Local changes in potassium ions regulate input integration in active dendrites.

During neuronal activity, the extracellular concentration of potassium ions ([K+]o) increases substantially above resting levels, yet it remains unclear what role these [K+]o changes play in the dendritic integration of synaptic inputs. We here used mathematical formulations and biophysical modeling...

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Bibliographic Details
Main Authors: Malthe S Nordentoft, Naoya Takahashi, Mathias S Heltberg, Mogens H Jensen, Rune N Rasmussen, Athanasia Papoutsi
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2024-12-01
Series:PLoS Biology
Online Access:https://doi.org/10.1371/journal.pbio.3002935
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Summary:During neuronal activity, the extracellular concentration of potassium ions ([K+]o) increases substantially above resting levels, yet it remains unclear what role these [K+]o changes play in the dendritic integration of synaptic inputs. We here used mathematical formulations and biophysical modeling to explore the role of synaptic activity-dependent K+ changes in dendritic segments of a visual cortex pyramidal neuron, receiving inputs tuned to stimulus orientation. We found that the spatial arrangement of inputs dictates the magnitude of [K+]o changes in the dendrites: Dendritic segments receiving similarly tuned inputs can attain substantially higher [K+]o increases than segments receiving diversely tuned inputs. These [K+]o elevations in turn increase dendritic excitability, leading to more robust and prolonged dendritic spikes. Ultimately, these local effects amplify the gain of neuronal input-output transformations, causing higher orientation-tuned somatic firing rates without compromising orientation selectivity. Our results suggest that local, activity-dependent [K+]o changes in dendrites may act as a "volume knob" that determines the impact of synaptic inputs on feature-tuned neuronal firing.
ISSN:1544-9173
1545-7885