Canada/UK

Brenda Milner

2009 Balzan Prize for Cognitive Neurosciences

For her pioneering studies of the role of the hippocampus in the formation of memory and her identification of different kinds of memory system

Brenda Milner is one of the founders and pioneers of the field of cognitive neurosciences, that links the study of the brain with the study of mental processes. Milner demonstrated the crucial role of one part of the brain, the medial temporal lobe, especially the hippocampus and related structures, in the formation of memory.
Milner first reported her seminal findings as a result of the study of a patient, HM, who underwent surgery to control epilepsy in 1953. The surgery involved bilateral removal of the major portion of the hippocampus and associated structures.

Milner showed that, as a result of the surgery, HM was unable to retain memories of newly experienced events. But the most remarkable aspect of HM was that some aspects of his memory were unaffected by the surgery. These included his memory of events in the distant past and his ability to learn new skills. These results, together with many other subsequent studies, have shown that human memory, and indeed the memory of other mammals, is of more than one kind. One distinction is between long term and short term memory: HM retained memories for long past events, but was unable to translate immediate memory into a longer-term store. Another is the distinction between memory for specific events, people, and places, referred to as episodic memory, and memory for motor skills such as riding a bicycle, or procedural memory. HM could learn new skills even though he had no recollection of having learned them: the damage to his hippocampal region affected episodic but not procedural memory.
As a result of many thousands of studies that have followed on from Milner’s pioneering work, these different kinds of memory are now well established. Equally, her finding that one particular part of the brain, the hippocampal formation, plays a key role in memory, has had a long-lasting impact and spawned a very large body of research on the precise role of the hippocampus and related structures.
The focus of much research on neurodegenerative diseases such as Alzheimer’s is closely linked to Milner’s discoveries. Like HM, patients with dementia, are often unable to form new memories, whilst retaining memory for past events. There is also evidence that dementia patients frequently suffer from degeneration of the hippocampal region.

In addition to her work on the hippocampal formation and memory, Milner has made major contributions to our understanding of the roles of other parts of the brain, notably the frontal cortex, in the processing of information. She has also studied the specialisation of the left and right hemispheres of the brain, and the effects of specific brain lesions on the functional reorganization of the hemispheres.
For her truly pioneering work that has shaped the field of cognitive neurosciences for over half a century, Brenda Milner is a most distinguished recipient of the Balzan Prize.