Imaging Reveals Changes in Alzheimer’s Disease and New Insights into the Origins of Humanity News Roundup: September 2012 4th Edition

Clinical Psychiatry News have an interesting and balanced piece on the fast approaching new edition of the diagnostic manual – DSM-V.

Scientific American has a brief article by Gary Stix on drug development for the treatment of Schizophrenia in light of recent findings on gene activation in the brain.

Researchers in one study used a 7-Tesla MRI scanner to investigate Alzheimer’s Disease. MRI scanners or Magnetic Resonance Imaging scanners use powerful magnets to image the brain. 7-Tesla scanners are state-of-the-art scanners which allow a very high resolution of the brain. The team based at Stanford have previously published research in which they imaged a very small area within the Hippocampus – the CA1 layer and specifically within this area – the Stratum Radiatum/Stratum Lacunosum-Moleculare (SRLM). The researchers in this study wanted to connect the brain changes with changes seen on psychological testing. They took a battery of psychological tests including episodic recall, delayed recall and recognition memory and looked to see if there was a link with the changes in this part of the Hippocampus. Previous research has shown less detailed links between brain changes and performance on specific psychological tests. However in this study the researchers had some very interesting results. They found a very strong connection between performance on the delayed recall task and the width of CA1-SRLM in the left hemisphere. When they looked at CA3, another area in the Hippocampus they found no significant relationship. This study suggests that with sufficient resolution, there may be a clear relationship between performance on specific memory tests and neuroanatomy

Explanation of MRI

MRI of Brain

The Hippocampus

The Parahippocampal Gyrus Which Surrounds the Hippocampus

Researchers have found differences in the prevalence of Alzheimer’s Disease between people living in the urban and rural areas with the latter group showing a significantly higher prevalence in their international study.

A successful model of Alzheimer’s Disease needs to explain a broad range of research findings. The authors of this paper suggest two main strands to such a model (based on CSF ABeta(42) and CSF tau) and propose a need for a third strand to a successful model.

Researchers in one study were looking to find out how Parkinson’s Disease differed from a Parkinson’s like disease resulting from vascular damage (Vascular Parkinsonism). They found that people developing Vascular Parkinsonism were older and didn’t experience visual hallucinations compared to people with Parkinson’s Disease.

Acetylcholine is a neurotransmitter involved in memory. Disturbances of Acetylcholine can be associated with memory problems. In hospitals, older adults can frequently develop episodes of confusion. These episodes are referred to as Delirium and can either involve agitation or withdrawal. The researchers in one study wanted to see if they could replicate previous findings showing an association between delirium and anticholinergic activity in the bloodstream (Serum Anticholinergic Activity = SAA). The suggestion was that this could be used as a blood marker of Delirium. They looked at SAA in people undergoing surgery for hip fractures and did find changes that were associated with Delirium. However when they looked at other factors that could have changed SAA and caused Delirium they found that SAA by itself was no longer significant. In other words their study suggested this wasn’t a useful blood marker of Delirium.

The ENCODE project has involved 442 scientists internationally collaborating on understanding the human genome. Their efforts have amongst other developments resulted in a reevaluation of the so-called junk DNA which up till now has been thought to play no useful role in the human genome. The researchers have found that this DNA influences a number of cellular processes. Furthermore changes in this DNA have been associated with mental illnesses.

Researchers in one study looked at a test which could characterise the cognitive profile of people with Idiopathic Normal Pressure Hydrocephalus. They compared twenty people with Idiopathic Normal Pressure Hydrocephalus with 20 people with Alzheimer’s Disease and administered a specially developed test which examined executive function. They compared their test with a neuropsychological test battery and found that their test correlated well with some of the tests on the Neuropsychological test battery and helped to characterise the performance of people with idiopathic Normal Pressure Hydrocephalus in their sample. It will be interesting to see the results of further replication studies.

Researchers used functional Magnetic Resonance Imaging to investigate the functional connection between brain regions in people with Amnestic Mild Cognitive Impairment compared to a control group without memory impairment. They compared 30 people with Amnestic MCI with 26 controls and found that the connections between the Insular Cortex and other parts of the brain were reduced in people with Amnestic MCI. Furthermore this reduction was correlated with Episodic Memory impairment. These are interesting findings although they occur in the context of other robust findings showing a significant contribution by other brain regions.

The researchers in this case-control study were interested in predicting who might go on to develop acute confusional episodes (Delirium). They looked at people in long term care over a 6-month period. Delirium was assessed on a weekly basis using a confusion assessment tool. The researchers found that inattention, disorganised thinking and new-onset perceptual disturbances were associated with subsequent onset of Delirium. The finding of inattention fits with previous findings by Meagher and colleagues in which inattention was one of the main findings characterising Delirium.

One group of researchers suggest a new hypothesis about cognitive impairment based on their post-mortem findings in people who had been diagnosed with Alzheimer’s Disease. The researchers found evidence of increased Sodium in the Frontal and Parietal cortex compared to the control group. Although there is redistribution of fluid post-mortem, the researchers provided supporting evidence from other research and suggest this may be related to the Amyloid Beta Peptide. It will be interesting to see if further evidence supports this hypothesis.

Membrane Potential

An Italian group have reported their findings in which they found a subset of amyloid-beta 1-42-specific T-cells which were found only in people with Alzheimer’s Disease and not in a control group or in people with Lewy Body Dementia. The significance of these findings is that ABeta Peptide plays an important role in Alzheimer’s Disease pathology according to the Amyloid Cascade Hypothesis. According to the hypothesis there is a central role for the immune system and so having a peripheral marker of this process would be useful. However the researchers caution that these are early findings with unclear significance.

A group of researchers in France present a case series highlighting Portosystemic shunts (shunts between the brain and the liver) as important although rare and reversible causes of cognitive impairment.

Researchers have found a variant of the gene C9ORF72 associated with Amyotrophic Lateral Sclerosis and Frontotemporal Dementia. However the gene variant is also frequently found in the general population and so the significance of this finding is still being investigated.

Researchers have looked at the development of symptoms in Huntington’s Disease in 111 people in a longitudinal study. They found in their sample that apathy increases with age whilst irritability increases only in the early stages.

One treatment for Parkinson’s Disease involves a technique known as Deep Brain Stimulation. This is a neurosurgical procedure in which a neurostimulating device is inserted into the brain in carefully selected people with Parkinson’s Disease as well as a number of other conditions as a treatment approach particularly for movement disorders. The authors of this paper suggest that some people may develop Mania after Subthalamic Nucleus Deep Brain Stimulation (STN DBS). Furthermore in their review they note that Mania is more likely after ventromedial versus dorsolateral placement of the electrodes and identify a number of other factors associated with Mania. In another paper they note that left STN DBS is more likely to be associated with improvement in mood compared to right STN DBS. Deep Brain Stimulation has also been successfully trialled in the treatment of carefully selected cases of Treatment Resistant Depression.

Deep Brain Stimulation Effects on the Finger Tapping Test

The researchers in this study (n=72) identified an interaction between Depression and Amnestic Mild Cognitive Impairment which was associated with grey matter volume reduction in specific brain regions. The severity of the depressive symptoms and the impairment in Episodic Memory were associated with grey matter volume reduction in the Left Medial Frontal Gyrus, the Right Inferior Frontal Gyrus and the Anterior Insular Cortex.

The Inferior Frontal Gyrus

Neuroscience News

Craig Bennett has received an Ig Nobel Prize for his work on the neuroimaging of a dead salmon. The Ig Nobel awards for ‘improbable research’ highlight research that make people ‘laugh and think’. Bennett’s study showed activity in the brain of a dead Salmon facilitating a discussion about MRI methodology.

A new brain atlas has been created from 2 whole male brains and one hemisphere from another brain. The researchers from the Allen Institute divided the brains into 900 subdivisions and utilised 60,000 gene expression probes.

Evidence linking overeating of chocolate to an opiate-like substance in the neostriatum has been identified in this study.

There is an NIMH video on the promise of neuroscience here.

MRI researchers have found evidence in a multidisciplinary study that reading novels activates a number of areas in the brain involved in higher cognitive functions. They also found that changing from reading for pleasure to reading for study altered the areas involved.

Professor Eric Kandel looks at the neuroscience of interpreting the art of Gustav Klimt in this piece by Columbia Magazine.

Dr Roy Baumeister has an interesting presentation on self-control here.

Open Science

There is an interesting piece (via @VaughanBell) on the success of crowdsourcing volunteers for cognition studies online.

The American organisation ProPublica have launched a Facebook patient safety website.

Via @VaughanBell there is an organisation ‘Psychology Tools’ that provides freely available online tools for therapists.

The HHMI UCI Professor Program have a YouTube Channel which is a great resource for biology education.

Evolutionary Psychiatry

Researchers have looked at the genomes of the Khoe-San people in Africa and identified evidence of early diversity in the human genome approximately 100,000 years ago. They are making the genome data available. An important set of changes that appeared before humans migrated out of Africa were gene changes associated with the processing of fatty acids which may have contributed to successful adaptation.

Recent research has suggested that mutations in human DNA do not occur as rapidly as previously thought. The revised findings have helped to explain the divergence of hominids in recent times (by evolutionary standards) including the relationship between Homo Heidelbergensis and the Neandertals. However this new calibration throws up new problems further back in time in the divergence of our human lineage with Old World Monkeys for example.

Archaeologists have discovered evidence that Neandertals were actively hunting birds and using their feathers. These inferences were drawn from an observation of the markings on raptor bones located at Neandertals sites and suggests that they may have been used for social purposes. Neandertals are extinct as a distinct species but have passed on their DNA to modern humans through one or more hybridisation events.

A dental filling dating back 6500 years ago made from Beeswax has been located in Slovenia. It would be interesting if that knowledge had been transmitted in culture and has implications for the history of the treatment of illness.

One theory about human evolution suggests that human ancestors have passed through phases of isolation and integration and this may help to explain the rapid evolution of human culture and biology.

Were early Europeans animating cave art? This is an interesting question asked by researchers recently. The idea is that the illusion of movement in cave art can be created by changing the lighting. If this is valid it means that the artists intended for the art to illustrate movement and had an intricate understanding of lighting in artwork. The video below demonstrates this.

Humans were recycling flint tools as long ago as 13,000 years ago, new research suggests.

Finally while not directly related to Psychiatry, this video fly-through of the Universe based on data from the Sloan Digital Sky Survey III is inspiring!

Appendix

News Round-Up 2008-2011

Index: There are indices for the TAWOP site here and here 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.

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