Researchers have recently discovered a specific network of regions in the brain that are more susceptible to degenerative diseases and brain disorders like schizophrenia. The study, entitled “A common brain network links development, aging, and vulnerability to disease” was published in the Proceedings of the National Academy of Sciences journal by Dr. Gwenaëlle Douau, a funded researcher from the Medical Research Council at the Oxford University Functional MRI of the Brain (FMRIB) Centre. This study was the result of an international collaboration between the University of Oxford neuroscience imaging team, neuroscience researchers from the University of Oslo, and research clinicians from the University Hospital Basel, Imperial College London, and the University of Oxford’s Department of Psychiatry.
It has been postulated since 1881 in “loi de régression” (Ribot’s law) by Théodule Ribot, a French philosopher, that the destruction of memories occurs in a reverse order to that of memories’ formation, from the unstable to the stable, from recently-formed memories to older “sensory, instinctive” memories.
Researchers from University of Oxford scanned the brain of 484 healthy subjects between the ages of 8 to 85 years old using magnetic resonance imaging (MRI) to observe the alterations in the structure of the brain. The team analyzed all the results to see which features were revealed in all of the age groups. The findings revealed a particular network of nerve cells within the grey matter associated mainly with higher order regions of the brain that develop later into adolescence or early adulthood, which correlates more with intellectual ability and long-term memory than the rest of the brain, and was the first to degenerate in older age. These mental features are significantly affected in subjects with schizophrenia and with Alzheimer’s. The data fit perfectly with the ‘last in, first out’ or ‘retrogenesis’ theory of brain alteration across life. It establishes that brain capacity decreases in reverse order than it develops. This large scale study is the first in showing for the first time this theory in one particular network region in the grey matter which is more susceptible to age induced neurodegeneration.
It has been shown in previous studies that in the brains of chimpanzees and other primates, this particular network of nerve cells within the grey matter is underdeveloped when compared with humans. It has been suggested that the absence of schizophrenia or Alzheimer’s in primates may be linked to this underdevelopment.
“Our results show that the same specific parts of the brain not only develop more slowly, but also degenerate faster than other parts. These complex regions, which combine information coming from various senses, seem to be more vulnerable than the rest of the brain to both schizophrenia and Alzheimer’s, even though these two diseases have different origins and appear at very different, almost opposite, times of life,” said Dr. Douaud, in a press release. ”These results, which might seem surprising at first, are really exciting as they actually reconcile two historical hypotheses — until now presented completely separately in the scientific literature — that the brain damage observed in Alzheimer’s and schizophrenia is related to these higher order regions of the brain.”
“Early doctors called schizophrenia ‘premature dementia’ but until now we had no clear evidence that the same parts of the brain might be associated with two such different diseases. This large-scale and detailed study provides an important, and previously missing, link between development, aging and disease processes in the brain,” said Professor Hugh Perry, chairman of the MRC’s Neurosciences and Mental Health Board that supported financially the work. “It raises important issues about possible genetic and environmental factors that may occur in early life and then have lifelong consequences. The more we can find out about these very difficult disorders, the closer we will come to helping sufferers and their families.”