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[Neuroscience] Re: Depression, behavior, and Neurobiology

Glen M. Sizemore gmsizemore2 at yahoo.com
Thu May 18 07:05:39 EST 2006


"John H." <j_hasenkam at yahoo.com.au> wrote in message 
news:1147939992.896303.206750 at 38g2000cwa.googlegroups.com...
> 18/05/2006 2:56PM
>
> Caveat: the hypothesis, more correctly appelled as a fancy, is that
> depression is caused by a chemical imbalance. Since the mental health
> community has felt free to engage this fancy I'm quite happy to carry
> it to its logical conclusion and in so doing note the warning of Camus,
> "It is always easy to be logical, it is almost impossible to be logical
> to the bitter end." (The Myth of Sisyphus)
>
> Low serotonin, dopamine, or norepinephrine are neurobiological
> correlates of depression(perhaps, maybe, so we are led to believe). To
> state that low serotonin causes depression is to overlook the fact that
> both occur simultaneously where as a cause needs to be antecedent.
> Hence what should be addressed is not low serotonin, but what has
> caused the low serotonin. The great danger is that in treating
> depression with drugs we are never getting at the primary causes of
> depression. Drugs cannot cure depression they can only manage it. Drugs
> should be seen as managing the condition and the commencement of
> treatment, not the end of treatment. Thankfully over the last several
> years the trend has been towards a more comprehensive therapeutic
> regime.
>
> What if you made a group of people behave in a depressive fashion,
> particularly with respect to neurotic thinking? For example, take a
> group of Australians and put them in one of their migrant detention
> centre camps. How long ... .Will this eventually lead to low
> serotonin\nore\dopamine? If so, what sorts of preconditions (eg. 5ht
> short allele, recent psychological or physical trauma, childhood
> neglect) will make individuals within this group more likely to show
> the neurobiological correlates typically associated with depression?
> Apart from the obvious neurotransmitters other candidates for
> observation would include: CRF - ACTH - CORT dynamics (depressives can
> exhibit high, low , and normal cort readings), acetylcholine, GABA
> (some evidence to suggest it falls in depression), interleukins 1,6,
> ifn gamma.
>
> In short, can depressive behavior induce the neurobiological correlates
> of depression?


I've read in secondary sources that one may make it so animals move around 
less in a variety of environments (and maybe show other signs of 
 "depression") if one arranges operant extinction in one environment. That 
is, if you conduct two experimental sessions a day, one in which a response 
is reinforced (lever-press-->food), and another a simple "open field" 
session (the animal is placed in a chamber and the amount it moves around is 
measured), the amount the animal moves around in the open field will 
decrease if the feeder is disconnected in the operant chamber. An elegant 
experiment would be to do in vivo microdialysis during the course of the 
experiment (no easy feat, incidentally) and analyze the dialysate using 
HPLC. I don't think that this experiment has been done. Some behaviorists 
have speculated for decades that the etiology of depression has something to 
do with operant extinction. I don't know what clinical evidence there is 
that this might be the case. I assume that some sort of temporary depression 
is induced by loss (plausibly viewed as extinction) but I don't know about 
evidence concerning the sort of long-term symptoms that get labeled 
"depression."



Cordially,

Glen



> 




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