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Dr. Bob is Robert Hsiung, MD,
bob@dr-bob.orgShown: posts 1 to 14 of 14. This is the beginning of the thread.
Posted by linkadge on May 19, 2009, at 19:43:25
Linkadge
Posted by SLS on May 19, 2009, at 20:33:09
In reply to This study makes no sence, posted by linkadge on May 19, 2009, at 19:43:25
Maybe there is a lack of neuronal pruning in an environment where there is too much stimulation.
- Scott
Posted by SLS on May 20, 2009, at 4:51:53
In reply to Re: This study makes no sence » linkadge, posted by SLS on May 19, 2009, at 20:33:09
> > http://www.biomedexperts.com/Abstract.bme/16477619/Early_social_enrichment_augments_adult_hippocampal_BDNF_levels_and_survival_of_BrdU-positive_cells_while_increasing_anxi
> >
> > Linkadge
>
>
> Maybe there is a lack of neuronal pruning in an environment where there is too much stimulation.I almost forgot that when rats are placed in an overcrowded environment, their behavior becomes dysfunctional. This is a consistent finding. I would have to research exactly what are the resultant behaviors, but they do become hostile and fail to mate for breeding.
- Scott
Posted by SLS on May 20, 2009, at 5:00:29
In reply to Re: This study makes no sence, posted by SLS on May 20, 2009, at 4:51:53
> > > http://www.biomedexperts.com/Abstract.bme/16477619/Early_social_enrichment_augments_adult_hippocampal_BDNF_levels_and_survival_of_BrdU-positive_cells_while_increasing_anxi
> > >
> > > Linkadge> > Maybe there is a lack of neuronal pruning in an environment where there is too much stimulation.
> > I almost forgot that when rats are placed in an overcrowded environment, their behavior becomes dysfunctional. This is a consistent finding. I would have to research exactly what are the resultant behaviors, but they do become hostile and fail to mate for breeding.----------------------------
This following study reports some very salient findings:
1. The overcrowding paradigm does reliably produce depressive behavior in rats.
2. Swimming-induced head twitching in rats in the forced swimming test represents a new marker for depression and drug studies.
3. Antidepressants work.
:-)
- Scott
************************************************
http://www.ncbi.nlm.nih.gov/pubmed/1479766
1: Keio J Med. 1992 Dec;41(4):221-4.Links
"Swimming-induced head twitching" in rats in the forced swimming test induced by overcrowding stress: a new marker in the animal model of depression?
Naitoh H, Nomura S, Kunimi Y, Yamaoka K.Department of Psychiatry, Fujita Health University, School of Medicine, Aichi, Japan.
We have used overcrowding stress to study the pathogenesis of depression and the action of antidepressant drugs. In the present study, the influence of overcrowding on behavior was assessed by the forced swimming test. All the stressed rats revealed highly characteristic head twitching movement, which was not inhibited by repeated administration of diazepam and haloperidol, but was markedly suppressed by repeated administration of desipramine and mianserine. A significant positive correlation in the number of twitching episodes in each stressed rat between the first and second forced swimming test was seen. These findings support the use of overcrowding of rats as a stressor in the animal depression model because it fulfills the criteria of the model; face validity, construct validity and predictive validity. We propose the adoption of "swimming head twitching" as a new marker in the animal model of depression.
- Scott
Posted by linkadge on May 20, 2009, at 8:09:56
In reply to This study makes no sence, posted by linkadge on May 19, 2009, at 19:43:25
But read the study I gave very carefully:
1) Nowhere was the term overcrowding used in the CN mice - they used the term social enrichment and they way they describe it - it doesn't sound particularly stressful.
2) The mice that were reared with social enrichment had more neurogenesis cellular servival and higher levels of BDNF *but* also more depression
Linkadge
Posted by SLS on May 20, 2009, at 10:44:34
In reply to Re: This study makes no sence, posted by linkadge on May 20, 2009, at 8:09:56
> 1) Nowhere was the term overcrowding used in the CN mice
But, isn't the CN environment defacto overcrowding? Besides, there is probably little, if any, bonding between mother and pup. More stress. Too much competition for teats.
It really does make sense.
> 1. they used the term social enrichmentAsk the rats if they are enriched.
Enrichment is not necessarily used as a positive attribute to CN. It just means more stimulation. I have already addressed this issue with the concept of a lack of neuronal pruning, ESPECIALLY in the context of increased BDNF. Too much BDNF is not necessarily a good thing. Here, it prevents the pruning necessary for a healthy brain. Depression can come from hyperactivity in certain areas of the brain, including Brodman's area 25 (subgenual cortex). Too much BDNF at critical periods of development? Too much neurogenesis at a time where pruning should be occurring?
Your study SO makes sense.
- Scott
Posted by desolationrower on May 20, 2009, at 14:30:57
In reply to Re: This study makes no sence » linkadge, posted by SLS on May 20, 2009, at 10:44:34
rats aren't primates. different need for social interaction.
-d/r
Posted by SLS on May 20, 2009, at 14:42:59
In reply to Re: This study makes no sence, posted by desolationrower on May 20, 2009, at 14:30:57
> rats aren't primates. different need for social interaction.
Perhaps, but they do demonstrate strong bonding behaviors between mother and pups.
- Scott
Posted by desolationrower on May 20, 2009, at 19:36:53
In reply to Re: This study makes no sence » desolationrower, posted by SLS on May 20, 2009, at 14:42:59
hm, i was wrong about teh nesting, the 3 mothers together might not be unusual. see http://www.ratbehavior.org/CommunalNesting.htm
-d/r
Posted by linkadge on May 20, 2009, at 20:59:29
In reply to Re: This study makes no sence » linkadge, posted by SLS on May 20, 2009, at 10:44:34
>Ask the rats if they are enriched.
Well, the study suggested they have a higher rate of hippocampal neurogenesis as well as cellular survival. They also showed higher levles of BDNF, these kinds of synaptic differences are seen in other forms of environmenal enrichment.
>I have already addressed this issue with the >concept of a lack of neuronal pruning, >ESPECIALLY in the context of increased BDNF.
You havn't "adressed" anything.
>Too much BDNF at critical periods of >development? Too much neurogenesis at a time >where pruning should be occurring?
What constitutes too much BDNF? BDNF is not just a factor promoting neurogenesis, it also affects the way that neurons survive and connect with other neurons. Mice with elevated levels of BDNF perform better than regular rats on several tests of memory and cognition. Some studies suggest that elevated hippocampal BDNF confers a phenotype resistant to depression.
This study doesn't make sense to me. I don't really uderstand what you are trying to say (no offence) - or see how it proves anything. I think I the explaination for this phenomina is far beyond my understanding.
Linkadge
Posted by SLS on May 20, 2009, at 21:37:48
In reply to Re: This study makes no sence » SLS, posted by linkadge on May 20, 2009, at 20:59:29
> This study doesn't make sense to me. I don't really uderstand what you are trying to say (no offence) - or see how it proves anything. I think I the explaination for this phenomina is far beyond my understanding.
I don't think you have understood a single thing that I have had to say about the phenomena reported in your study.This is where I get off the ride.
- Scott
Posted by ricker on May 20, 2009, at 22:04:49
In reply to Re: This study makes no sence » linkadge, posted by SLS on May 20, 2009, at 21:37:48
> This is where I get off the ride.
>
>
> - ScottAbout time! Now get down to my seroquel post and help me out.... pretty please... :-)
Posted by linkadge on May 21, 2009, at 7:47:40
In reply to Re: This study makes no sence » linkadge, posted by SLS on May 20, 2009, at 21:37:48
>I don't think you have understood a single thing >that I have had to say about the phenomena >reported in your study.
I don't think you understood a single thing you said either.
Linkadge
Posted by metric on May 21, 2009, at 14:06:24
In reply to This study makes no sence, posted by linkadge on May 19, 2009, at 19:43:25
Hey guys,
I've uploaded the full text of the study, which you can download from the following URL (should be available for 7 days):
http://uploadfile.org/download.php?id=8XlvTty9PIZzfbuEg9DY
This is the end of the thread.
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