Can you improve your body’s ability to remember by making it move? That rather odd-seeming question stimulated researchers at the University of Copenhagen to undertake a reverberant new examination of just how the body creates specific muscle memories and what role, if any, exercise plays in the process.
To do so, they first asked a group of young, healthy right-handed men to master a complicated tracking skill on a computer. Sitting before the screen with their right arm on an armrest and a controller similar to a joystick in their right hand, the men watched a red line squiggle across the screen and had to use the controller to trace the same line with a white cursor. They aimed to remain as close to the red squiggle as possible, a task that required input from both the muscles and the mind.
The men repeated the task multiple times until the motion necessary to track the red line became ingrained, almost automatic. They were creating short-term muscle memory.
But muscle memory — or “motor memory,” as it is more correctly referred to among scientists — exists and can be pretty potent. Learn to ride a bicycle as a youngster, abandon the pastime and 20 years later, you’ll be able to hop on a bike and pedal off.
To date, most studies of the effect of exercise on memory have looked at more intellectual tasks, like memorizing lists of words. In those cases, regular exercise appears to improve the brain’s general ability to remember.
But the Copenhagen scientists wanted to see how exercise influences the development and consolidation of physical memories. So before having their volunteers master the squiggle test, they first had a third of the group ride a bike at an intense but not exhausting pace for 15 minutes. The other two-thirds of the group rested quietly during this time.
Then, after the computer motor-skill testing, a third of those who’d previously rested completed the same strenuous 15-minute bike ride. The others rested.
All of the volunteers then repeated the follow-that-squiggle test after an hour, a day and a week to see how well they’d learned and remembered that particular skill.
Their scores for speed and accuracy of squiggle shadowing were almost identical at the one-hour point, although the group that had ridden the bike after the first computer practice session was slightly less accurate.
After a week, though, things looked different. The men who had exercised just after first learning the motor skill were noticeably better at remembering the task, with their tracing of the red line on the computer more agile and accurate. The men who’d exercised before learning the new skill were not quite as adept now, although they were better than those in the group that hadn’t exercised at all.
What this result suggests is that physical exercise may help the brain to consolidate and store physical or motor memories.
Consolidating a memory is not instantaneous, after all, or even inevitable. Every memory must be encoded and moved from short-term to long-term storage. Some of those memories are, for whatever reason, more vividly imprinted than others.
It may be that physical, aerobic exercise performed right after a memory has been formed intensifies the imprinting. It makes the memory stronger.
In the short term, though, exercise may leave the brain overstimulated, making it less able to pinpoint and access new memories. That may be why men who exercised after learning the new skill performed worst during the first motor-memory recall test.
But they performed better long-term because their memory of the new skill would seem sturdier.
How a single workout can strengthen a particular memory is uncertain, but one suspects biochemistry. “There is evidence that aerobic exercise produces substances” in the brain, like brain-derived neurotrophic factor and noradrenaline, that drive memory consolidation and learning, he says.
Ultimately, how exercise operates in this context may be less significant for most of us than when. The timing of the exercise is critical. To be maximally effective, it needs to be performed “right after exposure to the information to be remembered.”
Want to remember how to ride that bike, in other words? Then ride it as soon as you have managed to stop wobbling. The exercise seems able then to cement the memory of how to ride. Ditto if you’ve just perfected the snap of your tennis serve or the spin on your soccer kick. Go for a run or perform Tai Chi immediately afterwards, and your body may later better remember.
From The Newyork Times
