15 th Annual Computational Neuroscience Meeting CNS*2006 Decoding modulation of the neuromuscular transform

Abstract

Question. Neuromodulators regulate many neurophysiological processes. These processes are often modeled as input-output relationships. Here we consider, for example, the neuromuscular transform [1]: in a neuromuscular system, the transformation of the pattern of motor neuron spikes to the waveform of muscle contractions that the spikes elicit (Fig. 1). Consider a modulator that, to meet some physiological demand, must alter the output contractions in a particular way. How can the modulator accomplish this? Experimentally, it is observed that it generally alters the input spike pattern. Yet both theory and experiment strongly suggest that this alone will often be insufficient. This is because the neuromuscular transform acts as a constraining channel whose properties are tuned, at any particular time, only to a narrow range of input patterns. When the input pattern is modulated outside this range, the output contractions will not be able to follow [2]. To allow them to follow, the properties of the neuromuscular transform must be retuned correspondingly [3]. We predict, therefore, that physiological modulators of neuromuscular function, and o