Tag Archives: anatomy

In Our Head Facts- Asymmetry

To break up the time between main blog instalments I thought a nice addition to All In Our Head would be short weekly posts featuring established, but often little known, brain facts. To begin this planned series I have for you one of my favourite snippets of information concerning the anatomy of the brain…

Your brain, my brain, Putin’s brain, Obama’s brain, all brains, are in fact, asymmetrical. Despite being encased in a largely symmetric skull, the human brain is broader on the right at the front and broader on the left at the back. It also slightly juts forward and backward


Cross-sectional sketch of the asymmetric brain

It’s almost as if someone has taken it out of its skull box, given it a sharp twist, and placed it gently back in again…


Researchers have taken this as evidence for the profoundly divided nature of the brain. If the two sides of the brain didn’t evolve to serve different purposes than some bits of one side wouldn’t be so distinctly and consistently different in size to the same bits of the other, or so the reasoning goes.

As depicted in the first picture above, the brain is divided down the middle by the midsagittal plane. Research, such as that done on split brain patients, has shown that the hemispheres on each side of this split do indeed serve certain differing functions. Unfortunately this idea has seeped like mercury into the veins of popular media, poisoning the general public’s understanding of what is really meant by the term “divided brain”.

This important subject requires an essay of its own to adequately explain, one I hope to provide in an upcoming blog post…do call back then.

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Are we living inside one enormous Brain?

I’ve always been struck by how alike microscopic images of the brain are to depictions of the universe. The pictures of neuronal connections and other microscopic brain images in biology books appeared to me to bear a striking resemblance to many of those portraying aspects of outer space in physics books and related media.

Having only what you might call a pop scientific education in matters of the cosmos, I never thought of this connection as anything more than a superficial coincidence. However, after recently coming across the following excerpt from a 2006 edition of the New York Times, I’ve been spurred into reconsidering the relationship.


The picture on the left is a microscopic segment of a mouses brain, the one on the right is a computer simulation of the structure of the universe.  According to the text written above the images, the picture of the neuron is “only micrometres wide” whereas the image of the universe is “billions of light-years across” and yet, as the text points out,  “together [the images] suggest surprisingly similar patterns found in vastly different natural phenomena.”

The fact this connection had been acknowledged outside the realm of my own imagination unleashed a whole swarm of ardent notions (it’s amazing what a bit of reassurance can do).

For instance, if a similarity exists between the connections of neurons in our head and connections between galaxies in our universe, what’s to say a similar connection might not be found between each and every individual in our world, or each and every world in any one galaxy.

What if, and this one’s going to sound particularly outlandish, humans are just the equivalent of a collection of neurons in one gigantic brain, one gigantic brain inside many gigantic brains even. What if, that is, we’re all living inside one enormous Brain. Consider it something of a “Russian doll theory of life”, a human brain, functioning within a world brain, functioning within a galactic brain…you get the picture.

Sure, it might seem a thing of the most far-fetched science fiction, but even at that, it is fun to allow the mind a boggle every once and awhile…



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Your Brain

images-1In a recent post I emphasised how alike our brains are in the performance of many functions including processing, encoding, storing and recalling information. While this remains very much the case it’s also important to acknowledge the unique aspects of individual brains. As I put it before we are all walking the same internal path, but the details are different. The complex interaction between genes and environment mean that our brains, just like our bodies, come in different sizes, shapes and colours with individual features and peculiarities.

Through post-mortem dissections, brain-imaging studies and electrophysiological recordings of brain activity researchers have exposed many biological differences in individual brains, including variability in the

  • average speed at which synapses-the point on our brain cells at which information is exchanged- pass information to one another
  • pathways in which neural information flows from one area to another
  • size of the surface area of functionally independent neural regions
  • size and sensitivity of various neural structures
  • presence of various neurotransmitters and hormones

It should go without saying that differences in brain composition and function give rise to the varying dimensions of personality observed within a population. In fact, the developing field of personality neuroscience has been using the advanced methods and technologies of the neurosciences to correlate identified personality “types” with variations in brain organization, neuronal connectivity and cerebral structures.

As well as contributing to biological theories of personality however, the ability to measure and observe material differences in individual brains has important pragmatic implications. Within the clinical setting for instance, disparities in the brains of different individuals equates to variations in individual responses to a whole range of very common health issues including ageing, recovery from stroke, depression and other mental conditions. Physicians for this reason, have had to become adept at tailoring the treatment and treatment schedules prescribed for most medical conditions to the specific needs of the patient.

Identifying differences in individual brains may also soon be an invaluable aid1702-1252709341CgRp in the diagnostic process. For instance, recent studies have found a reliable association between the presence of an Alzheimer’s risk gene and differences in the volume of certain brain areas in young adults, long before the typical age onset of Alzheimer’s disease. With further research into such associations and the development of more advanced, user-friendly brain-imaging and recording devices it might some day be possible to diagnose a persons susceptibility to various medical conditions through an assessment of the individual morphology of their brain.

Other research into brain differences has revealed structural differences between male and female brains as well as how neuronal differences might influence peoples conscious experience of the world. Both areas I hope to explore in future posts.

For now however, I’ll leave you with a final thought. Much like your unique body, your brain is distinctly yours. As well as being endowed with specific neuronal characteristics from your inherited genetic program, certain details of your brain have changed themselves to suit you, to respond to your experiences, to adapt to your environment. Another thrilling feature of the neuronal galaxy that brings about our being. 


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