Phineas Gage: The brain and the behavior

Phineas Gage has long occupied a privileged position in the history of science. Few isolated cases have been as influential, in the neurological and neuroscientific thinking, and yet the documentation on which conclusions and interpretations rest are remarkably incomplete [1] , [2] . We do have a number of sure facts: – Gage did suffer a well-described accident, which resulted in major damage to his skull and brain; – we do know that after the accident his personality underwent a major change and that his reliability was compromised; – we do have his actual, damaged, skull as well as the weapon that traversed it, both preserved as museum artifacts. By undertaking a direct analysis of the skull and taking direct advantage of novel neuroimaging techniques, we took a new look at the Gage case [3] . After analyzing, measuring and photographing the skull at the museum of the Harvard Medical School, we modeled a restricted number of trajectories for the weapon and for the respective sites of brain injury. We were then able to interpret aspects of Gage's behavior that were credibly compromised in the setting of Gage's presumed lesions. The confidence we were able to place on these interpretations depended on the fact that we had extensive experience with the systematic study of brain lesions and their consequences — namely with frontal lobe lesions — in cases that were well documented neuroanatomically and neuropsychologically and were even included in neuropsychological experiments. Our goal, nearly a quarter of a century ago, was to add a chapter to the Gage history and enrich this historical case with the benefits of modern techniques and theoretical advances. We did not intend to use Phineas Gage to advance knowledge in neuroscience, rather we used advances in neuroscience to complete the study that Harlow had obviously intended to author about Phineas Gage. Interest in the Gage case has not waned, and two additional studies are worth mentioning. Of interest, in 2004, Ratiu et al. [4] replicated our findings and suggested that the Gage lesion was probably confined to the left hemisphere, something entirely compatible with our views but that, on the basis of our own data, we could not conclude with confidence. In 2012, yet another research group addressed the likely disruption of white matter tracks in relation to cortical networks [5] . I plan to discuss these results in light of current knowledge of frontal lobe dysfunction.