<P> The amount of cortex devoted to any given body region is not proportional to that body region's surface area or volume, but rather to how richly innervated that region is . Areas of the body with more complex and / or more numerous sensory or motor connections are represented as larger in the homunculus, while those with less complex and / or less numerous connections are represented as smaller . The resulting image is that of a distorted human body, with disproportionately huge hands, lips, and face . </P> <P> In the sensory homunculus, below the areas handling sensation for the teeth, gums, jaw, tongue, and pharynx lies an area for intra-abdominal sensation . At the very top end of the primary sensory cortex, beyond the area for the toes, it has traditionally been believed that the sensory neural networks for the genitals occur . However, more recent research has suggested that there may be two different cortical areas for the genitals, possibly differentiated by one dealing with erogenous stimulation and the other dealing with non-erogenous stimulation . </P> <P> Dr. Wilder Penfield and his co-investigators Edwin Boldrey and Theodore Rasmussen are considered to be the originators of the sensory and motor homunculi . They were not the first scientists to attempt to objectify human brain function by means of a homunculus . However, they were the first to differentiate between sensory and motor function and to map the two across the brain separately, resulting in two different homunculi . In addition, their drawings and later drawings derived from theirs became perhaps the most famous conceptual maps in modern neuroscience because they compellingly illustrated the data at a single glance . </P> <P> Penfield first conceived of his homunculi as a thought experiment, and went so far as to envision an imaginary world in which the homunculi lived, which he referred to as "if". He and his colleagues went on to experiment with electrical stimulation of different brain areas of patients undergoing open brain surgery to control epilepsy, and were thus able to produce the topographical brain maps and their corresponding homunculi . </P>

Who is credited with creating the motor and somatosensory homunculi