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Daniel Cattaert - One of the best experts on this subject based on the ideXlab platform.

  • In vivo analysis of proprioceptive coding and its antidromic modulation in the freely behaving crayfish.
    Journal of Neurophysiology, 2005
    Co-Authors: Didier Le Ray, Denis Combes, Cyril Déjean, Daniel Cattaert
    Abstract:

    Although sensory nerves in vitro are known to convey both Orthodromic (sensory) and antidromic (putatively modulating) action potentials, in most cases very little is known about their bidirectional characteristics in intact animals. Here, we have investigated both the sensory coding properties and antidromic discharges that occur during real walking in the freely behaving crayfish. The activity of the sensory nerve innervating the proprioceptor CBCO, a chordotonal organ that monitors both angular movement and position of the coxo-basipodite (CB) joint, which is implicated in vertical leg movements, was recorded chronically along with the electromyographic activity of the muscles that control CB joint movements. Two wire electrodes placed on the sensory nerve were used to discriminate Orthodromic from antidromic action potentials and thus allowed for analysis of both sensory coding and antidromic discharges. A distinction is proposed between 3 main classes of sensory neuron, according to their firing in relation to levator muscle activity during free walking. In parallel, we describe 2 types of antidromic activity: one produced exclusively during motor activity and a second produced both during and in the absence of motor activity. A negative correlation was found between the activity of sensory neurons in each of the 3 classes and identified antidromic discharges during walking. Finally, a state-dependent plasticity of CBCO nerve activity has been found by which the distribution of sensory Orthodromic and antidromic activity changes with the physiological state of the biomechanical apparatus.

  • Effects of antidromic discharges in crayfish primary afferents.
    Journal of Neurophysiology, 2002
    Co-Authors: Daniel Cattaert, Michelle Bévengut
    Abstract:

    Contrary to Orthodromic spikes that are generated in sensory organs and conveyed to CNS, antidromic spikes are generated in the axon terminals of the sensory neurons within the CNS and are conveyed to the peripheral sensory organ. Antidromic discharges are observed in primary afferent neurons of both vertebrates and invertebrates and seem to be related to the rhythmic activity of central neural networks. In this study, we analyzed the effect of antidromic discharges on the sensory activity of a leg proprioceptor in in vitro preparations of the crayfish CNS. Intracellular microelectrodes were used both to record the Orthodromic spikes and to elicit antidromic spikes by injecting squares pulses of depolarizing current at various frequencies. Experiments were performed on the three types of identified sensory afferents (tonic, phasotonic, and phasic). The main results showed a reduction of the firing frequency of the Orthodromic activity in 82% of the tested afferents. In tonic afferents, during their occurrences and according to their frequency, antidromic spikes or bursts reduced or suppressed the Orthodromic activity. Following their terminations, they also induced a silent period and a gradual recovery of the Orthodromic activity, both of which increased as the duration and the frequency of the antidromic bursts increased. In phasotonic and phasic afferents, antidromic bursts reduced or suppressed the phasic responses as their frequency and durations increased. In phasotonic afferents, if elicited prior to the movements, long-duration bursts with increasing frequency reduced more rapidly the tonic background activity than the phasic one whereas short-duration bursts at high frequency produced strong decreases of both. The effect of antidromic bursts accumulated when they are repetitively elicited. Antidromic bursts induced a much larger decrease of the sensory activity than adaptation alone. The occurrences of antidromic spikes or bursts may have a functional role in modulating the incoming sensory messages during locomotion. The mechanisms by which antidromic spikes modulate the firing sensitivity of the primary afferents may well lie in modifications of the properties of either mecanotransduction and/or spike initiation.

Ja Hea Gu - One of the best experts on this subject based on the ideXlab platform.

Paul Seror - One of the best experts on this subject based on the ideXlab platform.

  • the medial antebrachial cutaneous nerve antidromic and Orthodromic conduction studies
    Muscle & Nerve, 2002
    Co-Authors: Paul Seror
    Abstract:

    Medial antebrachial cutaneous nerve (MABCN) conduction studies were performed antidromically and Orthodromically in 70 control subjects to determine normal values and define the lower limits of normality. The mean sensory action potential (SAP) amplitudes were 17.7 and 17.5 μV and the sensory conduction velocities were 60 and 61 m/s, respectively, with the antidromic and Orthodromic techniques. With both techniques, no SAP amplitude was lower than 6 μV. The lower limits of normal of the interside amplitude ratio were 1.66 when both techniques were used and 2.0 when only one was used. © 2002 Wiley Periodicals, Inc. Muscle Nerve 26: 421–423, 2002

  • comparative diagnostic sensitivities of Orthodromic or antidromic sensory inching test in mild carpal tunnel syndrome
    Archives of Physical Medicine and Rehabilitation, 2000
    Co-Authors: Paul Seror
    Abstract:

    Abstract Seror P. Comparative diagnostic sensitivities of Orthodromic or antidromic sensory inching test in mild carpal tunnel syndrome. Arch Phys Med Rehabil 2000;81:442-6. Objectives: To compare the reliability, sensitivity, and specificity of the "inching test" (IT) or "centimetric test," performed Orthodromically (OIT) and antidromically (AIT). Methods: Incremental palmar study of the sensory fibers of the median nerve was evaluated over 10cm across the wrist in 20 patients with mild carpal tunnel syndrome (CTS) and in 20 controls. Mild CTS was defined as clinical features of CTS with normal electrophysiologic findings by standard methods. The CTS patients were preselected with abnormal Orthodromic median-ulnar latency difference of the fourth digit (mean.66 ±.21ms; nl Results: In controls, the mean conduction delay per centimeter (CD/cm) was.192ms for OIT and.191ms for AIT; the mean maximum conduction delay per centimeter (MCD/cm) was.250 ±.032ms for OIT and.344 ±.10ms for AIT. MCD/cm was located inside the carpal tunnel in 85% of patients (OIT) versus 80% for AIT. No MCD/cm was greater than.32ms (OIT) or.60ms (AIT). With corresponding pathologic thresholds of.36ms (mean + 3.4 standard deviation [SD]) for OIT and.64ms (mean + 2.6 SD) for AIT, IT was abnormal in 20 patients (100%) with OIT compared with only 4 patients (20%) with AIT. Conclusions: The Orthodromic method was superior to the antidromic method in controls and in patients (χ 2 = 23; p = 1.8 × 10 −6 ). These findings suggest that Orthodromic IT should be used when standard electrodiagnostic tests fail to reveal median nerve sensory abnormality in persons with mild CTS. © 2000 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation

Raju Metherate - One of the best experts on this subject based on the ideXlab platform.

  • thalamic stimulation largely elicits Orthodromic rather than antidromic cortical activation in an auditory thalamocortical slice
    Neuroscience, 2001
    Co-Authors: Heather J Rose, Raju Metherate
    Abstract:

    Stimulation of the medial geniculate body in an auditory thalamocortical slice elicits a short-latency current sink in the middle cortical layers, as would be expected following activation of thalamocortical relay neurons. However, corticothalamic neurons can have axon collaterals that project to the middle layers, thus, a middle-layer current sink could also result from antidromic activation of corticothalamic neurons and their axon collaterals. The likelihood of thalamic stimulation activating corticothalamic neurons would be reduced substantially if the corticothalamic pathway was not well preserved in the slice, and/or if the threshold for antidromic activation was significantly higher than for Orthodromic activation. To determine the prevalence and threshold of antidromic activation, we recorded intracellularly from day 14-17 mouse brain slices containing infragranular cortical neurons while stimulating the medial geniculate or thalamocortical pathway. Antidromic spikes were confirmed by spike collision and characterized according to spike latency "jitter" and the ability to follow a high-frequency (100 Hz) stimulus train. The ability to follow a 100-Hz tetanus was a reliable indicator of antidromic activation, but both antidromic and Orthodromic spikes could have low jitter. Thalamic stimulation produced antidromic activation in two of 69 infragranular cortical neurons (<3%), indicating the presence of antidromic activity, but implying a limited corticothalamic connection in the slice. Antidromic spikes in 13 additional neurons were obtained by stimulating axons in the thalamocortical pathway. The antidromic threshold averaged 214+/-40.6 microA (range 6-475 microA), over seven times the Orthodromic threshold for medial geniculate-evoked responses in layer IV extracellular (28+/-5.4 microA) or intracellular (27+/-5.6 microA) recordings. We conclude that medial geniculate stimulation activates relatively few corticothalamic neurons. Conversely, low-intensity thalamic stimulation strongly activates thalamocortical neurons. Thus, at low-stimulus intensities, the auditory thalamocortical slice can be used to probe mechanisms of thalamocortical function with limited antidromic activation of corticothalamic neurons.

  • thalamic stimulation largely elicits Orthodromic rather than antidromic cortical activation in an auditory thalamocortical slice
    Neuroscience, 2001
    Co-Authors: Heather J Rose, Raju Metherate
    Abstract:

    Abstract Stimulation of the medial geniculate body in an auditory thalamocortical slice elicits a short-latency current sink in the middle cortical layers, as would be expected following activation of thalamocortical relay neurons. However, corticothalamic neurons can have axon collaterals that project to the middle layers, thus, a middle-layer current sink could also result from antidromic activation of corticothalamic neurons and their axon collaterals. The likelihood of thalamic stimulation activating corticothalamic neurons would be reduced substantially if the corticothalamic pathway was not well preserved in the slice, and/or if the threshold for antidromic activation was significantly higher than for Orthodromic activation. To determine the prevalence and threshold of antidromic activation, we recorded intracellularly from day 14–17 mouse brain slices containing infragranular cortical neurons while stimulating the medial geniculate or thalamocortical pathway. Antidromic spikes were confirmed by spike collision and characterized according to spike latency ‘jitter’ and the ability to follow a high-frequency (100 Hz) stimulus train. The ability to follow a 100-Hz tetanus was a reliable indicator of antidromic activation, but both antidromic and Orthodromic spikes could have low jitter. Thalamic stimulation produced antidromic activation in two of 69 infragranular cortical neurons ( We conclude that medial geniculate stimulation activates relatively few corticothalamic neurons. Conversely, low-intensity thalamic stimulation strongly activates thalamocortical neurons. Thus, at low-stimulus intensities, the auditory thalamocortical slice can be used to probe mechanisms of thalamocortical function with limited antidromic activation of corticothalamic neurons.

Dong Hee Kang - One of the best experts on this subject based on the ideXlab platform.

  • Orthodromic transfer of the temporalis muscle in incomplete facial nerve palsy
    Archives of Plastic Surgery, 2013
    Co-Authors: Dong Hee Kang, Sang Ah Oh, Ja Hea Gu
    Abstract:

    Background Temporalis muscle transfer produces prompt surgical results with a one-stage operation in facial palsy patients. The Orthodromic method is surgically simple, and the vector of muscle action is similar to the temporalis muscle action direction. This article describes transferring temporalis muscle insertion to reconstruct incomplete facial nerve palsy patients.

  • Orthodromic Transfer of the Temporalis Muscle in Incomplete Facial Nerve Palsy
    Korean Society of Plastic and Reconstructive Surgeons, 2013
    Co-Authors: Jae Ho Aum, Dong Hee Kang
    Abstract:

    Background Temporalis muscle transfer produces prompt surgical results with a one-stage operation in facial palsy patients. The Orthodromic method is surgically simple, and the vector of muscle action is similar to the temporalis muscle action direction. This article describes transferring temporalis muscle insertion to reconstruct incomplete facial nerve palsy patients.Methods Between August 2009 and November 2011, 6 unilateral incomplete facial nerve palsy patients underwent surgery for Orthodromic temporalis muscle transfer. A preauricular incision was performed to expose the mandibular coronoid process. Using a saw, the coronoid process was transected. Three strips of the fascia lata were anchored to the muscle of the nasolabial fold through subcutaneous tunneling. The tension of the strips was adjusted by observing the shape of the nasolabial fold. When optimal tension was achieved, the temporalis muscle was sutured to the strips. The surgical results were assessed by comparing pre- and postoperative photographs. Three independent observers evaluated the photographs.Results The symmetry of the mouth corner was improved in the resting state, and movement of the oral commissure was enhanced in facial animation after surgery.Conclusions The Orthodromic transfer of temporalis muscle technique can produce prompt results by applying the natural temporalis muscle vector. This technique preserves residual facial nerve function in incomplete facial nerve palsy patients and produces satisfying cosmetic outcomes without malar muscle bulging, which often occurs in the turn-over technique