Brain theory and minimal brain dysfunction.

Ever since the National Institutes of Health labeled the diffuse problems of learning disabilities in children as results of minimal brain dysfunction, a variety of research efforts have been made to explain the syndrome. To a large extent, these efforts have met with only limited success because of disagreement over whether, in fact, there is organic involvement. Even if there had been agreement on this point, however, the problem of determining the psychological dimensions of the disorder would still exist. Inattention, perceptual difficulties, impaired cognitive functioning, motor clumsiness, slow reaction time, and all the rest are commonly mentioned as aspects of the syndrome; all these problems and more surely exist. Rather than adding data to the studies of the problem, I would like to offer another perspective from which to view it. In particular, insights on cerebral functions offered by studying the bisected brain may apply to specific problems seen in some cases of minimal brain dysfunction (MBD). It seems fair to say that one of the clearest syndromes seen in clinical neurology results from brain bisection.' After observing cases with midline cerebral commissure section and studying the resulting deficits over a long period of time, one becomes convinced that the normal functioning of this information system ' is very important-especially during development. My own suspicion, moreover, is that when it does not function normally, it either produces or coexists with problems in the natural establishment of cerebral dominance and lateral specialization. Failure here may in turn be responsible for many of the problems seen in MBD: some aspects of MBD may reflect problems in the normal dynamics of cerebral activity, i.e., the shuttling of information between various specialized processing centers in the brain. It may well be that MBD reflects problems in this kind of neural integration more than it does neuronal disorders per se. Put differently, to some extent MBD may be the result of subtle software programming abnormalities that occur in the presence of poorly established cerebral dominance.