Psychopath white matter: Abnormal mostly on the right hand side

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Individuals afflicted with psychopathy have potholes in their right frontal lobe white matter and in some of the white matter that connects the brain hemispheres, according to a report from researchers in the UK, the island nation where many of the world’s bankers live and work making research on psychopathy particularly relevant, we would think.

Two years ago it was reported that psychopaths have a disconnect involving the white matter that runs longitudinally along the right hand side of the brain (the uncinate fasiculus, blogged here). This report adds to that additional white matter areas:

Significant [white matter signal] reduction and [microdeficit] increases were found respectively in ASPD subjects relative to controls. [White matter signal] was bilaterally reduced in the genu of corpus callosum while in the right frontal lobe [white matter signal] reduction was found in the [uncinate fasiculus], inferior fronto-occipital fasciculus (IFOF), anterior corona radiata and anterior limb and genu of the internal capsule. These differences negatively correlated with measures of psychopathy. Also in the right frontal lobe, increased [microdeficit] was found in the IFOF and [uncinate fasiculus], and the corpus callosum and anterior corona radiata. There was a significant positive correlation between [microdeficit] and psychopathy scores.

Sundram, F., Deeley, Q., Sarkar, S., Daly, E., Latham, R., Craig, M., Fahy, T., Picchioni, M.; the UK AIMS Network, Barker, G.J., Murphy, D.G.,”White matter microstructural abnormalities in the frontal lobe of adults with antisocial personality disorder,” Cortex. 2011 Jul 19. [Epub ahead of print] PubMed PMID: 21777912.

The frontal lobe microstructural deficits seem inconsistent with previous research on pathological liars. Pathological liars have extra white matter (blogged here).  Now, the two groups aren’t identical; yet, if one drew a Venn diagram, there would be an overlap between psychopaths and pathological liars, we suspect.  The psychopaths we know (our view) are pretty much recreational liars — they enjoy lying for fun.  And s0 — how is it that psychopaths can lie so much yet have defective white matter? Does the quantity make up for the lack of quality?

Maybe it’s the location. After all, the report notes that the frontal lobe white matter deficits are predominantly on the right, so the left is presumably OK.

This right-sidedness is interesting.  Another report came out saying that late life depression also involves right side uncinate fasiculus disconnects.   Steffens, D.C., Taylor W.D., Denny K.L., Bergman S.R., Wang L., “Structural Integrity of the Uncinate Fasciculus and Resting State Functional Connectivity of the Ventral Prefrontal Cortex in Late Life Depression,” PLoS ONE 6: e22697  doi:10.1371/journal.pone.0022697 (July 22, 2011).  None of the psychopaths we know are particularly depressed, at least that we can see. They claim to be depressed from time to time, as a utilitarian behavior to get whatever it is they think they want.  We wonder if  all this right-frontal-lobe business is related to geriatric induced sociopathy (blogged here), and that white matter degradation — misdiagnosed as depression — causes personality changes.

From a developmental perspective, what is it about the right side of the brain? Is that the last to develop (in right handed people)?

And, where the development is somehow thwarted (say, by in utero toxins, stress, gene regulation, or who knows what else), is the right hand side of the brain the first to feel the effects? Are left handed people quicker on the uptake (we’re guessing, blogged here) because their right brains are particularly overdeveloped?

The UK group also reports that psychopaths have  inter-hemispheric white matter deficits. That makes sense given that another report pointed to psychopaths having an extra hole in their brain (cavum septum pellucidum, blogged here).  There are all sorts of receptors along the midline, like vasopressin receptors.  (And, vasopressin is important in affiliative behavior). We wonder if this extra little “cavum” reduces the number of vasopressin receptors available/limits their connectivity to other areas. Maybe that’s why psychopaths have no real connection to others: their vasopressin receptors are out of commission along the brain midline. That probably goes along with the degraded white matter.

This “cavum” reminds us of the word “chasm” and that reminds us of a song by the noted 70s soft rock group Seals and Crofts, called Summer Breeze, having lyrics we always interpreted as “blowing through the chasm in my mind” when the lyrics really were “blow a little jasmine in my mind.”