This journey travels through “two little humanoids” who “live” on the brain surface. Dr Wilder Penfield and Edwin Boldrey “discovered” them in 1937.

This is an amazing story.

In 1937, while working at McGill University, Dr Wilder Penfield and Edwin Boldrey began mapping brain regions that receive sensory information from corresponding skin areas. Not only that, they mapped brain regions that send signals to move corresponding body parts. This laborious exercise became possible because they were operating under local anaesthesia at that time.

Together with Edwin Boldrey, the surgeon published their story in the “Brain” journal. It was a 50-page-long article with drawings. They found that our brain surface owns very distinct regions that exactly correspond to and account for different body regions. It is exactly similar to two little humans (humanoids) lying on the surface brain.

Figure 1: Dr Penfield and Boldrey and their little men Courtesy:

These “Two little humans” (Figure 1) – now famously called “Homunculus of the brain” – lie along the Central Sulcus, which separates the Frontal lobe from the Parietal and Temporal lobes.

Homunculus in the brain

Figure 2 depicts the two little humans who lie along the Central sulcus – a groove that separates the Frontal lobe from the Parietal lobe (You can read this on the Journeys to the brain -2: A walk over the brain surface).

Figure 2: Left homunculus

Source: Wikimedia commons: Polygon data are from BodyParts3D[1]. Author: Polygon data were generated by Database Center for Life Science(DBCLS)[2]. Permission: under the license of CC BY SA 2.1.

File:BA312 - Primary Somatosensory Cortex - lateral view - with homunculus.png

As you can see in Figure 3 (below), the upper inside surface area controls our feet and legs. Let us start with Figure 2. When we climb, we will step on the areas that receive information and send commands to the facial structures. Further up, we will find areas that receive the information and send instructions to move. It follows a highly organized distinct pattern. And, the more complex the job is, the larger the designated area.

Figure 3: Homunculus regions

Source: Wikimedia commons: OpenStax College Anatomy & Physiology, Connexions Website:, Jun 19, 2013, under the license of creative commons. CC BY 3.0

<strong>Figure 4: Image source</strong>: <a href="">Wikimedia Commons </a>

You can read about the brain’s blood supply by joining me on another journey.   

Leave a Reply