Timing dependent potentiation and depression of electrical synapses contributes to network stability in the crustacean cardiac ganglion.

Central pattern generators produce many rhythms necessary for survival (e.g., chewing, breathing, locomotion) and doing so often requires coordination of neurons through electrical synapses. Because even neurons of the same type within a network are often differentially tuned, uniformly applied neuromodulators or toxins can result in uncoordinated activity. In the crab (Cancer borealis) cardiac ganglion, potassium channel blockers and serotonin cause increased depolarization of the five electrically coupled motor neurons as well as loss of the normally completely synchronous activity. Given time, compensation occurs that restores excitability and synchrony. One of the underlying mechanisms of this compensation is an increase in coupling among neurons. However, the salient physiological signal that initiates increased coupling has not been determined. Using male C. borealis, we show that it is the loss of synchronous voltage signals between coupled neurons that is at least partly responsible for plasticity in coupling. Shorter offsets in naturalistic activity across a gap junction enhance coupling, while longer delays depress coupling. We also provide evidence as to why a desynchronization-specific potentiation or depression of the synapse could ultimately be adaptive through using a hybrid network created by artificially coupling two cardiac ganglia. Specifically, a stray neuron may be "brought back" in line by increasing coupling if its activity is closer to the remainder of the network. However, if a neuron's activity is far outside network parameters, it is detrimental to increase coupling and therefore depression of the synapse removes a potentially harmful influence on the network.SIGNIFICANCE STATEMENTUnderstanding how neural networks maintain output over years despite environmental and physiological challenges requires understanding the regulatory principles of these networks. Here we study how cells that are synchronously active at baseline respond to becoming desynchronized. In this system, a loss of synchrony causes different parts of the heart to receive uncoordinated stimulation. We find a calcium-dependent control mechanism which alters the strength of electrical connections between motor neurons. While others have described similar control mechanisms, here we demonstrate that voltage changes are sufficient to elicit regulation. Furthermore, we demonstrate that strong connections in a sufficiently perturbed network can prevent any neuron from producing its target activity, thus suggesting why the connections are not constitutively as strong as possible.

Motor neurons within a network use cell-type specific feedback mechanisms to constrain relationships among ion channel mRNAs.

Recently, activity has been proposed as a primary feedback mechanism used by continuously bursting neurons to coordinate ion channel mRNA relationships that underlie stable output. However, some neuron types only have intermittent periods of activity and so may require alternative mechanisms that induce and constrain the appropriate ion channel profile in different states of activity. To address this, we used the pyloric dilator (PD; constitutively active) and the lateral gastric (LG; periodically active) neurons of the stomatogastric ganglion (STG) of the crustacean Cancer borealis. We experimentally stimulated descending inputs to the STG to cause release of neuromodulators known to elicit the active state of LG neurons and quantified the mRNA abundances and pairwise relationships of 11 voltage-gated ion channels in active and silent LG neurons. The same stimulus does not significantly alter PD activity. Activation of LG upregulated ion channel mRNAs and lead to a greater number of positively correlated pairwise channel mRNA relationships. Conversely, this stimulus did not induce major changes in ion channel mRNA abundances and relationships of PD cells, suggesting their ongoing activity is sufficient to maintain channel mRNA relationships even under changing modulatory conditions. In addition, we found that ion channel mRNA correlations induced by the active state of LG are influenced by a combination of activity- and neuromodulator-dependent feedback mechanisms. Interestingly, some of these same correlations are maintained by distinct mechanisms in PD, suggesting that these motor networks use distinct feedback mechanisms to coordinate the same mRNA relationships across neuron types.NEW & NOTEWORTHY Neurons use various feedback mechanisms to adjust and maintain their output. Here, we demonstrate that different neurons within the same network can use distinct signaling mechanisms to regulate the same ion channel mRNA relationships.

Imaging neuro-urodynamics of mouse major pelvic ganglion with a micro-endoscopic approach.

Postganglionic neurons of the autonomic nervous system lie outside of the central nervous system and innervate specific target effectors such as organs or glands. The major pelvic ganglion (MPG) is one such ganglion that plays a significant role in controlling bladder function in rodents. However, because of technical and physical constraints in recording electrophysiological signals from these neurons in vivo, the functional neural activity in MPG is mostly unknown. Transgenic animal models expressing genetically encoded calcium indicators now provide opportunities to monitor the activity of populations of neurons in vivo to overcome these challenges related to traditional electrophysiological methods. However, like many peripheral neurons, the MPG is not conducive to conventional fluorescent microscopy techniques, as it is located in the pelvic cavity, thus limiting robust optical access by benchtop microscopes. Here, we present an endoscopic approach based on a custom miniscope system (UCLA V3) that allows for effective in vivo monitoring of neural activity in the MPG for the first time. We show that our imaging approach can monitor activity of hundreds of MPG neurons simultaneously during the filling and emptying of the bladder in a urethane-anesthetized transgenic mouse line expressing GCaMP6s in cholinergic MPG neurons. By using custom analysis scripts, we isolated the activity of hundreds of individual neurons and show that populations of neurons have distinct phasic activation patterns during sequential bladder filling and voiding events. Our imaging approach can be adapted to record activity from autonomic neurons across different organs and systems in both healthy and disease models.NEW & NOTEWORTHY The functional activity and information processing within autonomic ganglia is mostly unknown because of technical and physical constraints in recording electrophysiological signals from these neurons in vivo. Here, we use a micro-endoscopic approach to measure in vivo functional activity patterns from a population of autonomic neurons controlling bladder function for the first time. This approach can be adapted to record activity from autonomic neurons across different organs and systems in both healthy and disease models.

Spinal cord injury is associated with changes in synaptic properties of the mouse major pelvic ganglion.

Spinal cord injury (SCI) has substantial impacts on autonomic function. In part, SCI results in loss of normal autonomic activity that contributes to injury-associated pathology such as neurogenic bladder, bowel, and sexual dysfunction. Yet little is known of the impacts of SCI on peripheral autonomic neurons that directly innervate these target organs. In this study, we measured changes in synaptic properties of neurons of the mouse major pelvic ganglion (MPG) associated with acute and chronic SCI. Our data show that functional and physiological properties of synapses onto MPG neurons are altered after SCI and differ between acute and chronic injury. After acute injury excitatory postsynaptic potentials (EPSPs) show increased rise and decay time constants leading to overall broader and longer EPSPs, whereas in chronic-injured animals EPSPs are reduced in amplitude and show faster rise and decay leading to shorter EPSPs. Synaptic depression and low-pass filtering are also altered in injured animals. Finally, cholinergic currents are smaller in acute-injured animals but larger in chronic-injured animals relative to control animals. These changes in synaptic properties are associated with differences in nicotinic receptor subunit expression as well. MPG CHRNA3 mRNA levels decreased after injury, whereas CHRNA4 mRNAs increased. Furthermore, changes in the correlations of α- and ß-subunit mRNAs suggest that nicotinic receptor subtype composition is altered after injury. Taken together, our data demonstrate that peripheral autonomic neurons are fundamentally altered after SCI, suggesting that longer-term therapeutic approaches could target these neurons directly to potentially help ameliorate neurogenic target organ dysfunction.NEW & NOTEWORTHY Spinal cord injury (SCI) has substantial impacts on autonomic function, yet little is known of the impacts of SCI on autonomic neurons that directly innervate effectors impacted by injury. Here we investigated changes at the cellular level associated with SCI in neurons that are "downstream" of the central injury. An understanding of these off-target impacts of SCI ultimately will be critical in the context of effective restoration of function through neuromodulation of pharmacological therapeutic approaches.

Accuracy of mixture item response theory models for identifying sample heterogeneity in patient-reported outcomes: a simulation study.

PURPOSE: Mixture item response theory (MixIRT) models can be used to uncover heterogeneity in responses to items that comprise patient-reported outcome measures (PROMs). This is accomplished by identifying relatively homogenous latent subgroups in heterogeneous populations. Misspecification of the number of latent subgroups may affect model accuracy. This study evaluated the impact of specifying too many latent subgroups on the accuracy of MixIRT models. METHODS: Monte Carlo methods were used to assess MixIRT accuracy. Simulation conditions included number of items and latent classes, class size ratio, sample size, number of non-invariant items, and magnitude of between-class difference in item parameters. Bias and mean square error in item parameters and accuracy of latent class recovery were assessed. RESULTS: When the number of latent classes was correctly specified, the average bias and MSE in model parameters decreased as the number of items and latent classes increased, but specification of too many latent classes resulted in modest decrease (i.e., < 10%) in the accuracy of latent class recovery. CONCLUSION: The accuracy of MixIRT model is largely influenced by the overspecification of the number of latent classes. Appropriate choice of goodness-of-fit measures, study design considerations, and a priori contextual understanding of the degree of sample heterogeneity can guide model selection.

Molecular profiling of single neurons of known identity in two ganglia from the crab Cancer borealis.

Understanding circuit organization depends on identification of cell types. Recent advances in transcriptional profiling methods have enabled classification of cell types by their gene expression. While exceptionally powerful and high throughput, the ground-truth validation of these methods is difficult: If cell type is unknown, how does one assess whether a given analysis accurately captures neuronal identity? To shed light on the capabilities and limitations of solely using transcriptional profiling for cell-type classification, we performed 2 forms of transcriptional profiling-RNA-seq and quantitative RT-PCR, in single, unambiguously identified neurons from 2 small crustacean neuronal networks: The stomatogastric and cardiac ganglia. We then combined our knowledge of cell type with unbiased clustering analyses and supervised machine learning to determine how accurately functionally defined neuron types can be classified by expression profile alone. The results demonstrate that expression profile is able to capture neuronal identity most accurately when combined with multimodal information that allows for post hoc grouping, so analysis can proceed from a supervised perspective. Solely unsupervised clustering can lead to misidentification and an inability to distinguish between 2 or more cell types. Therefore, this study supports the general utility of cell identification by transcriptional profiling, but adds a caution: It is difficult or impossible to know under what conditions transcriptional profiling alone is capable of assigning cell identity. Only by combining multiple modalities of information such as physiology, morphology, or innervation target can neuronal identity be unambiguously determined.

Troy D. Zars: a personal tribute to a scientist, colleague, and friend.

I knew Troy for nearly 15 years, and in that time I don't recall hearing any childhood stories like those in seemingly every personal statement I've read from aspiring scientists or medical students. No stories about hours spent gazing at an anthill. I don't recall hearing about shelves crowded with insects collected on Styrofoam, or animal skulls kept in a shoebox under his bed. If these collected crania existed, it was more likely because Troy was a crack shot with a pellet gun than a need to know adaptations in the dentition of local squirrel populations. I don't recall hearing about science projects taken to the Iowa State Capitol to share with politely interested legislators. But I do recall hearing about spending the entirety of the daylight hours in the summer, with his brother Doug, finding where the crappie were biting. About crystal clear water on a lake in Minnesota that you didn't quite need to know the exact location of, just in case you were thinking of going and plundering the walleye within. I definitely heard about triumphs as a starting lineman not only for his high school football team, but the mighty Norse of Luther College. I heard about summer warehouse jobs in sweltering Iowa Julys. And I saw, firsthand, love and commitment and family. Troy's story demonstrates that the finest scientists are not just cultivated in narrow STEM curricula that begin at age 5. They are just as likely to be football-playing fishermen, fathers, husbands, and friends who can navigate an operant conditioning paradigm during the week, and dance a polka and produce a magnificent smoked pork shoulder on Saturday. Nature and an independent spirit and a little bit of mischief is a different kind of Magnet school. And it gave us truly one of the best.

Dopaminergic neurons can influence heat-box place learning in Drosophila.

Dopamine provides crucial neuromodulatory functions in several insect and rodent learning and memory paradigms. However, an early study suggested that dopamine may be dispensable for aversive place memory in Drosophila. Here we tested the involvement of particular dopaminergic neurons in place learning and memory. We used the thermogenetic tool Gr28bD to activate protocerebral anterior medial (PAM) cluster and non-PAM dopaminergic neurons in an operant way in heat-box place learning. We show that activation of PAM neurons influences performance during place learning, but not during memory testing. These findings provide a gateway to explore how dopamine influences place learning.

Optic Nerve Atrophy in N-methyl-D-aspartate (NMDA) Encephalitis.

N-methyl-D-aspartate receptor (NMDA) encephalitis is a recently described autoimmune disease that typically presents with prodromal symptoms including upper respiratory tract infection, headache, fever, nausea, vomiting and diarrhea. Psychiatric symptoms follow within weeks, including anxiety, insomnia, mania, paranoia and grandiose delusions. The diagnosis is confirmed by the detection of NMDA antibodies in the serum or cerebrospinal fluid (CSF).1 Tumours, especially teratomas, are frequently associated with NMDA encephalitis; however, only 5% of male patients older than 18 years have been found to have an underlying tumour. Optic neuropathy associated with NMDA encephalitis is being increasingly recognised in the literature2-6 and was reviewed most recently by Mugavin et al.2 in 2017. In this report, we present a case of bilateral optic neuropathy in a young man diagnosed with NMDA receptor encephalitis.

The differential contribution of pacemaker neurons to synaptic transmission in the pyloric network of the Jonah crab, Cancer borealis.

Many neurons receive synchronous input from heterogeneous presynaptic neurons with distinct properties. An instructive example is the crustacean stomatogastric pyloric circuit pacemaker group, consisting of the anterior burster (AB) and pyloric dilator (PD) neurons, which are active synchronously and exert a combined synaptic action on most pyloric follower neurons. Previous studies in lobster have indicated that AB is glutamatergic, whereas PD is cholinergic. However, although the stomatogastric system of the crab Cancer borealis has become a preferred system for exploration of cellular and synaptic basis of circuit dynamics, the pacemaker synaptic output has not been carefully analyzed in this species. We examined the synaptic properties of these neurons using a combination of single-cell mRNA analysis, electrophysiology, and pharmacology. The crab PD neuron expresses high levels of choline acetyltransferase and the vesicular acetylcholine transporter mRNAs, hallmarks of cholinergic neurons. In contrast, the AB neuron expresses neither cholinergic marker but expresses high levels of vesicular glutamate transporter mRNA, consistent with a glutamatergic phenotype. Notably, in the combined synapses to follower neurons, 70-75% of the total current was blocked by putative glutamatergic blockers, but short-term synaptic plasticity remained unchanged, and although the total pacemaker current in two follower neuron types was different, this difference did not contribute to the phasing of the follower neurons. These findings provide a guide for similar explorations of heterogeneous synaptic connections in other systems and a baseline in this system for the exploration of the differential influence of neuromodulators.NEW & NOTEWORTHY The pacemaker-driven pyloric circuit of the Jonah crab stomatogastric nervous system is a well-studied model system for exploring circuit dynamics and neuromodulation, yet the understanding of the synaptic properties of the two pacemaker neuron types is based on older analyses in other species. We use single-cell PCR and electrophysiology to explore the neurotransmitters used by the pacemaker neurons and their distinct contribution to the combined synaptic potentials.

Open Source Software Tools for Teaching Neuroscience.

We developed an interdisciplinary course in computational neuroscience to address the need for students trained in both biological/psychological and quantitative sciences. Increasingly, exposure to advanced math and physics is important to stay on the cutting edge of developments and research in neuroscience. Additionally, the ability to work in multidisciplinary teams will continue to be an asset as the field develops. This course brings together students from biology, psychology, biochemistry, engineering, physics, and mathematics. The course was designed to highlight the importance of math in understanding fundamental neuroscience concepts and to prepare students for professional careers in neuroscience. They learn neurobiology, via a 'biology to model and back again' approach involving wet- and software/modeling-labs, with the latter being the focus of this paper. We presented a subset of the software activities described here at the 2017 Faculty for Undergraduate Neuroscience Workshop.

Removal of endogenous neuromodulators in a small motor network enhances responsiveness to neuromodulation.

We studied the changes in sensitivity to a peptide modulator, crustacean cardioactive peptide (CCAP), as a response to loss of endogenous modulation in the stomatogastric ganglion (STG) of the crab Cancer borealis Our data demonstrate that removal of endogenous modulation for 24 h increases the response of the lateral pyloric (LP) neuron of the STG to exogenously applied CCAP. Increased responsiveness is accompanied by increases in CCAP receptor (CCAPr) mRNA levels in LP neurons, requires de novo protein synthesis, and can be prevented by coincubation for the 24-h period with exogenous CCAP. These results suggest that there is a direct feedback from loss of CCAP signaling to the production of CCAPr that increases subsequent response to the ligand. However, we also demonstrate that the modulator-evoked membrane current (IMI) activated by CCAP is greater in magnitude after combined loss of endogenous modulation and activity compared with removal of just hormonal modulation. These results suggest that both receptor expression and an increase in the target conductance of the CCAP G protein-coupled receptor are involved in the increased response to exogenous hormone exposure following experimental loss of modulation in the STG.NEW & NOTEWORTHY The nervous system shows a tremendous amount of plasticity. More recently there has been an appreciation for compensatory actions that stabilize output in the face of perturbations to normal activity. In this study we demonstrate that neurons of the crustacean stomatogastric ganglion generate apparent compensatory responses to loss of peptide neuromodulation, adding to the repertoire of mechanisms by which the stomatogastric nervous system can regulate and stabilize its own output.

Neuropeptide receptor transcript expression levels and magnitude of ionic current responses show cell type-specific differences in a small motor circuit.

We studied the relationship between neuropeptide receptor transcript expression and current responses in the stomatogastric ganglion (STG) of the crab, Cancer borealis. We identified a transcript with high sequence similarity to crustacean cardioactive peptide (CCAP) receptors in insects and mammalian neuropeptide S receptors. This transcript was expressed throughout the nervous system, consistent with the role of CCAP in a range of different behaviors. In the STG, single-cell qPCR showed expression in only a subset of neurons. This subset had previously been shown to respond to CCAP with the activation of a modulator-activated inward current (IMI), with one exception. In the one cell type that showed expression but no IMI responses, we found CCAP modulation of synaptic currents. Expression levels within STG neuron types were fairly variable, but significantly different between some neuron types. We tested the magnitude and concentration dependence of IMI responses to CCAP application in two identified neurons, the lateral pyloric (LP) and the inferior cardiac (IC) neurons. LP had several-fold higher expression and showed larger current responses. It also was more sensitive to low CCAP concentrations and showed saturation at lower concentrations, as sigmoid fits showed smaller EC50 values and steeper slopes. In addition, occlusion experiments with proctolin, a different neuropeptide converging onto IMI, showed that saturating concentrations of CCAP activated all available IMI in LP, but only approximately two-thirds in IC, the neuron with lower receptor transcript expression. The implications of these findings for comodulation are discussed.

Deep sequencing of transcriptomes from the nervous systems of two decapod crustaceans to characterize genes important for neural circuit function and modulation.

BACKGROUND: Crustaceans have been studied extensively as model systems for nervous system function from single neuron properties to behavior. However, lack of molecular sequence information and tools have slowed the adoption of these physiological systems as molecular model systems. In this study, we sequenced and performed de novo assembly for the nervous system transcriptomes of two decapod crustaceans: the Jonah crab (Cancer borealis) and the American lobster (Homarus americanus). RESULTS: Forty-two thousand, seven hundred sixty-six and sixty thousand, two hundred seventy-three contigs were assembled from C. borealis and H. americanus respectively, representing 9,489 and 11,061 unique coding sequences. From these transcripts, genes associated with neural function were identified and manually curated to produce a characterization of multiple gene families important for nervous system function. This included genes for 34 distinct ion channel types, 17 biogenic amine and 5 GABA receptors, 28 major transmitter receptor subtypes including glutamate and acetylcholine receptors, and 6 gap junction proteins - the Innexins. CONCLUSION: With this resource, crustacean model systems are better poised for incorporation of modern genomic and molecular biology technologies to further enhance the interrogation of fundamentals of nervous system function.

In Vitro Biomechanical Testing of the Tube Knot.

OBJECTIVE: To compare in vitro biomechanical properties of the tube knot (TB) to a crimp clamp (CC) system, and square knot (SQ) using 3 monofilament materials. STUDY DESIGN: In vitro biomechanical study. SAMPLE POPULATION: Suture loops (n=20 per material/knot construct). METHODS: Monotonic tensile loading (300 mm/min single pull to failure) was performed on knots tied using 3 knots (TB, 5-throw SQ, and CC system) with each of 3 materials (40# Securos® nylon, #2 polypropylene, and #2 nylon). Ultimate tensile strength, elongation, and stiffness were measured and compared by sequential 1- and 2-way ANOVA. RESULTS: Ultimate tensile strength was greatest with 40# nylon CC (mean ± SD, 293.6 ± 26.2 N), followed by TB (289.8 ± 9.2 N) and SQ (252.2 ± 8.5 N) with no significant difference between CC and TB. TB with #2 polypropylene (158.1 ± 7.4 N) and #2 nylon (126.3 ± 5.5 N) had significantly greater tensile strength than SQ with #2 polypropylene (143.6 ± 5.3 N) and #2 nylon (110.7 ± 6.2 N). Elongation at failure was significantly greater in 40# nylon TB (25.3 ± 3.2 mm) and SQ (10.8 ± 1.6 mm) compared to CC (5.3 ± 1.0 mm). Both material and knotting method had an effect on ultimate tensile strength, elongation at failure, and stiffness, based on 2-way ANOVA. CONCLUSION: Ultimate tensile strength of TB was equivalent to that of CC; however, elongation at failure was greatest for TB, which may be of concern for clinical applications.

Five key factors determining pairwise correlations in visual cortex.

The responses of cortical neurons to repeated presentation of a stimulus are highly variable, yet correlated. These "noise correlations" reflect a low-dimensional structure of population dynamics. Here, we examine noise correlations in 22,705 pairs of neurons in primary visual cortex (V1) of anesthetized cats, during ongoing activity and in response to artificial and natural visual stimuli. We measured how noise correlations depend on 11 factors. Because these factors are themselves not independent, we distinguished their influences using a nonlinear additive model. The model revealed that five key factors play a predominant role in determining pairwise correlations. Two of these are distance in cortex and difference in sensory tuning: these are known to decrease correlation. A third factor is firing rate: confirming most earlier observations, it markedly increased pairwise correlations. A fourth factor is spike width: cells with a broad spike were more strongly correlated amongst each other. A fifth factor is spike isolation: neurons with worse isolation were more correlated, even if they were recorded on different electrodes. For pairs of neurons with poor isolation, this last factor was the main determinant of correlations. These results were generally independent of stimulus type and timescale of analysis, but there were exceptions. For instance, pairwise correlations depended on difference in orientation tuning more during responses to gratings than to natural stimuli. These results consolidate disjoint observations in a vast literature on pairwise correlations and point towards regularities of population coding in sensory cortex.

Neurons within the same network independently achieve conserved output by differentially balancing variable conductance magnitudes.

Biological and theoretical evidence suggest that individual neurons may achieve similar outputs by differentially balancing variable underlying ionic conductances. Despite the substantial amount of data consistent with this idea, a direct biological demonstration that cells with conserved output, particularly within the same network, achieve these outputs via different solutions has been difficult to achieve. Here we demonstrate definitively that neurons from native neural networks with highly similar output achieve this conserved output by differentially tuning underlying conductance magnitudes. Multiple motor neurons of the crab (Cancer borealis) cardiac ganglion have highly conserved output within a preparation, despite showing a 2-4-fold range of conductance magnitudes. By blocking subsets of these currents, we demonstrate that the remaining conductances become unbalanced, causing disparate output as a result. Therefore, as strategies to understand neuronal excitability become increasingly sophisticated, it is important that such variability in excitability of neurons, even among those within the same individual, is taken into account.

Electrical coupling and innexin expression in the stomatogastric ganglion of the crab Cancer borealis.

Gap junctions are intercellular channels that allow for the movement of small molecules and ions between the cytoplasm of adjacent cells and form electrical synapses between neurons. In invertebrates, the gap junction proteins are coded for by the innexin family of genes. The stomatogastric ganglion (STG) in the crab Cancer borealis contains a small number of identified and electrically coupled neurons. We identified Innexin 1 (Inx1), Innexin 2 (Inx2), Innexin 3 (Inx3), Innexin 4 (Inx4), Innexin 5 (Inx5), and Innexin 6 (Inx6) members of the C. borealis innexin family. We also identified six members of the innexin family from the lobster Homarus americanus transcriptome. These innexins show significant sequence similarity to other arthropod innexins. Using in situ hybridization and reverse transcriptase-quantitative PCR (RT-qPCR), we determined that all the cells in the crab STG express multiple innexin genes. Electrophysiological recordings of coupling coefficients between identified pairs of pyloric dilator (PD) cells and PD-lateral posterior gastric (LPG) neurons show that the PD-PD electrical synapse is nonrectifying while the PD-LPG synapse is apparently strongly rectifying.

Rapid homeostatic plasticity of intrinsic excitability in a central pattern generator network stabilizes functional neural network output.

Neurons and networks undergo a process of homeostatic plasticity that stabilizes output by integrating activity levels with network and cellular properties to counter longer-term perturbations. Here we describe a rapid compensatory interaction among a pair of potassium currents, I(A) and I(KCa), that stabilizes both intrinsic excitability and network function in the cardiac ganglion of the crab, Cancer borealis. We determined that mRNA levels in single identified neurons for the channels which encode I(A) and I(KCa) are positively correlated, yet the ionic currents themselves are negatively correlated, across a population of motor neurons. We then determined that these currents are functionally coupled; decreasing levels of either current within a neuron causes a rapid increase in the other. This functional interdependence results in homeostatic stabilization of both the individual neuronal and the network output. Furthermore, these compensatory increases are mechanistically independent, suggesting robustness in the maintenance of neural network output that is critical for survival. Together, we generate a complete model for homeostatic plasticity from mRNA to network output where rapid post-translational compensatory mechanisms acting on a reservoir of channels proteins regulated at the level of gene expression provide homeostatic stabilization of both cellular and network activity.