Temporally Dissociable Contributions of Human Medial Prefrontal Subregions to Reward-Guided Learning.
In decision making, dorsal and ventral medial prefrontal cortex show a sensitivity to key decision variables, such as reward prediction errors. It is unclear whether these signals reflect parallel processing of a common synchronous input to both regions, for example from mesocortical dopamine, or separate and consecutive stages in reward processing. These two perspectives make distinct predictions about the relative timing of feedback-related activity in each of these regions, a question we address here. To reconstruct the unique temporal contribution of dorsomedial (dmPFC) and ventromedial prefrontal cortex (vmPFC) to simultaneously measured EEG activity in human subjects, we developed a novel trialwise fMRI-informed EEG analysis that allows dissociating correlated and overlapping sources. We show that vmPFC uniquely contributes a sustained activation profile shortly after outcome presentation, whereas dmPFC contributes a later and more peaked activation pattern. This temporal dissociation is expressed mainly in the alpha band for a vmPFC signal, which contrasts with a theta based dmPFC signal. Thus, our data show reward-related vmPFC and dmPFC responses have distinct time courses and unique spectral profiles, findings that support distinct functional roles in a reward-processing network.


CONCLUSIONS
Multiple subregions of the medial prefrontal cortex are known to be involved in decision making and learning, and expose similar response patterns in fMRI. Here, we used a novel approach to analyzing simultaneous EEG-fMRI that allows to dissociate the individual time courses of brain regions. We find that vmPFC and dmPFC have distinguishable time courses and time-frequency patterns.
Wellcome Trust Centre for Neuroimaging, University College London, London WC1N 3BG, United Kingdom, University Clinic for Child and Adolescent Psychiatry (UCCAP), University of Zurich, 8032 Zürich, Switzerland, t.hauser@ucl.ac.uk laurence.hunt@ucl.ac.uk.
Tobias U
http://orcid.org/0000-0002-7997-8137
TU
Hauser
Wellcome Trust Centre for Neuroimaging, University College London, London WC1N 3BG, United Kingdom, t.hauser@ucl.ac.uk laurence.hunt@ucl.ac.uk.
Laurence T
http://orcid.org/0000-0002-8393-8533
LT
Hunt
University Clinic for Child and Adolescent Psychiatry (UCCAP), University of Zurich, 8032 Zürich, Switzerland.
Reto
R
Iannaccone
University Clinic for Child and Adolescent Psychiatry (UCCAP), University of Zurich, 8032 Zürich, Switzerland, Neuroscience Center Zurich, University of Zurich and ETH Zurich, 8057 Zurich, Switzerland, Zurich Center for Integrative Human Physiology, University of Zurich, 8057 Zurich, Switzerland.
Susanne
S
Walitza
University Clinic for Child and Adolescent Psychiatry (UCCAP), University of Zurich, 8032 Zürich, Switzerland, Neuroscience Center Zurich, University of Zurich and ETH Zurich, 8057 Zurich, Switzerland, Zurich Center for Integrative Human Physiology, University of Zurich, 8057 Zurich, Switzerland, Department of Child and Adolescent Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, 68159 Mannheim, Germany, and.
Daniel
D
Brandeis
University Clinic for Child and Adolescent Psychiatry (UCCAP), University of Zurich, 8032 Zürich, Switzerland, Neuroscience Center Zurich, University of Zurich and ETH Zurich, 8057 Zurich, Switzerland.
Silvia
S
Brem
Wellcome Trust Centre for Neuroimaging, University College London, London WC1N 3BG, United Kingdom, Max Planck UCL Centre for Computational Psychiatry and Ageing Research, London WC1B 5EH, United Kingdom.
Raymond J
RJ
Dolan
D000328:Adult; D001931:Brain Mapping; D002755:Choice Behavior / Q000502:physiology*; D004569:Electroencephalography; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D017397:Prefrontal Cortex / Q000502:physiology*; D012193:Reversal Learning / Q000502:physiology*; D012201:Reward; D013997:Time Factors; D055815:Young Adult
activation time-courses; medial prefrontal cortex; reward prediction error; simultaneous EEG-fMRI