Are whole muscles the fundamental substrate for the CNS control of movement?

Method for identification and classification of single motor unit potentials in diagnostic electromyography

It is important to have an objective method for recording jaw muscle capacity such as EMG before, during and after treatment of muscle dysfunction and also for oral rehabilitation with dentures, implants or other types of restorations. Because measurements of motor unit potentials (MUPs) are needed in several areas of EMG analysis, algorithms have been developed in our laboratory for use in a small computer-aided system for semi-automatic detection and pattern recognition of MUPs. Based upon the test recordings it is suggested that a characteristic 'maximal voltage increase per microsecond during the spike-phase' can be used as a supplement to the more generally used parameter 'rise-time'. Examples are given of how the programs can be useful in the study of the functional anatomy of jaw muscles by recording normative values for MUPs and their recruitment patterns.

Functional muscle partitioning during voluntary movement: facial muscle activity for speech

Electromyographic activity was recorded from multiple intramuscular sites in the orbicularis oris muscle for a set of speech and other motor tasks. Because of its geometric heterogeneity and multiple functions, it was hypothesized that this muscle might be partitioned in a task-dependent manner. Comparison of the timing and amplitude of the EMG activity among the multiple recording sites supported this hypothesis. Because some facial motoneurons in primates, including humans, are monosynaptically activated from area 4 of the motor cortex, it is suggested that this task-dependent muscle partitioning may reflect an aspect of cortical organization.