[Paleopsych] BBC: Brain structure link to anxiety

[Lynn D. Johnson, Ph.D.]

Comment: We know now that activity changes the structure of the brain. 
Violinists, for example, have a larger motor strip; London taxi drivers 
have a larger hippocampus. So what this news doesn't say is the 
cause/effect relationship. Why wouldn't enough trauma overwhelm and 
ventromedial prefrontal cortex? Hum??? Why wouldn't children taught 
hardiness cognitive strategies then develop a more robust frontal lobe? 
We have seen a number of these studies, and all are vulnerable to the 
post hoc ergo propter hoc fallacy. Another factor they seem to overlook 
is habitual level of happiness. People who are more happy are less 
intimidated by pain (like the small shocks) and actually rate the same 
cold-pressor pain stimulus as less painful than less happy people.

Thanks for the provocative article, Frank.
Lynn


Premise Checker wrote:

> Brain structure link to anxiety 
> http://news.bbc.co.uk/go/pr/fr/-/2/hi/health/4671483.stm Published: 
> 2005/10/31 00:17:25 GMT [Thanks to Laird for this.]
>
> Vulnerability to anxiety may be down to the size of a brain structure 
> involved in fearful memories, say US scientists.
>
> People with a thicker ventromedial prefrontal cortex were better able 
> to cope with stressful experiences.
>
> The findings may help explain why some people develop post-traumatic 
> stress disorder (PTSD) while others bounce back after adversity, say 
> the authors.
>
> The Massachusetts General Hospital study appears in Proceedings of the 
> National Academy of Science.
>
> Fear factor
>
> While it is normal to experience physical and psychological symptoms 
> after an extremely stressful event, such as the recent London 
> terrorist attacks, some people will continue to be consumed by 
> overwhelming fear and may develop PTSD.
>
> "Certainly, that part of the brain is associated with a whole manner 
> of psychiatric vulnerabilities," Dr Cosmo Hallstrom, consultant 
> psychiatrist in London
>
> A person with PTSD may experience unwanted flashbacks, poor sleep and 
> depression, and avoidance certain situations that could trigger 
> memories of the event.
>
> Studies in animals suggest that the ventromedial prefrontal cortex 
> (vmPFC) is involved with helping the brain forget fearful events.
>
> Also, studies of have shown that people with PTSD have unusually 
> inactive vmPFCs, again suggesting that this brain region is important 
> in anxiety.
>
> In the current study, Dr Mohammed Milad and colleagues scanned the 
> brains of 14 volunteers.
>
> Sweaty palms
>
> The volunteers were also exposed to a series of experiments, involving 
> harmless but uncomfortable electric shocks, which were designed to 
> cause anxiety.
>
> The volunteers who had the least anxiety responses, gauged by how 
> sweaty their palms were during the tests, tended to have thicker 
> vmPFCs and vice versa.
>
> Dr Milad said: "These results suggest that a bigger vmPFC may be 
> protective against anxiety disorders or that a smaller one may be a 
> predisposing factor."
>
> However, he said they did not yet know who that might work.
>
> His colleague Dr Scott Rauch said the next step was to look at genetic 
> and factors in the environment that might explain the brain differences.
>
> In the future, it might be possible to measure a person's vmPFC to 
> predict whether they are more prone to anxiety disorders such as PTSD.
>
> Dr Cosmo Hallstrom, consultant psychiatrist in London, said: "We know 
> that some people are more vulnerable to stress and anxiety and it is 
> nice to have a biological correlate of that.
>
> "Certainly, that part of the brain is associated with a whole manner 
> of psychiatric vulnerabilities.
>
> "It is not surprising that anxiety disorders may also have part of 
> their underlying vulnerability in that area."
>
> He said important thing was to recognise was that PTSD is treatable 
> and should be managed as early as possible.
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