[Juris Graney]

Juris Graney  asked the Naked Scientists:
   
Hi team. Just wanted to say that I love your show, especially your podcasts, which I routinely put on while doing the house work.

My name is Juris (pronounced You-Ree) and I am an Australian living in Vancouver, Canada. My question relates to my wife, Emma.

The other night we were talking and she alerted me to the fact that she gets a tickling sensation, especially in her feet but sometimes in her hands, when she thinks about smooth rocks or when she touches smooth bark trees. Emma is not ticklish on her feet and we tossed around a few ideas, maybe a kickback to our evolutionary brothers and sisters in the apes but we were wondering whether you could shed some light on this. The fact that there is a physical manifestation for even a thought would suggest to me to be a rather interesting response.

Hope you can help.

What do you think?

[Nizzle]

Ooh,

Brain Chemistry is far from clear in modern day science.
But my guess is that when Emma thinks about, or remembers smooth rocks or bark trees, some neuron paths in her brain fire signals, and by association from past experiences, some sensoral nerves will be fired as well, giving her the tickling sensations.