You Can Teach an Old Brain New Tricks
The manifestations of aging depend not only on the aging process itself, but also on the reserves we have accumulated to help our body withstand time’s inevitable losses. This is no different in the brain department. It seems that the chances of dementia are lowest in those with bigger brains and better education and in people whose work has required more mental activity.
Although many important neural connections form when we are young, it is never too late to build additional brain reserves. Even in aging adults, the brain can adapt to form new connections and generate new cells. A long-term commitment to keeping active – both mentally and physically – can delay the impacts of aging on the brain and give us a good excuse to have a lot of fun! By contrast, each additional hour of watching mind-numbing television seems to make dementia more likely as you age.
Some will prefer to retain brain reserves by solving crosswords, playing chess, bridge, Sudoku or other mind-games. Crafts, reading, learning new languages or skills can all be stimulating activities. Join a club or society and stay socially active as well as mentally active. The trick is to find something challenging that you can enjoy and commit to it. Try to avoid fads, which may look like fun, but are rarely sustainable. A number of simple exercises are available that will help give you a mental edge in the short term, regardless of your age.
Sensory experience can also help to keep the brain active as we age. A study conducted by the Max Planck Florida Institute and Columbia University in New York found that sensory experience can cause massive rewiring of the brain, even as one ages.
The first author of the paper, neuroscientist Marcel Oberlaender, PhD, said, “By changing the nature of sensory experience, we were able to demonstrate that the brain can rewire, even at an advanced age. This may suggest that if one stops learning and experiencing new things as one ages, a substantial amount of connections within the brain may be lost.”
The rewiring involves the fibers that supply the main input to the cerebral cortex, the part of the brain that is responsible for sensory perception, motor control and cognition. These findings open up a plethora of opportunity for further research on brain remodelling and aging.
During the study, the researchers examined the brains of older rats, focusing on the thalamus, which processes and delivers information obtained from sensory organs to the cerebral cortex. Until now it was thought that connections between the thalamus and the cortex stop changing by early adulthood. However, the researchers found that this is not the case in the rats they studied.
Rats, being nocturnal, rely on their whiskers as sensory organs to explore and navigate their environment, making them prime candidates when studying whether the brain can be remodelled by changing sensory experience. The researchers trimmed the whiskers of the rats, preventing them from receiving sensory input, to determine whether extensive rewiring between the thalamus and cortex would occur.
The study found that the animals with trimmed whiskers had altered axons, nerve fibers which carry information from one neuron (nerve cell) to many others, whilst those with untrimmed whiskers had no axonal changes. The findings were significant considering the age of the rats – meaning rewiring can occur at an older age, something that was not previously thought possible. Furthermore, the findings suggest this happened in as little as a few days.
Dr. Oberlaender said, “We’ve shown that the structure of the rodent brain is in constant flux, and that this rewiring is shaped by sensory experience and interaction with the environment. These changes seem to be life-long and may pertain to other sensory systems and species, including people”.
Recent advances in high-resolution imaging and reconstruction techniques, developed in part by Dr. Oberlaender, helped enable the study. The researchers were able to automatically and reliably trace the fine and complex branching patterns of individual axons, with typical diameters less than a thousandth of a millimetre.
Whether any sensory experiences or any other types of stimulation can keep you from developing dementia is unknown; what is probably more relevant is that such exercises increase your chances of reaching old age with as many marbles left as possible. As the number of marbles you have appears to determine the threshold of almost every degenerative problem, it’s surely worth giving your brain a regular workout.
- Part of the above story is reprinted from materials provided by Max Planck Florida Institute.
- Marcel Oberlaender, Alejandro Ramirez, Randy M. Bruno. Sensory Experience Restructures Thalamocortical Axons during Adulthood. Neuron, 2012; 74 (4): 648 DOI: 10.1016/j.neuron.2012.03.022
Last Reviewed 11/Mar/2014