BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Talks.cam//talks.cam.ac.uk// X-WR-CALNAME:Talks.cam BEGIN:VEVENT SUMMARY:"\;Bonsai trees in your head: the powerful influence of reflex ive processes on goal-directed decision-making"\;. - Dr Jon Roiser\, I nstitute of Cognitive Neuroscience\, University College London DTSTART:20130517T153000Z DTEND:20130517T170000Z UID:TALK44193@talks.cam.ac.uk CONTACT:Louise White DESCRIPTION:Decision-making in the real world is tricky\, because the deci sions we make now\naffect future choices\, and future choices and outcomes should guide current\ndecisions. The exponentially increasing number of c ombinations of future\nchoices and actions means that brute-force approach es to sequential\ndecision-making only work for trivially small problems. Using a computational\nmodelling approach to analyse responses on a determ inistic sequential\ndecision-making task\, we demonstrate a novel and powe rful influence on\ngoal-directed decision-making in humans\, "pruning"\, a simple reflexive process\nthat cuts down (or prunes) an expanding decisio n tree to a computationally\nmanageable size. Pruning involves automatical ly discounting sequences of\ndecisions that feature large negative outcome s\, no matter what the overall\noutcome\; it is different to loss aversion . Our participants used this pruning\nstrategy even when it was disadvanta geous\, and the tendency to prune was\nrelated to mild depressive symptoms . In a follow-up neuroimaging study we\nreplicated this behavioural patter n\, and found that pruning was associated with\nresponses in the subgenual anterior cingulate cortex and periaqueductal grey\,\nwhich are implicated in mood and anxiety disorders. Finally\, initial\npsychopharmacological e vidence supports the hypothesis that pruning is\ninfluenced by serotonin s ignalling. We interpret these findings within a\ntheoretical framework tha t relates Pavlovian behavioural inhibition to\nserotonin and mood disorder s.\n\n\nBiography: Jonathan Roiser\n\nJonathan Roiser studied Natural Scie nces at Trinity College\, Cambridge\, as an undergraduate and remained the re for his doctorate in the Department of Psychiatry. His PhD examined the effects of monoamine depletions on mood and cognitive performance\, with a particular emphasis on demonstrating that genetic variation can explain some of the inter-subject variability in response to perturbations of the serotonin system. He then spent a year conducting a pharmacological fMRI s tudy at the National Institute of Mental Health (NIMH)\, USA\, the results of which suggested a potentially important role for the habenula in depre ssion\, a focus of his current research.\n\nFollowing a post-doctoral appo intment at the UCL Institute of Neurology\, London\, where he investigated the neural mechanisms underpinning psychotic phenomena and cognitive impa irment in schizophrenia\, he was appointed to a faculty post at the UCL In stitute of Cognitive Neuroscience where he is currently Reader (Associate Professor) in cognitive neuroscience. He has published over 50 articles\, with an h-index of 21\, and his work has been funded by the British Academ y and Medical Research Council. In 2008 he founded the UCL-NIMH Joint Doct oral Training Program in Neuroscience\, which he co-directs. His research aims to understand the neurobiological basis of psychiatric symptoms\, com bining behavioural\, psychopharmacological and genetic approaches with neu roimaging techniques and computational analysis. In the future he hopes to further understand the sources of individual differences in response to d ifferent therapeutic approaches in depression\, with the ultimate goal of realising the potential for using neuroscience to inform treatment strateg ies in mental health\n LOCATION:Ground Floor Lecture Theatre\, Department of Psychology END:VEVENT END:VCALENDAR