How efficient are central mechanisms for the learning and retention of coincident timing actions? (original) (raw)

We compared the adaptive strategy and retention capacity of a dea}erented subject and control subjects when intercepting\ with a sliding!throw\ an apparent movement coming at various speeds[ Subjects were submitted to _ve practice sessions "29 trials per session# and to a retention test[ The throwing kinematics was analysed\ and spatial and temporal performance errors were measured[ With practice\ the dea}erented subject showed modi_cations in movement initiation strategies and throwing patterns[ With a slow apparent movement\ the dea}erented subject|s initial behavior was characterized by short movement initiation and movement times[ With practice\ she showed an important increase in movement time in session 4\ allowing longer visual control and leading to better temporal and spatial accuracy than that shown in session 0[ In the retention session\ the dea}erented patient showed a late movement initiation strategy\ similar to that of the control subjects[ This increased movement initiation time was accompanied by an improved temporal accuracy compared to the dea}erented subject|s early results[ However\ spatial accuracy improvement was labile and could not be maintained over the retention interval[ At the fast speed\ all temporal components of the response\ namely\ movement initiation time "MIT#\ movement time "MT#\ and disk travel time "DTT#\ were similar for the dea}erented and control subjects[ Overall\ the dea}erented subject reduced her temporal error through practice\ though without attaining the control subjects| accuracy[ However\ with a fast!moving stimulus\ she showed a deteriorated spatial accuracy\ even doubling her spatial errors at retention[ In brief\ the dea}erented subject achieved proper temporal "perceptivo!cognitive# lasting control of her interceptive action\ whereas spatial "sensorimotor# regulation raised mnemonic problems[ Þ 0888 Elsevier Science Ltd[ All rights reserved[