Postnatal Changes in the Inactivation Properties of Voltage-Gated Sodium Channels Contribute to the Mature Firing Pattern of Spinal Motoneurons

Carlin, Kevin P.; Liu, J.; Jordan, Larry M.

doi:10.1152/jn.00059.2008

Cited by 8 publications

(6 citation statements)

References 71 publications

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“…The resting membrane potential ( E m ) obtained via the Goldman-Hodgkin-Katz equation is also shown. Conductance of the sodium channels is reduced in response to an increase in the membrane potential or the potassium reversal potential, and this voltage dependence has been previously reported (Kim and Chung, 1999; Carlin et al, 2008). In other words, the sodium channel is inactivated, i.e., there is no inward flow of current, if the neuron is excessively depolarized.…”

Section: Resultssupporting

confidence: 62%

Prediction of the Seizure Suppression Effect by Electrical Stimulation via a Computational Modeling Approach

Ahn

Jun

et al. 2017

Front. Comput. Neurosci.

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In this paper, we identified factors that can affect seizure suppression via electrical stimulation by an integrative study based on experimental and computational approach. Preferentially, we analyzed the characteristics of seizure-like events (SLEs) using our previous in vitro experimental data. The results were analyzed in two groups classified according to the size of the effective region, in which the SLE was able to be completely suppressed by local stimulation. However, no significant differences were found between these two groups in terms of signal features or propagation characteristics (i.e., propagation delays, frequency spectrum, and phase synchrony). Thus, we further investigated important factors using a computational model that was capable of evaluating specific influences on effective region size. In the proposed model, signal transmission between neurons was based on two different mechanisms: synaptic transmission and the electrical field effect. We were able to induce SLEs having similar characteristics with differentially weighted adjustments for the two transmission methods in various noise environments. Although the SLEs had similar characteristics, their suppression effects differed. First of all, the suppression effect occurred only locally where directly received the stimulation effect in the high noise environment, but it occurred in the entire network in the low noise environment. Interestingly, in the same noise environment, the suppression effect was different depending on SLE propagation mechanism; only a local suppression effect was observed when the influence of the electrical field transmission was very weak, whereas a global effect was observed with a stronger electrical field effect. These results indicate that neuronal activities synchronized by a strong electrical field effect respond more sensitively to partial changes in the entire network. In addition, the proposed model was able to predict that stimulation of a seizure focus region is more effective for suppression. In conclusion, we confirmed the possibility of a computational model as a simulation tool to analyze the efficacy of deep brain stimulation (DBS) and investigated the key factors that determine the size of an effective region in seizure suppression via electrical stimulation.

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Section: Resultssupporting

confidence: 62%

Prediction of the Seizure Suppression Effect by Electrical Stimulation via a Computational Modeling Approach

Ahn

Jun

et al. 2017

Front. Comput. Neurosci.

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“…The AP and half decay AHP are found to shorten significantly in duration (Table 1 ). The shape of AP is modified with a higher speed of depolarization in older animals probably linked with the density of sodium channels (García et al, 1998 ; Carlin et al, 2008 ) and a faster repolarization indicating potassium channels maturation (McLarnon, 1995 ; Gao and Ziskind-Conhaim, 1998 ; Nakanishi and Whelan, 2010 ). During the same time, some parameters of electrical properties remain constant such as the membrane potential, AP threshold and amplitude, gain at steady state and after hyperpolarization duration and amplitude (Table 1 ).…”

Section: Discussionmentioning

confidence: 99%

Developing electrical properties of postnatal mouse lumbar motoneurons

Durand

Filipchuk

Pambo-Pambo

et al. 2015

Front. Cell. Neurosci.

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We studied the rapid changes in electrical properties of lumbar motoneurons between postnatal days 3 and 9 just before mice weight-bear and walk. The input conductance and rheobase significantly increased up to P8. A negative correlation exists between the input resistance (Rin) and rheobase. Both parameters are significantly correlated with the total dendritic surface area of motoneurons, the largest motoneurons having the lowest Rin and the highest rheobase. We classified the motoneurons into three groups according to their discharge firing patterns during current pulse injection (transient, delayed onset, sustained). The delayed onset firing type has the highest rheobase and the fastest action potential (AP) whereas the transient firing group has the lowest rheobase and the less mature AP. We found 32 and 10% of motoneurons with a transient firing at P3–P5 and P8, respectively. About 20% of motoneurons with delayed onset firing were detected at P8. At P9, all motoneurons exhibit a sustained firing. We defined five groups of motoneurons according to their discharge firing patterns in response to ascending and descending current ramps. In addition to the four classical types, we defined a fifth type called transient for the quasi-absence of discharge during the descending phase of the ramp. This transient type represents about 40% between P3–P5 and tends to disappear with age. Types 1 and 2 (linear and clockwise hysteresis) are the most preponderant at P6–P7. Types 3 and 4 (prolonged sustained and counter clockwise hysteresis) emerge at P8–P9. The emergence of types 3 and 4 probably depends on the maturation of L type calcium channels in the dendrites of motoneurons. No correlation was found between groups defined by step or triangular ramp of currents with the exception of transient firing patterns. Our data support the idea that a switch in the electrical properties of lumbar motoneurons might exist in the second postnatal week of life in mice.

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“…Intracortical inhibition is not mature until adulthood and is reduced in the elderly (Peinemann et al, 2001;Mall et al, 2004;Walther et al, 2009). The morphological properties of alpha-motoneurons and their excitatory and inhibitory control mature during development and are altered in the elderly (O'Sullivan et al, 1991;Erim et al, 1999;Mc Donough et al, 2001;Mentis et al, 2002;Furlan et al, 2007;Carlin et al, 2008;Sibilla and Ballerini, 2009). Finally, both the diameter and excitability of corticospinal axons increase during adolescence Müller and Hömberg, 1992) while white matter hyperintensities within the corticospinal tract become prevalent in old age (Moscufo et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

Developmental Tuning and Decay in Senescence of Oscillations Linking the Corticospinal System

Graziadio¹,

Basu²,

Tomasevic³

et al. 2010

J. Neurosci.

101

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There is increasing evidence of the importance of synchronous activity within the corticospinal system for motor control. We compared oscillatory activity in the primary sensorimotor cortex [EEG of sensorimotor cortex (SMC-EEG)] and a motor neuronal pool [surface electromyogram of opponens pollicis (OP-EMG)], and their coherence in children (4 -12 years of age), young adults (20 -35 years of age), and elderly adults (Ͼ55 years of age). The ratio between lower (2-13 Hz) and higher (14 -32 Hz) frequencies in both SMC-EEG and OP-EMG decreased with age, correlating inversely with motor performance. There was evidence for larger, more distributed cortical networks in the children and elderly compared with young adults. Corticomuscular coherence (CMC) was present in all age groups and shifted between frontal and parietal cortical areas. In children, CMC was smaller and less stationary in amplitude and frequency than in adults. Young adults had single peaks of CMC clustered near the modal frequency (23 Hz); multiple peaks with a broad spread of frequencies occurred in children and the elderly; the further the frequency of the maximum peak CMC was from 23 Hz, the poorer the performance. CMC amplitude was inversely related to performance in young adults but was not modulated in relation to performance in children and the elderly. We propose that progressive fine-tuning of the frequency coding and stabilization of the dynamic properties within and between corticospinal networks occurs during adolescence, refining the capacity for efficient dynamic communication in adulthood. In old age, blurring of the tuning between networks and breakdown in their integration occurs and is likely to contribute to a decrement in motor control.

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Postnatal Changes in the Inactivation Properties of Voltage-Gated Sodium Channels Contribute to the Mature Firing Pattern of Spinal Motoneurons

Cited by 8 publications

References 71 publications

Prediction of the Seizure Suppression Effect by Electrical Stimulation via a Computational Modeling Approach

Prediction of the Seizure Suppression Effect by Electrical Stimulation via a Computational Modeling Approach

Developing electrical properties of postnatal mouse lumbar motoneurons

Developmental Tuning and Decay in Senescence of Oscillations Linking the Corticospinal System

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