Thursday, September 29, 2011

Von Economo Cells, Autism, and Intuition - A Few Special Brain Cells May Produce Social Awareness

Von Economo Neurons, Autism, and Intuition.

Recently discovered brain cells called Von Economo cells (VENs), named after the neurobiologist who described them, are unique in that there are only about 200,000 of them in a normal adult human. That's amazing because just about any other type of brain cell we have number in the billions. Up until just recently, we saw these cells only in the great apes and not in any other animals. They are present but rare numbering only five or six thousand in the solitary gorilla, but relatively more numerous in the hyper-social bonobo monkey.

VENS can be seen in just two parts of the most recently evolved part of our brains, the neocortex. They are present in the anterior cingulate gyrus (ACC), and the frontal insula (FI).

Other brain cells in the neocortex, the pyramidal cells, have a long process on the apical end but many shorter processes on the basal side (apical and basal dendrites). The VEN is unique in that it has very long dendrites on both poles and the cell body is 4.5 times larger than an ordinary pyramidal cell. Large size is conducive to high speed transmission of signals. VENs are just now being mapped thoroughly but in essence they seem to pick up signals from several deeper, more primitive brain centers regulating fight or flight, pleasure/reward, punishment, fear, and uncertainty and quickly process and simplify what might be a cacophony of signals and transmit the result to the frontal and temporal cortex. VENs are thus implicated in "gut feelings", intuition, and the rapid first impressions we all get when we meet someone new. In the frontal and temporal cortex, these instant impressions are blended with more deliberate and slower more rational judgments formed there. In fact, one fascinating feature of VENs is that they, unlike any other brain cell, express serotonin 2b receptors on their surface. These receptors are also present on cells in the stomach and small intestine and are responsible for peristalsis. Unconscious or "gut" feelings might be picked up more rapidly by the brain this way rather than have rely on detection what the gut is doing, allowing for more rapid and perhaps socially appropriate or danger avoiding response.

The right side of the brain contains 30% more VENs than the left side and this right dominance seems to be important for normal functioning of the brain. In fact, MRI studies of the FI can demonstrate that the right FI is larger in normal individuals and not in autistic kids. Furthermore, normal brains react to uncertainty, facial expressions and pictures of loved ones strongly in these areas on functional MRI scans but not in autistic brains.

I have spoken with high functioning autistic people who say that to navigate a new social situations they often must have a kind of script in their minds. They use past experience and logic to generate appropriate responses to ever changing social situations. This compensatory method for coping with uncertainty seems to be a hallmark of autism. I've encountered many autistic children who may do very well if everything in their world is expected and routine, but totally decompensate in the face of change. Furthermore, humans are not born with a full complement of VENs, but only sprout them in early childhood until age four. This is about the time autism seems to manifest in childhood. And it is this time of life that both genetic and environmental factors can be influential. Indeed some studies have shown autistic kids to have fewer VENs and other studies show and excess of VENs but with disorganized or truncated dendrites, consistent with theories that autism involves failed "pruning" of neurons in early childhood. Perhaps genetic influences inhibit "pruning" and environmental or inflammatory conditions shut down the development of VENs. Either way, the result is an inability to cope with social situations and uncertainty, arguably some of the most highly developed and evolutionarily recent manifestations of consciousness.

Now very recently VENs have been found in whale brains, dolphins, and elephants. This is quite interesting because VENs therefore must have evolved convergently in these species which are unrelated to us. Similar selective pressures must encourage the production of VENs. Perhaps large brain size itself triggers the secondary enhancement of consciousness as a byproduct of needed upgrades in connectivity!

To your health,

Dr Z

Peter Zvejnieks, MD is a board certified physician in Columbia SC. His blog can be found at

Article Source:,_M.D

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