Planning ahead through space and time: from neuropsychology to motor control

Planning ahead through space and time: from neuropsychology to motor control Mariama C.Dione (mariama.dione@univ-lille3.fr) Laurent Ott (laurent.ott@univ-lille3.fr) Yvonne Delevoye-Turrell (yvonne.delevoye@univ-lille3.fr) URECA EA 1059, University Lille Nord de France, rue du Barreau, BP 60149 Villeneuve d’Ascq, 59653, France Abstract The executive functions have been studied separately in the fields of neuropsychology and of motor control. However, it is not clear whether across fields one is referring to similar cognitive functions. In the present study, we compared the performance scores obtained in a motor spatial-tapping task with those scores obtained in a battery of three neuropsychological tasks which assess respectively the executive functions of updating (N-back task), inhibiting (Go- noGo task) and switching (Letter-number task). Multiple regression analyses revealed significant and specific effects between the motor task and the classical neuropsychological tasks: the timing error measured at slow tempi in the tapping task predicted the scores observed in the updating task only; the spatial error at faster tempi predicted the scores obtained in the switching task only; the contact times at intermediate tempi predicted the scores obtained in the inhibiting task only. Hence, we introduce this easy-to-use non-verbal task as a novel paradigm to assess executive functioning. Keywords: planning; executive functions; motor control; neuropsychology; regression; space; time. Introduction Neuropsychological approach of Planning Research on the executive functions has historical roots in the study of patients with frontal lobe damage. These patients were the first to demonstrate disruptions to control and organize daily activities independent of any language or memory disorders (Damasio, 1994; Harlow, 1868). The so- called 'frontal' or 'executive' tasks were specifically developed to assess how the main functional deficit encountered by frontal patients, i.e. the planning of daily activities, was affected following brain injury. For example, the Tower of London (Shallice, 1982), a task inspired by a logical reasoning game (the Tower of Hanoi) was proposed to evaluate the ability to inhibit a routine schema – that consisted in producing each move in an isolated and impulsive fashion in response to the true visual configuration of the Tower – in order to define and adopt a cognitive plan to achieve the puzzle in fewer moves (see the model of SAS/GOC, Shallice, 1988). The Wisconsin Card Sorting Test (WCST, Grant & Berg, 1948), on the other hand, was proposed to target individuals’ inability to switch efficiently from an ongoing plan to a novel one. In this task, perseverating errors were measured and used as indicators of cognitive flexibility (Milner, 1963). Finally, working memory tasks, e.g., the n-back task, were developed to target a person’s ability to maintain a cognitive plan active and to update between relevant parts of the plan in function of a given situation. Hence, the executive functions are here directly related to the abilities to inhibit a routine schema in order to adopt and adapt a novel more cognitive plan, to maintain and update parts of a given plan across time and/or to switch flexibly from one plan to another. In the last decade, these cognitive abilities have been referred to in the literature as the inhibiting, the updating, and the switching executive functions (Miyake & Friedman, 2012; Miyake et al., 2000) and it is common today to use a multiple-test battery to assess the well functioning of the executive functions related to planning abilities. However, it is the case that the neuropsychological tasks that are classically used to assess the executive functions suffer from a number of validity problems that limits severely the possibility to compare the functions between them. Indeed, the tasks are known to have impurity issues because of the presence of non-executive demands specifically related to the various contents that are used in the tasks (e.g., language, limb displacements, object identification, etc., Burgess, 1997; Phillips, 1997). Second, they present a lack of test-retest reliability, i.e. people can adopt different executive strategies to perform the same task across sessions (Rabbitt, 1997). For example, although the WCST has been designed to reveal a lack of cognitive flexibility, subjects may perform the task by inhibiting certain responses that are no longer appropriate (Miyake et al., 2000). Thus, scores in different sessions may reflect different cognitive strategies, with participants who are sometimes switching between rules and at other times using inhibition to solve the task. The difficulty to characterize the possible relationships between the executive functions is in itself a motivator to consider today a different approach to the evaluation of executive functioning. Planning in the Motor Control domain A major interest in the field of motor control is to understand how actions are coordinated to enable the execution of complex sequential motor activities, e.g. playing a musical instrument or dancing in rhythm. This question has been particularly studied in the context of sensorimotor synchronization (for a review on SMS, see Repp, 2005). Even if synchronized behaviors require motor coordination both through space and time, research has focused historically on the timing aspects of motor planning and experimental findings have led to the acceptance today