Fusiform gyrus key to understanding neuroanatomic basis of Capgras delusion

Thanks to Doug Shevlin, MD (pictured with crawdaddy) for steering me toward this TED talk by neuroscientist Vilayanura Ramachandran, MD, PhD. Dr. Ramachandran discusses the neuroanatomical substrate of the Capgras delusion, a neurological deficit about which I have blogged before. Dr. Ramachandran explains that the origin of this fascinating deficit stems from a severing (typically resulting from a stroke or neurodegenerative disorder) of the connection between the fusiform gyrus (the face perception area of the brain) and the amygdala (which gages the emotional significance of a perception). Good stuff....  including the crawdaddy.

Best Post of July '09: Behold! Phineas Gage revealed!

The next in our series of "Best Posts of the Month" is from July 30, 2009:

The Los Angeles Times reports that a daguerreotype depicting Phineas Gage has been discovered. In the next issue of the Journal of the History of the Neurosciences, an article establishing the identity of the man holding an iron rod (see photo above) is that of Mr. Gage. This is the only known photograph of perhaps the most legendary neurology patient in history. To illustrate the executive function orchestrated by the prefrontal lobes, medical students throughout the country are told the story of the railroad construction foreman Phineas Gage, who, in 1848, suffered an accident on the job which resulted in a 13-pound iron rod shooting through the front of his brain. Gage survived the accident, and lived 11 years more. But he was never the same, exhibiting "frontal release" signs characterized by disinhibition and impulsivity.

The photograph was discovered by Jack and Beverly Wilgus, a couple from Massachusetts who owned the photograph for 30 years, thinking it depicted a whaler holding a harpoon. When they posted the picture online, an anonymous tipster suggested it might be Gage. The LA Times article continues the story: "Intrigued, the Wilguses compared their image to that of a life mask at Harvard Medical School's Warren Anatomical Museum and found it could be superimposed perfectly, with scars lining up correctly. Apparent writing on the metal rod in the image matches writing on Gage's iron rod, which is also in the Warren Museum."

Behold! Phineas Gage revealed!

The Los Angeles Times reports that a daguerreotype depicting Phineas Gage has been discovered. In the next issue of the Journal of the History of the Neurosciences, an article establishing the identity of the man holding an iron rod (see photo to right) is that of Mr. Gage. This is the only known photograph of perhaps the most legendary neurology patient in history. To illustrate the executive function orchestrated by the prefrontal lobes, medical students throughout the country are told the story of the railroad construction foreman Phineas Gage, who, in 1848, suffered an accident on the job which resulted in a 13-pound iron rod shooting through the front of his brain. Gage survived the accident, and lived 11 years more. But he was never the same, exhibiting "frontal release" signs characterized by disinhibition and impulsivity.

The photograph was discovered by Jack and Beverly Wilgus, a couple from Massachusetts who owned the photograph for 30 years, thinking it depicted a whaler holding a harpoon. When they posted the picture online, an anonymous tipster suggested it might be Gage. The LA Times article continues the story: "Intrigued, the Wilguses compared their image to that of a life mask at Harvard Medical School's Warren Anatomical Museum and found it could be superimposed perfectly, with scars lining up correctly. Apparent writing on the metal rod in the image matches writing on Gage's iron rod, which is also in the Warren Museum."



The four-second video above is a computer simulation of the path taken by the tamping iron through Mr. Gage's skull. (Source: Ratiu P, Talos IF. The Tale of Phineas Gage: Digitally Remastered. New England Journal of Medicine. Vol 351:e21. Number 23. December 2, 2004.)

More News From Nowhere

The good Dr. Doug Shevlin suggested that I relate a story I told to him this morning which has a neuropsychiatric theme. The other night, I was in bed holding my 11-month-old son when I asked my wife to hold the baby. She replied that I must be joking. I answered that I needed her to hold the baby. She replied: "Ah, you're holding my leg." At that point, I awakened to find that I wasn't holding my little boy at all. He was asleep in his crib in the next room. It seems that I had experienced a hypnopompic hallucination, which, according to medicinenet.com is a vivid dreamlike hallucination that occurs as one is waking up. Usually these are auditory and visual in nature, but mine actually had a tactile component to it. In the opposite situation, if one hallucinates as one is falling asleep, it is referred to as a hypnogogic hallucination. Very strange. Dr. Shevlin's blog post today (see Music is My Savior link below) is titled 'More News From Nowhere', which is certainly where I was reporting from during my recent hallucinogenic state!

The Ice Pick Lobotomy

My wife, Jennifer, and I recently watched a PBS documentary called “The Lobotomist”, which explores the background of the procedure popularization during the 1940’s through the ‘60’s of the prefrontal lobotomy. The neurologist Walter J. Freeman of Washington, DC was primarily responsible for the widespread performance of this surgery in the United States by developing the 10-minute, outpatient “ice pick lobotomy”. Quite literally, an ice pick was inserted beneath the eyelid and over the eyeball of a patient who was rendered temporarily unconscious by electroshock. When the instrument hit the thin orbital plate of the frontal bone, a few taps with a mallet would allow entrance into the intracranial cavity. The ice pick was then advanced upward, after which it was swept back and forth like a windshield wiper blade. The instrument was then extracted and the procedure was repeated on the opposite side. Approximately 30,000 of these procedures were performed before the medical establishment decided that it was ill-advised.

These procedures were designed to sever the connections of the brain with the prefrontal cortex (the anterior-most portion of the frontal lobes, not including the motor and premotor gyri, which does not cause movements when stimulated by electodes). Patients were left with varying degrees of abulia, but with no motor deficits.

The Capgras Delusion in Dementia with Lewy Bodies

Southern Illinois University medical students Sameer Vohra and Teschlyn Woods were discussing Dementia with Lewy Bodies today and mentioned that Capgras syndrome can sometimes be a manifestation of this particular type of dementia. I had never heard of Capgras syndrome, but they explained it to me. Here’s what Wikipedia has to say about it:

"The Capgras delusion (or Capgras's syndrome) is a rare disorder in which a person holds a delusional belief that an acquaintance, usually a spouse or other close family member, has been replaced by an identical looking imposter.... It can occur in acute, transient, or chronic forms.
The delusion is most common in patients diagnosed with schizophrenia, although it can occur in a number of conditions including after brain injury and dementia. Although the Capgras delusion is commonly called a syndrome, because it can occur as part of, or alongside, various other disorders and conditions, some researchers have argued that it should be considered as a symptom, rather than a syndrome or classification in its own right."

It is named after Joseph Capgras (1873-1950), a French psychiatrist who first described the disorder in a 1923 paper by Capgras and Reboul-Lachaux. Here’s the link to the Wikipedia site describing the Capgras delusion:
http://en.wikipedia.org/wiki/Capgras_delusion