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> Understanding OCD (help needed), caudate nucleus, OFC, amygdala? Could someone help me understand the pathways involved.
Josh_651989
post Mar 23, 2007, 05:59 PM
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I don't understand the relationship between the cudate nucleus, OFC, cingulate gyrus and amygdala. Any sort of help regarding the brainchemistry or brain structures involved in Obsessive Compulsive Disorder would be much appreciated.
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lucid_dream
post Mar 23, 2007, 06:20 PM
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http://www.ncbi.nlm.nih.gov/entrez/query.f...20Word%5D%29%29

for example, this article might be informative:
http://www.ncbi.nlm.nih.gov/entrez/query.f...l=pubmed_docsum
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Josh_651989
post Mar 24, 2007, 06:14 AM
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thanks lucid. Trouble is I'm completely ignorant of the brain. Article after article point me towards the structures involved, but they don't explain the relationship between them. I think I have heard that the caudate acts to filter unimportant information (thoughts?), and in OCD this function is partly inhibited. This feeds to the orbital frontal cortex?
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lucid_dream
post Mar 25, 2007, 09:52 PM
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the caudate feeds indirectly to most of prefrontal cortex, including orbital frontal. I will have to get back to you on the details of OCD.
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OddDuckNash4348
post Mar 27, 2007, 11:36 AM
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The basal ganglia is the area where unwanted sensory information is filtered. In OCD, this goes haywire, and the filtering does not occur. Thus, the same thoughts keep coming back in a "feedback loop" of sorts. The caudate nucleus, being part of the basal ganglia, is the main player in all of this. Dr. Jeffrey Schwartz, author of the immensely popular Brain Lock, and his teammembers discovered back in the 80's (through PET scans) that increased glucose activity occurred in the orbitofrontal cortex and basal ganglia, so too much is going on, leading to the obsessions and compulsions.

The amygdala, known to be the "fear center" of the brain, is also overactive in OCD, which is why Obsessive-Compulsive Disorder is the most severe of the anxiety disorders. It seems that, somehow, the amygdala overreacts to the unwanted sensory information from the basal ganglia. It takes thoughts that are silly or abnormal, and puts a sort of "danger" alert on them, saying that they are harmful and should be taken care of.

The prefrontal cortex is involved in understanding logic and higher cognitive processes, so the orbitofrontal cortex is also involved in these functions to a degree. In OCD, the ability to understand that a thought is illogical is impaired, due to structural abnormalities in the prefrontal cortex. It is interesting to note some similarities in pure obsessional OCD (the type I suffer from) and schizophrenia. Both involve problems with the prefrontal cortex being unable to reason out bizarre thoughts. However, the area of prefrontal cortex affected is what creates the drastic difference in symptoms and severity of the disorders. I believe it is the dorsal area of the prefrontal cortex that malfunctions in schizophrenia and the ventral area in OCD (they may be switched; correct me, if I'm wrong), so just that simple switch causes anxiety vs. psychosis. In addition, dopamine has long been thought to play a role in schizophrenia, and the center for dopamine is none other than the substantia nigra, a subset of the basal ganglia.

An interesting theory that I have read about regarding OCD is the "pruning theory." It is thought that, during adolescence, our brains "prune" and get rid of excess brain cells (gray matter). We are born with millions of neurons that we will never use. During this phenomenon, the myelinated connections (white matter) between neurons that already have been put into use are strengthened. This leads to higher cognitive abilities, and it explains why a typical 7-year-old cannot solve an algebra problem but a 16-year-old can. It is thought that this pruning doesn't occur in OCD (or certain Autism Spectrum Disorders, like Asperger's, which I also have), so the result is that OCD-ers simply "think too much." This view was stated by Dr. Ian Osborn in his amazing book Tormenting Thoughts and Secret Rituals: The Hidden Epidemic of Obsessive-Compulsive Disorder. The theory also explains why many OCD-ers have some form of Nonverbal Learning Disorder- because their higher cognitive functions do not develop properly. Asperger's is considered by some to be a form of NVLD, and the high comorbidity rate of Asperger's and OCD and the learning problems that result also are explained by this theory, one that I greatly support.

And then, of course, there is the role of serotonin. It isn't really known why low serotonin leads to obsessiveness, but it has been shown time and time again to have some key role in the development of obsessive-compulsive behaviors, whether in OCD, Obsessive-Compulsive Spectrum Disorders (such as impulse control disorders, trichotillomania, and Body Dysmorphic Disorder), and Autism Spectrum Disorders. I don't know much about the role of the cingulate gyrus. It doesn't seem to be as prominent, so I haven't seen as much information about it. If you have any questions, feel free to ask!
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Josh_651989
post Mar 27, 2007, 12:15 PM
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Thank you very much OddDuckNash4348. I found your post extremely helpful. I too have OCD. I also have Jeffrey Schwartz' "Brain Lock", and recomend it to anyone who is interested in the disorder.

P.S. does pure "O" ivolve no mental rituals what so ever?
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OddDuckNash4348
post Mar 27, 2007, 12:24 PM
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Actually, pure "O's" are the ones that have solely mental compulsions. We have few, if any, overt/visible compulsions. Some pure "O's" don't have any compulsions, but this is pretty rare. Even if they don't think they have compulsions, they most likely do- they're just mental ones that they don't think about. Common mental compulsions are mentally praying, mentally counting, mentally repeating phrases, and the "counter-image." This is another thing Osborn chronicles- it's when you take a "bad" thought/image and make it "good." For example, somebody seeing themself stab a loved one will immediately try and see themself hugging the loved one. Or if you hear, "I hope he dies," you may instead say, "I hope he lives." Things like that. Personally, I think pure obsessional OCD is the worst to have- nobody sees our suffering, and it is hardly known about. OCD isn't all about handwashing...
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trojan_libido
post Mar 28, 2007, 10:59 AM
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very enlightening
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Josh_651989
post Mar 28, 2007, 11:16 AM
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I appologise that my last post was insensitive.

A large number of my compulsions are inconspicious. I also suffer from compulsive counting. I was just wondering how pure "O" can be classified as such if it involves compulsions of any kind.

Anyway, its not really important since its just a techincality. Both visible and inconspicious compulsions are essentially the same thing. I don't think its reasonable to brand one subcateogory of OCD as worse than another. Hope I haven't offended you.
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Rick
post Mar 28, 2007, 01:44 PM
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I wonder if meditation has ever been found helpful to OCD sufferers.
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lucid_dream
post Mar 28, 2007, 08:03 PM
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QUOTE(OddDuckNash4348 @ Mar 27, 2007, 12:36 PM) *
And then, of course, there is the role of serotonin. It isn't really known why low serotonin leads to obsessiveness, but it has been shown time and time again


If the caudate or striatum is implicated in OCD then dopamine D1 and D2 receptor agonists or antagonists should either alleviate or aggravate OCD symptoms. Is there any evidence for this?


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OddDuckNash4348
post Mar 28, 2007, 09:41 PM
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I haven't heard much about the role of dopamine, but I'm sure it most likely does play a role, due to the fact that the basal ganglia is the center of the troubles. Plus, there are the similarities with schizophrenia. With some OCD-ers, atypical anti-psychotics (and sometimes the traditional anti-psychotics) are added to the SSRI's to augment treatment or to be used in severe, treatment-resistant OCD, and these medications, of course, work on the dopamine receptors. There is actually a type of OCD called refractory OCD where the OCD-er doesn't recognize that their obsessions are illogical. The ego-dystonic nature of obsessions and recognizing their irrationality once they have passed is a key feature of OCD, but in refractory OCD, psychosis is present, as the patient is unable to separate fantasy from reality. This is very rare- only seen in about 1% of cases. I'd imagine that dopamine must play a role, to bring all of this about. However, not a lot of generalized findings have been set out about the role of dopamine. I believe there are many journal articles out there on the subject, but it isn't as well-supported, and I'm not as well-versed on it, due to that fact.
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Josh_651989
post Mar 30, 2007, 02:41 AM
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The use of meditation (or similiar spiritual techniques) for OCD sufferers is advocated by Jeffrey Schwartz. The first step of his 4-R therapy, relabelling OC thoughts, involves "mindful awarness". It is developed from the buddist technique of meditation, and allows sufferers to be more objective.Since this conscious decision to change behaviour leads to rewiring the brain, Schwartz believes that this is proof of interactionism.
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Rick
post Mar 30, 2007, 10:21 AM
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It would be interesting to see if meditation is effective in clinical trials. One group could meditate daily in a controlled classroom environment, one group could exercise daily, or something, and the control group could do nothing, but be monitored periodically.
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lcsglvr
post Mar 30, 2007, 12:04 PM
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I'm sure there has been tests done like that. I almost guarantee it.

I just searched Google Scholar and there's a lot.
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