Schizophrenia

If you’ve ever seen a man’s scalp peeled off and folded over his face, so that a plate of skull can be removed to expose the brain’s protective sac, you’ll perhaps have a sense of how hard it is to get brains to open up. Especially when there’s something going wrong.

The brain pulsates with each heartbeat, as the vascular neuronal jelly is pumped with oxygen and sugar rich blood. If starved of either of these for even a matter of seconds, it is irreparably damaged, and the consciousness it gives rise to can be permanently altered or destroyed. But that’s not the only thing that can go wrong in this fragile bag of saltwater and fat. The brain is built from biochemistry, in the same way a computer chip is comprised of silicon and conductors. But just as an OS can crash or slow without an obvious physical insult, so too can an abstract entity such as consciousness. Produced by the machinery of millions of networks of cells, our minds can go askew without a bleed, stroke or bullet. At least 1 in 4 of us will experience first hand the trials of mental illness. I want to briefly discuss some of the prevailing theories of what goes on in the darkness behind the eyes, in one of the more misunderstood dysfunctions of the mind, schizophrenia.

To begin, it is worth mentioning that schizophrenia is more correctly referred to as a collection of symptoms or a ‘syndrome’ than a specific and easily defined disease. It is a long term mental health condition, said to be a ‘psychotic illness’ – a term meaning that it can cause the sufferer to become unable to distinguish their internal thoughts and imaginations from their external reality. It cannot be emphasised enough, that the condition has nothing to do with a ‘split personality’, and that people with the condition are very rarely dangerous. It affects roughly 1 in 100 people at some point in their lives. Delusions, disorders of thought, and auditory hallucinations are said to be ‘positive’ symptoms of the condition, in the sense that they are an unwelcome addition to the content of a mind, whilst reduced emotional and social engagement are described as ‘negative’ symptoms, detracting from the original functionality and well-being of a person’s personality.

Before I discuss the proposed neurological mechanisms of schizophrenia, I’d like to be clear that the hypotheses  to which I will allude are not suggested to be the complete explanation of the syndrome, and my explanations of them are at best grossly incomplete. In spite of this, I hope this simplified explanation is a helpful starting point for anyone looking to further their understanding of schizophrenia, and might dispel some of the mystique that exacerbates the stigma of this branch of mental illness.

Schizophrenia is thought by some to be a ‘disorder of salience’. One of the key evolutionary advantages of humanity’s unique consciousness, is the ability to pick out minute features from the monotony of our lives, and see significance and importance in stimuli that would fail to faze even the most neurotic antelope. Noting the value of a particularly sharp rock for use in an abstract construction like an axe or spear, or picking up on the increasingly subtle social cues of a developing tribal society, warranted the evolutionary refinement of a mechanism by which we could pick the wheat from the chaff.  Our brains are capable of extraordinary and often totally subconscious multitasking, to the extent that we are often totally unaware that we’ve adjusted our sitting position a dozen times since we started reading a blog post about schizophrenia. The experience of residing in a body that’s half run on autopilot is universal, with cereal boxes being put ‘back’ in the fridge, and commutes to work occurring at weekends (sometimes even by doctors /s). But all the while, each part of our sensory input is mutely inspected, and assessed for novelty or significance by some part of our mind, drawing our attention to visual and audio cues that might make us put the lid back on the milk or tidy up a discarded Doctor Who sock in response to a frustrated sigh.

This flavouring of otherwise neutral and unremarkable stimuli with a sense of importance, leaning towards either attractiveness or aversion, is attributed to the ‘mesolimbic pathway’ or ‘reward pathway’, which uses the chemical dopamine as its pepper.

What happens then, when this process goes awry, and all the pepper spills into the soup? When the gain is turned up too high, be it through genetic or environmental factors (especially the judicious consumption of THC), a mind can begin to perceive significance in anything, from the car parked outside the house, to the tie worn by a news presenter. When a mind is faced with the knowledge that there is ‘something’ important about the way your neighbour said “hello!” yesterday, as well as the fact the batteries in the remote need changing, it will often construct a narrative to make sense of it all. The nature of this narrative will vary from person to person based on their cultural background, with explanations ranging from governmental conspiracies to religious, supernatural or extra-terrestrial encounters. Such narratives, whilst partly derived from a person’s environment, are classified as ‘delusions’ or ‘false beliefs’ when they fall too far from the social norms of their community. Similarly, ‘delusions of reference’ occur when a sufferer perceives a personal significance to something said by a public figure or newspaper, and will often incorporate it into their delusion.

Auditory hallucinations – ‘hearing voices’ – a classic hallmark of the syndrome of schizophrenia, can also be explained through excessive dopamine signalling.  Such signalling has been shown to cause abnormal connections between the sites of the brain that produce language (Broca’s area) and the part of the brain which understands it (Wernicke’s area). In the way the brain adapts to these abnormal connections, new links are then formed between Broca’s area and the centres that are responsible for processing auditory information. Once this has occurred, the auditory system, unable to discern the source of this speech, attributes it to an external source. In the context of a mind already perceiving conspiracy and threats at every corner, the content of this speech can often be alarming, and might take the form of ‘third person’ commentaries of the sufferers actions, or, more worryingly, ‘second person’ commands, which might compel the sufferer to odd behaviours, or even self-harm.

This hypothesis of ‘aberrant salience’ (Kapur 2003), and the ‘dopamine hypothesis’ were proposed based on the fact that the blockage of dopamine receptors through certain antipsychotic medications seems to help alleviate some of the positive symptoms of schizophrenia, whilst conversely a potential side effect of medications that stimulate dopamine receptors is psychosis. Sadly, it remains clear that this isn’t the whole picture, with some patients failing to respond to such medications, and other medications working through totally different receptors and transmitters in ways we are still yet to fully understand.

The negative symptoms I mentioned previously, as well as the complex relationship with depressive illness and anxiety disorders also remain poorly understood, and difficult to treat. Alternative and additional theories of schizophrenia, both neurological and psychological, will all reflect and explain different facets of a very complicated disorder we continue to unravel. Despite this uncertainty about the precise nature of mental illness and how best to treat it, with the proper support, education and management plan, many people with schizophrenia can return to living normal lives. Openly communicating about mental illness, and being comfortable discussing it with our friends and family, can only help to dispel the stigma that can lead to late diagnoses and more difficult treatment. I hope this brief post has provided some insight into this condition, and I look forward to any feedback or corrections.

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Sleep

I hope to revisit sleep and dreams at a later point, but here is a brief crack at providing something interesting before I delve into exam season, and is the first piece I have written particularly for the purposes of this blog! Enjoy.

Almost every single organism we know of, from bacteria to blue whales has a some manner of circadian rhythm, and all of those with a brain have some manner of equivalent to sleeping.

While the simplest explanation for why we must sleep is that we become sleepy, sleep deprivation is eventually 100% fatal. A study into sleep deprivation in rodents was conducted, and within two weeks, every single subject died. When autopsies were conducted, nothing was found to be obviously wrong, except for the tell-tale signs of not breathing and zero blood pressure, commonly found in things that are not alive.

But beyond this perhaps ethically troubling experiment, a rare condition exists in humans by the name of fatal familial insomnia. It will come as no surprise to the more attentive reader that this too is invariably fatal, and is a condition caused by prion buildup in the brain leading to progressive deterioration of the ability to sleep. Death usually follows within 7 to 36 months of the onset of symptoms, which progresses from a state of partial insomnia leading to panic attacks and hallucinations, to total insomnia leading to dementia and death.

What is sleep? I think of myself as a consciousness generated by my own neuroanatomy, so when I am unconscious, to an extent you could argue that I no longer exist. You could use an analogy with the image produced on a computer screen as the conscious awareness produced y the unknown workings of a humming desktop computer. The screen will go into standby after a while, but the overall hum of the computer will not disappear entirely.

The analogy, while perhaps already a strain, ought not be taken much further. Computer screens will turn themselves off to prevent ‘burn in’, and while an interesting case could be made to apply this analogy to the mind, the reality is that scientists are still struggling to provide a definitive reason for why we need to sleep, or indeed point to the mechanisms through which insomnia causes immune suppression, depression, and even death.

Consciousness

Written ‘A while back’, by Barney Low

This was written a while back to try and summarize and present some concepts I was introduced to by an fascinating book on consciousness (Going Inside, by John McCrone). Please feel free to comment or correct.

Each instant of consciousness is the result of intense competition between the firing of neurones representing different facets of our mind, with some representing long term memories, objectives and desires, others the raw sensory input of the moment, and others still continuing to fire from the previous instant of consciousness. The thought, sensation or emotion that is potentiated is selected based on the frequency of its firing and its synergy with others that fired along with it, with neurones that fire for the abstract concept of a tree being more likely to fire off when preceded with the firing of subjectively linked ideas, such as forests or nature.

When the victor of this competition is pain, such as when we tread on a pin whilst dancing in our pyjamas, that instant of consciousness will be dominated almost completely by a redirecting of awareness to the overriding stimulus: making us aware of the noxious stimuli, diverting our gaze to the source of the pain as reported by our proprioception, and alerting us to the fact that we have instinctively pulled our foot away.

If we are aware of incoming pain, such as when we are given an injection by a doctor, our mind is primed to suppress the reflex withdrawal and perhaps even anger that would normally result from the sensory stimuli we are subjected to. Here is an example of where the higher cognitive levels of the frontal lobes associated with planning might become involved, interacting and modulating the more primal and reflex orientated aspects of our brain’s functions in preparation for the instants to come. We might even be able to continue a stream of verbal or internal dialogue with our friendly doctor (or our disgruntled complaining self); ensuring by concentrating and the suppression of other input, that the chain of neuronal firing responsible for producing logical sentences is not interrupted from one instant to the next.

This continuity is an essential feature of our conscious experience, with our more recently active (or generated) neuronal networks firing off with greater frequency than less relevant neurones, which might for example represent our mind’s map of our primary school or the visual stimuli of a long lost toy. Examples of this continuity in action would be the continual firing of a neurone representing anything from the earlier content (or the general gist) of a friend’s tale as they expand into gory details, to recalling which seat at the dinner table is our own. This form of recall is essentially what is known as ‘working memory’, and I will go on to discuss how the brain might be able to potentiate the raw content of a moment in a more long term form in another spiel.

Published in Pi Magazine: The Stuff of Thought

Published in Pi Magazine: The Stuff of Thought

Published on 2nd March 2013 in Pi Magazine. It’s basically a rehash of the ‘Consciousness’ and ‘Representation and Memory’ spiels, so if you’ve seen them, then maybe give it a miss. Alternatively, if you’d prefer a condensed summary of the two, then go right ahead!

Click on the link above to read the article online.

The Stuff of Thought. By Barney Low

stuffofthought