The Cortical Homunculus

Sensory Homunculus

Motor Homunculus

Remember these weird looking humans from neuro A&P class? In the 1940s Dr. Wilder Penfield used electric shocks on people and then asked where they felt the sensation. Based on his research he drew this funny homunculus, or “little man” in Latin, showing how much sensory and motor brainpower is dedicated to a body part. You can see A LOT  is dedicated to our lips, mouth and tongue!

The primitive brain rules our habit loops. So . . . . the habits that support overeating and eating calorically dense sugary food because it tastes, smells, and feels awesome it is FULLY supported by this “little man”.

This “little man” developed so we wouldn’t eat things that smell bad, feel gross, taste awful or harm us.


We now live in a modern world that doesn’t sell ugly looking, bad tasting, gross feeling, terrible smelling food. Well, maybe Spam.

The food sold now looks beautiful, smells terrific, feels wonderful and tastes marvelous to the “little man” in our brain.

It is our choice to not overeat and feed this “little man” just because he evolved this way.

These are some triggers employed by food marketing that turn on my “little man” and engage my primitive brain overeating habits:

  • The diffusing hoagie scent outside Subway stores – like a tiny whiff of crack cocaine each time I pass.
  • Hot rotisserie chicken wafting its smell by grocery store checkouts.
  • Food-tasting stations inside stores.
  • Fast food commercials on at 5 am when I am at the gym.
  • Snack food packaging emitting an audible “I’m here snacking on something sweet, sugary, salty and crunchy!” sound, announcing its presence to my nearby primitive brain.

The food industry has mastered how to stimulate our food-related sensory input! My primitive brain immediately thinks – “Go get that torso sized bag of potato chips now!”

But, I can choose to think – “Wait, What? Is this going to help me lose weight?” NO!! This thought helps me deal with the urge to buy the torso bag of potato chips until it goes away in 10-30 seconds.

I have to practice watching my “little man” having a fit until he gets tired and settles down in 10-30 seconds. I can do anything for 30 seconds, right?

Interestingly, the disease diagnosed by Penfield’s homunculus is phantom pain. Despite missing a limb the brain still feels its presence. I postulate that even though we choose to not eat unhealthy foods our brain will always remember eating them, this is why our urge to overeat unhealthy foods will never completely go away.

And this is why I need to choose again and again what I should be eating.



One of my favorite quotes is from Liz Lemon on 30 Rock, “That’s a DEALBREAKER!”

Liz referred to a dealbreaker as something that would lead to a relationship breakup. So I thought, why not use a dealbreaker to end a crappy relationship I have with food.

We can use “Dealbreakers” as a strategy for interrupting the  pleasure-seeking, stress-feeding thoughts the primitive brain habitually produces.

Brainpower or willpower is a limited commodity. It is gone by the end of the workday.

Dealbreakers are recognizable stop points for the primitive brain, which ALWAYS rules after a long, tiring or stressful day.

Dealbreakers remind me when to ask a USEFUL NO question of my primitive brain.

Dealbreakers will interrupt primitive brain thoughts that are screaming “I WANT!” and “I NEED!”

My easy to remember diet-focused Dealbreakers are:

  • 5 pound weight gain.
  • Food that gives me diarrhea or constipation. (Duh!)
  • Processed foods.
  • Dried stuff in a box or bag.
  • Eating after 7:00 pm.
  • Sugar.
  • Fast food made by random teenagers.
  • Food shopping on a fast day.

Dealbreakers, Useful No questions, and great habits are simple resources to control your primitive toddler brain.

Bring out your dealbreakers and use them consciously!


Yesterday we were talking about Fritos at work. Everyone in the OR loved Fritos. But most of us agreed that no matter how much we loved Fritos we don’t buy them.

I remember feeling frustrated and thinking, “I love Fritos but I can’t eat them!”

It felt frustrating because I was thinking, “I’m missing out on all the Fritos in life!” I felt angry, frustrated, cheated, and all the other emotions when I think I can’t have what I want when I want it!

By now I recognize this is my toddler primitive brain starting to have a tantrum.

This is how I visualize my primitive brain.

She was easy to ignore when I was in the OR because there was no opportunity to eat Fritos there.


But she came back to life as I drove home in Friday rush hour traffic. Each of the four times I passed a grocery store or Wawa she continued her tantrum screaming:

  • “It has been a long week, you deserve some Fritos!”
  • “Come on, you followed a good diet all week, you can Frito cheat this once!”
  • “This traffic is the worst, you need Frito food to make it home!”
  • “Get Fritos they will make you happy!”

I’m happy to report I did not get the Fritos. I kept answering each of her statements with, “Are Fritos healthy for me?” She answered, “NO!” but she is tenacious and kept coming up with all the other arguments that usually convinced me in the past to get the Fritos and eat them.

However, a new diet theory was also in my head during the Frito fight. New research is showing that processed foods actually make my primitive toddler brain stronger at convincing me to eat Frito type foods. Here is a quote from the Scientific American article:

“Eating large amounts of ultraprocessed foods may actually change brain circuitry in ways that increase sensitivity to food cues, adds Kent Berridge, a professor of psychology and neuroscience at the University of Michigan. He has shown this effect in rodents. “When you give rats junk-food diets, some gain weight, but others do not. In those that became obese, their dopamine systems changed, and they became hypersensitive to food cues—they became superfocused on that one reward. They showed no more pleasure, but they did show more wanting, and that wanting led to more actions—that is, more food-seeking behavior.”

I’m not a rat but I recognize this wanting and food-seeking behavior in myself. Yep, it’s what I do every time I overeat or eat off plan or off protocol.

This little critter lives in me but it is my choice to follow her advice or not.

As you make a choice about food listen to whose advice you are following. If the choice is in the moment, easy, pleasurable, or buffers uncomfortable emotions then the toddler primitive brain is ruling.

Tell her to go sit in the corner till she settles down!