Striatal dopamine and learning strategy-an (123)I-FP-CIT SPECT study.
Patients with Parkinson's disease (PD) have difficulty in processing learning tasks that lack external guidelines and, consequently, necessitate the subjects to generate their own problem-solving strategy. While the contribution of striatal dopaminergic deficiency to PD-specific motor symptoms is well established, its role in the PD-characteristic deviant learning style remains unclear. The aim of this study was to assess the relation between striatal dopamine activity as revealed by single photon emission computed tomography (SPECT) with (123)I-FP-CIT, a ligand for the dopamine transporter (DaT), and type of learning strategy, as identified by the California Verbal Learning Task (CVLT) in 19 patients with probable PD. The results showed a robust inverse correlation between striatal dopamine DaT binding and the externally guided, serial learning strategy: the lower the DaT in caudate nucleus as well as in putamen, the more the patient group appeared to rely on externally structured learning. Additionally, a significant positive correlation was found between caudatal DaT activity and the internally generated, semantic learning strategy. Unlike these strategic learning characteristics, IQ equivalent and recall total score appeared to vary independently from striatal DaT availability.


CONCLUSIONS
our findings provide direct evidence that striatal dopaminergic activity is specifically involved in the regulation of strategic learning processes.
Berger
Hans J C
HJ
Department of Medical Psychology, University Medical Centre Nijmegen, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands. H.Berger@neuro.umcn.nl
Cools
Alexander R
AR
Horstink
Martin W I M
MW
Oyen
Wim J G
WJ
Verhoeven
Elisabeth W M
EW
van der Werf
Sieberen P
SP
D000328:Adult; D000368:Aged; D002421:Caudate Nucleus / Q000000981:diagnostic imaging; D003342:Corpus Striatum / Q000000981:diagnostic imaging*; D004298:Dopamine / Q000378:metabolism*; D050483:Dopamine Plasma Membrane Transport Proteins; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007859:Learning Disabilities / Q000000981:diagnostic imaging*; D008297:Male; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins / Q000378:metabolism; D008875:Middle Aged; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000000981:diagnostic imaging*; D011340:Problem Solving / Q000502:physiology*; D011699:Putamen / Q000000981:diagnostic imaging; D012016:Reference Values; D012660:Semantics; D015899:Tomography, Emission-Computed, Single-Photon; D014706:Verbal Learning / Q000502:physiology
D050483:Dopamine Plasma Membrane Transport Proteins; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; C493214:SLC6A3 protein, human; D004298:Dopamine