Jean Massion

• MD,PhD
• Managing Director at French National Centre for Scientific Research: emeritus

The french qnd russian authors of this article offer detailed analyses bearing on convergences and complementarities between russian and french researches in the field of motor control. They placed within the long historical duration of physiological research up to the present. Without neglecting administrative difficulties, the authors bear witnes...

The goal of the paper is to present an example of integrated analysis of electrical, hemodynamic, and motor activity accompanying the motor function recovery in a post-stroke patient having an extensive cortical lesion. The patient underwent a course of neurorehabilitation assisted with the hand exoskeleton controlled by brain-computer interface ba...

This article reviews the contributions of Ivan Michailovich Sechenov [1829-1905] to the neurophysiological concept of central inhibition. He first studied this concept in the frog and on himself. Later his trainees extended the study of central inhibition to other mammalian species. Outside his own country, Sechenov is better known for his prescien...

Many currently accepted notions of motor control originate from a few seminal concepts developed in the latter half of the 19th century (see Bennett and Hacker, 2002). The goal of this review is to retrace some current ideas about motor control back to the thought of three French neurologists of Hospital of the Salpetrière hospital in Paris during...

This article reviews the scientific contributions of Jacques Paillard (1920-2006), who strengthened substantially the role of physiological psychology in the field of movement neuroscience. His research began in 1947 under the direction of the French neurophysiologist, Alfred Fessard (1900-1982), with whom he then collaborated for 9 years while an...

François Clarac and Jean Massion recount the creation of an institute dedicated to psychophysiology and neurophysiology in the 1960s in Marseille.

The aim of this investigation was to study the adaptation to an unstable support surface of kinematic synergy responsible for equilibrium control during upper trunk movements. Eight adult subjects were asked to bend their upper trunk forward to an angle of 35 degrees and then to hold the final position for 3 s, first in a standard condition, with t...

Lateral leg movement is accompanied by opposite movements of the supporting leg and trunk segments. This kinematic synergy shifts the center of mass (CM) towards the supporting foot and stabilizes its final position, while the leg movement is being performed. The aim of the present study was to provide insight in the behavioral substitution process...

AimsTo evaluate the interest of the sporting practice on the quality of life of the young child with autism.

To investigate the ability of patients with Parkinson's disease to perform a rotation around the longitudinal axis of the body. Three questions were raised. Is body rotation impaired in Parkinson's disease? Is there a level of the kinematic chain from the head to the foot at which the impairment is more severe? Is the deficit related to the general...

This study deals with the quantitative assessment of exchanged forces and torques at the restraint point during whole body posture perturbation movements in long-term microgravity. The work was based on the results of a previous study focused on trunk bending protocol, which suggested that the minimization of the torques exchanged at the restraint...

This article focuses on postural anticipation and multi-joint coordination during locomotion in healthy and autistic children. Three questions were addressed. (1) Are gait parameters modified in autistic children? (2) Is equilibrium control affected in autistic children? (3) Is locomotion adjusted to the experimenter-imposed goal? Six healthy child...

In most motor acts, posture and movement must be coordinated in order to achieve the goal of the task. The focus of this chapter is on why and how this coordination takes place. First, the nature of posture is discussed. Two of its general functions are recognized; an antigravity role, and a role in interfacing the body with its environment such th...

To determine why parkinsonian patients (PP) present some difficulties to initiate locomotion, a diagonal step has been investigated in two tasks in five control subjects (CS) and in ten PP. In the first task, the subjects had to perform one diagonal step without change in their orientation (WR); in the second task, they had to perform one diagonal...

Present investigation faces the question of quantitative assessment of exchanged forces and torques at the restraints during whole body posture exercises in long-term microgravity. Inverse dynamic modelling and total angular momentum at the ankle joint were used in order to reconstruct movement dynamics at the restraining point, represented by the...

The involvement of the motor cortex in learning movements has recently attracted much attention. One aspect of motor learning is the inhibition of innate synergies which interfere with performance of the acquired movement. Various models of operant responses in dogs have demonstrated the critical role of the motor cortex in the reorganization and i...

After 7 years of studies on Euromir 95 T4 experiment 'Human Posture in microgravity' dataset, some important remarks can be proposed for best exploiting future experimental campaigns as well as for neurophysiological investigations on-ground. The main focus of such experiments was to monitor the process of learning and adapting to the new environme...

The present investigation describes for the first time leg lateral abduction performance during long-term microgravity exposure. Two astronauts took part in the experiments, starting 2 weeks into the mission and lasting for 5 months. Results on joint angles kinematics confirm previous investigations on parabolic flights, showing good task fulfillme...

This work was aimed at identifying changes in posturomotor control strategies in patients with unilateral total knee arthroplasty. Using kinetic and kinematic data, a previous study had revealed that, during a side step, patients with unilateral knee arthritis showed a shortened monopodal phase and a lengthened postural phase when the affected leg...

Nous présentons dans cet article la synthèse d'un projet coopératif qui a regroupé une équipe de cliniciens hospitaliers et trois équipes de chercheurs du CNRS et de l'Université, et destiné à tester une nouvelle hypothèse unificatrice dans l'autisme. La question était de savoir si les troubles communicatifs et relationnels typiques de l'autisme so...

The functional approach to studying human motor systems attempts to give a better understanding of the processes behind planning movements and their coordinated performance by relying on weightlessness as a particularly enlightening experimental condition. Indeed, quantitative monitoring of sensorimotor adaptation of subjects exposed to weightlessn...

The findings suggest that a particular function of MCx in motor learning involves suppression of synergies and co-ordination which interferes with acquisition of new motor patterns. Experimental animal models based on inhibition of certain natural synergies or reflexes in the process of learning new co-ordination have been developed where the MCx i...

Two behavioral goals are achieved simultaneously during forward trunk bending in humans: the bending movement per se and equilibrium maintenance. The objective of the present study was to understand how the two goals are achieved by using a biomechanical model of this task. Since keeping the center of pressure inside the support area is a crucial c...

The large mass of the human upper trunk, its elevated position during erect stance, and the small area limited by the size of the feet, stress the importance of equilibrium control during trunk movements. The objective of the present study was to perform a biomechanical analysis of fast forward trunk movements in order to understand the coordinatio...

The adaptation of dynamic movement-posture coordination during forward trunk bending was investigated in long-term weightlessness. Three-dimensional movement analysis was carried out in two astronauts during a 4-mo microgravity exposure. The principal component analysis was applied to joint-angle kinematics for the assessment of angular synergies....

Les recherches sur le langage des sujets autistes et dysphasiques sont restées essentiellement descriptives, reposant la plupart du temps sur des descriptions de deficit de langage et non de bilan de langue. Le propos de cette étude est de connaître plus précisément la présence ou non d'une perturbation du système phonologique chez ces enfants-là....

The primary purpose of this paper was to compare the effect of reversing the direction of step initiation in Parkinson's disease. Forward (FDS) and backward (BDS) oriented stepping initiation analyses were conducted on combined kinematic and kinetic data recorded on Parkinsonian patients (PD) and healthy age-matched subjects. Two successive phases...

Patients with Parkinson's disease often have difficulty maintaining postural stability. This impairment is attributed to postural adjustment deficits. We studied the postural adjustments associated with the performance of two complex tasks which differed only in the final equilibrium constraints. Ten patients with Parkinson's disease and six age-ma...

This study was aimed at identifying changes in equilibrium and movement control strategies in trans-tibial amputees (TTA) related to both the biomechanical changes and the loss of afferent inflow. The coordinations between equilibrium and movement were studied in traumatical TTA and in controls during transition from bipedal to monopodal stance. TT...

To identify how patients with knee arthritis modify their equilibrium and movement control strategies during gait initiation. Observational study. University hospital movement analysis laboratory. Twelve patients with unilateral knee arthritis and 12 healthy control subjects. Durations of the phases of gait initiation (ie, postural, monopodal, and...

The aim of the present investigation was to see whether the kinematic synergy responsible for equilibrium control during upper trunk movement was preserved in absence of gravity constraints. In this context, forward trunk movements were studied during both straight-and-level flights (earth-normal gravity condition: normogravity) and periods of weig...

The aim of the present investigation was to study the adaptation of the kinematic synergy responsible for equilibrium control during upper trunk movements to a 10-kg load added to the subject's shoulders. Five adult subjects were asked to bend their upper trunk forward to an angle of 35 degrees and then to hold the final position for 3 s, first wit...

The aim of the present experiment was to study the central organization of equilibrium control during arm raising in the frontal plane. Nine adult subjects (five seniors and four young adults) were asked to raise their right arm to a horizontal position in the frontal plane in two support conditions (bipedal vs. unipedal) and two load conditions (u...

The aim of this work was to study the relations between equilibrium and movement in patients after total knee arthroplasty. A previous study, conducted in patients with unilateral knee osteoarthritis, had shown that the timing of the events occurring during a side-step was modified in an asymmetrical way according to the supporting leg with respect...

Orbital microgravity represents a unique environment, which allows the isolation of variables assumed to be involved in the mechanism of body positioning in space. In this context, the alignment of the trunk axis along allocentric references and the positioning of the body center of mass inside the supporting base compete for the role of the primar...

Anticipatory adjustments of forearm posture are associated with a voluntary load-lifting movement in bimanual load-lifting tasks. Three aspects of these adjustments are analyzed: their goal, their central organization, and their acquisition. The goal of the anticipatory adjustment in this task is to minimize the perturbation of forearm posture that...

Introduction The aim of this work was to study the relations between equilibrium and movement in patients after total knee arthroplasty. A previous study, conducted in patients with unilateral knee osteoarthritis, had shown that the timing of the events occurring during a side-step was modified in an asymmetrical way according to the supporting leg...

The purpose of this study was to identify changes in equilibrium and movement control strategies in patients with arthritis of the knee. These strategies were expected to be different from those of healthy subjects because of the impairments caused by knee arthritis. The different phases of a side step were studied in patients with severe knee arth...

In this study, the equilibrium-point hypothesis of muscle-torque generation is used to evaluate the changes in central control parameters in the process of postural-maintenance learning. Muscle torque is described by a linear spring equation with modifiable stiffness, viscosity, and equilibrium angle. The stiffness is considered to be the estimatio...

The aim of this work was to study movement control strategies in patients with knee arthritis. These strategies were expected to be different from healthy subjects because of deficiencies due to knee arthritis (i.e. pain, altered proprioception). A kinetic and kinematic analysis was performed in a population of 10 patients with unilateral knee arth...

The present paper focuses on the organization of posture and movement under normal and microgravity conditions. Two reference values subserving the control of erect posture and the performance of movements are analyzed. The first is 'geometrical' in nature and corresponds to the orientation of a body segment with respect to the external world. The...

During upper trunk movements, the axial kinematic synergies (opposite movements of upper and lower segments) preserve the balance by minimizing the antero-posterior center of gravity (CG) shift due to the movement. Forward and backward upper trunk movements were analyzed in a population of parkinsonian patients (PD) that were subject to falling, in...

Introduction The aim of this work was to study movement control strategies in patients with knee arthritis. These strategies were expected to be different from healthy subjects because of deficiences due to knee arthritis (i.e, pain, altered proprioception), Method A kinetic and kinematic analysis was performed in a population of 10 patients with u...

The position of the center of gravity (CG) is a reference value that is controlled by the nervous system during the performance of movements. In order to maintain equilibrium, leg movement is preceded by a shift of the CG towards the supporting side. This CG shift is initiated by an early displacement of the center of pressure (CP) towards the movi...

How can the adult postural organisation be elucidated using an ontogenetic approach, and what questions can be raised about ontogenesis starting from the organisation of adult posture? These questions will be addressed taking three aspects of postural organisation. The first is the internal representation of erect posture, including the role played...

The main aim of this study is to provide a quantitative evaluation of motor strategies used during the performance of a lateral step in subjects presenting poliomyelitis sequelae affecting a lower limb. These subjects present frequent falls due to destabilization of the knee. The motor strategies used to control the center of gravity displacement,...

The purpose of this study was to identify the postural adjustments associated with a leg movement observed at the spinal column level in order to stabilize the vertical orientation of the head or head–trunk axes. Two different strategies of shifting the projection of the center of gravity to the supporting leg were described in untrained subjects a...

Upper trunk bending movements were accompanied by opposite movements of the lower body segments. These axial kinematic synergies maintained equilibrium during the movement performance by stabilizing the center of gravity (CG), which shifted on average across all the subjects by 1±4 cm in the anteroposterior direction and thus always remained within...

The ability voluntarily to stabilize the head in space during lateral rhythmic oscillations (0.59+/-0.09 Hz) of the trunk has been investigated during microgravity (microG) and normal gravity (nG) conditions (parabolic flights). Five healthy young subjects, who gave informed consent, were examined. The movements were performed with eyes open or eye...

In the present experiments carried out in microgravity two questions were addressed. First, when the subject was instructed to adopt a vertical erect posture in microgravity with his feet fixed to the floor of the space cabin, would he control anteroposterior position with respect to the ankle joint axis of the "vertical projection" of his center o...

1. Investigations on stance regulation have already suggested that the body's center of mass is the variable controlled by the CNS to maintain equilibrium. The aim of this study was to determine how the center of mass of the body is regulated when leg movements are made under different gravitoinertial force conditions. 2. Kinematic and electromyogr...

The aim of the present study was to determine (i) whether the centre of gravity (CG) shift resulting from the mechanical effect of arm raising in the frontal plane is minimized in standing subjects and (ii) whether this putative minimization is affected by the support conditions (unipedal vs bipedal) and/or by adding a load (3.5 kg) to the moving h...

The present experimental series was designed to test the possibility that an anticipatory postural adjustment learned during the performance of a bimanual load lifting task may be transferred between the upper extremities. Eight seated subjects were asked to maintain horizontally one forearm (postural arm) loaded with a 1-kg load, which was fixed t...

In order to differentiate between a specific impairment affecting gait initiation and a non-specific deficit in the postural adjustment which occurs prior to any forward oriented stepping movement, 3 forward oriented movements (FOMs), performed by a group of parkinsonian patients and a group of healthy age-matched subjects, were compared in the pre...

The question was addressed in this study as to whether the kinematic synergy responsible for equilibrium control during upper trunk movements may involve an actual evaluation of the weight of the body segments. Five adult subjects were asked to bend the upper trunk forward or backward to an angle of about 35 degrees, first without any load and then...

In normal subjects, the gait initiation mechanisms have been previously studied by performing multiparametric analyses relying on kinematic, dynamic and EMG recordings (Carlsoo, 1966; Brenière et al., 1981; Burleigh et al., 1994; Elble et al., 1994). The gait initiation process can be described as the succession of a postural phase and a subsequent...

Two aspects of the target article, (1) the extension of the equilibrium point theory to multi-joint movements, and (2) the consequence that the EMG pattern is not directly controlled by the central nervous system (CNS), are discussed in light of the experiments on upper trunk bending in humans. The principle component kinematic analysis and the ana...

The ability to voluntarily stabilize the head in space during lateral rhythmic oscillations of the trunk has been investigated during parabolic flights. Five healthy young subjects, who gave informed consent, were examined. The movements were performed with eyes open or eyes closed, either during phases of microgravity or phases of normal gravity....

The control of the body orientation and the center of mass position with respect to the feet was investigated under normo- and microgravity (space flight Altair), during erect posture and at the end of a forward or backward upper trunk movement. It was observed that during erect posture, the trunk orientation with respect to the vertical was inclin...

Postural instability is a common problem in patients with Parkinson's disease. This paper reports results of a study undertaken to investigate some of the possible mechanisms responsible for this instability. Preparatory postural adjustments associated with a lateral leg raising task were studied in five parkinsonian patients and four age-matched c...

Professional divers were instructed to adopt a vertical posture under water with their feet fixed to the ground and to perform a fast forward or backward upper trunk bending movement in response to a tone. Kinematic and EMG analyses were performed. It was first noted that the divers adopted a forward inclined, erect posture, suggesting that the ver...

The postural control system has two main functions: first, to build up posture against gravity and ensure that balance is maintained; and second, to fix the orientation and position of the segments that serve as a reference frame for perception and action with respect to the external world. This dual function of postural control is based on four co...

Maintaining equilibrium is one of the main constraints involved in the performance of movements. Moving the arms or the upper trunk in the sagittal plane while standing tends to shift the center of gravity (CG) in the same direction as the movement, thus resulting in imbalance. As first observed by Babinski (1899), simultaneous shifts of hip and kn...

Upper trunk bending in humans is always accompanied by lower segment movements in the opposite direction, as first described qualitatively by Babinski (1899). He called this phenomenon “axial synergy” and suggested that it may serve to maintain equilibrium.

This chapter provides an overview of an elementary framework of the field of interlimb coordination. Humans are capable of coordinating various limbs and body parts with each other—for example, the left and right hands or thumbs, the hand and foot, and the head and arm. One of the most intensively studied examples of interlimb coordination in the f...

In his original description of cerebellar asynergia, Babinski, in 1899, presented a patient with cerebellar dysfunction performing a backward upper trunk bending. When the patient tried to bend his head and trunk, his lower limbs stayed almost motionless, because the associated flexion of the knee and hip, usually observed in a normal subject, did...

This book [studies] motor control with respect to the coordination of limb movement. Contributions from internationally renowned experts in various fields of research, including the neurosciences, experimental and developmental psychology, and kinesiology, offer a multidisciplinary approach to interlimb coordination. "Interlimb Coordination: Neur...

Naive subjects and dancers were instructed to raise a leg laterally toward 45 degrees. The final position reached by the leg by each group of subjects was quite different: 48 degrees in dancers, i.e. close to the required value, and 56 degrees in the naive subjects. The reason for this difference was investigated. During the body weight transfer to...

Fast forward and backward upper trunk movements were analyzed and compared under microgravity and under preflight and postflight conditions. The kinematic analysis showed that the upper trunk movements were accompanied by hip and knee movements in the opposite direction both under microgravity and under normal gravitational conditions. This suggest...

In this paper the main anatomico-functional data concerning the cerebellum are presented. The numerous hypotheses put forward on the functions of the cerebellum, such as they are listed in introduction, illustrate both the advances achieved and the problems awaiting to be solved. Following a general view of phylogenesis, the peculiar characteristic...

Summary form only given. When a voluntary movement is performed, the displacement of the moving segments toward a goal is only one aspect of the motor act. Other goal-directed actions are achieved simultaneously, which is necessary for the accuracy of the performance. Leg raising is presented as an illustration of a task with multiple goals achieve...