scholarly journals Homeostatic plasticity rules that compensate for cell size are susceptible to channel deletion

2019 ◽  
Author(s):  
Srinivas Gorur-Shandilya ◽  
Eve Marder ◽  
Timothy O’Leary
Keyword(s):  
Cell Size ◽  
Activity Patterns ◽  
Central Pattern Generators ◽  
Homeostatic Plasticity ◽  
Regulation Mechanism ◽  
Neuron Models ◽  
Size Change ◽  
Biological Regulation ◽  
Simple Activity ◽  
Pattern Generators

AbstractNeurons can increase in size dramatically during growth. In many species neurons must preserve their intrinsic dynamics and physiological function across several length scales. For example, neurons in crustacean central pattern generators generate similar activity patterns despite multiple-fold increases in their size and changes in morphology. This scale invariance hints at regulation mechanisms that compensate for size changes by somehow altering membrane currents. Using conductance-based neuron models, we asked whether simple activity-dependent feedback can maintain intrinsic voltage dynamics in a neuron as its size is varied. Despite relying only on a single sensor that measures time-averaged intracellular calcium as a proxy for activity, we found that this regulation mechanism could regulate conductance densities of ion channels, and was robust to changes in the size of the neuron. By mapping changes in cell size onto perturbations in the space of conductance densities of all channels, we show how robustness to size change coexists with sensitivity to perturbations that alter the ratios of maximum conductances of different ion channel types. Our findings suggest that biological regulation that is optimized for coping with expected perturbations such as size changes will be vulnerable to other kinds of perturbations such as channel deletions.

scholarly journals Asymmetric and transient properties of reciprocal activity of antagonists during the paw-shake response in the cat

2021 ◽  
Vol 17 (12) ◽  
pp. e1009677
Author(s):  
Jessica R. Parker ◽  
Alexander N. Klishko ◽  
Boris I. Prilutsky ◽  
Gennady S. Cymbalyuk
Keyword(s):  
Activity Patterns ◽  
Central Pattern Generators ◽  
Emg Activity ◽  
Rhythmic Movements ◽  
Related Activity ◽  
Fast Transient Response ◽  
Hindlimb Muscles ◽  
Pattern Generators ◽  
A Current

Mutually inhibitory populations of neurons, half-center oscillators (HCOs), are commonly involved in the dynamics of the central pattern generators (CPGs) driving various rhythmic movements. Previously, we developed a multifunctional, multistable symmetric HCO model which produced slow locomotor-like and fast paw-shake-like activity patterns. Here, we describe asymmetric features of paw-shake responses in a symmetric HCO model and test these predictions experimentally. We considered bursting properties of the two model half-centers during transient paw-shake-like responses to short perturbations during locomotor-like activity. We found that when a current pulse was applied during the spiking phase of one half-center, let’s call it #1, the consecutive burst durations (BDs) of that half-center increased throughout the paw-shake response, while BDs of the other half-center, let’s call it #2, only changed slightly. In contrast, the consecutive interburst intervals (IBIs) of half-center #1 changed little, while IBIs of half-center #2 increased. We demonstrated that this asymmetry between the half-centers depends on the phase of the locomotor-like rhythm at which the perturbation was applied. We suggest that the fast transient response reflects functional asymmetries of slow processes that underly the locomotor-like pattern; e.g., asymmetric levels of inactivation across the two half-centers for a slowly inactivating inward current. We compared model results with those of in-vivo paw-shake responses evoked in locomoting cats and found similar asymmetries. Electromyographic (EMG) BDs of anterior hindlimb muscles with flexor-related activity increased in consecutive paw-shake cycles, while BD of posterior muscles with extensor-related activity did not change, and vice versa for IBIs of anterior flexors and posterior extensors. We conclude that EMG activity patterns during paw-shaking are consistent with the proposed mechanism producing transient paw-shake-like bursting patterns found in our multistable HCO model. We suggest that the described asymmetry of paw-shaking responses could implicate a multifunctional CPG controlling both locomotion and paw-shaking.

scholarly journals Activity-dependent compensation of cell size is vulnerable to targeted deletion of ion channels

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Srinivas Gorur-Shandilya ◽  
Eve Marder ◽  
Timothy O’Leary
Keyword(s):  
Ion Channels ◽  
Cell Size ◽  
Calcium Influx ◽  
Central Pattern Generators ◽  
Feedback Mechanism ◽  
Regulation Mechanism ◽  
Membrane Area ◽  
Channel Density ◽  
Channel Expression ◽  
Regulation Mechanisms

Abstract In many species, excitable cells preserve their physiological properties despite significant variation in physical size across time and in a population. For example, neurons in crustacean central pattern generators generate similar firing patterns despite several-fold increases in size between juveniles and adults. This presents a biophysical problem because the electrical properties of cells are highly sensitive to membrane area and channel density. It is not known whether specific mechanisms exist to sense membrane area and adjust channel expression to keep a consistent channel density, or whether regulation mechanisms that sense activity alone are capable of compensating cell size. We show that destabilising effects of growth can be specifically compensated by feedback mechanism that senses average calcium influx and jointly regulate multiple conductances. However, we further show that this class of growth-compensating regulation schemes is necessarily sensitive to perturbations that alter the expression of subsets of ion channel types. Targeted perturbations of specific ion channels can trigger a pathological response of the regulation mechanism and a failure of homeostasis. Our findings suggest that physiological regulation mechanisms that confer robustness to growth may be specifically vulnerable to deletions or mutations that affect subsets of ion channels.

scholarly journals Diversity of molecularly defined spinal interneurons engaged in mammalian locomotor pattern generation

2017 ◽  
Vol 118 (6) ◽  
pp. 2956-2974 ◽  
Author(s):  
Lea Ziskind-Conhaim ◽  
Shawn Hochman
Keyword(s):  
Activity Patterns ◽  
Central Pattern Generators ◽  
Pattern Generation ◽  
Model Systems ◽  
Locomotor Rhythm ◽  
Spinal Interneurons ◽  
Adult Mice ◽  
Descending Fibers ◽  
Experimental Model Systems ◽  
Pattern Generators

Mapping the expression of transcription factors in the mouse spinal cord has identified ten progenitor domains, four of which are cardinal classes of molecularly defined, ventrally located interneurons that are integrated in the locomotor circuitry. This review focuses on the properties of these interneuronal populations and their contribution to hindlimb locomotor central pattern generation. Interneuronal populations are categorized based on their excitatory or inhibitory functions and their axonal projections as predictors of their role in locomotor rhythm generation and coordination. The synaptic connectivity and functions of these interneurons in the locomotor central pattern generators (CPGs) have been assessed by correlating their activity patterns with motor output responses to rhythmogenic neurochemicals and sensory and descending fibers stimulations as well as analyzing kinematic gait patterns in adult mice. The observed complex organization of interneurons in the locomotor CPG circuitry, some with seemingly similar physiological functions, reflects the intricate repertoire associated with mammalian motor control and is consistent with high transcriptional heterogeneity arising from cardinal interneuronal classes. This review discusses insights derived from recent studies to describe innovative approaches and limitations in experimental model systems and to identify missing links in current investigational enterprise.

scholarly journals Compensatory plasticity restores locomotion after chronic removal of descending projections

2015 ◽  
Vol 113 (10) ◽  
pp. 3610-3622 ◽  
Author(s):  
Cynthia M. Harley ◽  
Melissa G. Reilly ◽  
Christopher Stewart ◽  
Chantel Schlegel ◽  
Emma Morley ◽  
...  
Keyword(s):  
Time Course ◽  
Central Pattern Generators ◽  
Homeostatic Plasticity ◽  
Descending Inhibition ◽  
Similar Time ◽  
Locomotor Recovery ◽  
Cord Injury ◽  
Hirudo Verbana ◽  
Pattern Generators ◽  
Compensatory Plasticity

Homeostatic plasticity is an important attribute of neurons and their networks, enabling functional recovery after perturbation. Furthermore, the directed nature of this plasticity may hold a key to the restoration of locomotion after spinal cord injury. Here we studied the recovery of crawling in the leech Hirudo verbana after descending cephalic fibers were surgically separated from crawl central pattern generators shown previously to be regulated by dopamine. We observed that immediately after nerve cord transection leeches were unable to crawl, but remarkably, after a day to weeks, animals began to show elements of crawling and intersegmental coordination. Over a similar time course, excessive swimming due to the loss of descending inhibition returned to control levels. Additionally, removal of the brain did not prevent crawl recovery, indicating that connectivity of severed descending neurons was not essential. After crawl recovery, a subset of animals received a second transection immediately below the anterior-most ganglion remaining. Similar to their initial transection, a loss of crawling with subsequent recovery was observed. These data, in recovered individuals, support the idea that compensatory plasticity directly below the site of injury is essential for the initiation and coordination of crawling. We maintain that the leech provides a valuable model to understand the neural mechanisms underlying locomotor recovery after injury because of its experimental accessibility, segmental organization, and dependence on higher-order control involved in the initiation, modulation, and coordination of locomotor behavior.

scholarly journals Speed dependency in α-motoneuron activity and locomotor modules in human locomotion: indirect evidence for phylogenetically conserved spinal circuits

2017 ◽  
Vol 284 (1851) ◽  
pp. 20170290 ◽  
Author(s):  
Hikaru Yokoyama ◽  
Tetsuya Ogawa ◽  
Masahiro Shinya ◽  
Noritaka Kawashima ◽  
Kimitaka Nakazawa
Keyword(s):  
High Speed ◽  
Neural Control ◽  
Activity Patterns ◽  
Central Pattern Generators ◽  
Indirect Evidence ◽  
Speed Control ◽  
Human Locomotion ◽  
Control Mechanisms ◽  
Activation Patterns ◽  
Pattern Generators

Coordinated locomotor muscle activity is generated by the spinal central pattern generators (CPGs). Vertebrate studies have demonstrated the following two characteristics of the speed control mechanisms of the spinal CPGs: (i) rostral segment activation is indispensable for achieving high-speed locomotion; and (ii) specific combinations between spinal interneuronal modules and motoneuron (MN) pools are sequentially activated with increasing speed. Here, to investigate whether similar control mechanisms exist in humans, we examined spinal neural activity during varied-speed locomotion by mapping the distribution of MN activity in the spinal cord and extracting locomotor modules, which generate basic MN activation patterns. The MN activation patterns and the locomotor modules were analysed from multi-muscle electromyographic recordings. The reconstructed MN activity patterns were divided into the following three patterns depending on the speed of locomotion: slow walking, fast walking and running. During these three activation patterns, the proportion of the activity in rostral segments to that in caudal segments increased as locomotion speed increased. Additionally, the different MN activation patterns were generated by distinct combinations of locomotor modules. These results are consistent with the speed control mechanisms observed in vertebrates, suggesting phylogenetically conserved spinal mechanisms of neural control of locomotion.

The Design of Central Pattern Generators Based on the Matsuoka Oscillator to Generate Rhythmic Human-Like Movement for Biped Robots

2007 ◽  
Vol 11 (8) ◽  
pp. 946-955 ◽  
Author(s):  
Guang Lei Liu ◽  
◽  
Maki K. Habib ◽  
Keigo Watanabe ◽  
Kiyotaka Izumi
Keyword(s):  
Degrees Of Freedom ◽  
Central Pattern Generators ◽  
Biped Robot ◽  
Coupling Coefficients ◽  
Neuron Models ◽  
Bipedal Robots ◽  
Biped Robots ◽  
Coupling Dynamics ◽  
Pattern Generators ◽  
6 Degrees Of Freedom

We propose a controller based on a central pattern generator (CPG) network of mutually coupled Matsuoka nonlinear neural oscillators to generate rhythmic human-like movement for biped robots. The parameters of mutually inhibited and coupled Matsuoka oscillators and the necessary interconnection coupling coefficients within the CPG network directly influence the generation of the required rhythmic signals related to targeted motion. Our objective is to analyze the mutually coupled neuron models of Matsuoka oscillators to realize an efficient CPG design that leads to have dynamic, stable, sustained rhythmic movement with robust gaits for bipedal robots. We discuss the design of a CPG model with new interconnection coupling links and its inhibitation coefficients for a CPG-based controller. The new design was studied through interaction between simulated interconnection coupling dynamics with six links and a musculoskeletal model with the 6 degrees of freedom (DOFs) of a biped robot. We used the weighted outputs of mutually inhibited oscillators as torques to actuate joints. We verified the effectiveness of our proposal through simulation and compared the results to those of Taga’s CPG model, confirming better, more efficient generation of stable rhythmic walking at different speeds and robustness in response to disturbances.

scholarly journals Central pattern generation underlying Limulus rhythmic behavior patterns

2010 ◽  
Vol 56 (5) ◽  
pp. 537-549 ◽  
Author(s):  
Gordon A. Wyse
Keyword(s):  
Sensory Input ◽  
Horseshoe Crab ◽  
Neural Circuits ◽  
Activity Patterns ◽  
Central Pattern Generators ◽  
Pattern Generation ◽  
Rhythmic Behavior ◽  
Behavioral Activities ◽  
Pattern Generators ◽  
Rhythmic Behaviors

Abstract Many behavioral activities of the horseshoe crab Limulus are rhythmic, and most of these are produced in large part by central pattern generators within the CNS. The chain of opisthosomal ('abdominal') ganglia controls gill movements of ventilation and gill cleaning, and the prosomal ring of fused ganglia (brain and segmental 'thoracic' ganglia) controls generation of feeding and locomotor movements of the legs. Both the opisthosomal CNS and the prosomal CNS can generate behaviorally appropriate patterns of motor output in isolation, without movements or sensory input. Preparations of the isolated opisthosomal CNS generate rhythmic output patterns of motor activity characterized as fictive ventilatory and gill cleaning rhythms. Moreover, CNS preparations also express longer-term patterns, such as intermittent ventilation or sequential bouts of ventilation and gill cleaning. Such longer-term patterns are commonly observed in intact animals. The isolated prosomal CNS does not spontaneously generate the activity patterns characteristic of walking, swimming, and feeding. However, perfusion of octopamine in the isolated prosomal CNS activates central pattern generators underlying rhythmic chewing movements, and injection of octopamine into intact Limulus promotes the chewing pattern of feeding, whether or not food is presented. Our understanding of the ability of neuromodulators such as octopamine to elicit or alter central motor programs may help to clarify the central neural circuits of pattern generation that produce and coordinate these rhythmic behaviors.

Effect of Central Pattern Generators Depended Different Walking Strategies on Gait Ability of Patients after Stroke

2017 ◽  
Vol 27 (2) ◽  
pp. 40
Author(s):  
Hua WU ◽  
Zaihua RU ◽  
Congying XU ◽  
Xudong GU ◽  
Jianming FU
Keyword(s):  
Central Pattern Generators ◽  
Pattern Generators

Rhythmic Pattern Generation in Invertebrates

2018 ◽  
pp. 390-400
Author(s):  
Astrid A. Prinz
Keyword(s):  
Central Pattern Generators ◽  
Pattern Generation ◽  
Rhythmic Pattern ◽  
Neuronal Circuit ◽  
Neuronal Circuits ◽  
Timing Circuit ◽  
Core Components ◽  
Pattern Generators

This chapter begins by defining central pattern generators (CPGs) and proceeds to focus on one of their core components, the timing circuit. After arguing why invertebrate CPGs are particularly useful for the study of neuronal circuit operation in general, the bulk of the chapter then describes basic mechanisms of CPG operation at the cellular, synaptic, and network levels, and how different CPGs combine these mechanisms in various ways. Finally, the chapter takes a semihistorical perspective to discuss whether or not the study of invertebrate CPGs has seen its prime and what it has contributed—and may continue to offer—to a wider understanding of neuronal circuits in general.

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