The father of the science of evolutionary medicine, Randolph (Randy) Nesse, has a favorite aphorism: “Medicine without evolution is like engineering without physics.” In the same way that it would be impossible to imagine building the Rosetta spacecraft, sending it 300 million miles to rendezvous with Comet 67P, and successfully deploying the Philae lander, chock-full with sampling instruments, without physics and specifically Newtonian mechanics, it proves similarly impossible, for instance, to get to the root of the horrifying scourge of Alzheimer's disease unless we ask deep and fundamental questions, informed by evolution, about what the alleged poisonous plaques of beta-amyloid protein are doing in the brain in the first place. Is amyloid pure pathology or does it have an vital evolved function in the brain? In this sense, Nesse has frequently claimed that the value of evolution to medicine is that it while it may lead directly to changes in medical practice or indeed to new therapies, more fundamentally its value lies in explaining why things are as they are. That is why Nesse argues that evolutionary biology should be the foundation and cornerstone for medicine as it should be for all biology. This book is an attempt to put yet more flesh on the bones of Nesse’s idea that evolution is the “physics” of medicine. I describe the evolutionary background to seven areas of human disease that are causing deep contemporary medical concern to explain why they exist in the first place—why things are how they are - and how evolution might help us to combat them. I hope it will leave readers with a new respect for evolution as the prime mover for the structure and function of human bodies, even if it does, on occasions, cause them to break down and drives us into ER!

Each chapter is built around the sometimes harrowing but always inspiring personal stories of people trapped in the disease process in question. Each chapter provides an evolutionary explanation for why the disease has come about, and each chapter shows how medical researchers, using powerful insights gained from thinking about disease in an evolution-informed way, are charting our way out of it.

How a modern version of the hygiene hypothesis - called the "old friends" hypothesis - explains why the Western world is riddled with allergic and autoimmune diseases, and what we can do about it.
How evolutionary theory explains why the battle between the different selfish genetic interests of mothers, fathers, and fetuses causes low fertility and can lead to diseases of pregnancy like recurrent pregnancy loss, preeclampsia and gestational diabetes.
What is the relationship between the fact that we have evolved to walk upright - our bipedalism - and a range of orthopedic illnesses?
Creationists have always used the example of the "irreducible complexity" of the human eye as the bedrock of their argument that God designed the human body, not evolution. Modern developmental biology, however, not only strongly rebuts creationism but explains the astonishing secret of how the recipe for eyes actually unfolds from within the developing eye itself, not from external influences, and is leading to cures for eye diseases like retinitis pigmentosa and macular degeneration.
How does cancer evolve so remorselessly towards malignancy that it is proving almost impossible to cure? Cancer evolution can be so extreme and drastic it is forcing us to re-write the rules of evolution by resuscitating a heresy from the 1940s.
Why are coronary arteries evolution's answer to feeding our powerful, muscular hearts with the food and oxygen they need and how has this led to the continuing pandemic of coronary heart disease?
Research into curing Alzheimer's disease has become hopelessly bogged down and billions of dollars have been wasted trying to turn the "amyloid hypothesis" into therapy. Can we use evolutionary thought to better explain why dementia comes about in a way that might lead to fresh hope for a cure?


Friday, 20 March 2015

Autistic and non-autistic brain differences isolated for first time

There are many, many theories for what causes and represents autism in the brain but this paper will bring joy to those researchers, like Simon Baron-Cohen, who have always maintained that autism is a defect in what is known as the "social brain" or social intelligence. Here the scientists link abnormality in the connections between that part of the visual cortex responsible for attention to faces, and the ventromedial prefrontal cortex which is responsible for higher order social cognition.

Autistic and non-autistic brain differences isolated for first time

19 March 2015 11:48 Warwick, University of

• New big data methodology can analyse over 1 billion pieces of data
• The methodology can potentially isolate the areas of the brain involved with other cognitive problems, including Obsessive Compulsive Disorder, ADHD and schizophrenia.
The functional differences between autistic and non-autistic brains have been isolated for the first time, following the development of a new methodology for analysing MRI scans.
Developed by researchers at the University of Warwick, the methodology, called Brain-Wide Association Analysis (BWAS), is the first capable of creating panoramic views of the whole brain and provides scientists with an accurate 3D model to study.
The researchers used BWAS to identify regions of the brain that may make a major contribution to the symptoms of autism.
BWAS does so by analysing 1,134,570,430 individual pieces of data; covering the 47,636 different areas of the brain, called voxels, which comprise a functional MRI (fMRI) scan and the connections between them.
Previous methodologies were process this level of data and were restricted to modelling only limited areas.
The ability to analyse the entire data set from an fMRI scan provided the Warwick researchers the opportunity to compile, compare and contrast accurate computer models for both autistic and non-autistic brains.
Led by BWAS developer Professor Jianfeng Feng, from the University of Warwick’s Department of Computer Science, the researchers collected the data from hundreds of fMRI scans of autistic and non-autistic brains.
By comparing the two subsequent models the researchers isolated twenty examples of difference, where the connections between voxels of the autistic brain were stronger or weaker than the non-autistic .
The identified differences include key systems involved with brain functions relating to autism. Professor Feng explained the findings:
“We identified in the autistic model a key system in the temporal lobe visual cortex with reduced cortical functional connectivity. This region is involved with the face expression processing involved in social behaviour. This key system has reduced functional connectivity with the ventromedial prefrontal cortex, which is implicated in emotion and social communication”.
The researchers also identified in autism a second key system relating to reduced cortical functional connectivity, a part of the parietal lobe implicated in spatial functions.
They propose that these two types of functionality, face expression-related, and of one’s self and the environment, are important components of the computations involved in theory of mind, whether of oneself or of others, and that reduced connectivity within and between these regions may make a major contribution to the symptoms of autism.
The researchers argue that the methodology can potentially isolate the areas of the brain involved with other cognitive problems, including Obsessive Compulsive Disorder, ADHD and schizophrenia.
By using meta-analysis and a rigorous statistics approach the Warwick researchers were able to collect and use a big data set to obtain significant results, the likes of which have not been seen in autistic literature before. Professor Feng explains:
“We used BWAS to analyse resting state fMRI data collected from 523 autistic people and 452 controls. The amount of data analysed helped to achieve the sufficient statistical power necessary for this first voxel-based, comparison of whole autistic and non-autistic brains. Until the development of BWAS this had not been possible.
“BWAS tests for differences between patients and controls in the connectivity of every pair of voxels at a whole brain level. Unlike previous seed-based or independent components-based approaches, this method has the great advantage of being fully unbiased in that the connectivity of all brain voxels can be compared, not just selected brain regions.”

Attached files

  • BWAS - Brain Model with Regions of Interest highlighted- 24.02.15
  • BWAS - Connections between Regions of Interest - 24.02.15
  • BWAS - Regions of Interest - 24.02.15

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