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Practice makes perfect, but how? Two groups of neuroscientists using MRI brain imaging announced last month that they were able to see changes inside the brains of people after mastering a new skill. The big surprise is that the part of the brain that changed has no neurons or synapses in it! The cerebral remodeling during learning was seen in the mysterious and still largely unexplored “white matter” region of the brain.
“Grey matter” is synonymous with smarts, but in fact only half of the human brain is grey matter. White matter, the “other brain tissue”, is rarely mentioned. Neurons in the cerebral cortex are packed into in the top layers of the brain, where they are connected together through synapses. Learning takes place in the grey matter by linking neurons together into new circuits by strengthening synapses or forming new ones.
But beneath the topsoil of the brain lies a dense network of fibers packed into a spaghetti-like snarl that is so complicated it is difficult to study or comprehend. These fibers are the wire-like axons projecting out from neurons in grey matter that transmit electrical impulses. Like buried telephone lines, these tightly bundled cables transmit information over long distances to communicate between distant regions of the cerebral cortex that are specialized to carry out different aspects of a complex cognitive function.
To understand the importance of white matter, consider what is happening under the baseball cap of a left fielder leaping over the wall to snatch a baseball in mid air. Visual processing in the back of his brain perceives and tracks the flying object and at the same time it monitors all the other objects on the field as the athlete runs to catch the ball. Then the motor control centers in the parietal region of his brain engage to launch his body on a running trajectory to intercept the projectile. Finally, precisely timed fine motor control extends his arm into space with millimeter precision to clench fingers at the right instant to pluck the speeding ball out of the sky. All the while the player simultaneously perceives the fluid situation on the field as runners advance and strategies unfold so that he can make critical split-second decisions—“Do I hold the ball or hurl it to home plate?” This higher level decision making is calculated in the frontal lobes, just behind the eye brows. All this vital communication sweeps across the entire brain from the back of the skull to the front to activate different regions of cerebral cortex specialized in executing individual aspects of the skill.
That’s the job of white matter—long distant speedy communication. The tissue is white because many axons are coated with tightly wrapped layers of electrical insulation called myelin. This insulation, made by non-neuronal cells (called oligodendrocytes), speeds the transmission of electrical impulses 100 times faster than transmission rates through bare axons. The complex skill of catching a baseball is a far cry from Pavlov and his slobbering dog learning to associate the sound of a bell with food. Skill learning is likely to involve different mechanisms. The kind of complex learning involved in mastering new skills such as catching a fly ball, takes time to learn and repetition over the course of days,weeks or years. This type of learning is what these neuroscientists dared to tackle.
In the first study, Jan Scholz and colleagues at the University of Oxford, England, used MRI brain imaging to obtain a detailed scan of the brain of 48 right-handed adults. Then they taught half of them to juggle. Anyone who has tried to master the three-ball-toss knows how difficult juggling is and how much practice it takes to learn it. But as in learning to ride a bike, once the complicated skill is mastered, suddenly everything “clicks” and the process becomes mysteriously automatic. Learning to read is like that too, which is what the second research group investigated, but first let’s have a look at the fascinating study peering into the brain of jugglers.
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7 Comments
Add CommentI'd like to see a study where images of a brain capture the learning paths of adults that know simple math and are then taught complex mathematics.
Reply | Report Abuse | Link to thisThere are multiple demonstrations of changes in the brains of children as a consequence of improved reading performance.
Reply | Report Abuse | Link to thisAylward, E. H., Richards, T. L., Berninger, V. W., Nagy, W. E., Field, K. M., Grimme A. C. et al. (2003). Instructional treatment associated with changes in brain activation in children with dyslexia. Neurology, 22, 212-219.
Meyler, A., Keller, T. A., Cherkassky, V. L., Gabrieli, J. D. E., & Just, M. (2008). Modifying the brain activation of poor readers during sentence comprehension with extended remedial instruction: A longitudinal study of neuroplasticity. Neuropsychologia, 46, 2580–2592.
Shaywitz, B. A., Shaywitz, S .E., Blachman, B., Pugh, K .R., Fulbright, R .K., Skudlarski, P., Mencl, W .E., Constable, R .T., Holahan, J .M., Marchione, K .E., Fletcher, J .M., Lyon, G .R., & Gore, J .C. (2004). Development of left occipitotemporal systems for skilled reading children after a phonologically-based intervention. Biological Psychiatry, 55, 926-933.
Simos, P .G., Fletcher, J .M., Bergman, E., Breier, J .I., Foorman, B .R., Castillo, E .M., Fitzgerald, M., & Papanicolaou, A .C. (2002). Dyslexia-specific brain activation profile becomes normal following successful remedial training. Neurology, 58, 1203-1213
Thank you for contributing these interesting references, which show functional differences in brain activation in children with dyslexia and changes in brain activation after intensive training. These results support the idea that brain wiring in cortical regions necessary for learning is different in people with dyslexia but that changes can be seen after learning. An important difference between these previous studies and the new study is that these are functional MRI, which measures local areas of brain activity while the subject reads. The new study used structural MRI, which finds physical changes in these brain areas after learning to read.
Reply | Report Abuse | Link to thisAlthough the subject of dyslexia having been evolved for a purpose is somewhat peripheral, I have argued that dyslexia reflects a functional use of the brain.
Reply | Report Abuse | Link to thisWe know that nearly anyone is or can be dyslexic with enough exhaustion or lack of rest.
A function of dyslexia?
Although many might be unfamiliar with the environment, in the wild, people clearly have varying degrees of ability to recognize reversed shapes, and find their way back in complex and novel terrain.
I would suggest that this is an evolved mechanism. It appears that evolution has a use for dyslexic perception. Right now this is mere hypothesis, as no formal study has, to my knowledge, taken place.
Reading uses cognitive areas that may have been developed for other purposes; if we can gain insight into some of those purposes, we can learn and teach better a greater proportion of our faculties (no pun, though it's tempting).
Since there is strong evidence that the brain divides its workload between the hemispheres, and the article points out increased symmetrical connection in the literate, what might be altered in cognitive ability?
Well, Socrates spoke against literacy as being hurtful to memory.
Rightbrain language focus on prosody (in language recognition areas) may be the area diminished in capacity by literacy. The once-popular rote learning had a valuable place in verbal as opposed to literate cultures. Yet perhaps the capacity is not diminished, but merely untutored.
I read of a certain anthropologist who was queried by a member of such a group as to what he was doing when taking notes; he answered that he took notes so he could remember.
The villager responded, "no, you take notes so you can forget."
There may be good reasons why reading can have debilitating effects, scrambling accuracy in memory. It increasingly appears that some verbal historical information of some Native American cultures are more accurate retelling of events than the written accounts. Since I'm not involved in this subject, you may have to seek references from modern historians involved with the subject.
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Mr. Fields, I understand. Thanks.
Reply | Report Abuse | Link to thisAlso, note that Keller and Just reported more recently that they have found changes in children's neural anatomy in the areas of the brain involved in skilled reading. These changes followed intensive remedial reading instruction.
DOI 10.1016/j.neuron.2009.10.018
This is a structural MRI study from 1999:
Reply | Report Abuse | Link to thisCastro-Caldas, A., Miranda, P., Carmo, I., Reis, A., Leote, F., Ribeiro, C. & Ducla-Soares, E. Influence of learning to read and write on the morphology of the Corpus Callosum. European Journal of Neurology, 6: 23-28, 1999
Very interesting article. A friend of mine suggests that the mechanism presented in the article is actually the biochemical (or neurophysiological) mechanism of the Pavlovian 'second signaling system':
Reply | Report Abuse | Link to thishttp://encyclopedia2.thefreedictionary.com/Second+Signaling+System.
http://encyclopedia2.thefreedictionary.com/Higher+Nervous+Activity
What do you think? Are his conclusions correct?