A new era of the Gene Jeanie…..

Has the Nature Vs Nurture debate finally been settled in regards to Schizophrenia?   In 2016 mainstream national newspapers ran the story;

‘Schizophrenia breakthrough as genetic study reveals link to brain changes’

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The  original journal article (Sekar, 2016) the headline relates to proposed that ‘synaptic pruning’ occurs at pivotal points in development, however, excessive pruning during adolescence are matched to the symptoms experienced by Schizophrenics.  The regulation of an individual’s synaptic pruning  is specifically related to the gene ‘complement component 4‘ referred commonly to as ‘C4’.

It has long believed that Schizophrenia had an innate component, however, the  difficulty in systematically testing the impact of the environment meant clear conclusions have always been difficult to draw.  The  Diathesis-Stress Theory suggest that Schizophrenia could be caused by a biological vulnerability (diathesis) triggered by environmental factors (stress).

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Gottesman and Shields (1972) classic study  attempted to pull research in the area together, by analysing a range of adoption and  twin studies including dizygotic (non-identical) and the rarer monozygotic (identical) twins, which only occur 3 in every 1000 live deliveries worldwide.  All adoption studies found an increased incidence of schizophrenia in adopted children with a schizophrenic biological parent. Kety (who was also known for his critique of Rosenhan’s study) found that biological siblings of children with schizophrenia showed a much higher percentage of schizophrenia. All twin studies found a higher concordance rate for schizophrenia in monozygotic (MZ) than dizygotic (DZ) twins.  In Gottesman and Shield’s own study the rate was 58% for identical twins, and 12% for non-identical twins.  The research was strongly suggestive of the genetic influence even back then, however, only took a reductionist biological view, largely ignoring the diathesis-stress model even though the results seem to support it. 

Is the genie finally out of the bottle?

The current Sekar 2016 research is an exciting development in answering the questions of the biological cause of schizophrenia as well as how an effective treatment may be developed. Watch this space….

Further reading

An article discussing a wide range of twin and adoption studies investigating Schizophrenia. 

 

 

Evolution calling….aquatic apes and religious chimps…..

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Atavism is a term to describe usually biological attributes which have no modern day function but are still if only partially, present as so-called ‘evolutionary throwbacks’.

These ” traits  such as ear wiggling, the appendix, the tail bone and even the ‘goosebump‘ response are all examples of such historical atavistic mechanisms that give us an insight into our past…..

But what about behaviour? To what extent are our current behavioural responses’atavistic’? How much of our ‘instinctual behaviours’ determined from our evolutionary past? The stress response is one of the most researched in terms of the ‘fight or flight‘ response, but how much more of our behaviour is influenced by such factors?

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Mammalian Diving Reflex

The mammalian diving reflex allows humans, although more prominently in young children and even babies, to hold their breath underwater for long periods of time (compared to above water).  When the face feels cold water (below 21 degrees), there is an involuntary physiological response from the body to reduce oxygen consumption as a survival mechanism.  The heart slows, blood flow is reduced to the hands and feet and at even greater depths the lungs are allowed to flood to help equalise pressure to increase survival.

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The mammalian diving reflex has caused some to examine the aquatic ape hypothesis, which says that the common ancestors of modern humans spent time adapting to life underwater. The hypothesis is based on the differences between humans and other great apes, and similarities between humans and some aquatic mammals. The theory uses many human functions to support the claims including hair loss, hair location, the subcutaneous fat on babies, the descended larynx, the hooded nose, voluntary breath control, the waxy coating on newborns, and the mammalian diving reflex.                                                                                                                              http://listverse.com/

The rise of religion in Chimpanzees

Recent footage released of chimps exhibiting what is described as ‘bizarre behaviour’ (throwing rocks at trees),  have been used to attempt to explain ritualistic behaviour in early humans that may have developed into religious activity.

This represents the first record of repeated observations of individual chimpanzees exhibiting stone tool use for a purpose other than extractive foraging at what appear to be targeted trees,” the researchers write in their abstract.

“The ritualised behavioural display and collection of artefacts at particular locations observed in chimpanzee accumulative stone throwing may have implications for the inferences that can be drawn from archaeological stone assemblages and the origins of ritual sites.

Cited from an article in the Independent  by Andrew Griffin Friday 4 March 2016

The work of Desmond Morris

Desmond Morris  explored  questions regarding the evolutionary aspects of humanity and more in his books and documentaries spanning the last decades of the twentieth century.

“Everywhere I go, I’m struck by how similar human beings are to one another in all important respects. Of course, there are many superficial differences and these are often so impressive that we pay too much attention to them and start treating one another as if we belong to different species — with disastrous results. But despite all our variations in costume, ritual and belief, biologically we’re all astonishingly close to one another — a fact that I find very reassuring.” ~ Desmond Morris

Further reading

The weird sound of the brain……..

What actual happens when a new memory is formed? The brain  produces chemical changes to create the physical deposit of a memory. The physical trace of the memory is often referred to as an engram. Neuroscientist David Eagleman explains the chemical reactions that take place in the brain when making a memory. Click on the picture below to listen to the eerie sound of your brain creating a new memory……

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