title: Changes in striatal dopamine release associated with human motor-skill acquisition.
abstract: The acquisition of new motor skills is essential throughout daily life and involves the processes of learning new motor sequence and encoding elementary aspects of new movement. Although previous animal studies have suggested a functional importance for striatal dopamine release in the learning of new motor sequence, its role in encoding elementary aspects of new movement has not yet been investigated. To elucidate this, we investigated changes in striatal dopamine levels during initial skill-training (Day 1) compared with acquired conditions (Day 2) using (11)C-raclopride positron-emission tomography. Ten volunteers learned to perform brisk contractions using their non-dominant left thumbs with the aid of visual feedback. On Day 1, the mean acceleration of each session was improved through repeated training sessions until performance neared asymptotic levels, while improved motor performance was retained from the beginning on Day 2. The (11)C-raclopride binding potential (BP) in the right putamen was reduced during initial skill-training compared with under acquired conditions. Moreover, voxel-wise analysis revealed that (11)C-raclopride BP was particularly reduced in the right antero-dorsal to the lateral part of the putamen. Based on findings from previous fMRI studies that show a gradual shift of activation within the striatum during the initial processing of motor learning, striatal dopamine may play a role in the dynamic cortico-striatal activation during encoding of new motor memory in skill acquisition.
authors.affiliation: Department of Neurology and Neuroscience, Nagoya City University Graduate School of Medical Science, Mizuho-ku, Nagoya, Japan.
authors.forename: Shoji
authors.initials: S
authors.lastname: Kawashima
authors.forename: Yoshino
authors.initials: Y
authors.lastname: Ueki
authors.forename: Takashi
authors.initials: T
authors.lastname: Kato
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Matsukawa
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Mima
authors.forename: Mark
authors.initials: M
authors.lastname: Hallett
authors.forename: Kengo
authors.initials: K
authors.lastname: Ito
authors.forename: Kosei
authors.initials: K
authors.lastname: Ojika
mesh_terms: D000368:Aged; D002250:Carbon Radioisotopes; D003342:Corpus Striatum / Q000000981:diagnostic imaging / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism*; D018492:Dopamine Antagonists / Q000378:metabolism; D005260:Female; D007839:Functional Laterality; D006801:Humans; D007858:Learning / Q000502:physiology*; D008297:Male; D009048:Motor Skills / Q000502:physiology*; D049268:Positron-Emission Tomography; D020891:Raclopride / Q000378:metabolism*
chemical_list: D002250:Carbon Radioisotopes; D018492:Dopamine Antagonists; D020891:Raclopride; D004298:Dopamine