Monthly Archives: February 2010

News Round-Up: February 2009 4th Edition

Just a brief round-up today.

An fMRI study provided evidence of different regions involved in learning new verbs (left posterior temporal gyrus and left inferior frontal gyrus) and nouns (left fusiform gyrus) as well as a relationship between hippocampal activity and the efficiency of learning new nouns. This information could be of relevance to a number of conditions which involve disorders of language and memory. For more information on the study see here.

A study involving neural prosthetic devices in people provided evidence of the function of the beta and delta oscillations identified in the EEG. Based on their findings about the timing of the oscillations, the researchers concluded that the beta oscillations were strongly associated with anticipating commands for initiating movements. For more information see here.

Discover reports on some experimental evidence to suggest that smells and sounds are perceived together as hybrid ‘smounds’ – at least in a murine model. These conclusions are based on the activity of cells in the olfactory tubercle which respond not only to smells but also auditory tones presented alone or in combination with smells*.

Vaughan Bell has a good round-up of Spike Activity where he looks at the recent findings on the XMR virus in Chronic Fatigue Syndrome amongst other studies.

Brain-Derived Neurotrophic Factor has been suggested as a possible therapeutic intervention in dementia. The authors of a new study reported on here found that slow versus rapid application of BDNF to cell cultures had different effects and this is discussed further in the report.

* Since smells are closely related to taste it is tempting to speculate that this could even be relevant to Pavlovian conditioning if confirmed in other species.

Index

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Responses

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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.

Review: Mind Podcast Episode 17

The podcasts reviewed here are the 17th  episode in the Mind Podcast series by Hoevens. In episode 17 (freely available here) Hoevens discusses sleep, hypnosis and psychoactive drugs in an episode lasting over 50 minutes. When looking at sleep, Hoevens describes the stages of sleep and the nature of the circadian rhythm. Although not delving too deeply into this very complex subject, Hoevens discusses dreams with a passing reference to Freud and also some interesting facts about sleep. Hoevens then covers hypnosis briefly while linking in with previous material on filtering of sensory information in the perceptual process. He finishes of with a look at psychoactive drugs. He emphasises the associated health risks. There is a lot of material covered here and I found it to be at a slightly more basic level than in previous podcasts which perhaps reflects the amount of material that was covered.

Twitter

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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

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Responses

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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.

Book Review: Delete

The book reviewed here is ‘Delete’ by Victor Mayer-Schonberger and narrated by Dennis Holland. Holland narrates at a moderate pace and with an upbeat style.  In the book, Mayer-Schonberger argues that the digital age has created a permanent store of memories which now poses a challenge to society. At several points he discusses individual memory in more detail, for instance outlining some of Baddeley’s ideas on how memory works. He compares the permanence of digital memory with the impermanence of biological memory and with the impermanence of cultural memory through the ages due to the absence of large-scale methods of storing memories. The large scale methods of storage later appear in the form of books and I was intrigued to hear of the output of scribes in the early middle ages in contrast to the capabilities of the printing press.  Mayer-Schonberger argues that the permanence of memory in the digital world has arrived suddenly:

A world without forgetting is difficult to predict

He provides the audience with some case examples showing how these memories have been problematic but argues speculatively that people will doubt their own memories if presented with ‘perfect’ digital memories of their life, many of which they themselves will have ‘forgotten’. Mayer-Schonberger also argues that our memories are impermanent because we ‘become’ someone different with time, learning from our mistakes. I thought these were perhaps existential themes and it was interesting to see them being considered in relation to the use of information technology.

The essence of Mayer-Schonberger’s argument is that we should have some degree of control over our personal information and he suggests digital rights management as a possible solution which he then further expands upon. He even suggests that such information can be monetised and I was somewhat bemused to think that the concepts of some of the existential philosophers might form the basis for a digital economy.

Going off at a slight tangent, Mayer-Schonberger’s arguments made me consider Jung’s writings on archetypes. If as Jung suggested, we have a collective unconscious that is stored within culture then how would this be affected by the advent of our present age of digital permanence? Would such archetypes, if they exist, be affected by the abundance of cultural memories stored without decay in our digital world? Would they become distilled within the ever expanding cultural heritage that is available on demand, where society is in the process of creating subculture upon subculture?

It would be interesting to see the results of general population-based surveys to see if people would want to manage their personal information in this way and perhaps a small pilot study to see if it is feasible and is capable of producing the expected outcomes. Even if all of this pointed in the right direction there would still be the matter of making it work economically which is obviously an important test of any technology.

Mayer-Schonberger has tackled an important issue in the digital age and it will be interesting to see how things develop in this area.

References

Viktor Mayer-Schonberger. Delete (Unabridged). Audible Inc. Narrated by Dennis Holland. 2009

Index

You can find an index of the site here. The page contains links to all of the articles in the blog in chronological order.

Twitter

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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

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Responses

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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.

Review: The Social Origins of Folk Epistemology

The paper reviewed here is ‘The social origins of folk epistemology’ by Hugo Mercier and available here. The paper is one of a series in the journal ‘Review of Philosophy and Psychology’ and I thought it interesting because Mercier develops an evolutionary argument for some of the properties of ‘reasoning’. Mercier presents his arguments very clearly and includes any additional material that might be needed by the reader thus avoiding the need to refer to additional papers (except perhaps for the explanation of the tests which are used to examine reasoning). In the introduction, Mercier presents two views of the function of reasoning. In the first, reasoning is to be used in discussion with others (or more specifically in arguments and persuasion) and in the second is used in rule-based systems to compensate for the innaccuracies that can sometimes result from intuition. The definition of reasoning is important for the discussion and he refers to tasks such as the Wason Selection Task which essentially tests the subject’s ability to use deduction (see here). Mercier cites the arguments of others who have proposed how reasoning might have developed in the progression from animals to humans. I thought perhaps it was entirely possible that non-human species are capable of reasoning. There certainly seems to be some evidence emerging in that direction particularly in chimpanzees. If that were so, then some of Mercier’s arguments would need to be amended since they are contingent on the assumption that reasoning has evolved specifically in humans and that it must be consistent with other unique properties of humans (strictly speaking this is not entirely true as Mercier does argue that reasoning does not take place in ‘most’ other animals although the explanation of ‘most’ is not expanded on at a later point). If considered in this manner, then it could be argued for instance that the process of deduction or more general features of logic are in turn dependent upon cause and effect (I have argued this elsewhere). These in turn are evident in the physical world and a ‘knowledge’ of how the physical world works is a necessary part of survival for most species (this statement is contingent on the definition of knowledge and I have used it here to exclude simple organisms without a nervous system which is capable of storing knowledge although even here it could be argued that ‘knowledge’ about the world is stored in the ‘successful’ genes contained within DNA).

However we can be certain that humans are able to reason as defined above and so it does seem like a sensible starting point. He argues that reasoning doesn’t necessarily replace other cognitive functions and as such would have an additional ‘cost’ – meaning that additional resources have to be allocated to the reasoning process (presumably genes, neurotransmitters, electrochemical energy in nerve transmission, time for neuronal firing and so on). I would argue here though that just because there is cost, it does not necessarily mean that it serves a necessary function for survival. Adaptation to the environment particulary in more complex organisms may not necessarily be an entirely ‘efficient’ process. He goes onto discuss communication and suggests that it is more complex than at first glance. Quite specifically he refers to deception and suggests that people have evolved mechanisms for detecting deceit.

The next stage in Mercier’s argument is quite interesting. He essentially argues that persuasion is an important part of communication and for this to take place, the person has to have an understanding of the other person’s beliefs and knowledge. It is the process of gauging these as the starting point for communication which requires a specific cognitive process which he suggests is reasoning. He then goes onto look at how reasoning has been used in groups and how in some situations the group may arrive at better decisions than the individual and in others worse decisions.

In summary, I thought Mercier’s paper was clearly argued and that he developed a particularly interesting argument around a role for reasoning in persuasion. If this holds then it would have implications for social cognition.

Index

You can find an index of the site here. The page contains links to all of the articles in the blog in chronological order.

Twitter

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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

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Responses

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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.

Review: Determinants of Healthy Eating

The paper reviewed here is ‘Determinants of Healthy Eating: Motivation, Abilities and Environmental Opportunities’ by Johannes Brug and freely available here. I thought was a useful topic to examine as patterns of eating behaviour can influence outcomes in a wide-range of mental illnesses and are indeed used in the diagnostic criteria of a number of illnesses. So it seems reasonable to ask what models are there relating to eating behaviour. Brug presents a very broad psychosocial model and I was particularly interested in the intentionality aspect of the psychological component of this model. He outlines a structure proposed by M Rothschild in which motivation, ability and opportunity provide an explanatory framework. The article is relatively brief and consists of an overview of a model of healthy eating determinants together with a precis of some of Brug et al’s  systematic analyses of intervention or observational trials relating to eating and modifiers of eating behaviours. He cites a model in which four determinants of intention are outlined – these are

1. Attitudes. The evidence base here points to a weighing-up of short-term and long-term outcomes – benefits and risks. Short-term outcomes are prioritised. Thus for instance short-term factors such as a pleasant taste would outweigh long-term health risks.

2. Self-efficacy. The extent to which a person believes that they have control over their behaviours will influence these same behaviours.

3. Self-identity. Apparently there isn’t much evidence in this area.

4. Social influences. According to the ANGELO framework these are divided into Axis 1 and Axis 2. Axis 1 consists of micro-environments – immediate locations for food e.g shops and macro-environments which consists of informal infrastructures which influence eating behaviours. Axis 2 consists of physical, political, economic and socio-cultural factors.

In terms of the trials, Brug tells us that the data could be stronger but draws conclusions about the importance of parental influence, modelling and social support, accessibility and availability of healthy/unhealthy foods and socioeconomic factors. In summary Brug presents us with a simple model of determinants of eating behaviour but a knowledge of this model can be used to offer another perspective on relevant illnesses.

Index

You can find an index of the site here. The page contains links to all of the articles in the blog in chronological order.

Twitter

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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

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Responses

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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.

Review: Roles of the Insular Cortex in the Modulation of Pain

The paper reviewed here is ‘Roles of the Insular Cortex in the Modulation of Pain: Insights from Brain Lesions’ by Starr and colleagues and freely available here. This is of relevance to a model of the insular cortex and emotions which i’ve been working on (rather slowly!). The researchers have identified two subjects who had developed middle cerebral artery strokes with resulting right sided insular lesions. They compare these subjects with a healthy control group and examine how pain is processed using a number of different methodologies.

Methodology

The methodology is complex as the study consists of multiple components – assessments of pain intensity, the unpleasantness of the pain, a characterisation of the individual responses to the pain and a between group comparison. 2 subjects with strokes involving the left Insular cortex were identified. They were compared with 14 healthy controls with a mean age of 59. The subjects themselves were aged 53 and 59. If the control group were healthy then I interpreted this as meaning that there was no significant medical illness. However conditions such as hypertension and diabetes are more prevalent with increasing age and it could be argued therefore that since the controls are reported as ‘healthy’ then they may not be representative of the general population. Additionally there might be expected to be evidence of white matter lesions however small in at least some of the control group although these are not reported although if they did exist they might not be too important for the current paradigm.

Subjects were administered a visual analogue scale for pain intensity and pain unpleasantness. Short and long duration noxious stimuli were applied to the calf (as this was unaffected by the lesions in the two subjects). Tactile and thermal thresholds were also identified in all subjects. fMRI was used to investigate brain activation during presentation with stimuli. There were parts of the methodology I didn’t understand even after looking for further information. The difficulties I had were with the ‘statistical analysis of regional signal changes within the brain’. For ‘pain-related activations’, the researchers used ‘boxcar activations’. Boxcar functions are described here. This much is reasonably straightforward. The researchers are modelling the pain activations (presumably in the brain regions) as signals of finite duration with a specific and constant amplitude meaning that if graphed against time it looks like a rectangle with no activity on either side of the signal. The use of activations suggested to me that they were referring to brain activations, after all this part of the study is concerned with fMRI. They then refer to the regressor and here I wasn’t entirely clear which variable they were referring to. They add that

the regressor was convolved with a gamma-variate model for the hemodynamic response … and its temporal derivative

I hadn’t come across the term convolved before but it appears to mean that two functions are combined (there’s a good illustration here). I presume that the gamma-variate model is equivalent to a gamma-distribution which would be determined by the relevant parameters. The individual components make sense but I couldn’t put it all together. The regressor (what is the regressor in this case?) is combined with a model of the hemodynamic response. The hemodynamic response is the change in blood flow to the region of interest representing a proxy marker for cerebral activity but why is the regressor being combined with this response? Why for instance would they not be using a correlation between the VAS responses and the hemodynamic response (approximated with the gamma-variate model)?  They further add that they are using a temporal derivative of the hemodynamic response. Presumably this would then refer to a change in change in blood flow (if the derivative is being used in the calculus sense) but why would they be interested in this? So, I couldn’t understand this section although the remainder of the paper was reasonably straightforward and in effect I had to then accept the results for this part of the paper without fully understanding the process. I have argued elsewhere that there is a place for having an accompanying video with papers (for instance that could be freely hosted on YouTube) and I suspect that a 5-minute video could save the reader at least 30 minutes of reading around the subject (or more) particularly when multiple methodologies (some esoteric) are being used. The end result is that when presented with the noxious stimuli, the researchers have used fMRI on the 2 subjects who have had a stroke and also the healthy control group to image where the activation is taking place. The methodology is more involved than that but I thought these were the most salient points.

Results

With a complex methodology there were lots of results. The ones I found most interesting were as follows

1. Patients 1 and 2 had involvement of the Sensory Cortex and Basal Ganglia as well as the Insular Cortex from the strokes.

2. Subjects 1 and 2 differed subtly in the regions that were affected

3. Subjects 1 and 2 had increased pain intensity (on the affected side) but lowered pain unpleasantness in response to the noxious stimuli in comparison to the control group

4. In the subjects, the affected insula was not activated in response to pain which the researchers reasonably suggest is due to the damage resulting from the stroke

5. In response to pain, in one of the subjects the prefrontal cortex is activated in contrast with the control group which the researchers suggest is being additionally recruited in processing pain without the insula being active.

6. Without going into the details too much, the researchers have identified somatosensory cortex activation on the side where the insula is not active which wasn’t present in the control group. They interpret this as meaning that this activity is not reliably picked up when the insular cortex is active. Does this mean that some areas mask others in fMRI studies?

Conclusions

On reading this paper, I thought that there were some obvious limitations which the authors acknowledge. Thus there are only 2 subjects and there are multiple areas involved – not just the insular cortex. However, the researchers were selecting for subjects that would have reasonably localised involvement of the insular cortex and the small sample size reflects the practical reality of recruitment for these very specific criteria. The involvement of multiple areas is characteristic of this paradigm and the evidence should be triangulated with evidence from elsewhere (which the researchers have done in the discussion). What I thought was slightly more tricky from the modelling perspective is that the subjects have separate responses both in terms of activation and also in terms of their responses to stimuli. However this could be a direct result of the above. In other words it they have slightly different patterns of injury then it is not unreasonable to suppose that they would have different consequences both in terms of conscious experience and therefore of the measurement of that experience. What is interesting from the modelling perspective is that some fairly broad conclusions can be drawn from this. There is some good evidence from this study that the insular cortex might be involved in gauging how unpleasant a pain stimulus is. Thus the subjects rated the pain as more intense on some occasions and yet they didn’t have a corresponding increase in the unpleasantness of that pain. This might also be described as a dissociation of the cognitive description of that pain and the emotional experience of that pain and elsewhere the insular cortex has been described as a region which is involved in the labelling of pain and emotional experiences. However that is not to say that the somatosensory cortex and basal ganglia might be involved in this process instead. The researchers though have arguments against these possibilities from their data. What is also interesting from a modelling perspective is the apparent collateral network that is invoked when the insular cortex doesn’t appear to be working properly. Thus the prefrontal cortex appears to be involved in one case suggesting that if one region is inactive there is possibly an automatic ‘redirect’ to an alternative region. Could the insular cortex be directly involved in tolerance of pain on the basis of these results? If so, then it might suggest that an understanding of the neurotransmitters used in this region might be of relevance to therapeutics in pain management. Additionally there may be implications for chronic illnesses where pain is a feature. Pain also has a complex relationship with depression. This part of the discussion is necessarily theoretical but this area thus has many possible ramifications.

Index

You can find an index of the site here. The page contains links to all of the articles in the blog in chronological order.

Twitter

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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

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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: February 2009 3rd Edition

A recent study showed a significant difference in visual impairment between those with and without subsequent dementia (n=625) although it will be interesting to see if there is a causal link or else explanatory confounders. There are results from a preliminary study involving the use of Oxytocin in people with Asperger Syndrome. The researchers concluded that there was evidence of increased responses to social cues including the degree of cooperativeness of other players in a ball game. However this was a small study with 13 subjects and it will be interesting to see the results of larger replication studies.

Over at the Alzheimer’s Forum there is coverage on some recent genetics papers showing the possible involvement of a number of Progranulin mutations in the pathogenesis of Frontotemporal Dementia. There is coverage here also. Scientific American has an article on neurogastroenterology – the study of the enteric nervous system and has some intriguing comments on how a ‘mental illness’ could affect this part of the nervous system which uses serotonin amongst other neurotransmitters. They suggest that there might be insights into irritable bowel syndrome and it will be interesting to see how this develops. The authors of a small study (n=54) found evidence of reduced response inhibition in subjects with Type 2 Diabetes.

There are further preliminary results on vascular decompression in Multiple Sclerosis and it will be interesting to see the results of further research in this area. The use of neuroscience in court cases was discussed at the annual meeting of the American Association for the Advancement of Science and a mock trial was staged and the associated complexities explored. A neurosurgeon commenting in the Journal of the American Medical Association has called for helmets to be used in skiing and snowboarding which to reduce the risk of head injuries in accidents. The authors of a Nature Neuroscience paper have found evidence that A-Type K+ channels and T-Type Ca Channels act together during action potential transmission.

A small chinese study has shown evidence of several structural differences between chinese and caucasian brains (Tang et al, 2010). Using structural MRI the team compared the brains of 35 caucasians and 35 chinese subjects and concluded that there were differences in the height, anterior-posterior length and width and then proceeded to construct a chinese reference database using 56 subjects. However this is a small study and there are difficulties in drawing conclusions on the basis of such broad racial ethnic categories*.

An american study looked at census data between the years 1990 and 2006 in the state of Virginia and concluded that socioeconomic status was strongly inversely associated with mortality and that if the mortality rates of the 5 most affluent states and cities were applicable throughout the state there would be a 25% reduction in mortality.

DSM-V

Dr Dan Carlat takes a further look at the DSM-V draft proposals here. Dr Charles Parker has further coverage here and also over at the Corpus Callosum blog. There is a look at grief in the draft DSM-V proposals at Psychotherapy Brown Bag.

Psychiatry 2.0

Buckeye Psychiatry covers a recent study looking at preference for sweet tasting drinks in children and an association with depressive symptoms and a family history of alcohol dependence.  Dr Shock has a link to a video by Dr Ben Goldacre on the placebo effect. Dr D has a post on parenting and choosing a book on the subject. Over at the FABLE blog there is a piece on sadness and growth. Over at Mind Hacks there is a link to a collection of artwork on mental illness. There is a look at a follow-up study of childhood ADHD at psychcentral.  Wray Herbert looks at subsidies for healthy food versus the effects of taxes on fats and sugars on healthy eating. There is detailed coverage of a conference on biological and social aspects of psychiatric disorders at Somatosphere and includes discussion of DSM-V as well as trajectories – the movement of a person from one diagnostic category to another over time. The Genetic Genealogist discusses a pending conference which will feature a small group of people who have had their genomes sequenced discussing their experiences. Over at the Wolfram Alpha Blog there are links to a collection of videos about Wolfram Alpha on YouTube.

Evolutionary Psychiatry

The Primatology blog has a look at a recent study on the length of Macaque ‘conversations’.

* On other measures in specific ethnic groups there are found to be larger variations within the ethnic groups than between them so the same argument could be applied here. Additionally the categories of ‘Chinese’ and caucasian are extremely broad and each contains further ethnic groups.

References

Tang Y, Hojatkashani C, Dinov ID, Sun B, Fan L, Lin X, Qi H, Hua X, Liu S, Toga AW.  Neuroimage. 2010 Feb 9. [Epub ahead of print]. The Construction of a Chinese MRI Brain Atlas: A Morphometric Comparison Studybetween Chinese and Caucasian Cohorts.

Index

You can find an index of the site here. The page contains links to all of the articles in the blog in chronological order.

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

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Responses

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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.