BU’s Mind and Brain Society is choosing among three (so far!) shirt designs to represent neuroscience at BU. Here they are! Please comment on which you like best!
“We were hardwired to eat and eat—and particularly to eat fatty foods because we didn’t get them often,” says Sharman Russell, author of Hunger: An Unnatural History. So if you’re among the 200 million Americans who have surpassed their target weight, don’t feel so bad. Somewhere in your brain, there is a circuit for food.
While eating is vital to life, it’s a voluntary action. But nature has made eating irresistible. So what is the science behind this irresistibility? Over the course of a year, the average adult male consumes about 900,000 calories, yet his weight doesn’t fluctuate by more than a pound. It takes a lot of effort from your internal systems to keep this balance, and an important substance behind this is a hormone called ghrelin.
Ghrelin, identified in 1999, is produced in the gut in response to meal schedules. Its purpose is to give the empty feeling we know as the need to eat. When ghrelin hits the brain, it affects three specific areas: the hindbrain, the hypothalamus, and the mesolimbic reward center. The hindbrain controls the body’s automatic and unconscious processes. It is responsible for the sensation of hunger. For the purposes of eating and digesting, the hypothalamus governs the rates of metabolism. And at the center of the midbrain lies the mesolimbic reward center, where the feelings of pleasure and satisfaction are processed. This is what motivates us to eat and keep eating.
Of course, other substances in our body govern our appetite as well as ghrelin. Even as ghrelin continues to arouse our appetite, other systems are standing by to slow down the process. The most basic such step occurs in the stomach and intestines. Distension sends a signal to the brain to stop eating. That message is then reinforced by a peptide called cholecystokinin (CCK) and two hormones called PYY and GLP-1. They all send complex chemical messages that literally tell the brain to stop eating. And, in the case that food consumption continues, the body has a last resort appetite-supressing hormone called leptin. Discovered in 1994, leptin affects the hypothalamus where it inhibits a pair of neuropeptides known to stimulate appetite.
So with all these measures in place to stop the body from eating, why do we overeat? Studies have shown that ghrelin hits the mesolimbic reward region very powerfully. It has been shown that this part of obese people’s brains activate very similarly to how the brains of drug addicts activate when exposed to their preferred substance. While the causes of over eating are very obvious, the real question is: how can we control it? Diet and exercise are often the recommendations (and should be followed), but the minds who discovered leptin, ghrelin, and all the other appetite-related peptides and hormones are also looking for ways to harness the power so we can take better control of it on our own.
Hunger: An Unnatural History – Sharman Russell
Encouraging Innovation in Undergraduate Neuroscience Education by Supporting Student Research and Faculty Development
Jean C. Hardwick,* Michael Kerchner,† Barbara Lom,corresponding author‡ Julio J. Ramirez,§ and Eric P. Wiertelak‖
The organization Faculty for Undergraduate Neuroscience (FUN; Ramirez and Normansell, 2003 ). The founders experienced a need for a community of neuroscience educators because no formal division existed within the Society for Neuroscience (SfN; ) to support undergraduates or the faculty who focus on undergraduate neuroscience education.) was established in 1991 by a group of neuroscientists dedicated to innovation and excellence in undergraduate neuroscience education and research (
Welcome to The Nerve Blog. This is an extension of the undergraduate neuroscience journal at BU, The Nerve. The Nerve is edited and managed by members of the BU Organization for the Mind and Brain Sciences. The first issue is due Fall 2009.
As the blog’s subtitle suggests, posts here will be reflections on the mind and brain: anything from the fields of psychology, biology, computer science, artificial intelligence, anthopology, philosophy, biomedical engineering, ethology, and whatever else you can think of (as long as it relates to the brain).