Ventromesial Frontal Lobes

The celebrated case of Phineas Gage illustrates the prototypical example of personality change after lesion to the frontal lobe. In the 1840s Gage was employed, in a supervisory and highly responsible role, laying railway tracks in the midwestern United States. He was pressing down a charge of dynamite into a rock formation, using a tamping rod, when the charge exploded, causing the rod to shoot through his head, from underneath his cheek into the frontal lobe of his brain and out the top of his skull. Partly because the rod passed through so rapidly, probably cauterizing the tissue on its way, the damage to Gage's brain was not widespread; only a relatively small area of frontal tissue was affected.6 Gage did not even lose consciousness, and he made a rapid physical recovery.

His physician, however, observed some interesting changes when he reported the case in a local medical journal a few years after the incident. Despite the good physical recovery and relatively small extent of the brain injury, Dr. Harlow noted that his patient was radically changed as an individual: His personality was changed. Before the accident Gage had been the foreman of his team—a position of some responsibility—he was regarded as a reliable character, and he was highly valued by his employers. However, this is what Harlow said about Gage after the accident:

His physical health is good, and I am inclined to say that he has recovered ... [but] the equilibrium or balance, so to speak, between his intellectual faculties and animal propensities, seems to have been destroyed. He is fitful, irreverent, indulging at times in the grossest profanity (which was not previously his custom), manifesting but little deference for his fellows, impatient of restraint or advice when it conflicts with his desires, at times pertinaciously obstinate, yet capricious and vacillating, devising many plans of future operation, which are no sooner arranged than they are abandoned ... In this regard his mind was radically changed, so decidedly that his friends and acquaintances said that he was "no longer Gage" (Harlow, 1868, p. 327).

Disregarding the now quaint language, the message of this physician's description still comes through clearly: As a result of his brain damage, Gage was "no longer Gage." The inescapable conclusion is that Gage's personality—his very identity—was

6See Damasio et al. (1994) for a precise description of the extent of the brain injury in this case.

somehow dependent upon the few cubic centimeters of brain tissue that were damaged in his accident. Today we know, from observing countless similar cases, that damage to this brain tissue almost always produces the very same type of personality change as it did in Gage. There is some variability, depending above all on the premorbid personality, but these patients are typically "fitful and irreverent, showing little deference for others, impatient of advice, especially if it conflicts with their desires," and so on. These are some of the cardinal features of what is now known as the frontal lobe personality. Practicing neuropsychologists have encountered literally hundreds of Phineas Gages, all with damage to the same part of the brain. This suggests that there is a predictable relationship between specific brain events and specific aspects of who we are. If any one of us were to suffer the same lesion in that specific area, we would be changed in much the same way that Gage was; and we, too, would no longer be ourselves.

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Anxiety and Depression 101

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