The main aims of this practical were to help you to achieve a better practical understanding of nerve excitation, action potential propagation and refractoriness of nervous tissue.

There were several objectives for you to achieve during the practical. Of these, objectives 1 through 3 are rather incidental to the main aims of the practical. In a sense they are necessary steps to enable you to identify appropriate levels of stimulus strength to use in steps 4 & 5. Your objectives were:

1. To determine the minimum voltage (threshold voltage) that could elicit an EMG response from the muscle (the subject would also be aware when this voltage was reached!)
2. To record and understand how the size of the EMG response increased with increasing stimulus strength (increasing voltage)
3. To recognise that the EMG amplitude reached a maximum value and that further increases in stimulus strength resulted in an EMG of the same amplitude.
4. To arrive at a practical and mechanistic understanding of how conduction velocity can be measured.
5. To demonstrate, using paired pulses, the existence of a refractory period and to map the approximate duration of the absolute and relative phases of refractoriness