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8 Headlines T he hippocampus also has a particular superpower. It is one of a very few parts of the brain that can generate new neurons throughout life, a process called adult neurogenesis. Neuron regeneration is critical to maintaining our memory capacity across our lifetime. This incredible finding was proven only a few decades ago, raising many exciting new avenues of research for neuroscientists. For instance, if the brain has the ability to create new neurons, could it be encouraged to heal itself from damage and disease? Enter a trio of University of Otago researchers who have completed two major studies funded by the Neurological Foundation to assess the unknown potential of neurogenesis. Professor Cliff Abraham, Associate Professor Stephanie Hughes, and Dr Shane Ohline have been studying if these ‘newborn’ neurons could be stimulated to help recover cognition andmemory impairment caused by neurological disease. “There is now growing evidence that this could indeed be the case,” Professor Abraham says. “The molecules controlling neuron birth and death work in complex ways, making it extremely challenging to understand them and harness their power. Still, one step at a time, the international community is making progress.” Their research has zeroed in on the naturally occurring brain protein ‘soluble amyloid precursor protein-alpha’ (sAPPa for short). When the brain is exposed to rich learning environments and exercise, the amount of sAPPa increases, encouraging neurogenesis. The team has demonstrated in the lab that when the production of sAPPa is reduced artificially, synaptic function and memory are impaired but, remarkably, this can be rescued by providing the protein back to the impaired cells. “We also found, using gene therapy, that increasing sAPPa production restores plasticity in the hippocampus, its neurogenesis and associatedmemory function in animal models of Alzheimer’s disease,” Associate Professor Hughes says. Other researchers internationally have also shown that the loss of sAPPa during disease reduces the number of synaptic contacts, and that delivering more sAPPa to the network helps restore their number. “Putting these findings together, sAPPa could be the basis of a new therapy for Alzheimer’s and potentially other brain diseases. However, clinical trials are dependent on many other streams of neurological research taking place at Otago and internationally, including figuring out how to get sAPPa to cross the nearly impenetrable blood-brain barrier (see our story on John Reynolds on page 7), and thus how to deliver treatments by intravenous injection or orally rather than through invasive neurosurgery and intracranial injections.” As well as potential treatments, the findings also contribute to the knowledgebase of dementia prevention. “We know that neurons born during adulthood have special properties that increase the plasticity of the hippocampus and its associated memory functions." “Understanding how this modifiable resource is controlled may help identify how cognitive stimulation and exercise help stave off cognitive decline in disorders such as Alzheimer’s disease, in which neurogenesis and memory are impaired.” The hippocampus is an extraordinary part of the brain. Located deep in the temporal lobe, it contributes mightily to emotions, learning and memory in all mammals. The self-healing brain? HARNESSING THE POWER OF NEWBORN NEURONS Images of brain cells born in adult animals. The figure at the right is an enlarged image of the cells in the yellow box on the left.