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Consolidation is a time-dependent process that is responsible for the storage of information in long-term memory. As such, it plays a crucial role in motor learning. Prior research suggests that some consolidation processes are triggered only when the learner experiences some success during practice. In the present study, we tested whether consolidation processes depend on the objective performance of the learner or on the learner's subjective evaluation of his or her own performance (i.e., how successful the learner believes he or she is). Four groups of participants performed 2 sessions of a visuomotor adaptation task for which they had to learn a new internal model of limb kinematics; these sessions were either 5 min or 24 hr apart. The task was identical for all participants, but each group was given a difficult or an easy objective that affected the participants' evaluation of their own performance during the initial practice session. All groups adapted their movements similarly to the rotation of the visual feedback during the first session. However, when retested the following day, participants who had a 24-hr rest interval and had initially experienced success performed significantly better than those who did not feel successful or who were given a 5-min rest interval. Our results indicate that a certain level of subjective success must be experienced to trigger certain consolidation processes. (Contains 5 footnotes and 4 figures.)

Consolidation is a time-dependent process responsible for the storage of information in long-term memory. As such, it plays a crucial role in motor learning. In two experiments, we sought to determine whether one's performance influences the outcome of the consolidation process. We used a visuomotor adaptation task in which the cursor moved by the participants was rotated 30[degrees] clockwise. Thus, participants had to learn a new internal model to compensate for the rotation of the visual feedback. The results indicated that when participants showed good adaptation in the first session, consolidation resulted in a persistent after-effect in a no-rotation transfer test; they had difficulty returning to their normal no-rotation internal model. However, when participants showed poor adaptation in the first session, consolidation led to significant off-line learning (between sessions improvement) but labile after-effects. These observations suggest that distinct consolidation outcomes (off-line learning and persistent after-effect) may occur depending on the learner's initial performance. (Contains 1 table and 5 figures.)

ABSTRACT. Research shows that individuals are able to correct for an experimentally-induced and unexpected aiming error (i.e., a cursor jump), even when they do not detect it consciously. Researchers have [...]

ABSTRACT. The authors investigated whether the salience of dynamic visual information in a video-aiming task mediates the specificity of practice. Thirty participants practiced video-aiming movements in a full-vision, a weak-vision, [...]

In the present study we wanted to determine why straight-ahead movements performed along one's midline are directionally more accurate than movements toward eccentric targets. We also wanted to determine whether the processes underlying this difference were the same in young children as in adults. Six-to-seven-year-old children and adults practiced a video-aiming task using different starting base and target combinations without vision of their ongoing movements. The results indicated that adults and children were directionally more accurate and less variable when pointing toward targets located straight ahead of the starting base rather than eccentric or concentric targets. This was true regardless of whether the movement was performed along one's midline or not. These results suggest that angled movements are directionally less accurate than straight-ahead movements because of difficulty in defining the orientation of the appropriate movement vector in the workspace and/or in transforming it into appropriate motor commands. A kinematic analysis revealed large coefficients of direction and of extent variability early after movement initiation. However, these coefficients of variability were largely reduced by the occurrence of peak extent velocity, revealing that noise in initial movement planning was quickly reduced by on-line control processes. Finally, the results indicated largely similar planning and control processes for young children and adults.

ABSTRACT. Mapping of arbitrary color cues onto object properties such as mass can influence the control of fingertip forces. One can view the development of that mapping as a motor [...]

ABSTRACT. Recent results indicate that adults modulate their initial movement impulse toward a stationary visual target by processing visual afferent information. The authors investigated whether the mechanisms responsible for those [...]

The goal of the present study was to determine the relative efficacy of verbal and auditory knowledge of results for promoting learning of a new constrained relative timing pattern. In a series of four experiments we compared the efficiency of verbal knowledge of results to that of auditory knowledge of results. The results of all four experiments revealed that verbal knowledge of result is a very effective source of information to promote learning of a new imposed relative timing pattern. Auditory knowledge of results favoured learning of a new relative timing pattern in a very limited set of circumstances. In the present study, this was only the case when movement velocity remained constant from one segment of the task to the next and if it resulted in an unfamiliar temporal pattern. The results of all four experiments also provided evidence that movement parameterization and relative timing are independent processes that can be developed in parallel.

Cette etude porte sur l'utilisation des signaux visuels de l'environnement stationnaire pour controler un geste d'atteinte d'une cible memorisee. La question est de savoir si des indices de l'environnement sont utilises pour indiquer rapidement avec l'index la position de la cible codee en memoire. La cible a pointer etait presentee sur un fond uniforme noir ou un fond fait de bandes verticales noires et blanches. Ce dernier pouvait etre stationnaire ou decale instantanement vers la droite ou vers la gauche au moment de l'extinction de la cible ou au depart du mouvement de la main. Les resultats montrent trois effets principaux: 1) la vision de la main pendant le geste ameliore la precision finale, 2) le fond visuel decale degrade la performance de pointage des participants uniquement lorsque la main n'est pas visible pendant le geste et toujours de la meme facon quelle que soit la direction du decalage, et 3) les effets de l'absence de vision de la main et du fond structure sur la precision du pointage dependent de la distance separant la cible de la main. L'effet systematique du fond decale sur la localisation manuelle suggere un role de l'environnement meconnu dans la retention de la cible. Les resultats suggerent en outre qu'un fond structure stationnaire est utilise pour soutenir la memoire de la position de la cible. L'utilisation du fond structure est plus prononcee lorsque la cible apparait en vision pripherique plutot qu'en vision centrale ce qui suggere une localisation a partir d'une memoire relative de la position peripherique de la cible.

ABSTRACT. The authors investigated (a) whether the specificity of practice hypothesis is mediated by the importance of visual afferent information for the control of manual aiming movements and (b) how [...]

ABSTRACT. The issues addressed in 2 experiments in which 10 younger and 10 older adults participated were (a) whether the retention of a target location in memory for motor control [...]

Observation directly contributes to the acquisition and refinement of motor skills. This study indicates that observing a model performing a motor task aids the observer in developing mechanisms for error detection and correction that are similar to those gained through physical practice.

A combination of observation and physical practice have shown to be significantly more effective in the learning of a new motor skill than practice alone. The results of the study suggest a similarity between the cognitive processes involved in observational and motor learning.

It has been proposed that motor learning is specific to the sources of afferent information available during practice (Proteau, 1992). That hypothesis has obtained support from studies of aiming but not from studies of gross motor skills. The many procedural differences between the two sets of studies might have caused the conflicting results. In the present investigation of a precision walking task, the validity of the specificity of practice hypothesis was tested. Thirty-two participants were asked to walk for 20 m on a 2.5-cm-wide line. Subjects practiced the task for either 20 or 100 trials under normal visual conditions or while blindfolded. Following acquisition, all subjects performed the task for 20 additional trials while blindfolded and without knowledge of results. Practice improved the performance of blindfolded participants. Withdrawing vision in transfer resulted in a large and significant increase in error, however, a finding that supports the specificity of practice hypothesis., Participants in a motor control vision experiment practiced walking, first using their vision and later blindfolded, in order for researcher to discover how they obtained support for motor skills. In another experiment participants were given knowledge of their results and after an extended period of time the participants that received kinesthetic feedback outperformed those who practiced with visual afferent information., Key words: motor control, motor learning, vision The general consensus concerning how a skilled movement can be produced suggests that performing a motor skill involves cooperation between central planning and [...]

The goal of the two experiments of the present study was to determine whether in an aiming task performed within a relatively long movement time (MT) bandwidth, older adults make similar use of visual information for motor control as younger adults. Older and younger subjects practiced a manual aiming task toward one (Experiment 1), or one of many (Experiment 2) small target(s) while only the target to be reached was visible (proprioception only: P) or under normal lighting condition (proprioception + vision: PV). Following practice, all subjects were transferred to the P conditions. The results of both experiments indicate that the older subjects were, during practice, as accurate as the younger ones in the PV condition. Moreover, both groups suffered a large and similar increase in aiming error in the transfer condition. This underlines that a useful source of sensory information, namely vision, has been withdrawn in transfer. This result is different from those of earlier studies in which a shorter target MT had been used (Chaput & Proteau, 1996; Proteau, Charest, & Chaput, 1994). This suggests that older adults process the sensory information available in that type of task similarly to younger subjects but at a lower speed. However, when the temporal constraints of the task are stringent, older adults might rely more on modes of control in which sensory information plays a minimal role when compared to younger subjects. Finally, the results of the second experiment suggest that, when multiple targets are used, older adults appear to program a response which is optimally suited for a 'central' target.

Results of recent research on motor control indicate that in an aiming task, visual information remains of primary importance for optimal accuracy even after extended practice. One of the points that is yet unclear is whether it is solely the dynamic visual information about the moving limb that is important for movement control. To shed some light on this issue, subjects practiced an oscilloscope aiming task. In a transfer test, the dynamic information regarding the displacement of the to-be-moved object could be withdrawn without altering the static visual information that had been available during the learning of the task. The results indicated that, after 200 trials of practice, withdrawing dynamic visual information regarding the displacement of the to-be-moved object produced a deterioration in the accuracy of the subjects' responses. This indicates that the role played by the dynamic visual information for aiming control does not diminish with practice. Moreover, although visual cues available before or after movement execution have been shown to help better plan an upcoming movement, the static cues available during movement execution do not appear to play an important role in the movement representation thought to develop through practice.

An analysis of the response flexibility of children between six and 10 years of age through a training program involving perceptual, motor and perceptive-motor components reveals a flexibility in the interceptive behavior of the older children while performing complex tasks. Environment-based alterations in the motor responses of children indicate the importance of incorporation of the motor component during practice.

Changes in the part played by various sources of afferent information for movement regulation brought about by aging were examined. Aging effected a change in the manner of processing different information on movement control.

Miller (1982) found faster reaction times when the responses cued before stimulus presentation were from the same hand as opposed to different hands. Miller assumed that the locus of this same-hand advantage effect was in the process of motor responses preparation. In contrast, Reeve and Proctor (1984) argued that the locus of this effect was in the nonmotoric process. Two experiments were conducted to determine which of these two interpretations ought to be retained. In the first experiment, a four-choice reaction task was used. When the two cues were presented on the same side and specified two responses of the same hand, the same-hand advantage was evident if the delay between the responses cues and the reaction stimulus was short (750 ms), whereas it was eliminated when the time delay was lengthened. However, when the same cues designated two responses from different hands, the same-hand advantage was not detected, irrespective of the time delay. In the second experiment, a much greater number of trials was used and the responses to prepare were indicated to the subject either visually or by vibration of the appropriate response keys. In the former case, the same-hand advantage obtained for the first series of trials was eliminated as a function of accrued practice. In the latter case, the same-hand advantage was not detected, irrespective of the time delay and the number of trials. The results of the two experiments were interpreted as supportive of the hypothesis that the locus of the same-hand advantage effect was the nonmotoric process alluded to by Reeve and Proctor (1984).

Movement specific correction mechanisms are thought to develop when learning a motor task (cf. Abbs, Gracco, & Cole, 1984). Our goal was to assess the efficiency of the correction mechanisms involved in amending a mechanically perturbed aiming movement performed while different afferent sources are available. Subjects performed a multi-degrees of freedom manual aiming movement, which could be unexpectedly perturbed. Subjects performed the task in either a full vision (FV) situation or while only the target to be reached was visible (TO). Neither the absolute constant error (/CE/) nor the variable error (VE) of aiming could differentiate the perturbed and unperturbed trials for the subjects submitted to the FV condition. However, significantly larger /CE/ and VE were observed for the perturbed trials in the TO condition. This is taken to indicate that the sensorimotor representation of the movement developed through learning is more precise when learning occurs in the presence of more afferent sources. Further, the larger spatial error found in the TO condition for the perturbed trials suggests that when a learned movement is forced out of its usual trajectory, the kinesthetic feedback available, and/or the corrective motor commands, are less accurate than those available when the movement follows its usual trajectory.

Au cours des dernieres annees il a ete demontre que la connaissance prealable de la localisation spatiale de la cible a atteindre dans un contexte d'incertitude evenementielle permettait de reduire les temps de programmation et d'execution d'un geste d'atteinte manuelle, et ce, meme si la trajectoire a emprunter n'etait pas connue a l'avance. L'objectif majeur de la presente etude etait de determiner si l'augmentation du temps d'execution trouvee en fonction de l'incertitude de l'evenement semble etre le produit d'une occurrence plus frequente d'ajustements mineurs requis par le mouvement amorce. Ils apparait que ces adjustements ne necessiteraient que de tres courts delais pour prendre place, possiblement parce que la tres grande variabilite du produit de la programmation centrale qui prend place avant l'amorce d'un geste d'atteinte manuelle les rendrait essentiels, donc previsibles. It was recently shown that in a multiple choice aiming task the knowledge of the target location prior to stimulus introduction, even though the trajectory to follow was still uncertain, reduced the time needed to initiate and execute the required response. The aim of the present study was to determine whether the increase in movement time observed as a function of event uncertainty (Girouard, Proteau, Laurencelle, & Black, 1987; Proteau, Girouard, & Black, 1987) reflects the need for more corrections as the movement unfolds or the need to check if the initiated response is the right one. The results of the present study indicate that the reported increase in movement time as a function of event uncertainty reflects the need for more frequent minor adjustments to the ongoing movement. It was also shown that the output of the central planning process thought to take place during the reaction time period is highly variable. This high variability makes the need for adjustments to the ongoing movement very predictable and thus may explain why they did not require much processing time.