Encoding of Muscle Movement on Two Time Scales by a Sensory Neuron That Switches Between Spiking and Bursting Modes

Aug 25, 2026

Encoding of muscle stretch by a crab sensory neuron was analyzed across two distinct activity regimes. Gastropyloric receptor (GPR) neurons that alternate between spiking and bursting modes were tested with sustained and rapidly varying imposed stretches. Spiking-mode firing rates tracked rapidly varying stretch amplitude, while persistent stretches induced adaptation, requiring interval-based reconstruction of time-dependent amplitude in the gastric mill range. Bursting-mode activity showed weak sensitivity to rapid variation but preserved amplitude information for long, sustained stretches. Spiking intervals reported fast changes, and burst intervals conveyed sustained length, enabling cycle-by-cycle and average tension encoding.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages12

Reading Time30 min

AccessFree to download

Introduction

Coding strategies in sensory neurons

Gastropyloric receptor neurons and two-mode behavior

Methods

Animals and solutions

Physiology

Encoding of Muscle Movement on Two Time Scales by a Sensory Neuron That Switches Between Spiking and Bursting Modes J. T. BIRMINGHAM, Z. B. SZUTS, L. F. ABBOTT, AND EVE MARDER Volen Center and Biology Department, Brandeis University, Waltham, Massachusetts 02454-9110 Birmingham, J. T., Z. B. Szuts, L. F. Abbott, and Eve Marder. Encoding of muscle movement on two time scales by a sensory neuron that switches between spiking and bursting modes. J. Neurophysiol. 82: 2786–2797, 1999. The gastropyloric receptor (GPR) neurons of the stomatogastric nervous system of the crab Cancer borealis are muscle stretch receptors that can ﬁre in either a spiking ora bursting mode of operation. Our goal is to understand what features of muscle stretch are encoded by these two modes of activity. To this end, we characterized the responses of the GPR neurons in both states to sustained and rapidly varying imposed stretches. The ﬁring rates of spiking GPR neurons in response to rapidly varying stretches were directly related to stretch amplitude. For persistent stretches, spikingmode ﬁring rates showed marked adaptation indicating a more complex relationship. Interspike intervals of action potentials ﬁred by GPR neurons in the spiking mode were used to construct an accurate estimate of the time-dependent amplitude of stretches in the frequency range of the gastric mill rhythm (0.05–0.2 Hz) . Spike trains arising from faster stretches (similar to those of the pyloric rhythm) were decoded using a linear ﬁlter to construct an estimate of stretch amplitude. GPR neurons ﬁring in the bursting mode were relatively unaffected by rapidly varying stretches. However, the burst rate was related to the amplitude of long, sustained stretches, and very slowly varying stretches could be reconstructed from burst intervals. In conclusion, the existence of spiking and bursting modes allows a single neuron to encode both rapidly and slowly varying stimuli and thus to report cycle-by-cycle muscle movements as well as average levels of muscle tension. I N T R O D U C T I O N Sensory neurons use a variety of coding strategies to deal with the wide dynamic range of the stimuli to which they respond. Some sensory neurons respond phasically to a signal, that is, their ﬁring rates are initially affected by rapid changes in the stimulus but subsequently adapt. Other sensory neurons show considerably less or no adaptation and encode sustained stimulus intensities. An advantage of sensory neurons that show adaptation is that they can report changes in stimulus intensity over a very large range, whereas neurons that do not have appreciable adaptation may only be able to report stimulus intensity over a more limited range of values. It is often assumed that information about changes in stimulus intensity and information about sustained stimuli are encoded by different neurons. In this paper we demonstrate that a single muscle stretch receptor neuron can encode information over two different time scales by ﬁring in two modes, spiking and bursting. Information about rapid changes in muscle stretch is encoded The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement”in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. by interspike intervals, whereas information about sustained muscle length is encoded by burst intervals. The gastropyloric receptor (GPR) neurons are two bilateral pairs of stretch-sensitive neurons that provide sensory input to the stomatogastric nervous system of the crab Cancer borealis (Katz et al. 1989) . The stomatogastric nervous system of C. borealis is a small, well-studied neural network that controls stomach movements (Harris-Warrick et al. 1992) . The 25–26 motor neurons (Kilman and Marder 1996) in the C. borealis stomatogastric ganglion (STG) can be divided roughly into two groups: those innervating the muscles that move thr

FAQs

What question does the study address about muscle stretch encoding?

It examines what features of muscle stretch are represented when a single GPR sensory neuron alternates between spiking and bursting modes.

How is stretch information encoded in the spiking mode?

For rapidly varying stretches, spiking firing rates track stretch amplitude, while for sustained stretches spike trains require interval-based decoding to estimate time-dependent amplitude.

How is stretch information encoded in the bursting mode?

Burst rate relates to the amplitude of long, sustained stretches, and very slowly varying stretches can be reconstructed from burst intervals.

Aug 25, 2026

Uploaded by Lucas Vance