The dynamic clamp comes of age

Prinz, Astrid A.; Abbott, L. F.; Marder, Eve

doi:10.1016/j.tins.2004.02.004

Cited by 261 publications

(213 citation statements)

References 51 publications

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“…We used the dynamic clamp technique (Prinz et al 2004) to produce a virtual version of the heart interneuron-to-heart motoneuron synapse. The dynamic clamp both computes and injects, in real time (time step: 0.0001 s), a model of the synaptic current (I Syn ) based on the recorded intracellular membrane potential (V m ), a conductance [g Syn (t)], and a reversal potential (E Syn ) according to Ohm's law.…”

Section: Methodsmentioning

confidence: 99%

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Contribution of motoneuron intrinsic properties to fictive motor pattern generation

Wright

Calabrese

2011

Journal of Neurophysiology

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Wright TM Jr, Calabrese RL. Contribution of motoneuron intrinsic properties to fictive motor pattern generation. J Neurophysiol 106: 538-553, 2011. First published May 11, 2011 doi:10.1152/jn.00101.2011.-Previously, we reported a canonical ensemble model of the heart motoneurons that underlie heartbeat in the medicinal leech. The model motoneurons contained a minimal set of electrical intrinsic properties and received a synaptic input pattern based on measurements performed in the living system. Although the model captured the synchronous and peristaltic motor patterns observed in the living system, it did not match quantitatively the motor output observed. Because the model motoneurons had minimal intrinsic electrical properties, the mismatch between model and living system suggests a role for additional intrinsic properties in generating the motor pattern. We used the dynamic clamp to test this hypothesis. We introduced the same segmental input pattern used in the model to motoneurons isolated pharmacologically from their endogenous input in the living system. We show that, although the segmental input pattern determines the segmental phasing differences observed in motoneurons, the intrinsic properties of the motoneurons play an important role in determining their phasing, particularly when receiving the synchronous input pattern. We then used trapezoidal input waveforms to show that the intrinsic properties present in the living system promote phase advances compared with our model motoneurons. Electrical coupling between heart motoneurons also plays a role in shaping motoneuron output by synchronizing the activity of the motoneurons within a segment. These experiments provide a direct assessment of how motoneuron intrinsic properties interact with their premotor pattern of synaptic drive to produce rhythmic output.

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Section: Methodsmentioning

confidence: 99%

“…To test this hypothesis, we used the dynamic clamp technique (Prinz et al 2004;Sharp et al 1993) to construct hybrid networks in which heart motoneurons in the living system received the same synaptic conductance waveform introduced into our model motoneurons (Fig. 1).…”

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confidence: 99%

Contribution of motoneuron intrinsic properties to fictive motor pattern generation

Wright

Calabrese

2011

Journal of Neurophysiology

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“…To test whether the proposed improvement in spike timing by distance-dependent inhibition also holds in real cells, we applied artificial compound inhibitory conductances to dentate gyrus GCs by a dynamic clamp (35) (Fig. 6).…”

Section: Distance-dependent Inhibition Improves Entrainment Of Princimentioning

confidence: 99%

Strength and duration of perisomatic GABAergic inhibition depend on distance between synaptically connected cells

Strüber

Jónás

Bartos

2015

Proc. Natl. Acad. Sci. U.S.A.

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GABAergic perisoma-inhibiting fast-spiking interneurons (PIIs) effectively control the activity of large neuron populations by their wide axonal arborizations. It is generally assumed that the output of one PII to its target cells is strong and rapid. Here, we show that, unexpectedly, both strength and time course of PII-mediated perisomatic inhibition change with distance between synaptically connected partners in the rodent hippocampus. Synaptic signals become weaker due to lower contact numbers and decay more slowly with distance, very likely resulting from changes in GABA A receptor subunit composition. When distance-dependent synaptic inhibition is introduced to a rhythmically active neuronal network model, randomly driven principal cell assemblies are strongly synchronized by the PIIs, leading to higher precision in principal cell spike times than in a network with uniform synaptic inhibition.interneurons | synaptic transmission | dentate gyrus | basket cell | gamma oscillations G ABAergic parvalbumin (PV)-expressing fast-spiking perisoma-inhibiting interneurons (PIIs) provide powerful synaptic inhibition to large numbers of target cells distributed over several hundred micrometers of cortical space (1-5). Extent and density of their axonal projection together with the perisomatic location of their output synapses close to the site of postsynaptic action potential generation are thought to provide tight control over the activity of target cells. Moreover, PIIs usually interact with other PIIs by reciprocal chemical and electrical synapses, thereby forming interneuron (IN) networks (4, 6, 7), which have been proposed to orchestrate the activity of cortical circuits. PIIs have been shown to receive rapid synaptic excitation (8) and to provide fast, strong, and faithful inhibitory signals to their postsynaptic partners (3,5,6). This fast and reliable signaling phenotype has been hypothesized to support the synchronization of neuronal networks leading to rhythmic activity patterns predominantly in the gamma frequency ranges [30-50 Hz, low gamma; 50-90 Hz, midfrequency gamma; 90-150 Hz, high gamma (7, 9)]. Several lines of evidence indeed indicate that PIIs are critical for the emergence of gamma activity. PIIs discharge at high frequencies tightly phase-locked to gamma cycles in vivo (10-13), they can entrain the activity of large principal cell assemblies (2, 14, 15), and silencing them impairs cortical gamma oscillations (14, 16). Thus, fast-spiking PIIs are generally regarded as a reliably active IN type that paces activity of large principal cell populations by strong and fast uniform inhibition.However, uniformity of PII output signaling has only been assumed and never been tested experimentally. In fact, quantitative analysis of the PII axon morphology shows a gradual decline in axon collateral density with distance from the soma (17-19) frequently interpreted as a reduction in connection probability at larger distances (20, 21), comparable to observations from excitatory glutamatergic neurons in the neo...

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“…The use of digital parameters (square or sinusoidal waves), devoid of any intrinsic noise, likely underestimates the role of intrinsically variable components in the operation of neuronal networks (Le Masson et al 2002;Prinz et al 2004). Previous studies have shown how the introduction of physiological noise into a network enhances neuronal firing properties (Stacey and Durand 2002;van Rossum et al 2003).…”

Section: Why Is Flistim Efficacy Different From An Artificial Waveform?mentioning

confidence: 99%

The locomotor central pattern generator of the rat spinal cord in vitro is optimally activated by noisy dorsal root waveforms

Taccola

2011

Journal of Neurophysiology

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The spinal cord contains an intrinsic locomotor program driven by a central pattern generator that rhythmically activates flexor and extensor limb motor pools. Although long-lasting locomotor activity can be generated pharmacologically, trains of afferent stimuli trigger only few locomotor cycles. The present study investigated whether a new electrical stimulation protocol (termed FL istim) could elicit long-lasting fictive locomotion (FL) in the rat spinal cord in vitro. Thus, after first inducing FL by bath application of N-methyl-d-aspartate and serotonin, the recorded waveform obtained from a lumbar ventral root was digitized and then applied to either a lumbar dorsal root or the cauda equina following washout of pharmacological agents. Two FL istim cycles were the threshold input to evoke an episode of FL from ventral roots. Longer cycles (up to 1 min) induced sustained FL (up to 1 min) with stereotyped periodicity (2.2 ± 0.5 s), despite changing frequency (2–4 s) or cycle amplitude of FL istim. Gradual filtering out of the noise from FL istim trace concomitantly decreased the efficiency of FL so that stimulation with equivalent pure sinusoids produced asynchronous, irregular discharges only that could not be converted to FL by adding spontaneous basal activity. This study is the first demonstration that epochs of rhythmic locomotor-like oscillations applied to a dorsal root represent an efficient stimulus to evoke FL as long as they contain the electrophysiological noise produced within FL cycles. These observations suggest novel strategies to improve the efficiency of electrical stimulation delivered by clinical devices for neurorehabilitation after spinal injury.

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The dynamic clamp comes of age

Cited by 261 publications

References 51 publications

Contribution of motoneuron intrinsic properties to fictive motor pattern generation

Contribution of motoneuron intrinsic properties to fictive motor pattern generation

Strength and duration of perisomatic GABAergic inhibition depend on distance between synaptically connected cells

The locomotor central pattern generator of the rat spinal cord in vitro is optimally activated by noisy dorsal root waveforms

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