The document discusses several factors related to obesity and weight loss. It notes that obesity is linked to increased healthcare costs and diseases. One proposed weight loss technique is to slow down eating by chewing food thoroughly and putting down utensils between bites. This allows the brain to register fullness before overeating. Several brain areas and mechanisms involved in mastication and eating behavior are discussed, including how histamine neurons may reduce food intake volume by modulating chewing speed. Studies suggest chewing more through high-fiber diets could help reduce obesity and cognitive decline.

1. Mastication: Slow
down and lose
weight
Understanding the Brain: The Neurobiology of everyday life
Final Project
Submitted by Anjali Khambete

2. Current healthcare issues
• It is common knowledge that we, as a society, have been
plagued with rampant obesity. Obesity is a pre-cursor to
lifestyle diseases (non-communicable diseases - NCD) such as
diabetes, heart disease and cancer. Additionally, obesity has
negative impacts on the quality of life and leads to low self-
esteem.
• As a nation, high prevalence of obesity and the resulting
diseases has led to spiraling healthcare costs .
• Additionally, we see Alzheimer's disease on the rise, as
cognitive function declines in aging populations.

3. Weight Loss Technique – Slow
down
• An important weight loss technique is to slow down and chew
thoroughly before swallowing.
• Keep the fork down between two bites.
• The idea is that if you slow down, you won’t have eaten far
too much before the fullness is registered by your brain.
• Could the solution be as simple as this?
• What other factors affect the process of chewing?
• Can chewing more also have an effect on other disorders such
as Alzheimer's?

4. What the class taught us
• Chewing is a function of the central pattern generator.
• The central pattern generators adapt to different patterns of
eating such as chewing gum vs chewing a tough candy.
• In order to understand mastication as a CPG, I did further
research into the central pattern generator mainly from
sources on the web. References to this are included in the
Citations slide.
• I realized that there is vast information that has been
understood as a result of scientific research and there is so
much more left to be researched.
• I realized that the more I read, the more I questions I had.

5. CPG of mastication
• CPG of mastication is divided into three processes
• Generation of the masticatory rhythm.
• Generation of a pattern of activities of the jaw, tongue and facial
muscles.
• Coordination of the activities of these muscles.
Evidence suggests that there are two neuronal groups involved in these
activities:
1) One for the generation of masticatory rhythm, giving timing signal
for rhythmical alternation of jaw opening and jaw closing.
2) The other group for the spatiotemporal pattern for the activities of
the jaw, tongue and facial muscles.
Mastication results from the intrinsic neural pattern as well as the
sensory input from the jaw, tongue and facial muscles. The pattern is
matched with the characteristics of the food but also changes with age.
The intrinsic pattern is generated by an assembly of neurons (CPG) in
the pons and the medulla.

6. Mesencephalic trigeminal
sensory nucleus (Me5)
• Elongated nucleus located in the midbrain that receives
proprioceptive (awareness) input from both the extraocular
(outside the body) and the masticatory muscles

7. Ventromedial nucleus (VMN) or
Ventromedial Hypothalamus (VMH)
• Ventromedial nucleus (VMN) is the nucleus of the
hypothalamus. It is commonly associated with satiety. Earlier
studies showed that lesions in the VMN caused hyperphagia
(overeating). However, that theory was discarded.
• The theory is now gaining ground again, and studies have
shown that hyperphagia and obesity are a consequence of the
VMN lesions. Some studies show that rats with VMH lesion
produce more leptin, but they are unable to respond to leptin,
leading to overeating.
• Neuroimaging of the brain has shown increase in activity in
the VHM during feeding. However, this does not explain why
we, as a population are becoming more obese.

8. Histamine(HA) Neurons
Histamine neurons in Me5 have been shown to modulate mastication
actions, particularly eating speed which reduces volume of food
consumed.
MesencephalicTrigeminal MotorNucleus
TMN is located in the pons and contains motor neurons that
innervate the mastication muscles.
MesencephalicTrigeminal SensoryNucleus
Located in the brainstem, the mesencephalic trigeminal sensory
nucleus receives proprioceptor input from the jaw and
mechanoreceptor input from the teeth.

9. Sensory processes involved in
eating

10. Role of Histamine neurons in
the intake volume at meals
• A study in rats showed that the Histamine neurons in the
mesencephalic trigeminal sensory nucleus modulate
masticatory functions, particularly eating speed through the
mesencephalic trigeminal motor nucleus, and activation of the
histamine neurons in the VMH suppress intake volume of
feeding at meals.

11. Mastication as a prevention of
Cognitive Decline
• Mastication (chewing) has been shown to promote preserving
cognitive function according to the research article link on this
slide.
• http://parkinsonstmj.com/wp-
content/uploads/2011/12/occlusion-and-brain-function.pdf

12. Role of diet: Low-calorieJapanesediet vs.
liquidformula diet
• Studies have shown that a low-calorie Japanese diet
containing protein from chicken, egg-white, fish and a non-
calorie fiber-rich vegetable helped in weight reduction and
long-term maintenance. However, the same did not hold for a
liquid formula diet.
• The low energy diet and the high fiber diet which requires
more chewing enhances the histamine based actions resulting
in activation of the satiety centers and suppression of food
intake.

13. Conclusion
Possibilities to explore –
• Could histamine blockers help individuals slow down when
eating food and thereby reduce obesity?
• Could eating high fiber food that requires chewing food longer
help reduce obesity?
• Could chewing food longer help reduce cognitive declines?
• Could access to calorie-dense, artificially concentrated and
fiber-removed diets of the modern day world be interfering
with the CPG functions of sensory feedback resulting in
hyperphagy?

14. Citations and References
• Brainstem circuits that control mastication: do they have anything to say during speech?
• Lund JP1, Kolta A.
• Generation of masticatory rhythm in the brainstem.
• Nakamura Y1, Katakura N.
• Anti-obesity actions of mastication driven by histamine neurons in rats.
• Sakata T1, Yoshimatsu H, Masaki T, Tsuda K
• http://blogs.scientificamerican.com/observations/2011/08/03/chew-on-this-more-
mastication-cuts-calorie-intake-by-12-percent/
• Hypothalamic neuronal histamine: implications of its homeostatic control of energy
metabolism.
• Sakata T1, Yoshimatsu H, Kurokawa M.
• http://brainmaps.org/index.php?pm=mesencephalic%20trigeminal%20nucleus
• http://en.wikipedia.org/wiki/Ventromedial_nucleus
• The rise, fall, and resurrection of the ventromedial hypothalamus in the regulation of
feeding behavior and body weight.
• King BM.
• http://neurolex.org/wiki/Category:Mesencephalic_nucleus_of_trigeminal_nerve
• http://parkinsonstmj.com/wp-content/uploads/2011/12/occlusion-and-brain-function.pdf
• http://ajcn.nutrition.org/content/89/3/794.full