Synaptic motility and functional stability in the whisker cortex

The high motility of synaptic weights raises the question of how the brain can retain its functionality in the face of constant synaptic remodeling. Here we used the whisker system of rats and mice to study the interplay between synaptic plasticity (motility) and the transmission of sensory signals...

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Main Authors: Nimrod Sherf, Maoz Shamir
Format: Article
Language:English
Published: American Physical Society 2025-01-01
Series:Physical Review Research
Online Access:http://doi.org/10.1103/PhysRevResearch.7.013113
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author Nimrod Sherf
Maoz Shamir
author_facet Nimrod Sherf
Maoz Shamir
author_sort Nimrod Sherf
collection DOAJ
description The high motility of synaptic weights raises the question of how the brain can retain its functionality in the face of constant synaptic remodeling. Here we used the whisker system of rats and mice to study the interplay between synaptic plasticity (motility) and the transmission of sensory signals downstream. Rats and mice probe their surroundings by rhythmically moving their whiskers back and forth. The azimuthal position of a whisker can be estimated from the activity of whisking neurons that respond selectively to a preferred phase along the whisking cycle. These preferred phases are widely distributed on the ring. However, simple models for the transmission of the whisking signal downstream predict a distribution of preferred phases that is an order of magnitude narrower than empirically observed. Here, we suggest that synaptic plasticity in the form of spike-timing-dependent plasticity (STDP) may provide a solution to this conundrum. This hypothesis is addressed in the framework of a modeling study that investigated the STDP dynamics in a population of synapses that propagates the whisking signal downstream. The findings showed that, for a wide range of parameters, STDP dynamics do not relax to a fixed point. As a result, the preferred phases of downstream neurons drift in time at a nonuniform velocity, which in turn induces a nonuniform distribution of the preferred phases of the downstream population. This demonstrates how functionality, in terms of the distribution of preferred phases, can be retained not simply despite, but because of constant synaptic motility. Our analysis leads to several key empirical predictions to test this hypothesis.
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spelling doaj-art-0e3014e82d004a0c9ebeea3cf5d915b02025-01-29T15:14:12ZengAmerican Physical SocietyPhysical Review Research2643-15642025-01-017101311310.1103/PhysRevResearch.7.013113Synaptic motility and functional stability in the whisker cortexNimrod SherfMaoz ShamirThe high motility of synaptic weights raises the question of how the brain can retain its functionality in the face of constant synaptic remodeling. Here we used the whisker system of rats and mice to study the interplay between synaptic plasticity (motility) and the transmission of sensory signals downstream. Rats and mice probe their surroundings by rhythmically moving their whiskers back and forth. The azimuthal position of a whisker can be estimated from the activity of whisking neurons that respond selectively to a preferred phase along the whisking cycle. These preferred phases are widely distributed on the ring. However, simple models for the transmission of the whisking signal downstream predict a distribution of preferred phases that is an order of magnitude narrower than empirically observed. Here, we suggest that synaptic plasticity in the form of spike-timing-dependent plasticity (STDP) may provide a solution to this conundrum. This hypothesis is addressed in the framework of a modeling study that investigated the STDP dynamics in a population of synapses that propagates the whisking signal downstream. The findings showed that, for a wide range of parameters, STDP dynamics do not relax to a fixed point. As a result, the preferred phases of downstream neurons drift in time at a nonuniform velocity, which in turn induces a nonuniform distribution of the preferred phases of the downstream population. This demonstrates how functionality, in terms of the distribution of preferred phases, can be retained not simply despite, but because of constant synaptic motility. Our analysis leads to several key empirical predictions to test this hypothesis.http://doi.org/10.1103/PhysRevResearch.7.013113
spellingShingle Nimrod Sherf
Maoz Shamir
Synaptic motility and functional stability in the whisker cortex
Physical Review Research
title Synaptic motility and functional stability in the whisker cortex
title_full Synaptic motility and functional stability in the whisker cortex
title_fullStr Synaptic motility and functional stability in the whisker cortex
title_full_unstemmed Synaptic motility and functional stability in the whisker cortex
title_short Synaptic motility and functional stability in the whisker cortex
title_sort synaptic motility and functional stability in the whisker cortex
url http://doi.org/10.1103/PhysRevResearch.7.013113
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AT maozshamir synapticmotilityandfunctionalstabilityinthewhiskercortex