Integrated Calendar

In the 1960’s, the Physics Department at Oxford University was particularly
proficient in electromagnetism and this, coupled with one-on-one tutoring, ensured that electrical fundamentals were firmly rammed into me as an undergraduate. When, therefore, I first encountered in the late 70’s the description of MRI (~ 0.15 T) signal reception as being due to radio waves, I knew with great certainty that this was nonsense. However, to my consternation I saw the description, replete with seductively simple twoquantum level pictures of absorption and emission, gain almost universal acceptance and appear in a growing number of texts containing “simple” explanations of imaging. By 1990, the situation had so deteriorated that newspapers were saying that MRI used radiation, and this concerned me to the point where I felt correction in print was needed. However, from that first publication on I sensed considerable embarrassment when I raised the topic, until a medical colleague gently pointed out that the physicists in his university said the whole issue had been settled some 40 years earlier by Nobel prize winners and that I was making a fool of myself. What does one do in such a situation – retire hurt, or fight and if the latter, how? I decided to fight and so, over twenty years later and the battle largely won, the talk will deal with the science, psychology and insights to be gained from a rather bruising encounter with entrenched thinking and excessive specialisation.
† T. H. Huxley (1825 – 1895) Eminent British biologist and evolutionist.

Computational and experimental studies of learning and memory have traditionally focused on the role of cognitive brain areas such as the cortex and hippocampus. This work has provided invaluable insights in the ways items are learned, stored and consolidated using a variety of neural mechanisms from molecular to network levels. Relatively little has however been done on understanding how and why some items are selected to be memorized while others are not. I will present a set of experimental results in the rodent showing that the dopaminergic neurons of the rodent ventral tegmental area are actively involved in the acquisition and consolidation of positively and negatively valued memories. The experiments will include optimal spatial navigation, memory reactivation and a rodent model of post-traumatic stress disorder. This ongoing work suggests that neuromodulatory centers may have a much more active and selective role in learning and memory than previously thought.