This is a brief post about depth illusions. Previous posts have looked at other aspects of illusions and give us an insight into how the brain processes the visual world. Potentially this can help us to understand other phenomenon such as hallucinations. The videos below show some great examples of depth illusions – generating the appearance of a 3 dimensional world in a 2 dimensional scene. An artist guides us on how some of the techniques that help to realise the effect of depth.
Depth Illusion
Pencil Drawing Depth Illusion
Tutorial on Bringing Depth to Drawings
An index of the site can be found 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). It is available for a limited period. 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.
Accident and Emergency Physician Dr Jock McKeen has spent a long time thinking about empathy. Empathy is the process of understanding another person’s mind. Here Dr McKeen discusses his profound insights which show that empathy is a multifaceted phenomenon which changes through the lifespan.
Index: There are indices for the TAWOP site here and hereTwitter: 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). It is available for a limited period. 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.
Researchers looked at involuntary treatment in people with Schizophrenia in Denmark using a Psychiatry register. The researchers looked at the data for 18599 patients over a 7 year period. Of these patients 3078 underwent involuntary treatment. The researchers found that treatment with antipsychotics accounted for 99.5% of involuntary psychotropic drugs administered. Electroconvulsive therapy accounted for only 4.8% of all involuntary treatments. These findings may not be generalisable to other countries as there are many factors that can influence these results including the structure of health services.
Neuroscience
Researchers have used atmospheric atomic explosions to examine neurogenesis in the human brain in adulthood. There has been a longstanding debate about whether the brain gives rise to new neurons in adulthood. This has been a tricky area to examine due to a number of technical difficulties.
However when nuclear weapons were detonated in the atmosphere between 1945 and 1963 this increased the amount of Carbon-14 in the atmosphere. Carbon is an essential component of living organisms and therefore the uptake of C14 during this period left a signature.
The ratio of these different forms of Carbon enabled researchers to calculate the age of organic tissue. By looking at the brains of several subjects region by region they were able to identify brain regions with evidence of neurogenesis. The analysis is complex but the researchers concluded that neurogenesis occurs in the Dentate gyrus throughout adult life. There were other findings and there is a good write-up at New Scientist.
Evolutionary Psychiatry
Researchers studying Chimpanzees at Lincoln Park Zoo have identified five personality dimensions that correlate well with behaviour. The researchers identified 5 Chimpanzee personality dimensions including dominance and agreeableness. They monitored the behaviour of 99 Chimpanzees over a two year period and correlated this with the personality measures. The researchers also used two raters to validate the personality measures. Chimpanzees are our nearest extant relative and the classification of Chimpanzee personality may be relevant to personality traits in humans.
Index: There are indices for the TAWOP site here and hereTwitter: 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). It is available for a limited period. 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.
ASAP science is a very successful YouTube Channel featuring videos created by biologists Mitchell Moffitt and Gregory Brown. Crying has a well known association with clinical Depression but the well researched and instructive video takes a broader look at some of the biopsychosocial associations of crying. I learnt a thing or two.
Index: There are indices for the TAWOP site here and hereTwitter: 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). It is available for a limited period. 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.
Researchers undertook a meta-analysis of 22 studies looking at the relationship between Mediterranean Diet adherence and risk for a number of diseases. They found a significant relationship between high adherence to the Mediterranean diet and reduced risk for Depression and Stroke as well as for cognitive impairment.
A Cochrane Database Systematic Review investigated Rivastigmine in the treatment of Vascular Dementia and Vascular Mild Cognitive Impairment. The researchers identified only three trials (n=800) with two trials showing no benefit but a third showing some benefit for cognition at 24 weeks versus placebo in Vascular Dementia (n=710). Nevertheless it will be interesting to see the findings in further meta-analyses as more studies become available for inclusion.
An intriguing Swedish study has looked at the effects of Acetylcholinesterase Inhibitors (ACHEI’s) on the risk of developing myocardial infarcts in people being treated for Alzheimer’s Disease (this included people with Alzheimer’s Mixed Dementia). This was a cohort study (n=7073) using data from the Swedish Dementia Register and national registers for other health outcomes. Amongst other findings the researchers found that people taking the highest dose of AChEI’s had a significantly lower risk of developing Myocardial Infarcts relative to the control group who had not used them. In this cases the hazard ratio was 0.35 (95% Confidence Interval 0.19-0.64).
Hazard Ratio Explained
Nevertheless studies of this type although good at finding possible relationships require further different types of studies to investigate these relationships more closely. It will be interesting to see the results of further studies in this area to clarify the nature of these initial findings.
One or more reported episodes of Delirium occurred in 25% of people with Lewy Body Dementia in comparison with 7% of people with Alzheimer’s Disease in this retrospective study (n=180).
Neuroscience
There is a write-up here about a consortium of organisations referred to as the ‘Global Alliance’ that are developing standards to share information about the human genome as well as clinical data. This has the potential to facilitate research in human genetics.
There is a write-up here of a study in which the researchers found a significant relationship between the width of the retinal venules (blood vessels on the back of the eye) and IQ in their subjects. It will be interesting to see the results of further replication studies.
In a study published in the Proceedings of the National Academy of Sciences, researchers have used a statistical model to investigate the origins of languages. The researchers concluded in their analysis that several groups of Eurasian languages had their roots in a 15,000 year old language.
Evolutionary Psychiatry
A fossil dating back 55 million years found in China is thought to be amongst the earliest Primates. The species has been named Archicebus and is just over 7 cm in length although there are similarly sized extant Primates (see video below). The dating of the specimen is relatively close to the end of the Cretaceous period. The expansion of the arboreal primates is an important stage in human evolution with some adaptations to this environment being conserved. This specimen may not have given rise to our lineage ultimately although in that case there are still likely to be important similarities to our ancestors at that time.
Pygmy Marmosets (Smallest Extant Primate)
There is evidence that one species of Lemur undergoes hibernation for up to 8 months of the year. This is the second Primate species that has been found to undergo hibernation.
Index: There are indices for the TAWOP site here and hereTwitter: 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). It is available for a limited period. 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.
Psychologist Professor Thomas Suddendorf gives a fascinating talk on the evolution of mind with reference to comparative primatology. Understanding other primates gives us profound insights into the human mind and brain. Professor Suddendorf also gives us a warning about how our own activities are endangering the lives of our nearest living relatives.
An index of the site can be found 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). It is available for a limited period. 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.
The optical illusion above was created by using a filter moving across a composite image. The video below shows you how to create this type of illusion.
Illusions tell us something about how our visual systems process the world around us and can help us to understand conditions where vision doesn’t work properly (e.g perceiving moving objects when there are none). The illusions above are interesting in that the brain perceives a rotational movement as the filter moves sideways.
The illusion reminded me of the zoetrope. The movement in the illusion above occurs because the sheet moves across the stationary image whereas in the zoetrope the images are moving in space. However there are filters in both cases that order the images across time to create the illusion. Recent examples of zoetropes use stroboscopic lighting in place of the line filters.
How to Create a Zoetrope
The BRAVIA-drome – An Example of a Zoetrope
The zoetrope is similar to films. Films and moving images are now pervasive. Considering the illusions above reminds us that when we watch a film we are using a technology which works because of our biology. Developments in the field of psychophysics contribute to film and television. The above illusions give us an insight into the building blocks of our biological visual motion processing.
Earliest Film (1888)
An index of the site can be found 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). It is available for a limited period. 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.
This is a brief post about depth illusions. Previous posts have looked at other aspects of illusions and give us an insight into how the brain processes the visual world. Potentially this can help us to understand other phenomenon such as hallucinations. The videos below show some great examples of depth illusions – generating the appearance of a 3 dimensional world in a 2 dimensional scene. An artist guides us on how some of the techniques that help to realise the effect of depth.
