Distinct ways of timing movements in bimanual coordination tasks: contribution of serial correlation analysis and implications for modeling

Bimanual coordination dynamics have been conceived as the outcome of a global coordinative system, and coordination stability properties and theories of underlying processes have often been generalized over various bimanual tasks. In unimanual timing tasks it has been shown that different timing processes are involved according to tasks, yielding distinctive correlation properties in the within-hand temporal patterns. In this study we compare unimanual with bimanual, tapping with oscillation, and self-paced with externally paced tasks, and we analyze the correlation properties of temporal patterns at both the component level and the coordinative level. Results show that the distinctive signatures of event-based versus emergent, and self-paced versus synchronization timing control known from unimanual tasks persist in the corresponding bimanual coordination tasks. Accordingly, we argue that these different timing processes, and related temporal patterns at the component level, constitute a task-dependent background on which coordination builds. One direct implication of these results is that the bimanual coordination paradigm should be considered multifaceted and not governed by some unitary generic principle. We discuss the need to assess the relationship between temporal patterns at the component level and the collective level, and to integrate serial (long-range) correlation properties into bimanual coordination models. Finally, we test whether the architectures of current bimanual coordination models can account for the experimentally observed serial correlations.     

Multiphasic neuronal transfer functions for representing temporal structure

Neural network models of timing have struggled to account for animal timing capabilities using the accepted connectionist assumptions, in most cases without postulating the existence of explicit neuronal time-keeping mechanisms. Current ethological and physiological data, however, suggest that cellular oscillators form the foundation for animals’ temporal capacities. We propose that these oscillators could be used as temporal filters that capture the temporal structure of the animal’s experience. A model is presented that accounts for a number of the salient features of the feeding anticipatory response with only a single circadian filter. This model goes beyond current entrainment models in that it correctly predicts the relationship between the feeding period and the anticipatory interval. An alternative approach using multiple filters is examined that can account for animals’ ability to correctly anticipate two daily feeding times.     

Temporal processing dysfunction in schizophrenia

Schizophrenia may be associated with a fundamental disturbance in the temporal coordination of information processing in the brain, leading to classic symptoms of schizophrenia such as thought disorder and disorganized and contextually inappropriate behavior. Despite the growing interest and centrality of time-dependent conceptualizations of the pathophysiology of schizophrenia, there remains a paucity of research directly examining overt timing performance in the disorder. Accordingly, the present study investigated timing in schizophrenia using a well-established task of time perception. Twenty-three individuals with schizophrenia and 22 non-psychiatric control participants completed a temporal bisection task, which required participants to make temporal judgments about auditory and visually presented durations ranging from 300 to 600 ms. Both schizophrenia and control groups displayed greater visual compared to auditory timing variability, with no difference between groups in the visual modality. However, individuals with schizophrenia exhibited less temporal precision than controls in the perception of auditory durations. These findings correlated with parameter estimates obtained from a quantitative model of time estimation, and provide evidence of a fundamental deficit in temporal auditory precision in schizophrenia.     

Temporal coordination between performing musicians

Many common behaviours require people to coordinate the timing of their actions with the timing of others' actions. We examined whether representations of musicians' actions are activated in coperformers with whom they must coordinate their actions in time and whether coperformers simulate each other's actions using their own motor systems during temporal coordination. Pianists performed right-hand melodies along with simple or complex left-hand accompaniments produced by themselves or by another pianist. Individual performers' preferred performance rates were measured in solo performance of the right-hand melody. The complexity of the left-hand accompaniment influenced the temporal grouping structure of the right-hand melody in the same way when it was performed by the self or by the duet partner, providing some support for the action corepresentation hypothesis. In contrast, accompaniment complexity had little influence on temporal coordination measures (asynchronies and cross-correlations between parts). Temporal coordination measures were influenced by a priori similarities between partners' preferred rates; partners who had similar preferred rates in solo performance were better synchronized and showed mutual adaptation to each other's timing during duet performances. These findings extend previous findings of action corepresentation and action simulation to a task that requires precise temporal coordination of independent yet simultaneous actions.     

标量计时模型的影响因素及发展

标量计时模型为人类时间知觉的研究提供了理论框架和研究范式, 它采用信息加工的观点, 包含时钟、记忆和决策三个阶段。时间二分任务是在标量计时模型的框架下研究时间知觉和加工的理想范式。它要求被试对时距进行与标量计时模型相对应的多阶段操作, 包含了时间知觉所涉及的各个过程, 能有效测量主观时距和时间敏感性的变化。通过这个范式, 研究者发现, 除了任务参数, 年龄和疾病都会影响人的主观时距和/或时间敏感性。这些时间二分任务的实验结果促进了标量计时模型的发展, 最近提出的两阶段决策模型和差别模型分别以不同的方式对标量计时模型进行了修正, 并解释了参数设置的影响和计时的个体差异。     

Temporal inhibition in character identification

Models of information processing tasks such as character identification often do not consider the nature of the initial sensory representation from which task-relevant information is extracted. An important component of this representation is temporal inhibition, in which the response to a stimulus may inhibit, or in some cases facilitate, processing of subsequent stimuli. Three experiments demonstrate the existence of temporal inhibitory processes in information processing tasks such as character identification and digit recall. An existing information processing model is extended to account for these effects, based in part on models from the detection literature. These experiments also discriminate between candidate neural mechanisms of the temporal inhibition. Implications for the transient deficit theory of dyslexia are discussed.     

A tuned-trace theory of interval-timing dynamics

Animals on interval schedules of reinforcement can rapidly adjust a temporal dependent variable, such as wait time, to changes in the prevailing interreinforcement interval. We describe data on the effects of impulse, step, sine-cyclic, and variable-interval schedules and show that they can be explained by a tuned-trace timing model with a one-back threshold-setting rule. The model can also explain steady-state timing properties such as proportional and Weber law timing and the effects of reinforcement magnitude. The model assumes that food reinforcers and other time markers have a decaying effect (trace) with properties that can be derived from the rate-sensitive property of habituation (the multiple-time-scale model). In timing experiments, response threshold is determined by the trace value at the time of the most recent reinforcement. The model provides a partial account for the learning of multiple intervals, but does not account for scalloping and other postpause features of responding on interval schedules and has some problems with square-wave schedules.     

Short-term recognition memory for serial order and timing

Recent evidence suggests that a common temporal representation underlies memory for serial order of items in a sequence, and the timing of items in a sequence. This stands in contrast to other data suggesting a reliance on only ordinal information in short-term memory tasks. An experiment is reported here in which participants were post cued to perform a comparison between a probe and study list of items irregularly spaced in time, on the basis of order or temporal information.Participants' performance on theserial recognition task was notaffected by the temporal proximity of items, although participants were able to use temporal information to perform a temporal recognition task. Application of a temporal matching model of serial and temporal recognition suggests that although participants were able to remember the timing of items, this memory for timing was unlikely to determine serial recognition performance. The results suggest a dissociation between ordinal and temporal information in short-term memory.     

Some Constraints for Models of Timing: A Temporal Coding Hypothesis Perspective

Most contemporary models of timing in animals were developed to account for the measurement of temporal intervals as they increase. Here we review growing evidence of timing in backward conditioning, which suggests that subjects exposed to Stimulus S1 followed by Stimulus S2 store information allowing the representation of S2 to retrieve both the occurrence and specific temporal location of S1. Such phenomena provide new and challenging constraints for models of timing.     

Temporal coordination between performing musicians

Many common behaviours require people to coordinate the timing of their actions with the timing of others' actions. We examined whether representations of musicians' actions are activated in coperformers with whom they must coordinate their actions in time and whether coperformers simulate each other's actions using their own motor systems during temporal coordination. Pianists performed right-hand melodies along with simple or complex left-hand accompaniments produced by themselves or by another pianist. Individual performers' preferred performance rates were measured in solo performance of the right-hand melody. The complexity of the left-hand accompaniment influenced the temporal grouping structure of the right-hand melody in the same way when it was performed by the self or by the duet partner, providing some support for the action corepresentation hypothesis. In contrast, accompaniment complexity had little influence on temporal coordination measures (asynchronies and cross-correlations between parts). Temporal coordination measures were influenced by a priori similarities between partners' preferred rates; partners who had similar preferred rates in solo performance were better synchronized and showed mutual adaptation to each other's timing during duet performances. These findings extend previous findings of action corepresentation and action simulation to a task that requires precise temporal coordination of independent yet simultaneous actions.     

Timing dysfunctions in schizophrenia as measured by a repetitive finger tapping task

Schizophrenia may be associated with a fundamental disturbance in the temporal coordination of information processing in the brain, leading to classic symptoms of schizophrenia such as thought disorder and disorganized and contextually inappropriate behavior. Although a variety of behavioral studies have provided strong evidence for perceptual timing deficits in schizophrenia, no study to date has directly examined overt temporal performance in schizophrenia using a task that differentially engages perceptual and motor-based timing processes. The present study aimed to isolate perceptual and motor-based temporal performance in individuals diagnosed with schizophrenia using a repetitive finger-tapping task that has previously been shown to differentially engage brain regions associated with perceptual and motor-related timing behavior. Thirty-two individuals with schizophrenia and 31 non-psychiatric control participants completed the repetitive finger-tapping task, which required participants to first tap in time with computer-generated tones separated by a fixed intertone interval (tone-paced tapping), after which the tones were discontinued and participants were required to continue tapping at the established pace (self-paced tapping). Participants with schizophrenia displayed significantly faster tapping rates for both tone- and self-paced portions of the task compared to the non-psychiatric group. Individuals diagnosed with schizophrenia also displayed greater tapping variability during both tone- and self-paced portions of the task. The application of a mathematical timing model further indicated that group differences were primarily attributable to increased timing – as opposed to task implementation – difficulties in the schizophrenia group, which is noteworthy given the broad range of impairments typically associated with the disorder. These findings support the contention that schizophrenia is associated with a broad range of timing difficulties, including those associated with time perception as well as time production.     

时间认知神经科学研究进展

当前对时间认知的脑机制探讨有三个模型：特异化计时模型、分布网络模型和定域计时模型。在这些模型的框架下,时间认知的神经心理学研究集中探讨了小脑、基底神经节、前额叶在时间信息加工中的作用和大脑两半球在时间认知中的不对称性。小脑作为内部计时系统对时间控制具有重要作用,在周期性动作任务中,小脑对不连续动作计时具有特异性。基底神经节在时间加工任务中与小脑存在明显的作用分离,其具体机制还有待深入研究。前额叶的计时功能可能与注意和工作记忆对时间信息的获得、维持和组织有关。此外,还发现大脑右半球与时问信息的加工关系密切。     

Timing dysfunctions in schizophrenia as measured by a repetitive finger tapping task

Schizophrenia may be associated with a fundamental disturbance in the temporal coordination of information processing in the brain, leading to classic symptoms of schizophrenia such as thought disorder and disorganized and contextually inappropriate behavior. Although a variety of behavioral studies have provided strong evidence for perceptual timing deficits in schizophrenia, no study to date has directly examined overt temporal performance in schizophrenia using a task that differentially engages perceptual and motor-based timing processes. The present study aimed to isolate perceptual and motor-based temporal performance in individuals diagnosed with schizophrenia using a repetitive finger-tapping task that has previously been shown to differentially engage brain regions associated with perceptual and motor-related timing behavior. Thirty-two individuals with schizophrenia and 31 non-psychiatric control participants completed the repetitive finger-tapping task, which required participants to first tap in time with computer-generated tones separated by a fixed intertone interval (tone-paced tapping), after which the tones were discontinued and participants were required to continue tapping at the established pace (self-paced tapping). Participants with schizophrenia displayed significantly faster tapping rates for both tone- and self-paced portions of the task compared to the non-psychiatric group. Individuals diagnosed with schizophrenia also displayed greater tapping variability during both tone- and self-paced portions of the task. The application of a mathematical timing model further indicated that group differences were primarily attributable to increased timing – as opposed to task implementation – difficulties in the schizophrenia group, which is noteworthy given the broad range of impairments typically associated with the disorder. These findings support the contention that schizophrenia is associated with a broad range of timing difficulties, including those associated with time perception as well as time production.     

传递性关系推理的简约模型——诠释传递性关系推理的新理论

Wynne的简约模型是基于动物的传递性关系推理研究所提出的理论模型。该模型假设：个体的传递性关系推理是通过运用刺激的强化值来表征顺序信息,并比较所呈现刺激之间强化值的差异来实现的。研究文献证实简约模型能够说明在人类和其它动物的传递性关系推理研究中所发现的大多数标准化效应,因此其被视为迄今解释传递性关系推理问题最经济的模型。但该模型将人类高级认知活动采用动物的机械学习方式来解释的还原论倾向是值得商榷的,它所探讨的传递性行为是否是“真传递性关系推理”也有待进一步验证。     

Timing in Eyeblink Classical Conditioning and Timed-Interval Tapping

Abstract—The cerebellum is implicated in interval timing for diverse tasks including eyeblink classical conditioning (EBCC) and repetitive tapping. We examined performance on both tasks across identical intervals ranging from 325 to 550 ms. In five weekly sessions, 23 participants used a different interval each week, both as the target for tapping and as the delay interval in EBCC. Changes in variability as a function of the tapping or delay interval were assessed using regression analyses. The slope for repetitive tapping was comparable to two measures of temporal acuity in EBCC, onset and peak latency of the conditioned response. Each of 80 additional participants was assessed in one session at one of four tapping and delay intervals. Results were similar to those observed in the repeated measures group. These findings provide further evidence that EBCC and repetitive tapping utilize common mechanisms for representing temporal information.     

Decision processes in temporal discrimination

The processing dynamics underlying temporal decisions and the response times they generate have received little attention in the study of interval timing. In contrast, models of other simple forms of decision making have been extensively investigated using response times, leading to a substantial disconnect between temporal and non-temporal decision theories. An overarching decision-theoretic framework that encompasses existing, non-temporal decision models may, however, account both for interval timing itself and for time-based decision-making. We sought evidence for this framework in the temporal discrimination performance of humans tested on the temporal bisection task. In this task, participants retrospectively categorized experienced stimulus durations as short or long based on their perceived similarity to two, remembered reference durations and were rewarded only for correct categorization of these references. Our analysis of choice proportions and response times suggests that a two-stage, sequential diffusion process, parameterized to maximize earned rewards, can account for salient patterns of bisection performance. The first diffusion stage times intervals by accumulating an endogenously noisy clock signal; the second stage makes decisions about the first-stage temporal representation by accumulating first-stage evidence corrupted by endogenous noise. Reward-maximization requires that the second-stage accumulation rate and starting point be based on the state of the first-stage timer at the end of the stimulus duration, and that estimates of non-decision-related delays should decrease as a function of stimulus duration. Results are in accord with these predictions and thus support an extension of the drift–diffusion model of static decision making to the domain of interval timing and temporal decisions.     

Temporal coordination of alternative and simultaneous aiming movements of constrained timing structure

Two experiments are reported addressing the preparation and initiation of movements with equal or unequal timing properties for both hands. Temporal coordination was examined in two movement tasks: one in which both hands performed the movements simultaneously (simultaneous aiming task) and one in which only one alternative of two possible movements was executed (choice aiming task). For each task a different group of subjects was used. Besides the timing relationships between both movements, the effects of preparation interval (1, 3, and 5 s), the average velocity (7, 14, 17.5, and 70 cm/s), the presence of advance information about the required velocity of the movement(s), and practice were investigated. Based on the common- and the specific-timing notions, distinct hypotheses were tested as to the effects of the variables on the temporal coordination as revealed by reaction time. A main result was that the effects of timing differences between the hands was task specific. For the choice task the data are in agreement with the common-timing notion of coordination, i. e., only one timing demand at a time can be prepared, whereas in the simultaneous task evidence was obtained for the specific-timing notion, i. e., independent preparation and initiation of different timing properties for the hands. However, it is argued that the results of the choice task probably do not reflect a general inability to prepare movements of different timing requirements for both hands, but is related to a task-specific strategy of selective preparation.     

Hierarchical control of rapid movement sequences

Are movement sequences executed in a hierarchically controlled fashion? We first state explicitly what such control would entail, and we observe that if a movement sequence is planned hierarchically, that does not imply that its execution is hierarchical. To find evidence for hierarchically controlled execution, we require subjects to perform memorized sequences of finger responses like those used in playing the piano. The error data we obtain are consistent with a hierarchical planning as well as execution model, but the interresponse-time data provide strong support for a hierarchical execution model. We consider three alternatives to the hierarchical execution model and reject them. We also consider the implications of our results for the role of timing in motor programs, the characteristics of motor buffers, and the relations between memory for symbolic and motor information.     

Time and memory: towards a pacemaker-free theory of interval timing

A popular view of interval timing in animals is that it is driven by a discrete pacemaker-accumulator mechanism that yields a linear scale for encoded time. But these mechanisms are fundamentally at odds with the Weber law property of interval timing, and experiments that support linear encoded time can be interpreted in other ways. We argue that the dominant pacemaker-accumulator theory, scalar expectancy theory (SET), fails to explain some basic properties of operant behavior on interval-timing procedures and can only accommodate a number of discrepancies by modifications and elaborations that raise questions about the entire theory. We propose an alternative that is based on principles of memory dynamics derived from the multiple-time-scale (MTS) model of habituation. The MTS timing model can account for data from a wide variety of time-related experiments: proportional and Weber law temporal discrimination, transient as well as persistent effects of reinforcement omission and reinforcement magnitude, bisection, the discrimination of relative as well as absolute duration, and the choose-short effect and its analogue in number-discrimination experiments. Resemblances between timing and counting are an automatic consequence of the model. We also argue that the transient and persistent effects of drugs on time estimates can be interpreted as well within MTS theory as in SET. Recent real-time physiological data conform in surprising detail to the assumptions of the MTS habituation model. Comparisons between the two views suggest a number of novel experiments.     

Models of Trajectory Formation and Temporal Interaction of Reach and Grasp

Our goal was to create a principled account of a body of behavioral kinematic data on reaching and grasping. We show how to transform an optimality principle for overall hand transport into a feedback control law and then incorporate look-ahead modules in the controller to compensate for delays in sensory feedback. This model describes the kinematics of hand transport under a variety of circumstances, including target perturbations. We then develop a model for the temporal coordination of reach and grasp. We provide an optimization principle for hand preshaping that trades off the costs of maintaining the hand in an open position and the cost of accelerating the change in grip size. This yields a control system for preshaping. We then show that a model that uses only expected duration for coordination, rather than kinematic or dynamic variables, can describe the kinematics of interaction of hand transport and preshape under a variety of circumstances, including perturbations of object position and object size.