Dr Shock MD PhD

The Functional Neuroanatomy of Depression

Dr Shock — Mon, 23 Nov 2009 07:39:49 +0000

Based on the results from functional neuroimaging studies, lesion patient studies and brain stimulation studies two important brain areas play an important role in the pathophysiology of depression. These two brain area s are the ventromedial prefrontal cortex and the dorsolateral prefrontal cortex. The ventromedial prefrontal cortex is depicted in red on the picture above and the dorsolateral prefrontalcortex in blue. The red part is in the forehead on the inside of the two brain half’s (hemispheres) (A) and the blue part is on the outside of the frontal part of both brain parts (B).

The funny thing is that with functional neuroimaging these centers show opposite changes during recovery. While depressed the ventromedial part of the brain is hyperactive and activity decreases during remission of depression and the dorsolateral part is hypoactive during depression and becomes more active during remission of symptoms. This makes it plausible that during depression there is an imbalance in activity between these two brain areas. However, from these studies it is not possible to point to cause and effect. These changes can be the cause of depression but it could also be a consequence of the disease.

Lesion studies demonstrate opposite effects of damage to these areas on depression: dorsolateral prefrontal cortex lesions exacerbate depressive symptoms whereas ventromedial prefrontal cortex lesions diminish depressive symptoms

The ventromedial prefrontal cortex plays an important role in negative affect. Damage to this brain area results in a reduction of negative affect such as guilt, shame, embarrassment and regret. Disturbances of activity of this brain area is believed to lead to these “depressed symptoms”.

The dorsolateral prefrontal cortex is important for “cognitive” and “executive” functions such as working memory, intention formation, goal-directed action, abstract reasoning, and attentional control. Moreover, this brain area is believed to be important for the regulation of negative affect. This brain area is important for the reappraisal/suppression of negative affect. A defect in this regulation of negative affect due to dysfunction of this brain area could be involved depression.

a large and growing body of research implicates the ventromedial and dorsolateral sectors of prefrontal cortex as key neural substrates underlying depression

In a recent study comparing nonrefractory depressed patients with refractory depressed patients and healthy controls the decreased activity in the prefrontal areas in the non refractory patients was mainly on the left frontal areas and in the refractory patients on both prefrontal areas (left and right, bilateral).

In the nonrefractory depressed patients the researchers also found over activity of the bilateral limbic system. They suggest that

Our study provides evidence of different neuropathophysiology in refractory depressive disorder and nonrefractory depressive disorder, which had been suggested in previous studies

This conclusion leaves the possibility that refractory depression might also be a more serious type of depression, due to lack of proper treatment or the consequence of more episodes resulting in brain changes or longer episode duration. More as a continuum instead of separate kind of depressions.

In a recent study published online in PLos ONE 37 patients with major depressive disorder (mean age 43.2 years), medication-free, in an acute depressive episode, and 37 healthy individuals were scanned with MRI scan. Following the MRI scan, 30 patients underwent treatment with the antidepressant medication fluoxetine or cognitive behavioural therapy (CBT). After treatment they were scanned again with MRI scans. Of the patients who subsequently achieved clinical remission with antidepressant medication, the whole brain structural neuroanatomy predicted 88.9% of the clinical response, prior to the initiation of treatment. Brain structure did not aid diagnosis. Changes after CBT were not related to remission status.

The structural neuroanatomy of depression shows high predictive potential for clinical response to antidepressant medication, while its diagnostic potential is more limited.

Koenigs, M., & Grafman, J. (2009). The functional neuroanatomy of depression: Distinct roles for ventromedial and dorsolateral prefrontal cortex Behavioural Brain Research, 201 (2), 239-243 DOI: 10.1016/j.bbr.2009.03.004
Lui, S., Parkes, L., Huang, X., Zou, K., Chan, R., Yang, H., Zou, L., Li, D., Tang, H., Zhang, T., Li, X., Wei, Y., Chen, L., Sun, X., Kemp, G., & Gong, Q. (2009). Depressive Disorders: Focally Altered Cerebral Perfusion Measured with Arterial Spin-labeling MR Imaging Radiology, 251 (2), 476-484 DOI: 10.1148/radiol.2512081548
Costafreda, S., Chu, C., Ashburner, J., & Fu, C. (2009). Prognostic and Diagnostic Potential of the Structural Neuroanatomy of Depression PLoS ONE, 4 (7) DOI: 10.1371/journal.pone.0006353

Training Pilots to Land on Skis

Dr Shock — Sun, 22 Nov 2009 20:48:24 +0000

Just came back from Oxford UK, flying with some heavy wind and rain, peace of cake compared to these guys.

Heidi Cullen visits the crew of the 109th Airlift Wing in Greenland to learn the challenges of flying and landing an airplane in the Arctic snow

Read more: http://www.time.com/time/video/player/0,32068,51162540001_0,00.html#ixzz0XcigUcOq

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Abolish The Off Side Rule in Soccer? Never!

Dr Shock — Sun, 22 Nov 2009 08:07:12 +0000

Dr Shock is a soccer fan, he’s Dutch, no wonder. One of the out most important topics discussed about the game is Off side. So much discussion is going on that people hope new technology will help with judgment of the off side rule. During a soccer game the referee as well as his two assistants are there to judge about off side or not. Since no one is perfect these call as reasons for debate way longer than the duration of the game.

Unfortunately recent research has shown that the human being and the technological media are both physically and technically incapable of detecting an offside position in real time, in zero milliseconds. The key of the offside position is a physical problem: time.

Some people believe football is a matter of life and death, I am very disappointed with that attitude. I can assure you it is much, much more important than that.

Thank god, we can still keep on talking about off side or not, technology isn’t going to spoil this fun.

No related posts.

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How to create a Great PowerPoint Presentation

Dr Shock — Sat, 21 Nov 2009 08:04:41 +0000

How to Create a Great PowerPoint – Take 2.0 from Alvin Trusty on Vimeo

This is a very long video but it addresses some useful tips and tricks how to make nice slides in powerpoint. It starts with a ballroom presentation or a presentation without bullet points. This will get you updated on death with powerpoint and how to create slides for different audiences. The biggest part is on how to create those slides. This topic is usually not covered in the books on presentations.

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Lying on Adolescents’ Blogs

Dr Shock — Thu, 19 Nov 2009 07:22:02 +0000

Adolescents are the most truthful about school and their life on blogs, whereas they are the least truthful about intimate topics such as family life and partnership. Adolescents present their personal information on blogs very truthfully. A girls of fourteen is really a girl of fourteen.

During adolescence forming an identity is a key developmental task in this period. Identity in the sense of a coherent sense of the self. This developmental phase is crucial to questions such as who am i and it’s the phase in which adolescents experiment with different social roles. A blog is an extraordinary place to experiment with identity and social roles and to experiment with relationships online.

Fifty percent of adolescents show their photograph on their blogs11; 54% present personal data, such as age, name, or domicile; and 61% present contact information, such as e-mail address, instant messaging username, and phone number.

From the popular press it’s usually reported that adolescents do not use their true identity online. In a recent published research the authors approached 120 adolescents with blogs, adolescents between 13 and 17 years old with at least 3 months of active blogging were sent a survey via e-mail, instant messages, or blogs. The data were collected in 2 steps, first an online questionnaire with questions about real-life identity and questions about the frequency of lying about important aspects and questions about the usual topics on their blog.

Next the participants real life identity was verified by a competition when they participated. 12 of them would be selected and given a price. Their real identity was checked for the price winning and they were informed that when they lied about their identity they would not receive the price. Therefore, adolescents knew that if they wanted to win a prize, they had to fill in the questionnaire truthfully, regardless of whether or not they lie on their blog.

From 120, 112 questionnaires were returned, 90% (101) were female, 9,8% (9) were male. Adolescents reported minimal lying on their blogs. Significantly more lying on their blog was done by the younger adolescents (13-14) compared to the older adolescents (15-17).

The adolescents admitted lying on their blogs the most in the questionnaire about their sexual experience. Interviews were conducted with 10 randomly selected participants whose answers were then verified. None of them had lied about their identity. Only one of 10 at random selected participants came to the meeting on her own and that she was in the upper age range (17 years old). Adolescents are not necessarily irresponsible as far as the relationship between the online and offline world is concerned.

From this and other research it can be concluded that:

For adolescents, the Internet tends to serve as an extension of the real-life identity rather than as a place where special identities are created. ……..blogs are not perceived as personal diaries but more as an instrument for communication, and thereby an extension of the blogger’s real-life identity

Do you lie on your blog?

Blinka, L., & Smahel, D. (2009). Fourteen Is Fourteen and a Girl Is a Girl: Validating the Identity of Adolescent Bloggers CyberPsychology & Behavior DOI: 10.1089/cpb.2009.0044

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Self Diagnosis in General Practice

Dr Shock — Wed, 18 Nov 2009 08:11:41 +0000

With the Internet many patients visit the GP after extensive searches on the Internet. They usually have an idea about what’s wrong with them. In a recent publication in the British Medical Journal I found a recent article on this subject. In visits to a GP patients the self diagnosis (also called self labelling) was responsible for initiating a diagnosis in 18% of consultations.

Few studies have been done on the accuracy of self diagnosis. These studies suggest that recurrent urinary tract infection, recurrent anterior uveitis, schistosomiasis, and head lice can all be self diagnosed correctly.

There are also studies suggesting that certain conditions are often misdiagnosed by patients. Examples from the literature search include pregnancy, vaginal candidiasis, and scabies.

Patients with recurrent conditions and chronic diseases are often experts about their illness. A collaborative approach within a traditional diagnostic framework with these patients yield the most satisfying results for all.

Prevalence, previous episodes, general awareness of condition, and patient education affect the accuracy of self diagnosis. Self diagnosis should always undergo subsequent refinement and challenge.

Excellent article, should have been free access.

Goyder, C., McPherson, A., & Glasziou, P. (2009). Self diagnosis BMJ, 339 (nov11 1) DOI: 10.1136/bmj.b4418

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Chocolate Craving and the Menstrual Cycle

Dr Shock — Tue, 17 Nov 2009 07:29:09 +0000

About chocolate craving:

Research suggests that up to 97% of women and 68% of men experience food cravings. Chocolate is the most common one of the craved foods, typically high calorie.
A number of situations have been shown to experimentally increase cravings of chocolate consumption. For example,chocolate abstinence, stress and exposure to chocolate cues increase urges to eat chocolate.
A 15 min bout of brisk walking, equivalent to ‘fairly light’ intensity exercise, reduces chocolate cravings, with moderate effect sizes, during and for at least 10 min following exercise cessation.
Higher intensity or longer bouts of physical activity may lead to compensatory dietary behavior and/or chocolate cravings.
Cravings are generally more prevalent in women than men and decrease somewhat with age, with 100% of young women and 70% of young men craving any food or drink, compared to 66% of older women and 62% of older men.
In American women, about half of cravings for chocolate occur perimenstrually with a marked increase in craving beginning a few days before and extending into the first few days of menses.
Chocolate craving is not uniquely associated with the menstrual cycle, compared to a range of other sweet and savory foods.
There is no significant link between levels of estradiol and the number, frequency, or types of cravings.
Exogenous administration of progesterone does not significantly reduce perimenstrual cravings.
Reduction of chocolate craving when chocolate is ingested results from the sensory experience of chocolate, and not of pharmacological origine.

From these observations it can be concluded that instead of it’s sensory characteristics responsible for chocolate craving, the hormonal changes during the menstrual cycle could possibly play an important role in chocolate craving.
A recent study investigated the chocolate craving in women post menopause to assess the presence, prevalence, temporal patterns, and perceived triggers for chocolate craving. Previous research has shown that there is no direct link between perimenstrual hormone levels and chocolate craving in women. Another factor linking chocolate craving and menstruation could be the stress during this period or an:

a socially sanctioned ‘‘excuse’’ to indulge in a highly calorically dense food, and thus comes to be used by women as a plausible and acceptable reason to consume chocolate.

The researchers randomly selected alumnae from the University of Pennsylvania from three cohorts (’46/’47, ‘62/’63, and ‘84/’85). They were sent anonymous questionnaires of which 35% were returned (n=280). The participants provided demographic information, regularity of periods, menopause status, use of hormonal birth control or hormone replacement therapy, liking for chocolate, craving for chocolate and it’s temporal pattern.

Pre-menopausal women reported a significant but small decrease in prevalence of chocolate cravings compared to postmenopausal women. The decrease is only 13.4% and thereby much smaller than a 38% drop predicted by a purely hormonal explanation. Of post-menopausal women very few reported of prior, pre-menopause chocolate cravings that were thought to be related to the menstrual cycle. This could be due to a lack of recall of any perimenstrual cravings premenopausally.

The latter assumption is supported by the fact that reports of past perimenstrual cravings are low in the 65-year-old women but absent entirely in the 80-year-old women.

Since hormonal changes don’t explain a minor drop in chocolate craving in women over the life cycle the authors sugest another explantion for the perimenstrual chocolate craving:

a major effect of low perimenstrual hormone levels may be to produce mood changes or dysphoria, which may prompt chocolate consumption as a reward or a means of coping.

What do you think?

Hormes, J., & Rozin, P. (2009). Perimenstrual chocolate craving. What happens after menopause? Appetite, 53 (2), 256-259 DOI: 10.1016/j.appet.2009.07.003

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The Neuroscience of Music Enjoyment and Depression

Dr Shock — Mon, 16 Nov 2009 07:35:44 +0000

When feeling down good music can cheer you up. But when depressed, I mean clinically depressed, can you enjoy music? How is music enjoyment processed by the brain and how is this influenced by depression?

All participants of this study enjoyed their favorite music more than the neutral music and depressed patients didn’t differ from the healthy subjects in scores for enjoyment of favorite music nor on the difference between the favorite and neutral music. On the fMRI the depressed patients showed less activation of parts of the brain: the medial orbital frontal cortex, the nucleus accumbens and the ventral striatum. In the pictures above you can see the areas more active in healthy controls compared to depressed patients.

These brain regions are known to be involved in reward processing in healthy controls. In depression the medial orbital frontal cortex shows dysfunction mainly hyperactivity. The lower difference in activation in depressed patients between neutral and favorite music listening can be explained by tonic hyperactivation of this region with consequent lack of signal change between the two conditions.

The nucleus accumbens and the ventral striatum also areas of reward processing are known to be affected during depression. Since the subjective rating of enjoyment of their favorite music was not significantly different the depressed patients differ in the processing of rewarding stimuli.

How was this study done?

investigated the use of an fMRI, passive musiclistening paradigm to evaluate the neurophysiological response to enjoying participant-specific, instrumental ‘favorite music’ versus ‘neutral music’ in healthy (n=15) and depressed patients (n=16). This paradigm took 10–12 min in the scanner and was not confounded by active decision making once scanning began.

Conclusion
From this research it’s concluded that in depressed patients the neurophysiological reward response is different from healthy subjects. depressed patients showed significant deficits in activation of the most important reward areas of the brain.
Can’t explain the fact that depressed patients scored their subjective liking of there favorite music comparable to healthy subjects. Remains a mystery to me since one of the characteristics of depression is the lack of experiencing pleasure at large and often also from music. Any suggestions?

Osuch, E., Bluhm, R., Williamson, P., Théberge, J., Densmore, M., & Neufeld, R. (2009). Brain activation to favorite music in healthy controls and depressed patients NeuroReport, 20 (13), 1204-1208 DOI: 10.1097/WNR.0b013e32832f4da3

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Dr Shock MD PhD

The Functional Neuroanatomy of Depression

Training Pilots to Land on Skis

Abolish The Off Side Rule in Soccer? Never!

How to create a Great PowerPoint Presentation

Recommended reading: From Statistics to Fort Hood

Lying on Adolescents’ Blogs

Self Diagnosis in General Practice

Chocolate Craving and the Menstrual Cycle

The Neuroscience of Music Enjoyment and Depression

Recommended Reading This Week: Empathy and Neurostimulation