The touch of a fly

Our sense of touch has an innate connection with our emotions. Gentle touches are soothing for not only us but also other animals. For example, classic experiments by psychologist Harry Harlow in the 1950s found that an infant monkey raised with two robots, one providing food and the other wearing soft cloth, spends more time cuddling with the cloth robot1. When scared, the infant monkey also goes to the cloth robot for protection. Clearly, there is a special pathway that guides touch sensation to the depths of animal instincts. Working out this pathway requires knowledge about the neural circuitry processing touch sensation.


[Throwback Thursday] A gene to unite hot and hot

It is no linguistic coincidence that high temperature and spiciness share the same word in the English dictionary: they induce the same burning sensation. The biological basis for this commonality was discovered in 1997 by David Julius’s group at UCSF1.


Toward a Molecular Lego Kit for Engineering Specialized Channels

“What I cannot create, I do not understand.” — Richard Feynman (1988)

An organism’s ability to sense the world ultimately relies on specialized proteins in its sensory neurons to probe the external world on behalf of the entire organism. Channels, a group of proteins that act as gatekeepers of ions, are often delegated to the front end of the job. As a result, highly specialized channels, such as those that sense odors, temperature, and even touch, have evolved in all corners of the world. Over the years, the genetic identities of many such channels have been demystified. Our current challenge lies in pinpointing the nanoscopic means by which they sense the world. To achieving this goal, an inevitable path is to locate the intramolecular modules (often referred to as domains) that grant channels their special ability to sense the environment. Several remarkable studies in recent years have made significant progress in attacking this problem.


The first complete structure of a channel, the bacterial potassium channel KcsA, obtained by Rod MacKinnon’s group in 19981. This work pioneered a new wave of channel structure-function analyses.


Getting a Sense of the Sixth Sense

“This “proprioception” is like the eyes of the body, the way the body sees itself.”

– Oliver Sacks in The Man Who Mistook His Wife For A Hat

Think about baseball. Right before the pitcher throws the ball, the ball and his hand are behind him, out of his sight. Yet, he knows where his hand and the ball are and how both are moving. How is this possible? The pitcher can tell where the ball is using his sixth sense. No, this is not the same sixth sense that the character played by Haley Joel Osment has in the movie The Sixth Sense. This sixth sense is known as proprioception (pronunciation: PRO-pree-o-SEP-shən). Proprioception is the sense that allows us to determine the relative position and movement of our body parts in space. So what do we know about proprioception? How does it work?