Papers by Daniel Cattaert
bioRxiv (Cold Spring Harbor Laboratory), Dec 22, 2023
During rapid voluntary limb movement about a single joint, a stereotyped triphasic pattern is typ... more During rapid voluntary limb movement about a single joint, a stereotyped triphasic pattern is typically observed in the electromyograms (EMGs) of antagonistic muscles acting at this joint. To explain the origin of such triphasic commands, two types of theories have been proposed. Peripheral theories consider that triphasic commands result from sensorimotor spinal networks, either through a combination of reflexes or through a spinal central pattern generator. Central theories consider that the triphasic command is elaborated in the brain. Although both theories were partially supported by physiological data, there is still no consensus about how exactly triphasic commands are elaborated. Moreover, capacities of simple spinal sensorimotor circuits to elaborate triphasic commands on their own have not been tested yet. In order to test this, we modelled arm musculoskeletal system, muscle activation dynamics, proprioceptive spindle and Golgi afferent activities and spinal sensorimotor circuits. Descending step commands were designed to modify the activity of spinal neurons and the strength of their synapses, either to prepare (SET) the network before movement onset, or to launch the movement (GO). Since these step commands do not contain any dynamics, changes in muscle activities responsible for arm movement rest entirely upon interactions between the spinal network and the musculo-skeletal system. Critically, we selected descending step commands using a Goal Exploration Process inspired from baby babbling during development. In this task, the Goal Exploration Process proved to be very efficient. It proficiently discovered step commands that enabled spinal circuits to handle a broad spectrum of functional behaviors. Notably, this accomplishment was predominantly realized while eliciting natural triphasic commands, thereby substantiating the inherent capacity of the spinal network. .
Human Factors, Aug 18, 2020
Objective: We investigated how participants controlling a humanoid robotic arm's 3D endpoint posi... more Objective: We investigated how participants controlling a humanoid robotic arm's 3D endpoint position by moving their own hand are influenced by the robot's postures. We hypothesized that control would be facilitated (impeded) by biologically plausible (implausible) postures of the robot. Background: Kinematic redundancy, whereby different arm postures achieve the same goal, is such that a robotic arm or prosthesis could theoretically be controlled with less signals than constitutive joints. However, congruency between a robot's motion and our own is known to interfere with movement production. Hence, we expect the human-likeness of a robotic arm's postures during endpoint teleoperation to influence controllability. Method: Twenty-two able-bodied participants performed a target-reaching task with a robotic arm whose endpoint's 3D position was controlled by moving their own hand. They completed a two-condition experiment corresponding to the robot displaying either biologically plausible or implausible postures. Results: Upon initial practice in the experiment's first part, endpoint trajectories were faster and shorter when the robot displayed human-like postures. However, these effects did not persist in the second part, where performance with implausible postures appeared to have benefited from initial practice with plausible ones. Conclusion: Humanoid robotic arm endpoint control is impaired by biologically implausible joint coordinations during initial familiarization but not afterwards, suggesting that the human-likeness of a robot's postures is more critical for control in this initial period. Application: These findings provide insight for the design of robotic arm teleoperation and prosthesis control schemes, in order to favor better familiarization and control from their users.
Journal of Neuroscience Methods, Mar 1, 1993
An original voltage-clamp technique on axons from crayfish Procambarus clarkii is described in th... more An original voltage-clamp technique on axons from crayfish Procambarus clarkii is described in this paper. Its advantages are: a fast dissection leading to the availability of several fibers of different diameters (10-500 microns) that may contain different ion channels; and use of a double-electrode voltage clamp on a chosen fiber with good clamping characteristics (short time clamp and good space clamp, small leak conductance). Because of the absence of exogenous lipidic phase in the superfusion chamber, this technique appears particularly suited to studying how liposoluble neurotoxins affect nerve conduction. This method has been successfully applied to test the effect of a synthetic derivative (2-(1non-8enyl)-5(1non-8enyl)pyrrolidine (Pyr 9)) of ant venom alkaloids from Monomorium species on nerve conduction. We present here evidence of a strong blocking effect on inward current involved in spike conduction. The resting potential of the treated axons did not change and it appears that only the inward current was affected.
Bio-protocol, 2015
ABSTRACT Crayfish are omnivorous freshwater arthropods that naturally explore their environment d... more ABSTRACT Crayfish are omnivorous freshwater arthropods that naturally explore their environment during day and night, but also frequently hide under a shelter or in a hole in case of danger. They may be submitted to various stressors, including predation, social interactions or changes in environmental parameters (temperature, water quality, oxygen, etc.). It has been recently demonstrated that, as a consequence of stress, crayfish is able to adapt its exploratory behavior by restricting movements to protective areas, a response similar to the anxiety-like behavior (ALB) observed in rodents. To reveal such a behavior in an aquatic species, we designed a plus-shaped sub aquatic maze divided in two protective dark arms and two more aversive illuminated arms.The aim of this paradigm was to place crayfish in a conflicting situation between its innate curiosity for novel environment and its aversion for light (Leo, 2014; Pellow et al., 1985). Unstressed crayfish generally explore the whole maze, including illuminated arms. By contrast stressed crayfish remain preferentially in the dark arms(Fossat et al., 2014). Stressed crayfish injected with anxiolitics (chlordiazepoxide-CDZ), behave as unstressed animals. Several parameters, related to the light arms can be easily measured from video records by commercial software This protocol could be suitable for analyzing the effects of any stressful situation on ALB in crayfish, as well as in many other aquatic species.
The Journal of Experimental Biology, 2018
We injected serotonin (5-HT) into adult male crayfish before pairing them with size-matched non-i... more We injected serotonin (5-HT) into adult male crayfish before pairing them with size-matched non-injected competitors, and observed dyadic agonistic interactions. Paradoxically, 5-HT elicited opposite behavioral responses if the injected animal was opposed by a smaller or larger rival: the level of aggressiveness of the injected crayfish was higher when facing a larger rival but lower when facing a smaller rival. Our results indicate that the effects of 5-HT on aggressiveness are dependent on the perception of the relative size difference of the opponent. In both cases, however, 5-HT significantly delayed the decision to retreat. We conclude that 5-HT does not primarily act on aggressiveness but rather on the brain centers that integrate risk assessment and/or decision making, which then modulate the aggressive response. Our findings support a reinterpretation of the role of 5-HT in crustacean agonistic behavior that may be of interest for studies of other animals.
Science, Jun 13, 2014
Anxiety, a behavioral consequence of stress, has been characterized in humans and some vertebrate... more Anxiety, a behavioral consequence of stress, has been characterized in humans and some vertebrates, but not invertebrates. Here, we demonstrate that after exposure to stress, crayfish sustainably avoided the aversive illuminated arms of an aquatic plus-maze. This behavior was correlated with an increase in brain serotonin and was abolished by the injection of the benzodiazepine anxiolytic chlordiazepoxide. Serotonin injection into unstressed crayfish induced avoidance; again, this effect was reversed by injection with chlordiazepoxide. Our results demonstrate that crayfish exhibit a form of anxiety similar to that described in vertebrates, suggesting the conservation of several underlying mechanisms during evolution. Analyses of this ancestral behavior in a simple model reveal a new route to understanding anxiety and may alter our conceptions of the emotional status of invertebrates.
HAL (Le Centre pour la Communication Scientifique Directe), 1987
1.In intactHomarus gammarus, the swimmeret motor patterns present during the startle response and... more 1.In intactHomarus gammarus, the swimmeret motor patterns present during the startle response and in gravid females, are very different. Kinetics and electromyograms (EMGs) reveal that the major difference is that the curler muscles of the rami (endopodite and exopodite) are active in the first response and silent in the second (Figs. 2, 3, 4).2.An in vitro preparation has been used
HAL (Le Centre pour la Communication Scientifique Directe), 1995
International audienc
Experimental brain research. Supplementum, 1983
The Journal of Experimental Biology, 1997
Ants of the genus Monomorium are natural predators of the termite genus Reticulitermes. They use ... more Ants of the genus Monomorium are natural predators of the termite genus Reticulitermes. They use a spatulated sting apparatus to apply small amounts of venom to the cuticle of their prey (Kugler, 1979; Jones et al. 1991). This venom induces paralysis within less than 1 min of topical application. Analysis of the venom of the genera Monomorium and Solenopsis, two taxa from the subfamily Myrmicinae, identified 2,5-dialkylpyrrolidines, 2,5-dialkylpyrrolines and 2methyl-6-alkyl-piperidines as almost the only components (
Journal of comparative neurology, 2005
The phenomenon of afferent presynaptic inhibition has been intensively studied in the sensory neu... more The phenomenon of afferent presynaptic inhibition has been intensively studied in the sensory neurons of the chordotonal organ from the coxobasal joint (CBCO) of the crayfish leg. This has revealed that it has a number of discrete roles in these afferents, mediated by distinct populations of interneurons. Here we examine further the effect of presynaptic inhibition on action potentials in the CBCO afferents and investigate the nature of the synapses that mediate it. In the presence of picrotoxin, the action potential amplitude is increased and its half-width decreased, and a late depolarizing potential following the spike is increased in amplitude. Ultrastructural examination of the afferent terminals reveals that synaptic contacts on terminal branches are particularly abundant in the neuropil close to the main axon. Many of the presynaptic terminals contain small agranular vesicles, are of large diameter, and are immunoreactive for gamma-aminobutyric acid (GABA). These terminals are sometimes seen to make reciprocal connections with the afferents. Synaptic contacts from processes immunoreactive for glutamate are found on small-diameter afferent terminals. A few of the presynaptic processes contain numerous large granular vesicles and are immunoreactive for neither GABA nor glutamate. The effect that the observed reciprocal synapses might have was investigated by using a multicompartmental model of the afferent terminal.
European Journal of Neuroscience, Mar 1, 2006
The aim of this study was to investigate a potential mechanism for state‐dependent regulation of ... more The aim of this study was to investigate a potential mechanism for state‐dependent regulation of sensory‐motor transmission from sensory afferents of a proprioceptor to motoneurons (MNs) in the walking system of the crayfish. This study was performed using an in vitro preparation of thoracic ganglia including motor nerves and the proprioceptor that codes movements of the second joint (coxo‐basal chordotonal organ − CBCO) of the leg. Application of movements to the CBCO elicits resistance reflex responses intracellularly recorded from Dep MNs. This reflex response is enhanced when Dep MNs are depolarized either spontaneously or by current injection. This enhancement is abolished in the presence of scopolamine (an antagonist of muscarinic acetylcholine receptors). Using pharmacology, we demonstrate that the monosynaptic connection from CBCO sensory neurons to the Dep MNs includes both nicotinic and muscarinic components. In addition, the shape of monosynaptic excitatory postsynaptic potentials (EPSPs) depends on the membrane potential: at a subthreshold depolarizing membrane potential, the time constant of the falling phase of the EPSPs is significantly increased compared with its value at resting potential. This change is suppressed in the presence of scopolamine, indicating that the muscarinic component may contribute to the activation of the Dep MN pool by sensory activity. This state‐dependent amplification of the sensory input may be important for increasing the strength of sensory feedback at times when central activation of the Dep MNs is very strong (e.g. during walking).
Journal of Comparative Physiology A-neuroethology Sensory Neural and Behavioral Physiology, Feb 1, 1993
The sensory inputs to the common inhibitory motoneuron that innervates every leg muscle of the cr... more The sensory inputs to the common inhibitory motoneuron that innervates every leg muscle of the crayfish Procambarus clarkii (Girard) were analyzed by performing intracellular recordings from its neurite within the neuropil of the 5th thoracic ganglion. Two types of sensory inputs involved in locomotion were studied, those from a movement coding proprioceptor (the coxobasal chordotonal organ) and those from sensory neu rons coding contact forces exerted at the tip of the leg on the substrate (the dactyl sensory afferents). Sinusoidal movements applied to the chordotonal organ strand induced a stable biphasic response in the common inhibitory motoneuron that consisted of bursts of spikes during release and stretch of the strand, corresponding to raising and lowering of the leg, respectively. Using ramp movements imposed on the chordotonal strand, we demonstrated that only movement-coding chordotonal afferents produce excitatory post-synaptic potentials in the common inhibitory motoneuron; these connections are monosynaptic. Mechanical or electrical stimulation of the dactyl sensory afferents resulted in an increase in the tonic discharge of the common inhibitory motoneuron through polysynaptic excitatory pathways. These two types of sensory cues reinforce the central command of the common inhibitory motoneuron and contribute to enhancing its activity during leg movements, and thus facilitate the relaxation of tonic muscle fibres during locomotion.
Journal of Neurophysiology, Oct 1, 2002
The Journal of Experimental Biology, Feb 15, 2008
According to the size principle the fine control of muscle tension depends on the orderly recruit... more According to the size principle the fine control of muscle tension depends on the orderly recruitment of motor neurons from a heterogeneous pool. We took advantage of the small number of excitatory motor neurons (about 12) that innervate the depressor muscle of the crayfish walking leg to determine if the size principle applies to this muscle. We found that in accordance with the size principle, when stimulated by proprioceptive input, neurons with small extracellular spikes were recruited before neurons with medium or large spikes. Because only a small fraction of the motor neurons responded strongly enough to sensory input to be recruited in this way, we extended our analysis to all neurons by characterizing properties that have classically been associated with recruitment order such as speed of axonal conduction and extracellular spike amplitude. Through a combination of physiological and anatomical criteria we were able to identify seven classes of excitatory depressor motor neurons. The majority of these classes responded to proprioceptive input with a resistance reflex, while a few responded with an assistance reflex, and yet others did not respond. Our results are in general agreement with the size principle. However, we found qualitative differences between neuronal classes in terms of synaptic input and neuronal structure that would in theory be unnecessary, according to a strict interpretation of the size principle. We speculate that the qualitative heterogeneity observed may be due to the fact that the depressor is a complex muscle, consisting of two muscle bundles that share a single insertion but have multiple origins.
Journal of Neurophysiology, Jun 1, 1993
1. Central electrical coupling between primary afferent axons was investigated in an in vitro pre... more 1. Central electrical coupling between primary afferent axons was investigated in an in vitro preparation of the crayfish thoracic locomotor system by using intracellular recordings. 2. Intracellular injection of the dye Lucifer yellow in single afferents resulted in staining of one to three additional afferents through dye-coupling. Three-dimensional confocal imaging of dye-coupled axons revealed a large zone of close apposition that may correspond to the gap junction site. 3. A depolarization preceding the spike in one sensory terminal was shown to facilitate the excitatory postsynaptic potential occurring in postsynaptic motoneurons. Further, a spike in one afferent axon can depolarize other, electrically coupled, axons above spike threshold, resulting in an increased number of active afferents. 4. The electrical coupling occurred between sensory afferents of similar function. It may therefore serve to facilitate sensory signal transmission from functionally homologous afferents onto postsynaptic target neurons.
Proceedings of the National Academy of Sciences of the United States of America, Jul 3, 2007
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Papers by Daniel Cattaert