[Samuel Ford]

Hi Luke – interesting paper!

I think in these cases the previous brain damage was so severe in the hemisphere being removed that before the operation it wasn’t contributing anything anyway? (Apart from severe epilepsy). It is surprising though.

[Luke Haskett]

Hi Samuel, thanks for your thoughts. I imagine that to be part of the story – is the idea that these patients have such severe epilepsy that pre-op all meaningful functions and processes essentially emigrate from the epileptic hemisphere to the non-epileptic one? We know from cases of child hemispherectomy that a hemisphere is capable of essentially rewiring itself to pick up the slack of a missing hemisphere, but these cases of adult ops are harder for me to reconcile.

[Whit Blauvelt]

Hi Luke,

A pertinent question: What should the prediction be based on the McGilchrist hypothesis? From my current perspective, of having read his books slowly and carefully, but having finished The Matter some months ago (and gone on to some similarly dense reading equally related to the core of my own interests that drew me to Iain’s speculations — variations in how we can use language in thought), I’m uncertain the degree to which he intends his claims regarding neuroscience and those regarding psychological enculturation to dovetail literally, as compared to just metaphorically.

There is certainly a way of reading him as making simply the claim that the spread of ideas, memes, framings and the like within a culture or civilization can hinder the optimal use of brains/minds. In other words, if we get our philosophy right, our mental well-being and productivity can improve. And to the extent we get our philosophy wrong, the results in mental function can resemble certain varieties of brain damage, in particular those associated with schizophrenic presentations.

If we are to take his hypothesis as being more in this metaphoric realm — as compared to some literal claim about widespread organic brain damage — then the ability of surgeons to remove major parts of already-malfunctioning brains without specifically producing schizophrenic symptoms might be somewhat beside the point.

In the paper you point to, this sentence stands out to me, “Brain injury that lead to hemispheric epilepsy occurred before 10 years of age in 41 (87%) patients.” In other words, the organic trouble had begun while most of the patients were quite young, when brain development is still quite plastic in its distribution of functions between the hemispheres. What Iain’s concerned with is the way that specific functions integrate, where those functions on average are distributed some to the left, some to the right hemisphere. It’s likely enough that in the cases covered in this paper, those functions were already consolidated to one side — the one which survived the surgery. As this is possible, even likely, should the results speak to McGilchrist’s hypothesis at all?

Whit

[Luke Haskett]

Hi Whit,

There’s a lot of food for thought in what you write and I appreciate the consideration. I have myself pondered this wider point myself often – that being, the extent to which the neuroscience and the philosophy should literally coincide or whether the metaphor stands irrespective of the empirical data. To me, the great strength of his work is the vast and substantial amount of empirical data that is knitted together to form the whole. It is also very compelling to be able to refer to healthy ways of being and thinking and feeling by explicit reference to the very structure of the brain itself. In it’s essence, the fact that the holding of contradiction might be built into that structure, metaphorically and literally, is why i keep returning to Iain’s work.

My feeling is this paper/work on hemispherectomy in adults should fit within the hypothesis as much as any of the other data, of which there is abundant amounts, that concerns hemisphere functioning. This procedure is fascinating at the very least and I don’t remember it being referred to in Iain’s work? I see these rare patients as offering yet more evidence, distinct from split brain patients, that might inform our understanding.

My suspicion is the tests performed on these patients before and after are exceedingly basic and do not capture more sophisticated cognitive and emotional deficits.

Thanks again for your thoughts. It is in itself, I think, quite remarkable if our brains are able to move all meaningful functions over to one hemisphere in the event of catastrophic unilateral epilepsy, regardless of which side has it.

[Luke Haskett]

Morning Whit, having pondered this some more I think I am feeling happy to incorporate this paper in the following light – while the surgery might occur in adults, it leads to little loss of function where onset of epilepsy was very early in life because the brain has long before reorganised itself. This in itself is an incredible possibility afforded our brains as dual hemispheric, this high level redundancy.

Of course, if a hemispherectomy were to be performed on a ‘healthy’ adult, there would be substantial difficulties and changes. I think this is the point that I needed to get my head around.

I’m very glad I finally joined this community as no one at my University, certainly not the professors, would engage with any of this sadly.

[Samuel Ford]

I’ve cared for a number of individuals who had suffered from a severe stroke / brain injury when they were young (some of whom then suffered from epilepsy afterwards – but in all cases this was more or less controlled by medication and wasn’t as severe as those who might require hemispherectomy).

In my experience these individuals can be profoundly disabled; one man I worked with was in his fifties but was mentally very childlike, required assistance in every basic aspect of living (washing, eating, travelling), he could speak but his vocabulary was extremely limited and repetitive. He did not understand much that you told him, any instructions needed to be broken down to extremley simple components. He had difficulty walking and could not use his left arm, difficulty with emotional regulation…etc (I’m not trying to diminish this person, I actually really got on with him and enjoyed caring for him.)

In table 3 some gross deficits are recorded before the operation – essentially could they walk, talk and did they have fine motor control (and it looks as if many of them couldn’t). This is not enough to see how these brain injuries/epilepsy have affected the person, I suspect from my own limited experience, and simply from the fact that this surgery is being performed at all, that these people were profoundly disabled to begin with.

Also I think what you said about the tests not being sophisticated enough is true, to be honest I don’t know how any test could fully capture somebody’s personality and individual, particular deficits – you would simply have to meet the people!

[Luke Haskett]

Evening Samuel, thanks so much for your thoughts. I think that helps a lot and is pretty obvious. I’ve recently started an MA and almost all of the professors seem to have no time at all for hemispheric difference and this was something that one of them recently brought up, as if to say case closed, don’t look into hemisphere difference expecting to find much. It’s been somewhat exhausting! Anyhow, what you’ve added makes perfect sense. Ta.