Limbic-prefrontal brain circuits in motivation and decision-making

Deep structures inside the brain are important for motivation and decision-making but difficult to study in humans. Classic tools for manipulating brain activity cannot reach them and neuroimaging is too imprecise to distinguish their component "nuclei" (cell clusters), each known to have differing functions in animals. Here I will exploit new techniques to study deep nuclei in humans at a scale thus far only considered in animals. First, I will create maps delineating different nuclei. Second, I will examine their individual contributions to motivation and decision-making in healthy people using two techniques I have pioneered: high-resolution neuroimaging and ultrasound neurostimulation, which together allow reliable recording and precise modulation of activity in deep nuclei. Finally, I will assess nuclei changes and decision preferences in depressed people, where these structures function abnormally. This will provide important missing links between animal and human research and insight into biological systems affected by mental illness.