Electrical match between initial segment and somatodendritic compartment for action potential backpropagation in retinal ganglion cells

Goethals, Sarah; Sierksma, Martijn C.; Nicol, Xavier; Goazigo, Annabelle Réaux‐Le; Brette, Romain

doi:10.1152/jn.00005.2021

Cited by 5 publications

(3 citation statements)

References 63 publications

(101 reference statements)

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“…At the same time, the impact on action potential generation of interactions among AIS, soma and somatic synaptic inputs, and the variations in these interactions across neuronal types remain to be clearly defined (e.g. Balbi et al., 2015; Goethals et al., 2021; Kole & Brett, 2018). Better understanding of these factors should clarify the potential relationship of the AIS plasticity described here to the associated behavioural change (i.e.…”

Section: Discussionmentioning

confidence: 99%

Motor learning changes the axon initial segment of the spinal motoneuron

Wang,

Chen,

Chen

et al. 2024

The Journal of Physiology

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We are studying the mechanisms of H‐reflex operant conditioning, a simple form of learning. Modelling studies in the literature and our previous data suggested that changes in the axon initial segment (AIS) might contribute. To explore this, we used blinded quantitative histological and immunohistochemical methods to study in adult rats the impact of H‐reflex conditioning on the AIS of the spinal motoneuron that produces the reflex. Successful, but not unsuccessful, H‐reflex up‐conditioning was associated with greater AIS length and distance from soma; greater length correlated with greater H‐reflex increase. Modelling studies in the literature suggest that these increases may increase motoneuron excitability, supporting the hypothesis that they may contribute to H‐reflex increase. Up‐conditioning did not affect AIS ankyrin G (AnkG) immunoreactivity (IR), p‐p38 protein kinase IR, or GABAergic terminals. Successful, but not unsuccessful, H‐reflex down‐conditioning was associated with more GABAergic terminals on the AIS, weaker AnkG‐IR, and stronger p‐p38‐IR. More GABAergic terminals and weaker AnkG‐IR correlated with greater H‐reflex decrease. These changes might potentially contribute to the positive shift in motoneuron firing threshold underlying H‐reflex decrease; they are consistent with modelling suggesting that sodium channel change may be responsible. H‐reflex down‐conditioning did not affect AIS dimensions. This evidence that AIS plasticity is associated with and might contribute to H‐reflex conditioning adds to evidence that motor learning involves both spinal and brain plasticity, and both neuronal and synaptic plasticity. AIS properties of spinal motoneurons are likely to reflect the combined influence of all the motor skills that share these motoneurons. imageKey points Neuronal action potentials normally begin in the axon initial segment (AIS). AIS plasticity affects neuronal excitability in development and disease. Whether it does so in learning is unknown. Operant conditioning of a spinal reflex, a simple learning model, changes the rat spinal motoneuron AIS. Successful, but not unsuccessful, H‐reflex up‐conditioning is associated with greater AIS length and distance from soma. Successful, but not unsuccessful, down‐conditioning is associated with more AIS GABAergic terminals, less ankyrin G, and more p‐p38 protein kinase. The associations between AIS plasticity and successful H‐reflex conditioning are consistent with those between AIS plasticity and functional changes in development and disease, and with those predicted by modelling studies in the literature. Motor learning changes neurons and synapses in spinal cord and brain. Because spinal motoneurons are the final common pathway for behaviour, their AIS properties probably reflect the combined impact of all the behaviours that use these motoneurons.

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Section: Discussionmentioning

confidence: 99%

Motor learning changes the axon initial segment of the spinal motoneuron

Wang,

Chen,

Chen

et al. 2024

The Journal of Physiology

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“…We note that the geometry of the neuron and the location of the AIS also influence neuronal excitability and the generation of the action potential as they control the electrical properties of the neuron. 44 , 45 …”

Section: Discussionmentioning

confidence: 99%

Location of the axon initial segment assembly can be predicted from neuronal shape

Xu,

Angstmann,

et al. 2024

iScience

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“…In neurons, the fire rate, pattern, directionality, and threshold of action potentials are determined by the location, distribution, kinetics, and expression level of Na v and K v channels [98,113,250]. Ultimately, the ensemble of functionally active Na v and K v channels in axons, dendrites, and somas will determine the likelihood of forward vs. backpropagation of action potentials, which, in turn, affects synaptic transmission at presynaptic axonal terminals (forward propagation) and synaptic input integration (backward propagation) in the dendritic tree [251][252][253].…”

Section: Potential Mechanisms By Which Gsk3β Influences Neuronal Exci...mentioning

confidence: 99%

Glycogen Synthase Kinase 3: Ion Channels, Plasticity, and Diseases

Marosi

Arman

Aceto

et al. 2022

IJMS

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Glycogen synthase kinase 3β (GSK3) is a multifaceted serine/threonine (S/T) kinase expressed in all eukaryotic cells. GSK3β is highly enriched in neurons in the central nervous system where it acts as a central hub for intracellular signaling downstream of receptors critical for neuronal function. Unlike other kinases, GSK3β is constitutively active, and its modulation mainly involves inhibition via upstream regulatory pathways rather than increased activation. Through an intricate converging signaling system, a fine-tuned balance of active and inactive GSK3β acts as a central point for the phosphorylation of numerous primed and unprimed substrates. Although the full range of molecular targets is still unknown, recent results show that voltage-gated ion channels are among the downstream targets of GSK3β. Here, we discuss the direct and indirect mechanisms by which GSK3β phosphorylates voltage-gated Na+ channels (Nav1.2 and Nav1.6) and voltage-gated K+ channels (Kv4 and Kv7) and their physiological effects on intrinsic excitability, neuronal plasticity, and behavior. We also present evidence for how unbalanced GSK3β activity can lead to maladaptive plasticity that ultimately renders neuronal circuitry more vulnerable, increasing the risk for developing neuropsychiatric disorders. In conclusion, GSK3β-dependent modulation of voltage-gated ion channels may serve as an important pharmacological target for neurotherapeutic development.

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Electrical match between initial segment and somatodendritic compartment for action potential backpropagation in retinal ganglion cells

Cited by 5 publications

References 63 publications

Motor learning changes the axon initial segment of the spinal motoneuron

Motor learning changes the axon initial segment of the spinal motoneuron

Location of the axon initial segment assembly can be predicted from neuronal shape

Glycogen Synthase Kinase 3: Ion Channels, Plasticity, and Diseases

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