mechanisms may not work optimally in psychological illnesses such as depression, leading people to evaluate their opportunities incorrectly and to feel apathetic.
Because these learning, decision-making, and motivation problems are so important, they depend on complex, coordinated neural activity between subcortical nuclei (groups of cells deep in the brain) and prefrontal cortex (more recently evolved brain regions some of which are especially prominent in humans). Recently, it became possible to measure and even alter activity levels in the brain circuits we think are important in humans. We seek to exploit these new techniques to understand how these circuits enable learning about costs and benefits of courses of action and to make decisions between them.
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Human decisions about when to act originate within a basal forebrain-nigral circuit. Khalighinejad N, Priestley L, Jbabdi S, Rushworth MFS. Proc Natl Acad Sci U S A. 2020 May 26;117(21):11799-11810. doi: 10.1073/pnas.1921211117. Epub 2020 May 8. PMID: 32385157.
Global reward state affects learning and activity in raphe nucleus and anterior insula in monkeys. Wittmann MK, Fouragnan E, Folloni D, Klein-Flügge MC, Chau BKH, Khamassi M, Rushworth MFS. Nat Commun. 2020 Jul 28;11(1):3771. doi: 10.1038/s41467-020-17343-w. PMID: 32724052 Free PMC article. PMID: 32724052.