The myotonic mouse—A realistic model for the study of human recessive generalized myotonia

Rüdel, Reinhardt

doi:10.1016/0166-2236(90)90049-g

Cited by 21 publications

(5 citation statements)

References 12 publications

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“…The thalamostriatal projection forms excitatory glutamatergic synapses onto both direct- and indirect-pathway MSNs (Kemp and Powell, 1971; Wilson et al, 1983; Smith and Bolam, 1990; Doig et al, 2010; Reiner et al, 2010) that have properties distinct from corticostriatal synapses (Ding et al, 2008) and have been hypothesized to play a distinct role in striatal computations (Smith et al, 2011). Most importantly, striatal projections from some thalamic nuclei have been shown to produce a localized and dense terminal plexus (Deschenes et al, 1995; Deschenes and Bourassa, 1996; McFarland and Haber, 2001), similar to that described above for cortical PT neurons.…”

Section: A Model Of Motor Learning With a Thalamic Source Of Efferencmentioning

confidence: 99%

Oculomotor learning revisited: a model of reinforcement learning in the basal ganglia incorporating an efference copy of motor actions

Fee¹

2012

Front. Neural Circuits

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In its simplest formulation, reinforcement learning is based on the idea that if an action taken in a particular context is followed by a favorable outcome, then, in the same context, the tendency to produce that action should be strengthened, or reinforced. While reinforcement learning forms the basis of many current theories of basal ganglia (BG) function, these models do not incorporate distinct computational roles for signals that convey context, and those that convey what action an animal takes. Recent experiments in the songbird suggest that vocal-related BG circuitry receives two functionally distinct excitatory inputs. One input is from a cortical region that carries context information about the current “time” in the motor sequence. The other is an efference copy of motor commands from a separate cortical brain region that generates vocal variability during learning. Based on these findings, I propose here a general model of vertebrate BG function that combines context information with a distinct motor efference copy signal. The signals are integrated by a learning rule in which efference copy inputs gate the potentiation of context inputs (but not efference copy inputs) onto medium spiny neurons in response to a rewarded action. The hypothesis is described in terms of a circuit that implements the learning of visually guided saccades. The model makes testable predictions about the anatomical and functional properties of hypothesized context and efference copy inputs to the striatum from both thalamic and cortical sources.

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Section: A Model Of Motor Learning With a Thalamic Source Of Efferencmentioning

confidence: 99%

Oculomotor learning revisited: a model of reinforcement learning in the basal ganglia incorporating an efference copy of motor actions

Fee¹

2012

Front. Neural Circuits

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“…In the late 1970s, two spontaneous mouse mutations were detected (as reviewed in Ref. 444), one in the A2G strain in London and the other in the SWR/J strain in Bar Harbor, Maine. The behavioral abnormalities of the affected animals were very similar, and in both mutations the traits were transmitted as an autosomal recessive trait.…”

Section: Myotonic Micementioning

confidence: 99%

Voltage-Gated Ion Channels and Hereditary Disease

Lehmann‐Horn

Jurkat‐Rott

1999

Physiological Reviews

491

382

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By the introduction of technological advancement in methods of structural analysis, electronics, and recombinant DNA techniques, research in physiology has become molecular. Additionally, focus of interest has been moving away from classical physiology to become increasingly centered on mechanisms of disease. A wonderful example for this development, as evident by this review, is the field of ion channel research which would not be nearly as advanced had it not been for human diseases to clarify. It is for this reason that structure-function relationships and ion channel electrophysiology cannot be separated from the genetic and clinical description of ion channelopathies. Unique among reviews of this topic is that all known human hereditary diseases of voltage-gated ion channels are described covering various fields of medicine such as neurology (nocturnal frontal lobe epilepsy, benign neonatal convulsions, episodic ataxia, hemiplegic migraine, deafness, stationary night blindness), nephrology (X-linked recessive nephrolithiasis, Bartter), myology (hypokalemic and hyperkalemic periodic paralysis, myotonia congenita, paramyotonia, malignant hyperthermia), cardiology (LQT syndrome), and interesting parallels in mechanisms of disease emphasized. Likewise, all types of voltage-gated ion channels for cations (sodium, calcium, and potassium channels) and anions (chloride channels) are described together with all knowledge about pharmacology, structure, expression, isoforms, and encoding genes.

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“…For example, muscle fibers lacking ClC-1 are hyperexcitable, usually undergoing involuntary contractions after periods of voluntary activity and leading to muscle stiffness (Pusch, 2002). This condition, called myotonia congenita in humans, has also been identified in naturally occurring mutants of goat and mice (Bryant and Morales-Aguilera, 1971;Adrian and Bryant, 1974;Rudel, 1990).…”

Section: Introductionmentioning

confidence: 99%

Chloride currents from the transverse tubular system in adult mammalian skeletal muscle fibers

DiFranco

Herrera

Vergara

2010

Journal of General Physiology

123

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Chloride fluxes are the main contributors to the resting conductance of mammalian skeletal muscle fibers. ClC-1, the most abundant chloride channel isoform in this preparation, is believed to be responsible for this conductance. However, the actual distribution of ClC-1 channels between the surface and transverse tubular system (TTS) membranes has not been assessed in intact muscle fibers. To investigate this issue, we voltageclamped enzymatically dissociated short fibers using a two-microelectrode configuration and simultaneously recorded chloride currents (ICl) and di-8-ANEPPS fluorescence signals to assess membrane potential changes in the TTS. Experiments were conducted in conditions that blocked all but the chloride conductance. Fibers were equilibrated with 40 or 70 mM intracellular chloride to enhance the magnitude of inward ICl, and the specific ClC-1 blocker 9-ACA was used to eliminate these currents whenever necessary. Voltage-dependent di-8-ANEPPS signals and ICl acquired before (control) and after the addition of 9-ACA were comparatively assessed. Early after the onset of stimulus pulses, di-8-ANEPPS signals under control conditions were smaller than those recorded in the presence of 9-ACA. We defined as attenuation the normalized time-dependent difference between these signals. Attenuation was discovered to be ICl dependent since its magnitude varied in close correlation with the amplitude and time course of ICl. While the properties of ICl, and those of the attenuation seen in optical records, could be simultaneously predicted by model simulations when the chloride permeability (PCl) at the surface and TTS membranes were approximately equal, the model failed to explain the optical data if PCl was precluded from the TTS membranes. Since the ratio between the areas of TTS membranes and the sarcolemma is large in mammalian muscle fibers, our results demonstrate that a significant fraction of the experimentally recorded ICl arises from TTS contributions.

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The myotonic mouse—A realistic model for the study of human recessive generalized myotonia

Cited by 21 publications

References 12 publications

Oculomotor learning revisited: a model of reinforcement learning in the basal ganglia incorporating an efference copy of motor actions

Oculomotor learning revisited: a model of reinforcement learning in the basal ganglia incorporating an efference copy of motor actions

Voltage-Gated Ion Channels and Hereditary Disease

Chloride currents from the transverse tubular system in adult mammalian skeletal muscle fibers

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