Monthly Archives: November 2009

Review: The Genetic Basis of Human Brain Evolution

The article reviewed here is ‘The Genetic Basis of Human Brain Evolution’ by Vallender and colleagues. This is the 150th Anniversary of Darwin’s ‘On the Origin of Species’ and I thought it would be interesting to have a look at this article on the brain from an evolutionary perspective. This is a review article in Trends in Neuroscience by two american researchers, one in neurochemistry and the other in genetics. In the abstract, the authors write

…it has become possible only very recently to examine the genetic basis of human brain evolution. Through comparative genomics, tantali(s)ing insights regarding human brain evolution have emerged

The selection criteria for inclusion of studies is not stated although this is usual in a number of the reviews that I have seen. Introducing the reader to the subject, the authors then move on to look at genes which have changed in moving along the primate lineage from new world monkeys to humans. These include genes implicated in microcephaly, the Sonic Hedgehog gene (yes really!), the popular FOXP2 gene and SRPX2. There are various suggestions for why changes in these genes may be important including the possibility that the microcephaly associated genes products are important in cell-cycle control which in turn may influence the number of neuroprogenitor cells produced and hence brain size.

The authors also discuss novel genes that have arisen in evolution including the mysterious Morpheus gene the function of which is as yet undetermined, the Opsin gene (thought to be directly related to the development of trichromatic vision in catarrhines) and GLUD2. They then go on to discuss the loss of genes including members of the olfactory gene family. They also look at the difficulties in understanding changes in gene expression in the human brain during evolution as well as some changes seen in non-coding regions. They also offer the following fascinating insight

..mammals in general and birds to some degree, exhibit a trend of brain expansion over evolutionary time that is absent in other vertebrates

The authors end by suggesting that future studies should focus on testing specific rather than general theories.

In conclusion, I found this to be a concise and accessible review of a fascinating subject. On the 150th Anniversay of the publication of ‘On the Origin of Species’ there has been much progress in evolutionary theory and subsequent reinterpretation of natural world phenomenon. In evolutionary psychiatry (see review here)  there has been an emphasis on laying the foundations with reference to common mental illnesses and how they might be shaped by the pressures of natural and sexual selection. The explanations have benefitted from insights gained from  the field of evolutionary psychology (see review of book on evolutionary psychology here). Adding a genetic strand to this understanding may give neuroanatomic insights into function and pathology which tie in with the understanding of neurodevelopment and neuropsychology. As the authors point out, this field is in its infancy and although it is too early to draw firm conclusions, I suspect these will quickly develop and form the foundations for this new discipline.

References

Vallender E J, Mekel-Bobrov N and Lahn B T. Genetic basis of human brain evolution. Trends in Neuroscience. Vol 31. No 12. pp636-644. 2008.

Twitter

You can follow ‘The Amazing World of Psychiatry’ Twitter by clicking on this link

Podcast

You can listen to this post on Odiogo by clicking on this link (there may be a small delay between publishing of the blog article and the availability of the podcast).

TAWOP Channel

You can follow the TAWOP Channel on YouTube by clicking on this link

Responses

If you have any comments, you can leave them below or alternatively e-mail justinmarley17@yahoo.co.uk

Disclaimer

The comments made here represent the opinions of the author and do not represent the profession or any body/organisation. The comments made here are not meant as a source of medical advice and those seeking medical advice are advised to consult with their own doctor. The author is not responsible for the contents of any external sites that are linked to in this blog.

News Round-Up: November 2009 5th Edition


Research in Dementia

A study in Nature Neuroscience suggests that Amyloid Beta is integral to memory function and that deviation from optimal levels is likely to lead to pathology. This in turn would suggest that removing Amyloid Beta from the plaque may not be a successful strategy in Alzheimer’s Disease if this optimal level is not addressed. However this discussion is taking place around cellular mechanisms and it will be useful to see how these predictions tie in with the relevant clinical trials. A suggestion has been made that a precursor to Nerve Growth Factor may be involved in the pathogenesis of Alzheimer’s Disease (AD) on the basis of a significant increase in the levels of the precursor in AD post-mortem samples and findings in a murine model. Stroke is related to dementia in a number of ways and modifying stroke risk factors can reduce the risk of dementia. Thus a prospective study (n=3298) with a follow-up period of 9 years showed that moderate or heavy exercise was asssociated with a significantly reduced risk of developing stroke. Thus the risk was 2.7% in those with moderate-to-heavy exercise and 4.6% in those with no exercise*. A potentially very useful study used the Alzheimer’s Disease Neuroimaging Initiative dataset to develop a method of analysing MRI data which involves two scans and a focus on loss of tissue in the Entorhinal Cortex and it will be intereresting to see the results of further research in this area. A 32-year prospective study – the Prospective Population Study of Women in Gothenburg found an association between central adiposity in middle age and prevalence of subsequent dementia. They did not find the same relationship between BMI and subsequent dementia but the central adiposity was associated with an approximate doubling of the prevalence of subsequent dementia.

General

The researchers in a study in Neuron found an association between modifications of cortical theta oscillations and the perception of intact sounds when presented with fragmentary sounds. Thus the implication is that there is an EEG correlate of auditory illusions. A recent study looking at falls in older adults found associations with a number of medications. The researchers in another study looking at falls in the elderly (the MOBILIZE study, n=729) found that those with chronic pain were significantly more likely to fall than their counterparts without*** An American study showed that just  under half of the 3 to 6 year olds in the study were concerned about becoming obese and one-third wanted to change an aspect of their appearance. Another American study (due to be published next year and with n=184) contrasted brief motivational interviewing with a control intervention (warning about the hazards of drinking and driving) in drink-driving recidivists was associated with a 30% reduction in repeat offences. Another study offers preliminary insights into the potential role of the delta waves generated in the hippocampus and the authors hypothesise on the basis of their results that the frequency of the delta waves code information about the type of processing that should take place in different regions – processing about the past or present.

Evolutionary Psychiatry

The new buzz word in this area is ‘primate archaeology’ which is an attempt to integrate a number of areas including primatology, anthropology and psychology. This article summarises this new ‘movement’ and looks at some very interesting research into the use of stone tools by chimpanzees in what is being described as a parallel with the advent of the stone age in humans.

DSM-V

DSM-V is due to appear in 2012. A twitter campaign has been started to petition for the inclusion of Depressive Personality Disorder in DSM-V. Professor Simon Baron-Cohen has argued against the removal of the Asperger Syndrome label in this New York Times article. Dr Anestis offers his views on this article and Baron-Cohen responds in this blog post.

Psychiatry 2.0

In a small study, participants were observed using search engines. The researchers concluded that search strategies were influenced by the learning styles of the participants and that participants often used search engines to confirm then own recall of a subject. A recent MyPublicServices event was held to discuss ways in which social media might impact on public services. It was suggested at the conference and reported in this article, that social media may impact on public health service delivery as it has done in many other sectors and that a constructive approach to using social media in th9s area could be adopted. One research study into viral marketing campaigns focused on the characteristics of e-mavens – people who spend a lot of time online**. E-maven’s characteristics were identified and those that were more likely to forward viral material onto others scored more highly on measures of individualism and altruism. On the subject of viral marketing – these usually pass me by but this one is pure genius! The video was made by the staff at Providence St Vincent Medical Centre in Portland, Oregon to raise awareness of Breast Cancer. Enjoy!

* The recent finding that dog owners get more exercise than gym-users may be of relevance in this regards. Thus it would be interesting to see the risk of dementia in dog owners (there are forms of pet therapy that have been employed for use in people with dementia although this is a slightly different issue)

** I’m not sure if this group would be considered at risk of the very controversial diagnosis of ‘internet addiction’ although this illustrates very nicely the balance between what some might consider illness behaviour and what others might consider socially constructive behaviour.

*** The study was partly funded by Pfizer

Twitter

You can follow ‘The Amazing World of Psychiatry’ Twitter by clicking on this link

Podcast

You can listen to this post on Odiogo by clicking on this link (there may be a small delay between publishing of the blog article and the availability of the podcast).

TAWOP Channel

You can follow the TAWOP Channel on YouTube by clicking on this link

Responses

If you have any comments, you can leave them below or alternatively e-mail justinmarley17@yahoo.co.uk

Disclaimer

The comments made here represent the opinions of the author and do not represent the profession or any body/organisation. The comments made here are not meant as a source of medical advice and those seeking medical advice are advised to consult with their own doctor. The author is not responsible for the contents of any external sites that are linked to in this blog.

Media Review: Social Phobia on YouTube

I’ve broadened out the podcast reviews to encompass media which include film and video particularly as there is an ever increasing amount of material on YouTube.

The topic I chose for this review is social anxiety and social phobia (or social anxiety disorder) on YouTube. I found quite a large number of videos on this topic but have just reviewed a small proportion of them here. The majority relate to social phobia and one to social anxiety and they are divided into education and experiential videos.

In this video, the lecturer gives a talk on social phobia with a case study and he also goes over some of the diagnostic criteria. He also goes over some of the treatments and is in two parts which in total runs to about 13 minutes. This cartoon features what sounded to me like adolescent narrators who explain social phobia with references to the amygdala and prefrontal cortex. The video also explains how it affects people and includes references to pharmacotherapy and psychotherapy runing to five and a half minutes. I wasn’t sure of the age of the target audience but the video is well presented and covers a lot of the basic information accessibly. This video is effectively a small number of slides displayed sequentially with background music. The slides contain some details about social phobia but I didn’t find them to be as informative as some of the other videos but this would be useful to someone who wants a rapid overview.

From the experiential perspective, there were a number of videos communicating the inner experience of social phobia. The diagnosis of social phobia is taken in good faith and the people in the videos explain what this means to them experientially. The videos can be very involved and would be orientated towards an adult audience. Certainly in putting together videos of their experiences these people are very courageous and I wondered how the nature of audience affected the social anxiety. For instance if the audience will view the video many years after it was made, how does this interact with the social anxiety? In this video, the quietangel123 has put together images and music to convey the experience of being alone although the term social anxiety disroder is used in the title. AlanJones78 narrates with a background picture about his experience of social anxiety over five minutes explaining the thoughts and feelings he has. Nayomee77 presents two videos (here and here)  on her experiences of social phobia and the difficulties she has had in trying to cope with this. These videos have generated a lot of viewings and comments.

These are just a few of the videos that I came across on YouTube but there is already quite a lot of material showing how differently people can communicate the theoretical aspects of social phobia and even how the experiences can be communicated by those suffering with social anxiety and just how much of an effect this can have on a person’s life. Communities can build up in the YouTube forum and it would be interesting to know if this is beneficial through text comments and video responses.

 

Twitter

You can follow ‘The Amazing World of Psychiatry’ Twitter by clicking on this link

Podcast

You can listen to this post on Odiogo by clicking on this link (there may be a small delay between publishing of the blog article and the availability of the podcast).

TAWOP Channel

You can follow the TAWOP Channel on YouTube by clicking on this link

Responses

If you have any comments, you can leave them below or alternatively e-mail justinmarley17@yahoo.co.uk

Disclaimer

The comments made here represent the opinions of the author and do not represent the profession or any body/organisation. The comments made here are not meant as a source of medical advice and those seeking medical advice are advised to consult with their own doctor. The author is not responsible for the contents of any external sites that are linked to in this blog.