Hiking
at Eagle Creek, Oregon for fun. Photo courtesy of Kelvin Kay and Wikipedia.Hiking
at Eagle Creek, Oregon for fun. Photo courtesy of Kelvin Kay and Wikipedia.A: The best way to improve our memories seems to be to increase the supply of oxygen to the brain, which we can do by aerobic exercising. Walking for three hours each week suffices, as does swimming or bicycle riding.
Such aerobic exercise has helped elderly people switch between mental tasks, concentrate better and improve their short-term memory, says Arthur Kramer of the University of Illinois, Urbana, commenting on a number of studies.
Moreover, we now know why. Kramer and his team studied 59 healthy volunteers 60 to 79 years old, and found that aerobic exercise increased the number of neurons in their brains and the number of connections between neurons.
Exercising the brain, itself, isn't as helpful as we might hope. Several big-name researchers (Columbia, Harvard, Brown, John Hopkins University, the University of Pennsylvania and the Mount Sinai School of Medicine) formed a consortium in 1992. They spent $11.4 million on studies researching memory loss due to aging. The upshot: intervention programs they devised produced only modest temporary improvement. Furthermore, results showed "training in a specific task did not lead to improvement in memory capacity overall."
However, if we train in a particular task we want to improve — like remembering names — then perhaps it doesn't matter whether or not we've increased our overall memory capacity. At least, we can remember names better. Also, we can keep up the training, so it lasts as long as we please.
Perhaps even more interesting: the consortium found memory improvement or maintenance depends highly on the individual. What works for some may not work for others.
I've listed some memory guides under Further Reading. These guides present a variety of ideas, so you can pick and choose what might help you. I've also included some demos of a program designed to improve mental skills. The demos are humbling but also fun.
And, if you want to know just how poor your memory is (and how little we pay attention to details), I've included a 'police sketch' program. First put away all pictures and mirrors, without peeking. Then use the sketch program to select the right features, and assemble them into a reasonable picture of your face. Now, try to picture, with the sketch program, a close friend or relative. By the way, you can stretch features with the mouse. Not easy, eh?
Further Reading
Aerobic exercise training increases brain volume in aging humans, The Journals of Gerontology Series A: Biological Sciences and Medical Sciences 61:1166-1170 (2006)
Exercise shown to reverse brain deterioration brought on by aging, University of Illinois, Urbana, November 2006
10 research-proven tips for a better memory, Harvard Health Beat
Improving your memory: tips and techniques for memory enhancement, wwwlHelpGuide.org
How to remember names better, 43 folders
Police sketch, FlashFace
Two weeks ago we considered how information flows through the brain, and how the brain places a new short-term memory into long-term memory. Last week we described how neuron networks store and retrieve memories. This week concludes our memory series by seeing how hippocampus synapse molecules change to define a network path and, hence, a pattern and memory.
The action takes place in the border region (called a synapse) between two neurons. A synapse is a small molecular-size gap (20 to 40 nanometers across) between two neuron cells and the cell membranes of both neurons at the gap. A nanometer is one billionth of a meter (or yard). This tiny region between neurons in the hippocampus is where a memory-defining path is born.
Neurons carry information across the brain in the form of electrical pulses. One neuron fires a signal, which propagates down its tail-like axon to the synapse. Chemical messengers at the synapse carry the disturbance across the synapse, and change the potential difference across the cell membrane of the second neuron. If the change is great enough (about 15 mV), the second neuron fires an outgoing signal (peak of +30 mV). So far, so good. That's how signals go down a neuron network. But there's more to establishing a long-term pattern.
For a preferred path, we need frequent-firings. If the incoming neuron fires frequently enough so that the outgoing neuron's cell membrane receives many jolts in a short period of time, the jolts excite the outgoing neuron's membrane long enough to elevate the voltage across the cell membrane for a sustained time. That's the ticket: jacking up the voltage for a goodly time. Five thousand or more molecules and ions drift and bop their way across the gap to the outgoing neuron. Molecules bond with molecules on the outgoing side. Each bonding releases energy. Activity avalanches into a frenzy of catalytic-induced growth. New proteins are born, which create new synapses, which define a new network.
The net result is to raise the resting potential in the outgoing neuron's membrane for a long period. The elevated resting potential makes it easier for an incoming signal to exceed the neuron's firing threshold voltage and, therefore, to fire the outgoing neuron. The synapse is strengthened, can fire more efficiently and a new preferred path is created.
Please click here for the details of how molecules change to establish a network path.
Note: The content of the site "The Brain from Top to Bottom" is
under
copyleft.
, which allows free
access to the material. I am in debt to Bruno Dubuc and his excellent
primer.
How memory works, part 1, WonderQuest
How memory works, part 2, WonderQuest
The brain from top to bottom by Bruno Dubuc, Canadian Institutes of Neuroscience, Mental Health, and Addiction
Medical, Science and Nature Images by Scott Camazine
Neuroscience for kids by Eric Chudler, University of Washington
Brain Facts and Figures by Eric Chudler, University of Washington
MIT team discovers memory mechanism, Science Daily, Feb. 9, 2004
Gene manipulation in mouse and applications to the study of memory, RIKEN, the Institute of Physical and Chemical Research, Brain Science Institute
Requirement for Hippocampal CA3 NMDA receptors in associative memory recall, RIKEN, the Institute of Physical and Chemical Research, Brain Science Institute
Learn like a human, Numenta, IEEE Spectrum, March 2007
Spatial short-term memory pinpointed in human brain, National Health Institutes, 1998.
Capacity limit of visual short-term memory in human posterior parietal cortex, Nature, 2004.
(Answered March 26, 2007)