M1 Somatotopic Map

1. The figure in the question shows the motor and sensory topographic organization through the use of a homunculus. The homunculus in the motor system figure is correct in both pathways due its somatosensory nature. There is evidence though that while this map technically is correct in broad terms, the M1 somatotopic map is much more complex and non-linear then this. It was originally thought that the motor system had sequential operations that were encoded at each step by a different neuronal population and its only role was that of which muscles to contract, when, and with how much effort. It is now understood that the motor system is not only just motor operations, but involves cognitive processes as well. The motor system has extensive overlap with different areas controlling different combinations of muscle …show more content…
It is now well understood that the neurons in the motor areas have very distinct properties that are highly interactive to perform a range of operations to select, plan, and generate the motor movement that is appropriate to the internal and external needs of the body. These motor pathways are very complex in their reciprocal, divergent, and convergent interconnected projections, instead of the simple step-by-step serial process pathway that was originally thought. While the pathways of the serial system are not correct, the general idea of the system is. This is due to the general idea of the serial need for the body to think of the voluntary action, plan it, and then to generate it. Finally, figure 37-2 shows the functional motor organization of the motor map in just two different arm muscles. It clearly shows that there is not a one-to-one ratio of the neurons to muscles here, but rather there are different stimulation demands by particular neurons in order for a response to be made by the