London: Scientists have for the first time discovered that neuronal connections grow excessively under stressful conditions as the brain ages, a finding they say could help them better understand neurodegenerative diseases such as Alzheimer's and Parkinson's.
   
A team from the University of York and Hull York Medical School and researchers from the Peninsula College of Medicine and Dentistry studied responses to stress in synapses -- a structure that permits a neuron to pass signal to another cell in the brain -- in fruit flies.
   
They found that under stressful conditions, such as neuro-degeneration resulting high energy forms of damaging oxygen cause synapses to grow excessively potentially contributing to dysfunction.

Such stresses occur during neurodegenerative disease such as Alzheimer's and Parkinson's Disease, said the researchers.
   
Laboratory modelling was carried out using Drosophila, but similar pathways are present in humans, they said.
   
The scientists studied the responses using a model of lysosomal storage disease, an inherited incurable childhood neurodegeneration where enlarged synapses have been observed, but the role that growth has in disease progression and brain function is not yet clear.
   
"The findings have strong implications for neuronal function as brains age, and will add significantl1y to our understanding of neurodegenerative disease such as Alzheimer's and Parkinson's disease," said study co-author Dr Sean Sweeney of the Department of Biology at the Unive1rsity of York.
   
Co-researcher Dr Iain Robinson of the Peninsula College of Medicine and Dentistry said neuronal contacts in brain are constantly changing which enable us to form short term or long term memories.
   
"Our work sheds light on how our brain becomes less able to make these changes in neuronal contacts as we age and helps explain the loss of neuronal contacts seen in several neurodegenerative diseases," he added.

(Agencies)