The brain's Venetian bridge

I returned to UCL today, after spending the first week of the new term writing my second piece of coursework for the M.Sc., a 2,000-word essay about AMPA receptor recomposition in synaptic plasticity, which I'll post on here soon.

The third block began today with a lecture on nociception (pain), and a brain dissection. It wasn't a dissection as such, because human brains are, for some reason, in short supply, so me and the other students spent nearly 2 hours gathered around two preserved specimens - a whole brain and a sagittal section.

This was disappointing, as I was hoping that we might be split into small groups, each with a brain to dissect, and I had even taken a small digital camera in case a photo opportunity arose.

I've dissected brains before, when I took a part-time job - 2 hours a week! - during my ill-fated Ph.D., teaching neuroanatomy to medical students. One cannot help but be amazed when holding a human brain in one's hands. How can this piece of meat, which weighs just under 1.5 kg, and has the consistency of jelly, control every thought and movement, store a lifetime of memories and be the very essence of its owner's existence?

Despite my initial disappointment, I'm very glad to have attended the session, as was led by Emeritus Professor of Neuroscience Mitchell Glickstein, who has an encyclopaedic knowledge of brain anatomy and the history of neuroscience. So, although the bread knife remained unused, the session was a detailed anatomical tour of the brain, peppered with fascinating historical anecdotes.

For example, I knew that the word pons is Latin, and means bridge. What I didn't know was that this brainstem structure, which is visibile at the top of the above figure from the classic 1918 edition of Gray's Anatomy, was first described by Costanzo Varolio in 1573, who named it as such because it appeared to him to resemble a Venetian bridge.

In biology, structure usually relates to function, and the pons follows this general rule, as it actually does form a bridge. It consists of three massive fibre tracts, called the superior, middle and inferior cerebellar peduncles, which relay sensory information between the cerebellum and the cerebral cortex.