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An efference copy or efferent ..

Efference copy of the CN waveform has been postulated as the mechanism by which individuals with CN suppress OSOP.

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Efference copy - an overview | ScienceDirect Topics

In a first stage, going minutely through three clinical case studies of psychotic patients cross-facing the psychodynamic and the sensorimotor data, has resulted in the proposition of an equivalence between the Freudian indices of reality and the sensorimotor efference copies. Though at the level of different psychological functions, our three cases of psychosis share as a common mechanism a failure of inhibition (at some level and at some moments). We propose to understand this failure of inhibition as equivalent to the psychodynamic understanding of the failure of repression in psychosis. Therefore, we end up with the idea that the attenuation enabled by the efference copy dynamics is, in some instances, the physiological instantiation of the mental mechanism of repression.

10Between “Abfuhrnachricht” (literally: efference message) and “efference copy.”

AB - Lesion studies argue for an involvement of cortical area dorsal medial superior temporal area (MSTd) in the control of optokinetic response (OKR) eye movements to planar visual stimulation. Neural recordings during OKR suggested that MSTd neurons directly encode stimulus velocity. On the other hand, studies using radial visual flow together with voluntary smooth pursuit eye movements showed that visual motion responses were modulated by eye movement-related signals. Here, we investigated neural responses in MSTd during continuous optokinetic stimulation using an information-theoretic approach for characterizing neural tuning with high resolution. We show that the majority of MSTd neurons exhibit gain-field-like tuning functions rather than directly encoding one variable. Neural responses showed a large diversity of tuning to combinations of retinal and extraretinal input. Eye velocity-related activity was observed prior to the actual eye movements, reflecting an efference copy. The observed tuning functions resembled those emerging in a network model trained to perform summation of 2 population-coded signals. Together, our findings support the hypothesis that MSTd implements the visuomotor transformation from retinal to head-centered stimulus velocity signals for the control of OKR.

Efference copy signals are used ..

10Between “Abfuhrnachricht” (literally: efference message) and “efference copy.”

N2 - The electrosensory system of elasmobranchs is extremely sensitive to weak electric fields, with behavioral thresholds having been reported at voltage gradients as low as 5 nV/cm. To achieve this amazing sensitivity, the electrosensory system must extract weak extrinsic signals from a relatively large reafferent background signal associated with the animal's own movements. Ventilatory movements, in particular, strongly modulate the firing rates of primary electrosensory afferent nerve fibers, but this modulation is greatly suppressed in the medullary electrosensory processing nucleus, the dorsal octavolateral nucleus. Experimental evidence suggests that the neural basis of reafference suppression involves a common-mode rejection mechanism supplemented by an adaptive filter that fine tunes the cancellation. We present a neural model and computer simulation results that support the hypothesis that the adaptive component may involve an anti-Hebbian form of synaptic plasticity at molecular layer synapses onto ascending efferent neurons, the principal output neurons of the nucleus. Parallel fibers in the molecular layer carry a wealth of proprioceptive, efference copy, and sensory signals related to the animal's own movements. The proposed adaptive mechanism acts by canceling out components of the electrosensory input signal that are consistently correlated with these internal reference signals.

AB - The electrosensory system of elasmobranchs is extremely sensitive to weak electric fields, with behavioral thresholds having been reported at voltage gradients as low as 5 nV/cm. To achieve this amazing sensitivity, the electrosensory system must extract weak extrinsic signals from a relatively large reafferent background signal associated with the animal's own movements. Ventilatory movements, in particular, strongly modulate the firing rates of primary electrosensory afferent nerve fibers, but this modulation is greatly suppressed in the medullary electrosensory processing nucleus, the dorsal octavolateral nucleus. Experimental evidence suggests that the neural basis of reafference suppression involves a common-mode rejection mechanism supplemented by an adaptive filter that fine tunes the cancellation. We present a neural model and computer simulation results that support the hypothesis that the adaptive component may involve an anti-Hebbian form of synaptic plasticity at molecular layer synapses onto ascending efferent neurons, the principal output neurons of the nucleus. Parallel fibers in the molecular layer carry a wealth of proprioceptive, efference copy, and sensory signals related to the animal's own movements. The proposed adaptive mechanism acts by canceling out components of the electrosensory input signal that are consistently correlated with these internal reference signals.

Efference copy | Wiki | Everipedia

The function of efference copy signals: Implications for symptoms of ..

The structural inhibition on emotional fragments thus induces (1) mental imagery with formal characteristics of the repressed fragment, i.e., phantoms, which result at the level of the psyche in mental preoccupation and symptoms (especially, symptoms with a signifier-marked form) and (2) spill-over effects which result in the return-of-the-repressed (such as e.g., forgetting of names and words, parapraxes, behavior tendencies etc.). Therefore the proposed model for the physiological instantiation of repression, with as a key supposition that the efference copy-induced attenuation of motor intentions is totally left unanswered, in order to radically prevent execution of an action which would lead to development of excess affect, yields the mental phenomena characteristic for neurosis (mental preoccupation, symptoms, and return-of-the-repressed). In addition, we have shown that not only in its results, but also in its dynamics, the sensorimotor model corresponds well with what Freud had already proposed starting from his Project in 1895. Note that this hypothesis also fits well with one of the main neuropsychoanalytic understandings of repression reviewed by Boag (, ), namely an inhibitory account with respect to competing responses and response selection.

So, at the one hand, inhibition mechanisms are structural for any targeted action or for normal language understanding and they are thought to induce representational activity or mental imagery through an efference copy-mechanism. At the other hand, due to this need for inhibitory selection, some emotional alternatives have to be submitted to a stronger form of inhibition. The degree of inhibition might determine the type of motor imagery induced. At the one hand, we propose that representations arise as the result of motor intention not exhaustively met by motor execution, i.e., in the gap between intended and executed movement. Therefore, they arise as a consequence of “normal” on-line action selection and inhibition in the course of targeting behavior. At the other hand, we propose that phantoms arise as the result of sustained motor activation which is systematically not met at all by any actual execution. Therefore, the species of mental imagery induced by this more radical inhibition, characteristic for repression, is thought to be of the “phantom”-type.

The Function of Efference Copy Signals: Implications for Symptoms of ..
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What Does Motor Efference Copy Represent? Evidence …

N2 - Lesion studies argue for an involvement of cortical area dorsal medial superior temporal area (MSTd) in the control of optokinetic response (OKR) eye movements to planar visual stimulation. Neural recordings during OKR suggested that MSTd neurons directly encode stimulus velocity. On the other hand, studies using radial visual flow together with voluntary smooth pursuit eye movements showed that visual motion responses were modulated by eye movement-related signals. Here, we investigated neural responses in MSTd during continuous optokinetic stimulation using an information-theoretic approach for characterizing neural tuning with high resolution. We show that the majority of MSTd neurons exhibit gain-field-like tuning functions rather than directly encoding one variable. Neural responses showed a large diversity of tuning to combinations of retinal and extraretinal input. Eye velocity-related activity was observed prior to the actual eye movements, reflecting an efference copy. The observed tuning functions resembled those emerging in a network model trained to perform summation of 2 population-coded signals. Together, our findings support the hypothesis that MSTd implements the visuomotor transformation from retinal to head-centered stimulus velocity signals for the control of OKR.

Efference copy is thought to reflect the ..

This mechanism is tenable only if the source of the subject's acquired oscillation occurred at a point beyond where the efference-copy signal is fed back.

Efference copy is an internal copy of a motor innervation

The authors conclude that the necessary condition for stable (i.e., no OSOP) vision in our subject was the ocular motor stability provided by repeatable, well-developed CN foveation periods (i.e., an efference copy of it) and without it, OSOP is not suppressed even during RIS.

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