Brain facts

What happens when a metal bar gets stuck between our cheek and forehead?

In this week post I will present to you the case of Phineas Gage, an American railroad worker whose case change drastically the knowledge of the frontal lobes (you can see one of his pictures below).

The famous picture of Phineas Gage, holding the metal bar that pierced is skull. From neuroscienze.net

This incredible story starts on the morning of the 13th December 1848, when Phineas Gage entered Dr. John Martin Harlow’s medical studio in Vermont with a metal bar passing through his skull. Phineas Gage was working as foreman for the railroads in Vermont and that day they had to blast a rock in order to lay down some tracks. Unfortunately, while he was compressing some gunpowder with a metal bar, he hit the rock with this bar, thus provoking a sparkle that made the gunpowder to explode and transformed the metal bar into a deadly bullet. This 1m long-3cm wide bar hit Phineas Gage and it got stuck in his left cheek, piercing his skull up to his forehead, from where it came out (have a look below for a reconstruction of the bar position in his skull).

3-D reconstruction of the metal bar trajectory across Phineas Gage skull. From neuroscienze.net

Dr. Harlow extracted the bar from Gage’s skull and he treated him in the best possible way. However, we do not have to forget that this story takes place in the first half of the XIX century and the neuroscientific knowledge is still pretty limited: the doctor had no clue about what would have happened next. Indeed, when Phineas recovered after a serious infection, he was no more himself: “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.” ~Dr. Harlow

Today, we know that lesions in the frontal lobes (such as Gage’s one) determine an atypical range of emotional, cognitive and motor changes. The frontal patients, as they are called, are usually apathetic, but with periods of euphoria. These patients tend to “forget” social conventions, leaving place to impulsive behaviours, such as audacity and stupidity, as well as a disinhibited sexual behaviour. Moreover, pain perception is generally attenuated and these patients show a diffuse disinterest for the past and the future.

Even though the IQ seems to be unaltered, these patients show forgetfulness in tasks that require sustained attention. As Harlow already wrote back in the XIX century, it seems like these patients are incapable of planning through time what they want to do. Yet, the biggest damages appear on a motor level: their faces become inexpressive and their ocular movements, and more in general their head movements, are decreased.

It is believed that some of the symptoms I just presented are due to the loss of the frontal control (that is inhibitory) on the parietal cortex, that controls some aspects of the sensory motor activity. It is believed that the connections between parietal and frontal cortex might be involved in the interplay among the individual and the environment, favoring the individual autonomy.

Even if the incredible story of Phineas Gage happened more than 170 years ago and it is difficult to distinguish between the real events and the exaggerated stories that arose from the behaviour of this man, this case changed dramatically the psychological theories of those and our times, contributing to shape the idea that there are specific areas in the brain destined to specific functions. Today, we know that this is not exactly the case: it is far more correct to say that some areas of our brain are more involved in some processes, since there is not a specific area that performs a specific task. Nevertheless, the case of Phineas Gage entered into the popular culture and his story has been told in many books, scientific articles and it even inspired a short movie (have a look here to watch it).

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