It is commonly said that "elephants never forget". From the website Elephant Voices:

Based on the evidence available, elephants seem to remember for years other individuals and places and learned skills. In experimental trials involving a large set of visual symbols and acoustic tones or commands captive elephants show exceptional ability to learn and retain information over long periods. Accounts by practised observers indicate that elephants are able to remember the voices (and perhaps scents) o individual people for over 12 years

How to explain this phenomenon? Recently came across some interesting research out of Caltech that looked at elephant brains with MRI technology:

The elephant has an unusually large and convoluted hippocampus compared to primates and especially to cetaceans.( MRI image above comes from the John Allman Lab at the California Institute of Technology).

In humans and other mammals, the hippocampus is the brain structure largely responsible for memory formation.

Within 5-8 years, I suspect neuroimaging technology will be far enough advanced that a quick 5 minute human brain scan will be able to assess hippocampal anatomy & connectivity, and rate a person’s:

1. Natural ability to memorize various pieces of information (semantic, episodic, procedural, etc…
2. Susceptibility to develop Alzheimer’s disease and other types of dementia- decades before actual memory impairment sets in

On a further note regarding elephant intelligence, a recent study [Reference below] reveals that elephants can recognize themselves in mirrors- a sign of self-awareness.

To date, only 3 other animals have shown themselves capable of this task:

• humans
• dolphins
• apes

Reference: Plotnik JM, de Waal FBM, Reiss D. Self-recognition in an Asian elephant. Proc Natl Acad Sci U S A. 2006 Nov 7;103(45):17053-7

The diagnosis mainly rests on the neurologist’s clinical impression, which is based on an interview, examination, as well as some blood tests and an MRI of the brain to rule out other conditions which may mimic Alzheimer’s. Many times, especially during the early stages of the disease, physicians are uncertain of the diagnosis. Families are told that more time is needed to observe the patient, to see how the disease process unfolds. This uncertainty can lead to frustration.

The only real way to be 100% certain of the diagnosis is to autopsy the brain, which of course is not a good option in a living person.

Things may have just changed though, as the UCLA School of Medicine has announced they’ve developed a PET scanning technique that seems to offer the promise of a definite answer.

While still experimental, the scan utilizes FDDNP, a radioactive tracer that binds to the plaques and tangles typically encountered in the Alzheimer brain. The PET technique then provides physicians an actual picture of how much and where this tracer shows up in the brain.

I’d say this is significant breakthrough, as we are now much closer to identifying which people are going to develop Alzheimer’s disease years before they become symptomatic (see a related post discussing the early signs of dementia).

Additionally, the new study will enable researchers to more rapidly develop effective treatments, since they’ll be able to more objectively see what drugs are effective and which ones aren’t.

The study was published in the New England Journal of Medicine, December 2006.

In a breakthrough research study, volunteers were shown one of several test objects, and based on MRI brain scanning data alone, researchers were able to tell what object the volunteers had seen. The research, conducted by Frank Tong out of Princeton University and Yukiyasu Kamitani out of ATR Computational Neurosciences Laboratories in Kyoto Japan, was published in Nature Neuroscience in 2005.

More recently, MRI brain scans are also proving themselves to be superior to the polygraph when it comes to lie detection. Two MRI lie detection companies are getting ready to launch:

• No Lie MRI, Inc in San Diego, California
• Cephos Corp.in Massachusetts

Furthermore, there is wide speculation that the government is already using this technology as an interrogation method.

The best information of the brain we can get today is taken with MRI machines featuring a large magnet combined with one radio-frequency detector.

The next generation of MRI machines, however, will use arrays of anywhere from 8 to 256 radio-frequency detectors, with even more powerful magnets.

It’s not hard to see how the era of mind reading made easy is just around the corner.

What would you want to ask your significant other? Your teenage kids? Your friends?

However, new research indicates a quick and painless skin test may prove to be most accurate. The test involves looking in fibroblasts (found in skin cells) for Alzheimer’s-type inflammation.

This goes along with the new concept many scientists have of Alzheimer’s disease: it is not only a disease of the brain, but also the body. In other words, changes seen with Alzheimer’s disease are not only found in the brain but throughout the whole body.

It’ll probably be a couple years before it’s commercially available, though.