In this slim volume, Antonio Battro, an Argentine physician who trained in Geneva with child-development theorist Jean Piaget, seeks to develop foundations for a new field—“neuroeducation”—based largely on his work with a single remarkable boy. Most of the right hemisphere of Nico’s brain was removed in an effort to control epileptic seizures he had suffered since birth. Battro argues that Nico’s remaining hemisphere has developed into a “full and healthy mind” and suggests that compensatory processes initiated by the boy and his teachers that have allowed the remaining hemisphere to substitute for functions of the missing one.
Battro argues that Nico, now eight years old, is a uniquely impressive case of how much education can accomplish in compensating for loss of cerebral tissue; but he is aware of the limits of this approach. At the end of the book he remarks, “I have only drawn a rough sketch of the epigenetic neurocognitive landscape of a half-brain person, but I hope many others will go more deeply into what I have explored superﬁcially.”
Although this is a small volume and a single case history, it also draws upon recent evidence from brain imaging, neural networks, and computer-based education. These three ﬁelds, together with new evidence from neuroscience, have profound implications for brain plasticity. Thanks to these developments, the prospects for neuroeducation are now much brighter; Battro’s book will help convey that point to the general public. Battro also attempts to relate these methods to the ideas of theorists such as Jean Piaget and Noam Chomsky, who have advanced somewhat opposing views, reﬂecting their emphasis upon environmental versus genetic factors in brain development. The theoretical issues are certainly not resolved by Nico’s story, but throughout the volume Battro applies his understanding of how brains work to Nico’s education.
Much of Nico’s right hemisphere was removed, and the remainder disconnected from his undamaged left hemisphere, when he was three and a half years old.
He now has a slight limp and difficulty in making fine movements with his left hand. He also suffers from a left-side visual defect, for which he compensates through head and eye movements. According to Battro, Nico’s cognitive abilities, are largely intact.
In the book’s early chapters, Battro paints a stark image of the brain tissue that Nico has lost, laying the foundation for his argument that Nico’s high ability must mean that a new brain has been “sculpted” in the remaining hemisphere. There is, however, no way to know what Nico’s potential for performance would have been had there been no epilepsy or no right hemisphere removal. Battro does say that Nico had problems with drawing and handwriting, possibly related to loss of the right hemisphere, which he compensated for by using a computer.
Battro asks what we can learn about how brains work in light of Nico’s high verbal IQ of 118 (on portions of the test related to vocabulary, common information, and so on) and his performance IQ of 97 (on portions of the test involving arranging pictures, copying block designs, and similar tasks). Battro sees these numbers as indicating Nico’s normality, despite having only half a brain, but of course such a large difference between verbal and performance IQ would also fit with the loss of a right hemisphere. Brain-imaging data give us clues to understanding the neural basis for IQ. For example, recent research shows that general intelligence is related to activation of two relatively small areas of the ventral prefrontal cortex, one on each side. These two areas may be involved in representing information in the absence of sensory input, an operation crucial in almost every problem-solving situation. When problems become difﬁcult, homologous areas on the opposite side of the brain are also recruited, suggesting a basis for compensation latent in all of us.
Battro also emphasizes how essential it is to trace the time course of normal brain development. This is now a very active area of research, with a consortium of universities and research centers using magnetic resonance imaging to trace the development of the normal brain and, using new methods, to observe at what stage various areas are ﬁrst linked by the brain’s connective white matter.
Nico’s many compensatory developments are analyzed as a way to understand the circuitry by which Nico’s reduced brain tissue can control his performance. Here Battro introduces a lovely illustrative experiment. He shows Nico random-dot stereograms. For normal people, this method shows that information from the left and right hemispheres is brought together over pathways between them to produce a uniﬁed, three-dimensional image. Nico, however, has no connections from the eye to the right hemisphere and no cortical connections between the left and what remains of the right hemisphere. Yet he sees the 3D images normally, showing that different pathways are allowing for the same functional outcome.
In his 1999 book, Mind Sculpture: Unlocking Your Brain’s Untapped Potential, Ian Robertson has revealed many ways by which the human brain can compensate for brain injury that occurs even in adulthood. There are now new opportunities to use stem cells to create replacement transplants for damaged cells. To make this therapy effective, however, we must understand more clearly the range of compensations possible in different brain areas and ages.
COMPENSATING BY COMPUTER
Nico was ﬁve when Battro ﬁrst met him and helped his family ﬁnd him a strong private school, with a warm, supportive environment. This school was particularly advanced in the use of computers. Battro, who had used computers to train children who were mentally retarded, autistic, or physically handicapped, could see the advantages for Nico of using the computer. For example, while Nico’s handwriting was slow and labored because of difﬁculty in managing his left hand, he was able to manage the mouse and do well with computer graphics.
Nico seems to have modest problems with some cognitive processes associated with the right hemisphere, such as drawing, and in his relatively weaker performance IQ. His use of language is advanced, as might be expected, given the presence of an intact left hemisphere and no right hemisphere to compete with it. Battro recognized, however, that it was crucial for Nico to have a way to communicate this verbal intelligence fluently. Children with difficulty in speaking or writing may be thought to be retarded, but another way of communicating can reveal their underlying intelligence. Battro therefore introduced e-mail correspondence to enable Nico to deal with the pragmatics of written language.
Battro interprets Nico’s use of the computer as a way to switch the performance of a given task from one brain circuit to another. For example, Nico has problems converting his visual image of a picture into a drawing. If the computer can be used to apply verbal instructions to a drawing, the manual output is no longer necessary. By using verbal output instead, Nico can produce a drawing that no longer uses the absent neural circuitry for controlling the ﬁne muscles of his left hand. Using a computer in this way enables the child to adapt his performance to his own particular strengths and weaknesses.
This compensation for input and output losses seems straightforward, but analyzing how it actually works may be complex. We know, for example, that some children have difﬁculty sounding out words that they see. It seems natural to compensate by a reading method like look-say based on learning to name whole words, reducing the need to sound them out. We do not know, however, if the visual areas of the brain involved in chunking letters into a unit (the visual word form) can succeed in handling novel words under these conditions. This is the level of analysis that would be needed to translate knowledge about the brain into effective methods of education.
Battro digresses a bit by introducing his experiments on how right- and left-handed children achieve some of the developmental milestones identiﬁed by Jean Piaget and his followers. In some cases, a child improved performance by using the hand opposite the brain hemisphere that was best able to carry out a function. These results are similar to many in the adult literature on lateralized input or output, suggesting somewhat the same point. These hemisphere differences are most striking in patients whose brain has been split by surgery separating the ﬁbers that allow transmission between the hemispheres. A picture, for example, presented in the left visual ﬁeld and going directly to the right hemisphere, might produce an emotional reaction, yet the person would be completely unable to say what had been seen, while still being able to pick out the appropriate object with the left hand. Data on young children can look somewhat like the split-brain data, because the connections between their two brain hemispheres develop very slowly.
THE CHALLENGE OF NEUROEDUCATION
Battro concludes with his vision for neuroeducation. He sees education, development, and the brain in the closest interaction and believes that computer technology can help sculpt new brains after either only brief training or, in some cases, many years of practice. He reports that the rate of growth in Nico’s ability to output words, mostly by copying text, is normal for his age and much better than is found in other types of brain injured patients. A graph of the number of words produced per hour plotted against hours of training shows that to obtain the same improvement in performance takes longer and longer as training proceeds. The result is the well known power function that relates practice to performance in many forms of learning. Battro concludes that this steady improvement in performance must reﬂect changes in brain circuitry— an argument that leads him to make a plea to neuroscientists to take up the challenge of developing neuroeducation.
There are signs that this goal is already being pursued. This is a unique moment in progress toward understanding how speciﬁc experiences change the brain, and neuroscience has increasingly put the issue of brain plasticity at the center of its research agenda. The doctrine that new cells cannot be formed after birth has been overturned by ﬁndings that new cells are created, at least in speciﬁc brain regions. The discovery of stem cells has given new hope to the concept of brain repair, in which one’s own cells might be used to regenerate areas of the brain that have been lost due to injury. Progress in developmental biology and developmental psychology has been swift. Noninvasive methods of imaging the brain have made it possible to see changes in brain anatomy and connectivity during the formative years of human development. In adult studies, it has become commonplace to view brain networks as they become active during the course of thought.
In our view, there is no answer to the question of how much brain is enough. Battro is certainly persuasive that Nico is capable of every basic human response. Despite the frequently heard comment that we use only 1/32nd—or 1/8, or 1/16th— of our brains, no current theory enables us to say how much of our brain we actually need to function as human beings. Imaging indicates that as tasks change, all areas of the brain can become more (or sometimes less) active. As far as we know, no areas remain unaffected. Humans probably differ in the degree to which various circuits are used, however, and Nico’s story shows that there can be considerable plasticity. But what would he have achieved if he had not had epilepsy and undergone the operation? We cannot know.
Although we have raised questions about some of Battro’s arguments, including his major thesis that half a brain is enough, in the end these concerns do not seem to matter very much. Half a Brain is Enough is about inspiration and what informed and caring people and a remarkable boy can do under devastating circumstances. This aspect made the book enjoyable, and it also made us wish to sit down with Battro to discuss our own perspectives on the ﬁeld of human brain development. A new report commissioned by the McDonnell Foundation about research opportunities in this ﬁeld (of which we are editors), has sections on pediatric brain imaging, genetics, temperament, and the development of perception and language. Methods are now available to link normal development to brain pathology, to understand what circuits are created during the acquisition of skills like reading and processing numbers, and to move toward a true science of human brain development.
Like Battro, we hope that scientists will take up the challenge of neuroeducation. If there is something missing from the McDonnell report, it is the spark needed to inspire devotion to that goal. In Half a Brain Is Enough, Battro provides that spark—not so much with his theories or data, but with his moving presentation of the strongest motive for advancing this new ﬁeld: helping a child lead a successful life. For that we found the book a privilege to read.
From Half a Brain is Not Enough: The Story of Nico by Antonio M. Battro. ©2000 by Antonio M. Battro. Reprinted with permission of Cambridge University Press.
It might be useful now to summarize our findings using Howard Gardner’s framework of multiple intelligences (MI)...Our pupil excels in interpersonal relations. He is a leader in many situations involving verbal interaction. It is interesting to see how he behaves in a social situation, for example. I first noted this when I invited him to visit my home with his family. I have a nice garden but rather than going out to play he preferred to stay with the adults, asking questions about everything and participating in our conversation...
Nico’s linguistic intelligence is remarkable. He began speaking quite fluently before the age of two and lost no linguistic ability at all following surgery. Nico’s verbal performance is now above average. This is not simply because he has scored 118 in verbal IQ (which is in any case a somewhat controversial measure of linguistic ability), but because of the richness of his vocabulary and syntax.... In the afternoons he attends English classes at school, in which he attains a high level of success, and has a collection of English songs at home which he loves and knows by heart. The extent of the so-called “neuronal crowding effect” in his left brain needs further exploration. So many compensatory functions and still enough “room” to incorporate a second language and maybe others as well!
His written language skills, on the other hand, seem to need extra space—a kind of external memory. As I have said, his laptop serves him as an “intellectual prosthesis.” It would be extremely difficult, if not impossible, for Nico to remain at school without his empowering instrument. And lately an innovation is bringing about a significant change: email is now transforming his life...
Nico loves music. A recent gift from me was a beautiful radio I brought back from Singapore. I know he is enjoying listening to it (I always try to make him participate in my travels—next time we should be in contact by email). I have a piano at home and the first time he came he asked my permission to play. I tried to teach him a short tune with his right hand and he was eager to learn...He needs some help with an instrument like this, but fortunately nowadays, digital synthesizers can supply the left-hand accompaniment... The development of a musical intelligence in a right hemispherectomized child is certainly a challenge for neuroeducation...
It is in the act of drawing that we see Nico’s principal cognitive deficit, but I have no proof that his visual-spatial intelligence is impaired. This raises a very interesting point of discussion. Many authors have linked the right hemisphere to spatial processing. As I have already mentioned Nico’s spatial sense was “forced” into his left hemisphere, first by the epileptic and disabled right hemisphere and subsequently by surgery. Furthermore, his left visual field is impaired. It is quite remarkable how he compensates for this major visual deficit by means of eye and head movements in most situations. As a consequence of the hemianopia his reading ability is somewhat diminished...I fully expect that with continuous exercise his eye-scanning pattern will improve and that new reading methods will develop with age and practice...
Nico is perfectly well oriented in space and time. With the exception of drawing I have so far been unable to find a single specific cognitive impairment produced by the right hemispherectomy. I have tested some aspects of his precocious spatial ability by means of the representation of the horizontal level of a liquid in a tilted cup. And now, at the age of eight, he has revealed full operatory spatial thinking in some Piagetian tasks: the construction of a projective line using the alignment of solid objects between two marks on a table. And if we shift to the circumscribed space of the computer screen, Nico’s spatial performance is outstanding...
Logical mathematical intelligence has been widely identified as a predominantly left brain activity. But studies on left hemispherectomized children show that under certain circumstances the right hemisphere can, to a large extent, compensate for the loss of the dominant hemisphere. Correspondingly, the development of logic in a right hemispherectomized child such as Nico should not be a problem. In fact I could show that his logical thinking follows the normal development patterns...
Finally, let us attempt to describe Nico’s bodily-kinesthetic intelligence. A right hemispherectomy produces a left hemiplegia and left hemianopia. These are Nico’s principal disabilities and they are in striking contrast to his cognitive and emotional capacities which are predominantly intact. His motoric handicaps are now the main focus of concern to family and teachers alike who try to provide him with the best physical rehabilitation available. From a neurological point of view he has some voluntary control of the axial and proximal set of muscles in his left limbs. These control the elbow, shoulder, hip and knee via the ventromedial corticospinal (ipsilateral) tract which represents one tenth of the pyramidal fibers coming from the left motor and premotor cortex. Nico’s motoric rehabilitation depends on this secondary bundle of ipsilateral connections (Muller et al., 1991). Thus, his remaining left hemisphere has the potential to control the proximal movements on both sides of his body. But the lack of contralateral motor connections from the right cortex via the lateral corticospinal tract disrupts the voluntary control of the distal muscles, especially of his left hand and fingers.
When I first met Nico he was a very slim, delicate boy. Now he has grown and is capable of some physical activities which were impossible a few years ago...Careful motoric rehabilitation will certainly help to enhance the bodily-kinesthetic intelligence of a half-brained child. To sum up, as expected, Nico shows the superior language skills of a left brained child. But we now also have a more coherent view of the large number of compensatory effects which take place following hemispherectomy, particularly in many spatial tasks.