WM training, D1 binding, and schizophrenia

[Pheonoxia]

From the February 26, 2009 issue of Science Magazine, the same study
that showed WM training affected dopamine receptors as seen on MRI
scans, "A negative correlation dominated for all regions, with larger
decreases in D1 BP being associated with larger improvements in
WM. ... An association between a decrease in BP and an increase in WM
is also consistent with the negative correlation observed between WM
capacity and D1 binding in individuals with schizophrenia."
http://brain-training.googlegroups.com/web/mcnab2009-nback-changes-dopamine.pdf

BP = binding potential, so improvements in working memory decrease
dopamine-1 binding potential. Are there any neuroscience experts here
who know exactly what that means? What does it mean if the dopamine in
my brain has less binding potential? It's possibly my unfamiliarity
with neuro-lingo, but a decrease in potential seems like a negative
effect.

Furthermore, why does an increased working memory and decreased D1 BP
correlate with schizophrenia? I forget who, but someone on this forum
wrote about the results of their intensive Quad N-Back training,
stating some symptoms seemingly somewhat schizophrenic.

Do keep in mind that the purpose of this study was to measure
neuroplasticity and how fast it could work. Cognitive training was
just the means to this end, for the study was neither designed nor
resulted in proving WM training creates positive or negative
structural changes to the brain.

[Reece]

I can't remember whether it was me who wrote about it or not, however
I've certainly experienced "schizophrenic-like" symptoms from playing
QNB (or at least they came across as that to me). Most notably, I
occasionally get "hallucinations" (even on days I don't play any n-
back, so it must be at least semi-permanent) that I never got prior to
QNB training (several months of DNB without problems and never before
had this happen in my entire life).

I'm not sure if that's the right word for them -- I know what I'm
"seeing" isn't real and what I "see" is actually thoughts/memories,
not anything delusional like thinking "God is talking to me" type of
schizophrenia.

It doesn't bother me at present.. I find it somewhat interesting
actually -- some sort of synesthesia-like induced condition?
Unsurprisingly, it does seem to make memories more memorable when it
does occur (which I have no control over). I guess I could crack a
joke and say QNB training is giving me photographic memory, however I
am being careful while training as I really don't know what to expect
and while I find this interesting, I can't say the same about the
prospect of developing full blown schizophrenia or constant
uncontrollable hallucinations.

On 31 oct, 04:12, Pheonoxia <b...@brockman.info> wrote:
> From the February 26, 2009 issue of Science Magazine, the same study
> that showed WM training affected dopamine receptors as seen on MRI
> scans, "A negative correlation dominated for all regions, with larger
> decreases in D1 BP being associated with larger improvements in
> WM. ... An association between a decrease in BP and an increase in WM
> is also consistent with the negative correlation observed between WM

> capacity and D1 binding in individuals with schizophrenia."http://brain-training.googlegroups.com/web/mcnab2009-nback-changes-do...

[Reece]

Adding to what I wrote: I did a bit of research into it to make sure
"I wasn't going crazy" and from what I've read, it appears that such
experiences are not uncommon in children (apparently somewhere around
2-5% of children).

I think theta waves are implicated in it somehow (higher in children).
Dopamine, from what I've read, increases theta waves and DNB (and I
would imagine QNB though I've seen no research on it) increases
dopamine receptors.

I have pretty bad concentration issues (not officially diagnosed,
though my pdoc prescribes me Ritalin) -- seems high theta is common in
people with ADD/ADHD to begin with which I may have further
exacerbated through working memory training.

Way too much unsupported speculaton on my part... Like you, I would
welcome an expert opinion on the subject.

[polar]

Hi,

I'm not an expert on this topic, but we've had serious introduction
into nerosciences in school, and there are some things which I think
are worth mentioning here. Firstly, most people have in mind that
there are like 2-3 neurotransmitters, when in fact there are about
dozen of them, and about 50 neuropeptides serve as modulators and
neurotransmitters too (Britannica guide to brain, 2008).

In addition, for every neurotransmitter there are several types of
receptors. You can see an example of the situation for serotonin
receptors here: http://en.wikipedia.org/wiki/5-HT_receptor . Next
thing is, that receptors not only excite neurons, but also inhibit
them - there are at least 50% of inhibiting receptors generally, some
claim more than 90%. As britannica puts it, if there were more than a
tiny fraction of neurons in the brain active at the same time, we
would got into epileptic convulsions immediately, which sound logical
to me.

Now to the point. There's not too much sense in talking about absolute
amounts of neurotransmitters in brain, because the dynamic is very
complex: you have some amount of, say, serotonin. AND, you have some
amounts of receptors for it. So when serotonin level goes down, more
of your serotonin receptors are pulled to the surface of the
serotonergic neurons to preserve the whole serotonergic system. And,
when you raise the levels of neurotransmitter too high, the brain will
cope through pushing the receptros down, to balance again the whole
system.

Another example - wikipedia says, that 90% of brain neurons release
only either glutamate or GABA. When you release/receive glutamate, you
excite. When GABA, you inhibit. So when you drink alcohol, it binds to
GABA receptors, so it inhibits the whole neuron. But inhibiting some
neuron(s) can paradoxically mean un-inhibited behavior, as it is the
case with alcohol. Actually this is because alcohol firstly inhibits
areas responsible for inhibition of behavior... than inhibits
everything (slower reaction times, and sleep).

So BP means the number of active receptors on the surface of dopamin
neurons. If BP raises, there's maybe low level of dopamin in the
brain, and you need more receptors to "catch it". And opposite, when
you have lower BP, it could mean that more dopamine is available.
Actually McNab in his n-back study showed that the latter case (less
BP so probably more dopamin) is good for WM: "larger decreases in D1
BP being associated with larger improvements in WM". Regarding the
schizophrenia I believe he works with the hypothesis that low WM is
associated with schizophrenia risk - so in schizophrenic people it's
"small WM, lot of D1 receptors, because dopamine is low".

Nevertheless, D2 dopamine receptor does not show these relationships,
and the question of the days of course is, what is the long term long
term dynamics of the whole system. Hope this was useful for you.

> October 31, 10:12 am, Pheonoxia <b...@brockman.info> wrote:
> From the February 26, 2009 issue of Science Magazine, the same study
> that showed WM training affected dopamine receptors as seen on MRI
> scans, "A negative correlation dominated for all regions, with larger
> decreases in D1 BP being associated with larger improvements in
> WM. ... An association between a decrease in BP and an increase in WM
> is also consistent with the negative correlation observed between WM

> capacity and D1 binding in individuals with schizophrenia."http://brain-training.googlegroups.com/web/mcnab2009-nback-changes-do...

[Mike^2]

Reece, can you be a bit clearer as to what exactly these
'hallucinations' are or rather, what they include, how potent they
are, and etc...?

[Reece]

Hi Mike,

A few times per day now I will "see" my thoughts. It's pretty random
-- some I've experienced in the past include cooking, travelling,
accidentally dropping things (in the hallucination, not in real life),
lecturing people / giving presentations. It's not so real as to be
indistinguishable from reality, so it hasn't caused me anything in the
way of problems, however I was quite frightened at first when they
started happening, not knowing what was going on. They seem to occur
almost exclusively in the morning and evening.

Polar, thanks for the very thorough explanation -- much appreciated.