The extended fronto-striatal model of obsessive compulsive disorder: convergence from event-related potentials, neuropsychology and neuroimaging

Abstract

In this work, we explored convergent evidence supporting the fronto-striatal model of obsessive-compulsive disorder (FSMOCD) and the contribution of event-related potential (ERP) studies to this model. First, we considered minor modifications to the FSMOCD model based on neuroimaging and neuropsychological data. We noted the brain areas most affected in this disorder -anterior cingulate cortex (ACC), basal ganglia (BG), and orbito-frontal cortex (OFC) and their related cognitive functions, such as monitoring and inhibition. Then, we assessed the ERPs that are directly related to the FSMOCD, including the error-related negativity (ERN), N200, and P600. Several OCD studies present enhanced ERN and N2 responses during conflict tasks as well as an enhanced P600 during working memory (WM) tasks. Evidence from ERP studies (especially regarding ERN and N200 amplitude enhancement), neuroimaging and neuropsychological findings suggests abnormal activity in the OFC, ACC, and BG in OCD patients. Moreover, additional findings from these analyses suggest dorsolateral prefrontal and parietal cortex involvement, which might be related to executive function (EF) deficits. Thus, these convergent results suggest the existence of a self-monitoring imbalance involving inhibitory deficits and executive dysfunctions. OCD patients present an impaired ability to monitor, control, and inhibit intrusive thoughts, urges, feelings, and behaviors. In the current model, this imbalance is triggered by an excitatory role of the BG (associated with cognitive or motor actions without volitional control) and inhibitory activity of the OFC as well as excessive monitoring of the ACC to block excitatory impulses. This imbalance would interact with the reduced activation of the parietal-DLPC network, leading to executive dysfunction. ERP research may provide further insight regarding the temporal dynamics of action monitoring and executive functioning in OCD.

Electrophysiology of facilitation priming in obsessive–compulsive and panic disorders

“…N2-P3 components index neural resources allocated to cognitive functions including neural inhibition mechanisms, selective attention and context updating (Falkenstein, et al, 1999;Polich & Herbst, 2000). Parietal lobe activation is strongly related to sustained attention, vigilance and effortful attention (Melloni et al, 2012;Tamm, Menon, & Reiss, 2006). Numbers of reports of parietal lobe dysfunction and structural abnormalities in OCD, which correlate with symptom severity, are increasing (Carmona et al, 2007;Ciesielski, Hämäläinen, Lesnik, Geller, & Ahlfors, 2005;Kang et al, 2003;Kwon et al, 2003;Melloni, et al, 2012;Okasha et al, 2000;Szeszko et al, 2005).…”

“…Parietal lobe activation is strongly related to sustained attention, vigilance and effortful attention (Melloni et al, 2012;Tamm, Menon, & Reiss, 2006). Numbers of reports of parietal lobe dysfunction and structural abnormalities in OCD, which correlate with symptom severity, are increasing (Carmona et al, 2007;Ciesielski, Hämäläinen, Lesnik, Geller, & Ahlfors, 2005;Kang et al, 2003;Kwon et al, 2003;Melloni, et al, 2012;Okasha et al, 2000;Szeszko et al, 2005). Additionally, a recent meta-analysis of ERPs in panic disorder reported significantly reduced parietal amplitude of the P3 component across studies, thought to index reduced neural resources for context updating, selective attention and neural inhibition mechanisms (Howe, Pinto, & De Luca, 2014).…”

The Relationship Between Brain Regions and Neuropsychological Deficits In Obsessive-Compulsive Disorder

“…[8,20] WKET, kategori değiştirebilme yeteneğinin değerlendirilmesinde en sık kullanılan testtir. Bu testte frontal lob disfonksiyonu olan hastalar, genellikle ilk kategoriyi bulabilmekte ancak ikinci kategoriyi soyutlama yetenekleri sağlam olduğu halde oluşturamamaktadırlar.…”

“…Bu testte frontal lob disfonksiyonu olan hastalar, genellikle ilk kategoriyi bulabilmekte ancak ikinci kategoriyi soyutlama yetenekleri sağlam olduğu halde oluşturamamaktadırlar. [1,8,20] WKET testinde sadece 'toplam perseveratif olmayan hata sayısı' kategorisinde kötü performans gösterilmesi, OKB hastalarındaki klinik gözlemlerle de saptandığı şekilde, bir şeylerin yanlış gittiğine dair düşüncelerinin ve mükemmele ulaşma çabalarının nedeni olan 'hata saptama sisteminin' aşırı çalışmasının bir yansıması olabilir. [8,11] Bu bulgunun nörobiyolojik karşılığı ise insanda hata saptama va sağlama yeteneğini temsil eden kortikal alanlar olan orbitofrontal korteks ve anterior singulat korteksteki, nörogörüntüleme çalışmalarıyla da gösterilebilen aşırı aktivitenin varlığı olarak değerlendirilebilir.…”

“…[22] Obsesif kompulsif hastalarda işlevi azalan bilginin bellekten geri çağrılarak amaca uygun bir şekilde filtre edilmesi ortaya konulması ve bu sırada perseverasyon eğilimlerine engel olunması; prefrontal-striatal-talamik devrenin bir işlevi-dir. [20] Kontrollü sözel akıcılık testi (Controlled oral word association test-COWAT) ile testiyle sözel akıcılık ve zihinsel geri getirme işlevleri değerlendi-rilebilir. [36] OKB hastalarında sözel akıcılık ve zihinsel geri getirme işlevle-rinde ortaya konan performans kaybı, prefrontal korteksten başlayan prefrontal-striatal-talamik devrelerdeki işlev bozukluğuyla uyumludur.…”