Lecture 4: Exploring Obesity: From the Depths of the Brain to the Far Pacific
by Jeffrey M. Friedman, M.D., Ph.D.
Play Lecture Four in Full
Introduction by HHMI Grants Program Director Dr. Dennis Liu
Introductory interview with Dr. Jeffrey Friedman
Outline of Lecture Four
Obesity is usually caused by leptin resistance, not leptin deficiency
How does leptin act on a neuron?
Animation: Neuroanatomy of the mouse hypothalamus
Functions of the hypothalamus
The leptin circuit in the hypothalamus
How to label two neuronal types differently
How does leptin affect the activity of hypothalamic neurons?
Animation: Leptin rewiring neuronal connectivity
Leptin rapidly rewires feeding circuits
We need to understand the overall wiring diagram
Feeding is a complex motivational behavior
Method for tracing connected neurons using the Cre recombinase
Where are the neuronal inputs to the leptin circuit?
Q&A: How did you initially isolate NPY and MSH neurons?
Q&A: Are there connections between skin pigmentation and eating?
How does variation in genes lead to obesity?
Hypothesis of human evolution: Hunter-gatherer and Fertile Crescent genes
Pacific island of Kosrae: A site to study genetic variation
Tracing inheritance of single nucleotide polymorphisms (SNPs)
Using DNA chips to analyze many SNPs at once
Studies of isolated populations can also find rare single-gene disorders
Mapping rare genetic markers by analyzing homozygous individuals
Developing a genetic framework to understand how leptin works
It's important not to blame and stigmatize the obese
Q&A: What are the disadvantages of studying an isolated population?
Q&A: Does the research provide any benefit to the Kosraeans?
Q&A: How often do you need to inject leptin?
Q&A: Can anorexia be caused by leptin oversensitivity?
Q&A: Is there a connection between depression and leptin?
Closing remarks by HHMI President Dr. Thomas Cech