Different mechanisms contributing to savings and anterograde interference are impaired in Parkinson’s disease
Front. Hum. Neurosci.. 2013-01-01; 7:
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1. Front Hum Neurosci. 2013 Feb 27;7:55. doi: 10.3389/fnhum.2013.00055. eCollection
Different mechanisms contributing to savings and anterograde interference are
impaired in Parkinson’s disease.
Leow LA(1), de Rugy A, Loftus AM, Hammond G.
(1)School of Psychology, University of Western Australia Crawley, WA, Australia.
Reinforcement and use-dependent plasticity mechanisms have been proposed to be
involved in both savings and anterograde interference in adaptation to a
visuomotor rotation (cf. Huang et al., 2011). In Parkinson’s disease (PD),
dopamine dysfunction is known to impair reinforcement mechanisms, and could also
affect use-dependent plasticity. Here, we assessed savings and anterograde
interference in PD with an A1-B-A2 paradigm in which movement repetition was (1)
favored by the use of a single-target, and (2) manipulated through the amount of
initial training. PD patients and controls completed either limited or extended
training in A1 where they adapted movement to a 30° counter-clockwise rotation of
visual feedback of the movement trajectory, and then adapted to a 30° clockwise
rotation in B. After subsequent washout, participants readapted to the first 30°
counter-clockwise rotation in A2. Controls showed significant anterograde
interference from A1 to B only after extended training, and significant A1-B-A2
savings after both limited and extended training. However, despite similar A1
adaptation to controls, PD patients showed neither anterograde interference nor
savings. That extended training was necessary in controls to elicit anterograde
interference but not savings suggests that savings and anterograde interference
do not result from equal contributions of the same underlying mechanism(s). It is
suggested that use-dependent plasticity mechanisms contributes to anterograde
interference but not to savings, while reinforcement mechanisms contribute to
both. As both savings and anterograde interference were impaired in PD, dopamine
dysfunction in PD might impair both reinforcement and use-dependent plasticity
mechanisms during adaptation to a visuomotor rotation.