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SUMMARY:Action decisions in health and Parkinson’s disease - Dr. James R
 owe\, Department of Clinical Neurosciences / MRC Cognition and Brain Scien
 ces Unit
DTSTART:20090930T084500Z
DTEND:20090930T091500Z
UID:TALK18694@talks.cam.ac.uk
CONTACT:Hannah Critchlow
DESCRIPTION:This talk is part of the Cambridge Clinical Neuroscience and M
 ental Health Symposium\, 29th - 30th September 2009 at West Road Concert H
 all. This event is free to attend for cambridge neuroscientists although r
 egistration is required. To register\, and for further information\, pleas
 e visit: http://www.neuroscience.cam.ac.uk/cnmhs/\n\nAbstract: Many neurol
 ogical and psychiatric disorders affect volition\, including disorders of 
 motivation\, selection\, inhibition and execution of voluntary actions. He
 re\, we focus on the problem of how we choose one action over other possib
 le actions when environmental cues (stimuli) and rewards (learned outcomes
 ) do not provide sufficient information for a preferred choice. We show ho
 w a race model between competitive response schemas can be used to inform 
 the analysis of fMRI data\, during a task that requires subjects to choose
  simple manual actions. The race model is in turn informed by neurophysiol
 ogical and behavioural decision paradigms\, which offer a parsimonious mec
 hanism for response selection with or without response biases that result 
 from reward or memory influences. The race model reveals a clear distincti
 on between lateral prefrontal and the pre-SMA\, premotor cortex and pariet
 al cortex. Activation of the latter regions correlates with the prediction
 s of the race model for selection among competitive response schemas. In c
 ontrast\, activation of the lateral prefrontal cortex correlates with swit
 ching to alternative successive responses\, and other forms of non-random 
 behaviour\, dependent on the monitoring of responses in working memory. Th
 e analysis of patients at different stages of Parkinson’s disease\, and h
 ealthy subjects with genetic polymorphisms affecting cortical dopamine met
 abolism\, suggests an important role of dopamine in the selection of volun
 tary action. Behavioural consequences are seen not in simple performance p
 arameters but rather in the degree of independence over successive choices
 . In addition to the differences in regional cortical activation\, dynamic
  causal modelling of cortical networks reveals how Parkinson’s disease af
 fects the interactions within an extended motor system. In a dopamine depl
 eted off”-state\, the selection of action becomes dependent on changes in
  prefrontal-premotor interactions rather than the normal dependence on cha
 nging prefrontal-preSMA interactions. The effect of Parkinson’s disease i
 s qualitatively different from healthy aging of the motor system. We discu
 ss the implications for understanding and improving behavioural control in
  health and neurological disease.\n\nBiosketch: James Rowe is a behavioura
 l neurologist\, working at the Cambridge University Department of Clinical
  Neurosciences and the MRC Cognition and Brain Sciences Unit. He has recen
 tly been awarded a Wellcome Trust Senior Fellowship in Clinical Research t
 o continue his work investigating behavioural and cognitive control in hea
 lth and neurodegenerative disease. As a medical student at Downing College
  Cambridge reading Experimental Psychology (1991)\, he was inspired by the
  rapidly advancing research into cognitive\, anatomic and pharmacological 
 basis of neuropsychiatric disorders. He completed clinical medicine at Mag
 dalen College Oxford (1994) and then with the support of a Wellcome Trust 
 Clinical Training Fellowship he undertook his PhD at the Functional Imagin
 g Laboratory of the Wellcome Department of Cognitive Neurology under the j
 oint supervision of Prof. Richard Frackowiak and Prof. Dick Passingham (19
 98-2001). He returned to full time specialist training before resuming res
 earch in Cambridge as a consultant neurologist with a Wellcome Trust Inter
 mediate Clinical Fellowship (2005-2009) to characterise the selection of r
 ules and actions in the context of structural and neurodegenerative diseas
 e. His work emphasises the advantages of neuroimaging and in particular th
 e additional insights into the mechanisms of disease and treatments that a
 re available from the analysis of network connectivity.  Over the next fiv
 e years with collaborators from Cambridge Neuroscience he will combine com
 putational modelling\, psychopharmacology and neuroimaging to investigate 
 new ways to enhance cognitive control in Parkinson’s disease and frontote
 mporal dementia.\n
LOCATION:West Road Concert Hall
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