Functional imaging of the human dopaminergic midbrain.
Invasive recording of dopamine neurons in the substantia nigra and ventral tegmental area (SN/VTA) of behaving animals suggests a role for these neurons in reward learning and novelty processing. In humans, functional magnetic resonance imaging (fMRI) is currently the only non-invasive event-related method to measure SN/VTA activity, but it is debated to what extent fMRI enables inference about dopaminergic responses within the SN/VTA. We consider the anatomical and functional parcellation of the primate SN/VTA and find that its homogeneity suggests little variation in the regional specificity of fMRI signals for reward-related dopaminergic responses. Hence, these responses seem to be well captured by the compound fMRI signal from the SN/VTA, which seems quantitatively related to dopamine release in positron emission tomography (PET). We outline how systematic investigation of the functional parcellation of the SN/VTA in animals, new developments in fMRI analysis and combined PET-fMRI studies can narrow the gap between fMRI and dopaminergic neurotransmission.
Düzel
Emrah
E
Institute of Cognitive Neuroscience, University College London, 17 Queen Square, London, WC13 NAR, UK. e.duzel@ucl.ac.uk
Bunzeck
Nico
N
Guitart-Masip
Marc
M
Wittmann
Bianca
B
Schott
Bjoern H
BH
Tobler
Philippe N
PN
D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D001931:Brain Mapping / Q000379:methods; D004298:Dopamine / Q000378:metabolism*; D000882:Haplorhini; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D009434:Neural Pathways / Q000033:anatomy & histology / Q000502:physiology; D009474:Neurons / Q000378:metabolism / Q000502:physiology; D010215:Papio; D049268:Positron-Emission Tomography / Q000379:methods*; D051381:Rats; D013378:Substantia Nigra / Q000033:anatomy & histology / Q000000981:diagnostic imaging* / Q000502:physiology; D009435:Synaptic Transmission; D017557:Ventral Tegmental Area / Q000033:anatomy & histology / Q000000981:diagnostic imaging* / Q000502:physiology
D004298:Dopamine