Pierre Fourneret

Limited conscious monitoring of motor performance in normal subjects

Normal subjects traced sagittal lines on a graphic tablet using a stylus held in their right hand. The hand was hidden by a mirror in which they saw the lines projected from a computer screen. In normal trials, the line seen in the mirror exactly corresponded to the traced line. In perturbed trials, a bias was introduced by the computer, so that the line appeared to deviate in one direction (right or left) by a variable angle (2, 5, 7 or 10 degrees). Subjects consistently displaced their hand in the opposite direction for producing a visually sagittal line. After each trial, they were asked in which direction they thought their hand had moved. In perturbed trials, they grossly underestimated the hand deviation. In addition, a post-hoc analysis revealed that one group of subjects misperceived the direction of their hand movement in the direction opposite to the perturbation (Group 1, including 9 Ss), whereas the other group gave responses in the correct direction (Group 2, including 4 Ss). In a second session using the same experimental paradigm, a motor response was asked for: subjects had to indicate the perceived direction of their hand during each trial by drawing a line with their eyes closed. Again, responses indicated a poor conscious monitoring of motor performance. These results suggest that normal subjects are not aware of signals generated by their own movements.

Preserved Adjustment but Impaired Awareness in a Sensory–Motor Conflict following Prefrontal Lesions

Control of action occurs at different stagesof the executive process, in particular at those of sensory-motor integration and conscious monitoring. The aim of this study was to determine the implication of the prefrontal cortex in the control of action. For that purpose, we compared the performance of 15 patients with frontal lobe lesions and 15 matched controls on an experimental paradigm generating a conflict between the action planned and the sensory-motor feedback. Subjects had to trace a sagittal line witha stylus on a graphic tablet. The hand was hidden by a mirror on which the traced line, processed by a computer, was projected. Without informing the subjects, the line traced was modified by introducing a bias to the right, which increased progressively from 2 to 42. To succeed the task, subjects had to modify their motor program and deviate their hand in the opposite direction. The sensory-motor adjustment to the bias was evaluated by the surface between the line traced and the ideal line to compensate for the deviation. The awareness of the conflict was measured by the angle of the bias at which subjects expressed the feeling that the line they traced was not the same as the line they saw. The deviation was similarly compensated for by patients and controls until24. Then 14 controls but only3 patients were aware of a conflict. After that, the variability of performance increased significantly for the unaware patients. These results suggest that the prefrontal cortex is required at the level of conscious monitoring of actions, but not at the level of sensory-motor integration.

Self-monitoring in schizophrenia revisited

According to a widespread theory, the first-rank symptoms such as delusions of control or thought insertion met in schizophrenia result from a failure in predicting the consequences of an action on the basis of a forward model based of the intended motor commands (efference copy). This assumption of an impairment in the central monitoring of their own actions is inferred from experiments showing that it is more difficult for schizophrenic patients than for controls to correct erroneous movements in the absence of visual feedback. In our study, 19 schizophrenic patients (10 with Schneiderian symptoms and nine without) and 19 paired control subjects were subjected to a sensorimotor adjustment task to reassess this hypothesis. We show that the patients who succeeded the task not differently from the control subjects were those who were aware of the manual correction (n = 9). Surprisingly, most of them presented Schneiderian symptoms. This suggests that the experience of alien control observed in certain schizophrenic patients cannot be directly related to an underlying cognitive deficit in the conscious monitoring of their own actions.

Lack of conscious recognition of one's own actions in a haptically deafferented patient.

How do we become aware of our own actions? This classical question is still a matter of debate: does consciousness depend on central efferent signals or derive from peripheral information? In this paper, we had the opportunity to study a haptically deafferented patient using a well-tested experimental paradigm where a cognitive conflict is produced between motor intention, proprioception and visual feedback. Our results show that the patient was able to solve the conflict and to generate accurate movements to a target in the absence of proprioceptive feedback and with very limited visual feedback from her movements. Yet, she could not report any conscious perception of the conflict and showed no conscious knowledge of her actual performance. We suggest that information derived from efferent processes cannot in themselves be a source for conscious experience about our own actions.

Perception of self-generated action in schizophrenia

Introduction. Self-generated actions involve central processes of sensorimotor integration that continuously monitor sensory inputs to ensure that motor outputs are congruent with our intentions. This mechanism works automatically in normal conditions but becomes conscious whenever a mismatch happens during the execution of action between expected and current sensorimotor reafferences. It is now admitted in the literature that sensorimotor processes as well as the ability to predict the consequences of our own actions imply the existence of a forward model of action, which is based on efference copies. Recently, it has been proposed that positive symptoms expressed by schizophrenic patients, such as delusions of control or thought insertions, arise because of a deficiency in this forward model, and more particularly, because of a lack of awareness of certain aspects of motor control derived from such an internal model. Method. To test further this hypothesis, 19 schizophrenic patients (10 with and 9 without Schneiderian symptoms) and 19 control subjects performed a visuo-motor conflict task and had verbally to report the felt position of their hand at the end of each trial. Results. Under this experimental procedure, schizophrenic patients - whatever their clinical phenotype - failed to switch to a conscious representation of their hand movements, and then consequently to maintain their level of performance for the sensorimotor adjustment in comparison with controls. Conclusion. Our findings suggest two facts. First, that a functional monitoring of action, based on a forward

The prefrontal cortex and conscious monitoring of action An experimental study

To investigate the role of the prefrontal cortex in conscious monitoring, we used an experimental paradigm generating a conflict between the action planned and the sensory-motor feedback. We analyzed the acquisition of explicit knowledge of the strategy for resolving the conflict and its influence on motor adaptation. Twenty patients with frontal lobe lesions and 18 controls had to trace a sagittal line with a stylus on a graphics tablet. A mirror on which the traced line, processed by a computer, was projected hid the hand. A mask limited visual feedback to the last third of the trajectory. Without informing the subjects, the line traced was modified by introducing a bias of 24 degrees to the right. To succeed in the task, subjects had to modify their motor program and to deviate their trajectory in the opposite direction. Conscious elaboration of the strategy was evaluated by the number of trials needed to explicitly report the required deviation. Three groups of patients were distinguished: (1). with normal explicit strategy; (2). with delayed explicit strategy, and (3). without explicit strategy at the last trial. They significantly differed by the severity of the dysexecutive syndrome, particularly of environmental adherence. Motor adaptation was evaluated by the area between the line traced and the ideal line to compensate for the deviation. In patients with normal elaboration of the strategy, motor control was similar to that of controls, but it was severely disturbed in the other two groups. These results suggest the involvement of the prefrontal cortex in conscious motor monitoring.

Behavioral Profiles of Clinically Referred Children with Intellectual Giftedness

It is common that intellectually gifted children—that is, children with an IQ ≥ 130—are referred to paediatric or child neuropsychiatry clinics for socio-emotional problems and/or school underachievement or maladjustment. These clinically-referred children with intellectual giftedness are thought to typically display internalizing problems (i.e., self-focused problems reflecting overcontrol of emotion and behavior), and to be more behaviorally impaired when “highly” gifted (IQ ≥ 145) or displaying developmental asynchrony (i.e., a heterogeneous developmental pattern, reflected in a significant verbal-performance discrepancy on IQ tests). We tested all these assumptions in 143 clinically-referred gifted children aged 8 to 12, using Wechslers intelligence profile and the Child Behavior Checklist. Compared to a normative sample, gifted children displayed increased behavioral problems in the whole symptomatic range. Internalizing problems did not predominate over externalizing ones (i.e., acted-out problems, reflecting undercontrol of emotion and behavior), revealing a symptomatic nature of behavioral syndromes more severe than expected. “Highly gifted” children did not display more behavioral problems than the “low gifted.” Gifted children with a significant verbal-performance discrepancy displayed more externalizing problems and mixed behavioral syndromes than gifted children without such a discrepancy. These results suggest that developmental asynchrony matters when examining emotional and behavioral problems in gifted children.

What MEG can reveal about inference making: the case of if...then sentences.

Characterizing the neural substrate of reasoning has been investigated with regularity over the last 10 years or so while relying on measures that come primarily from positron emission tomography and functional magnetic resonance imaging. To some extent, these techniques—as well as those from electroencephalography—have shown that time course is equally worthwhile for revealing the way reasoning processes work in the brain. In this work, we employ magnetoencephalography while investigating Modus Ponens (If P then Q; P//Therefore, Q) in order to simultaneously derive time course and the source of this fundamental logical inference. The present results show that conditional reasoning involves several successive cognitive processes, each of which engages a distinct cerebral network over the course of inference making, and as soon as a conditional sentence is processed. Hum Brain Mapp, 2013.

Wechsler profiles in referred children with intellectual giftedness: Associations with trait-anxiety, emotional dysregulation, and heterogeneity of Piaget-like reasoning processes

BACKGROUND/PURPOSE It is common that intellectually gifted children (IQ ≥ 130) are referred to paediatric or child neuropsychiatry clinics for socio-emotional problems and/or school underachievement or maladjustment. Among them, those displaying developmental asynchrony - a heterogeneous developmental pattern reflected in a significant verbal-performance discrepancy (SVPD) on Wechslers intelligence profile - are thought to be more emotionally and behaviourally impaired than others. Our purpose was to investigate this clinical dichotomy using a cognitive psychopathological approach. METHODS Trait-anxiety and emotional dysregulation were investigated in two groups of referred gifted children (n = 107 and 136, respectively), a pilot-study of reasoning processes on extensive Piaget-like tasks was also performed in an additional small group (n = 12). RESULTS Compared to those with a homogenous Wechsler profile, children with a SVPD exhibited: 1) a decreased prevalence of social preoccupation-anxiety (11.1% versus 27.4%; p < 0.05); 2) an increased prevalence of emotional dysregulation (58.7% versus 41.3%; p < 0.05); and 3) an increased prevalence of pathological cognitive disharmony on Piaget-like tasks (87.5% versus 0.0%; p < 0.05). CONCLUSION The results support a clinical dichotomy of behaviourally-impaired children with intellectual giftedness, with developmentally asynchronous ones exhibiting more severe psychopathological features. This suggests that developmental asynchrony matters when examining emotional and behavioural problems in gifted children and call for further investigation of this profile.

Syntax at hand: common syntactic structures for actions and language.

Evidence that the motor and the linguistic systems share common syntactic representations would open new perspectives on language evolution. Here, crossing disciplinary boundaries, we explore potential parallels between the structure of simple actions and that of sentences. First, examining Typically Developing (TD) children displacing a bottle with or without knowledge of its weight prior to movement onset, we provide kinematic evidence that the sub-phases of this displacing action (reaching + moving the bottle) manifest a structure akin to linguistic embedded dependencies. Then, using the same motor task, we reveal that children suffering from specific language impairment (SLI), whose core deficit affects syntactic embedding and dependencies, manifest specific structural motor anomalies parallel to their linguistic deficits. In contrast to TD children, SLI children performed the displacing-action as if its sub-phases were juxtaposed rather than embedded. The specificity of SLI’s structural motor deficit was confirmed by testing an additional control group: Fragile-X Syndrome patients, whose language capacity, though delayed, comparatively spares embedded dependencies, displayed slower but structurally normal motor performances. By identifying the presence of structural representations and dependency computations in the motor system and by showing their selective deficit in SLI patients, these findings point to a potential motor origin for language syntax.