Volumetric MRI study of key brain regions implicated in obsessive–compulsive disorder

AbstractObsessive-compulsive disorder (OCD) is a chronic psychiatric illness and 1 of the most common anxiety disorders with the prevalence of 3%. Although its pathogenesis remains unclear, the traditional model focused on alternations in the serotonin system. Selective serotonin reuptake inhibitors provide the most effective treatment; however, as much as 40–60% of patients do not respond to antidepressants therapy. Thus, attention has shifted towards other neurotransmitter systems and related neuroanatomical structures. Recently, there is extensive evidence showing a key role of glutamate pathways abnormalities within the cortico-striatal-thalamo-cortical circuitry and temporal lobes in OCD pathogenesis. In this review, we link together the existent neuroanatomical, neurophysiological, and neuropsychological evidence to argue for potential benefits of adjuvant treatment with glutamatergic agents, especially memantine. By a targeted de-excitation effect on the glutamatergic system in the temporal lobes and connected brain regions, memantine might further alleviate OCD symptoms. This effect should be even more pronounced in certain subtypes of patients with specific cognitive deficits and maladaptive compensatory memory processes (e.g., checkers).

Download Full-text

Task-Based Functional Neuroimaging Studies of Obsessive-Compulsive Disorder: A Hypothesis-Driven Review

10.1093/med/9780190228163.003.0022 ◽

2017 ◽

Author(s):

M. M Vaghi ◽

T. W Robbins

Keyword(s):

Obsessive Compulsive Disorder ◽

Functional Neuroimaging ◽

Neural Substrates ◽

Brain Regions ◽

Cognitive Tasks ◽

Functional Magnetic Resonance ◽

Obsessive Compulsive ◽

Compulsive Disorder ◽

Directed Learning ◽

Experimental Level

The neurobiological basis of Obsessive Compulsive Disorder (OCD) has been probed using functional magnetic resonance in hundreds of studies over three decades. This complex literature can be syntheized using a theory-informed approach. At a theoretical level, separable, independent, constructs of relevance to OCD have been identified. At the experimental level, extensive translational evidence has provided an account that relates specific brain systems to these neuropsychological constructs. Parallels between neural substrates implicated in OCD and functional specialization of different brain regions suggest that abnormalities within fronto-striatal circuitry impinge on executive functions, and their subcomponents, and on goal-directed learning and habit formation. In OCD, this is reflected at a functional level in patterns of abnormal activations in particular brain regions during specific cognitive tasks. However, many issues still need to be addressed. The authors suggest that the experimental context might represent a pivotal variable that should be taken into account.

Download Full-text

Functional Neuroimaging Studies in Obsessive-Compulsive Disorder: Overview and Synthesis

10.1093/med/9780190228163.003.0021 ◽

2017 ◽

Author(s):

Brian P. Brennan ◽

Scott L. Rauch

Keyword(s):

Obsessive Compulsive Disorder ◽

Functional Neuroimaging ◽

Critical Role ◽

Resting State Fmri ◽

Brain Regions ◽

Obsessive Compulsive ◽

Compulsive Disorder ◽

Additional Information ◽

Positron Emission ◽

Cortical Circuit

Studies using functional neuroimaging have played a critical role in the current understanding of the neurobiology of obsessive-compulsive disorder (OCD). Early studies using positron emission tomography (PET) identified a core cortico-striatal-thalamo-cortical circuit that is dysfunctional in OCD. Subsequent studies using behavioral paradigms in conjunction with functional magnetic resonance imaging (fMRI) have provided additional information about the neural substrates underlying specific psychological processes relevant to OCD. More recently, studies utilizing resting state fMRI have identified abnormal functional connectivity within intrinsic brain networks including the default mode and frontoparietal networks in OCD patients. Although these studies, as a whole, clearly substantiate the model of cortico-striatal-thalamo-cortical circuit dysfunction in OCD and support the continued investigation of neuromodulatory treatments targeting these brain regions, there is also growing evidence that brain regions outside this core circuit, particularly frontoparietal regions involved in cognitive control processes, may also play a significant role in the pathophysiology of OCD.

Download Full-text

Cortico-thalamo-striatal circuit components’ volumes and their correlations differ significantly among patients with obsessive–compulsive disorder: a case–control MRI study

Psychiatry and Clinical Psychopharmacology ◽

10.1080/24750573.2019.1583481 ◽

2019 ◽

Vol 29 (2) ◽

pp. 162-170 ◽

Cited By ~ 1

Author(s):

Bilge Dogan ◽

Ersen Ertekin ◽

Figen Tunali Turkdogan ◽

Cagdas Oyku Memis ◽

Levent Sevincok

Keyword(s):

Obsessive Compulsive Disorder ◽

Case Control ◽

Obsessive Compulsive ◽

Compulsive Disorder ◽

Circuit Components ◽

Mri Study

Download Full-text

New Methods of Brain Stimulation Are Improving Research and Therapy in Obsessive-Compulsive Disorder

CNS Spectrums ◽

10.1017/s1092852900024986 ◽

2000 ◽

Vol 5 (S4) ◽

pp. 12-17 ◽

Cited By ~ 3

Author(s):

Mark S. George

Keyword(s):

Obsessive Compulsive Disorder ◽

Brain Stimulation ◽

Functional Neuroimaging ◽

Brain Regions ◽

Current Status ◽

Obsessive Compulsive ◽

New Techniques ◽

Compulsive Disorder ◽

The Past ◽

The Brain

AbstractOver the past decade, new functional neuroimaging tools have enabled researchers to identify the specific brain regions involved in obsessive-compulsive disorder (OCD). More recently, researchers have perfected several new techniques for stimulating the brain. With some exceptions, these new brain stimulation techniques are regionally specific and less invasive than older methods. As a class, these “somatic interventions” build on prior neuroanatomic information about OCD. This article reviews the past and current status of these brain stimulation methodologies, which promise to revolutionize neuropsychiatric research and therapy over the next 10 to 20 years. As the brain circuits in OCD and the pharmacology within those circuits become better understood, these brain stimulation techniques hold particular promise in helping to understand and perhaps treat OCD.

Download Full-text