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The present study examined interactions of speech production and finger-tapping movement, using a syncopated motor task with two movements in 10 male right-handed undergraduate students (M age=21.0 yr.; SD = 1.4). On the syncopated task, participants were required to produce one movement exactly midway between two other movements (target interresponse interval: 250 msec.). They were divided into two groups, the tap-preceding group and speech-preceding group. The author observed that the right hand showed a more variable peak force and intertap interval than the left hand in the speech-preceding group, indicating an asymmetrical interference of two movements. On the other hand, the mean differences between onsets of speech and tapping movement were shorter than 250 msec. over all conditions (the shortest mean difference was 50 msec.), suggesting a mutual entrainment of two movements. An asymmetry of entrainment was observed in the speech-preceding group, in which speech production was more strongly entrained with movements of the right hand than with those of the left hand.

ABSTRACT. The author examined the lateralization of transfer of visuomotor information between the right and left hands during unimanual finger-tapping sequences with visual feedback. The finger-tapping task consisted of a [...]

The present study was designed to examine the retention of relative force in the scaling of a serial force pattern in finger-tapping sequences. On practice trials, 11 male college students tapped a force plate connected to strain gauges which provided feedback. On test trials, subjects recalled both the force pattern (100 g-100 g-100 g-300 g) and intertap interval (400 msec.) acquired during practice without feedback (recalled task) and then produced a halved (halved task) or doubled-force (doubled task) at the fixed intertap interval. Analysis showed that, although there was no difference for absolute forces between the recalled task and the halved task, the forces at the doubled task were three times as great as those at the recalled task. For relative forces, on the other hand, although there was no difference among the three tasks, the force ratios were closer to 1:1:1:2 than 1:1:1:3. This indicated that the scaling of force pattern was a more difficult adaptive task than that of the intertap interval in the previous study (Inui, Ishida, & Yamanishi. 1999).

This study examined effects of practice on timing of serial reactions by 7 adolescents diagnosed with autism by using a task requiring they track a series of timed lights. The adolescents showed significantly slower and more variable mean simple reaction time than 10 normal control subjects of the same age. On a task of tracking a serial light stimulation for 4 days, on the other hand, significant effects of practice on timing of serial reactions were observed for mean serial reaction times of them. In addition, from individual variations in reaction times and anticipatory reaction times, four of seven subjects with autism showed significant effects of practice. Analysis suggested that these autistic adolescents may be chunking together the whole series of responses and are unable to coordinate the timing of individual responses with individual stimuli. Our data indicate that at least some adolescents with autism are able to form and utilise a motor program with practice.

The timing control of serial reactions in 20 middle-aged (38-43 years) and 20 older men (57-63 years) was examined by using a task of tracking serial-light stimuli with and without the previous learning (Exps. III and II, respectively). In Exp. I, a control group of 20 college students (19-22 years) had significantly faster and less variable mean simple reaction times than the two other groups. For the serial reaction times (Exps. II and III), the control group had significantly faster mean reaction times than the other groups who did not differ. In Exp. III, there was no difference between the serial reaction times and the simple reaction times in the contrasting groups. In Exp. II, however, although the serial reaction times were significantly slower than the simple reaction times in the older group, the serial reaction times did not differ from the simple reaction times in the middle-aged group. The difference between these groups appeared to be due to the task in Exp. II being more difficult than that in Exp. III, suggesting the more complex the movement to be made, the slower the responses of older people. Advancing age seems to have a greater effect on central processing components than on the perceptual and motor output components of serial reactions.

This study examined transfer when different serial positions are changed in a task of tracking a sequence of light stimuli. Thirty subjects were divided into three groups, and all tracked a serial pattern of six movements for 20 acquisition trials. Then, on 20 more transfer trials, the last two movements were reversed for Group I, the second two movements reversed for Group II, and the first two movements reversed for the Group III. Performance during the transfer trials improved over performance during the acquisition trials for Groups I and II but not Group III. Thus, there appeared to be positive transfer when the last and middle parts of the serial pattern were changed. However, there was no positive transfer when the first part of the serial pattern was changed. This indicated a contextual interference effect dependent upon serial position in the performance of a serial tracking task.

The purpose of this study was to examine the serial information processing in adolescents with mental retardation, autism, and Down syndrome by using a serially patterned tracking task. Analyses indicated that 7 adolescents with mental retardation, 8 with autism, and 3 with Down syndrome had significantly slower and more variable simple reaction times than did 10 college students. Also, the autistic adolescents had significantly faster mean simple reaction time than those with Down syndrome. On a task of tracking serial light stimulation, mentally retarded adolescents had significantly faster reaction time than college students. The autistic subjects excessively had faster anticipatory reaction times than did the subjects in the other three groups. On the other hand, adolescents with Down syndrome had markedly slower and more variable reaction times than did adolescents with non-Down-syndrome mental retardation. As for motor organization of keystrokes on the tracking task, mentally retarded adolescents responded with six movements, in which these individuals pressed a series of keys 1, 2, 3, 4, 5, and 6, as a chunk, as exhibited by college students. Adolescents with autism and Down syndrome, however, did not produce this movement-output chunking.

We examined differences between the synchronization and self-pacing tasks using repetitive tapping with alternate hands. 9 adolescents with mental retardation made faster and more variable movements on the self-pacing task than on the synchronization task at target intervals of 400 and 800 msec. This suggests that they were able to coordinate the timing of individual responses with individual stimuli on the synchronization task but on the self-pacing task they controlled the timing by memory or generation or setting of an incorrect timer rate.

To examine the relation between timing and force control during finger-tapping sequences by both the 10 pianists and the 13 nonpianists, participants tapped a force plate connected to strain gauges. A series of finger-tapping tasks consisted of 16 combinations of pace and peak force. Analysis showed that pianists had smaller correlation between intertap interval and peak force than nonpianists. Thus, force control was more independent of timing for pianists than for nonpianists.

The present study examined whether the elderly produced a hastened or delayed tap with a negative or positive constant intertap interval error more frequently in self-paced tapping than in the stimulus-synchronized tapping for the 2 N target force at 2 or 4 Hz frequency. The analysis showed that, at both frequencies, the percentage of the delayed tap was larger in the self-paced tapping than in the stimulus-synchronized tapping, whereas the hastened tap showed the opposite result. At the 4 Hz frequency, all age groups had more variable intertap intervals during the self-paced tapping than during the stimulus-synchronized tapping, and the variability of the intertap intervals increased with age. Thus, although the increase in the frequency of delayed taps and variable intertap intervals in the self-paced tapping perhaps resulted from a dysfunction of movement timing in the basal ganglia with age, the decline in timing accuracy was somewhat improved by an auditory cue. The force variability of tapping at 4 Hz further increased with age, indicating an effect of aging on the control of force. [ABSTRACT FROM AUTHOR]

An experiment was conducted to examine the coupling of force variability in bimanual finger tapping sequences with asymmetrical forces. Right-handed participants were trained to produce bimanual finger tapping sequences consisted of an intertap interval of 500 ms and eight force conditions: two alternating force left high, two alternating force right high, two simultane-ous force left high, and two simultaneous force right high conditions. During practice, visual force feedback was provided for both hands performing the bimanual tapping sequences. After practice, the participants produced the learned tapping sequences in the absence of feedback. Most importantly, whereas the peak force variability of the nondominant left hand was larger than that of the dominant right hand under the right high conditions, there was no leftÐright difference under the simultaneous left high conditions. This suggests that under the simultaneous left high conditions, both hemispheres were activated, resulting in overflow in the right hand, and bringing the two force variabilities closer together. [ABSTRACT FROM AUTHOR]

An experiment was conducted to examine contextual effects of the magnitude of changes in force on force control in a finger-tapping sequence with an accentuated- (accentuated-force condition) or attenuated-force tap (attenuated- force condition). Participants were trained to produce a finger-tapping sequence with an intertap interval of 500 ms and four force patterns. During practice, visual force feedback pertaining to the two target forces in the tapping sequences was provided. After practice, the participants reproduced the learned tapping sequences in the absence of feedback. A main result was that the last accentuated-force tap affected the first three taps of the tapping sequence. For the accentuated-force conditions, the larger the difference between the first three target forces and the last target force, the larger the first three forces. This indicates the contextual effect of serial position for force control. This effect was not observed, however, under the attenuated-force conditions. An experiment was conducted to examine contextual effects of the magnitude of changes in force on force control in a finger-tapping sequence with an accentuated- (accentuated-force condition) or attenuated-force tap (attenuated- force condition). Participants were trained to produce a finger-tapping sequence with an intertap interval of 500 ms and four force patterns. During practice, visual force feedback pertaining to the two target forces in the tapping sequences was provided. After practice, the participants reproduced the learned tapping sequences in the absence of feedback. A main result was that the last accentuated-force tap affected the first three taps of the tapping sequence. For the accentuated-force conditions, the larger the difference between the first three target forces and the last target force, the larger the first three forces. This indicates the contextual effect of serial position for force control. This effect was not observed, however, under the attenuated-force conditions. [ABSTRACT FROM AUTHOR]

Examines age-related differences in the control of force and timing in a finger-tapping sequence with an attenuated-force tap among children and adolescents. Relations between peak force and parameters in force production; Possible mechanisms for control of attentuated-force tapping; Output chunking as a developmental milestone in serial reactions.

Compares the relation between timing and force control during finger tapping sequences by both the pianists and non-pianists. Intervals on the mechanical aspects of the muscle; Analysis on the timing of movement and force control; Variation in interlap interval of force production.

This study was designed to examine effects of somatosensory feedback on variations of intertap interval and muscle force in finger-tapping sequences over 10 minutes. Although intertap intervals were decreased on the massed task as the time passed, the intervals were constant in the distributed task. In finger-tapping for a long time, impulses perhaps circulate within the loop circuits between the cerebral motor cortex and the peripheral nerve and subsequently increase further the excitability of the circuits. This increase in the excitability within the circuits may shorten the interval and increase variation of the interval. On the other hand, although peak force increased up to the 5-min. mark on the massed task, the force decreased after the 6-min. mark. This increase of force also may be produced by increasing activation of the corticoperipheral loop circuits. Although the decrease of force was perhaps produced by the fatigue of finger muscles for tapping during a few minutes, fatigue appeared more clearly in muscle force than in timing control. However, the force and the variation were constant in the distributed task.

The present study was designed to examine the retention of relative force in the scaling of a serial force pattern in a finger-tapping sequence using an attenuated tap. On practice trials, i2 undergraduate students tapped a force plate connected to strain gauges that gave them feedback about the force. On test trials, participants recalled the force pattern (200 gm--200 gm-200 gm-100 gm) and the intertap interval (400 msec.) practiced during the practice period without the feedback (recalled task). Then, they adaptively produced a halved (halved task) or doubled force profile (doubled task) at the fixed intertap interval. Analyses showed that mean peak forces at the first three tap positions of the tapping sequence undershot the expected forces across all tasks. Hence, the ratios of the forces in Serial Positions 1:4, 2:4, and 3:4 were considerably lower than 2.0. This is a contextual effect suggesting that the last attenuated tap affected the first three taps of the tapping sequence. Thus, because the relative force of movements appears to be a weaker invariant feature than sequencing and relative timing for generalized motor program theory of Schmidt and Lee, this finding does not support the relative force for a generalized motor program.

The present study was designed to examine the retention and adaptive control of a force pattern in the scaling of speed profiles in a finger-tapping sequence with an attenuated tap. On practice trials, 11 college students tapped on a force plate connected to strain gauges with feedback. On test trials, participants recalled the force pattern (200 gm-200 gm-200 gm-100 gm) and the intertap interval (400 msec.) acquired during practice without feedback (recalled task). Then, participants adaptively tapped the acquired force pattern at the half (speeded task) and double (slowed task) the intertap interval acquired during the practice. Analyses showed that mean peak forces increased across tasks as the tapping speed was slowed down. Mean peak forces at the first three tap positions in sequence were smaller than the required forces in both the recall and speeded tasks. So, although the slowed task had the lowest ratio of forces in serial positions 1:4, 2:4, and 3:4, the ratios were less than 2 across tasks. These indicated that changing to a slow pace creates a more difficult adaptive task than changing to a fast pace, and further that a serial force pattern with an attenuated force creates a more difficult motor task for fine control than that with an accentuated-force.

The authors examined the force-sharing patterns in a joint action performed by a group of two, three, or four people compared with a solo action. In the joint actions, 28 participants produced periodic isometric forces such that the sum of forces they produced cycled between 5% and 10% maximum voluntary contraction with the right hand at 1 Hz. In both the three- and four-person tasks, the correlation between forces produced by two of the three or four participants was negative, and the remaining one or two participants produced intermediate forces. The errors of force and interval and force variabilities were smaller in four- and three-people groups than individuals. Four- and three-people groups thus performed better than individuals. [ABSTRACT FROM AUTHOR]

The present study tested the hypothesis that a load perturbation facilitates interpersonal compensation for force error. Ten groups performed both control and perturbation conditions. In the control condition, a target discrete peak force was the sum of 10% of the maximum voluntary contraction produced by two participants. In the perturbation condition, two cooperative participants a and b produced the same target force as the control condition, and the force produced by a non-cooperative participant c increased or decreased the total forces produced by participants a and b. The load perturbation facilitated interpersonal compensation for force error but negatively affected performance during joint action. The participants further learned to improve the error compensation over experimental blocks in the perturbation condition. [ABSTRACT FROM AUTHOR]