What actually happens in the brain when we think, when we feel, when we dream, believe, remember and lie to ourselves? The forthcoming Lecture on Everything explores all these issues and much more on Friday 5th October at Marsh Barn.
New ideas about life and death in the brain
The story begins with the Spanish doctor Santiago Ramón y Cajal, who specialised in histology and anatomical pathology at the turn of the 20th Century. It was Ramón y Cajal’s genius and exquisite drawings that established that the brain is composed of billions of individual but precisely interconnected cells. The complex networks that Ramón y Cajal described led to one of the main questions that occupied many researchers: how do nerve cells and their extensions make the correct connections to their targets? Rita Levi Montalcini discovered (in the midst of WWII, first in the kitchen of her little hideaway, later in the USA with Victor Hamburger) that the target provides the solution by producing factor(s) that announce to the incoming nerve that it has arrived. To solve the problem that a nerve cell or its extension may go astray whilst navigating, our body makes more nerve cells than it needs, thus those that find the target will survive and make strong bonds whilst those that don’t will die. Not all organisms are built this way: the tiny nematode worm pre-determines that precisely 131 cells, and always the same cells, will die during its development. Our model is stochastic whilst that of the worm is deterministic. Through work on the genes that control the death of the cells in the worm, it was soon realised that the cells do not just die willy-nilly as if they were poisoned with bleach. In fact, evolution has contrived a sequence of events so that the cells will die in an orderly fashion. This is termed programmed cell death (PCD). It was soon realised that PCD is wide spread in the animal and plant kingdoms: for example, our digits are formed because the tissue between them undergoes PCD. Our intestines need to make new cells continually, so these are balanced by PCD. In fact, cancers can occur because of failed PCD, and most chemo- and radiotherapy aim to instigate PCD. With the discovery of PCD, it was thought that neurodegenerative diseases like Alzheimer’s and Parkinson’s occur because of a surfeit of PCD. However, it turns out that PCD is rarely observed in most neurodegenerative diseases. Dr. Aviva Tolkovsky will show some of the latest research as to possible alternative pathways and the kinds of therapies that might be useful to treat nerve degeneration.
Aviva Tolkovsky was born in the USA and brought up in Israel from childhood. She completed her university education at the Hebrew University Jerusalem. After specialising in brain research in the USA, she began my research into factors that support nerve growth and survival. She held a Research Fellowship at University of Cambridge, a lectureship at the University of Oxford, returning to the Dept of Biochemistry at Cambridge until her recent retirement. Currently she holds a Principal Fellowship in the Cambridge Centre for Brain Repair and is continuing to investigate the causes of neurodegenerative diseases.
‘what loneliness/ to be blind in broad daylight-/and deaf, what loneliness/ when the song’s in full swing’
