Neurosurgical targets for compulsivity: what can we learn from acquired brain lesions?

Obsessive-compulsive disorder induced by donepezil in a patient with Alzheimer's disease

Background

Donepezil, an acetylcholinesterase inhibitor commonly used to treat Alzheimer's disease (AD), is generally well tolerated. There have been no previous reports on donepezil-induced obsessive-compulsive disorder (OCD).

Case Presentation

The patient, a retired man in his 70s diagnosed with AD, displayed OCD symptoms following donepezil initiation, exacerbating post-stroke-specifically, a cerebral infarction in the right posterior limb of the internal capsule. Remarkably, the symptoms abated upon discontinuation of donepezil.

Conclusion

Caution should be exercised when using donepezil in patients with a history of stroke.

Obsessive-compulsive disorder after traumatic injury to the right frontal and left temporal lobes: A case report

Background

Obsessive-compulsive disorder (OCD) is a common neuropsychiatric disorder affecting many behaviors in daily life. Hyperactivity of the fronto-striato-thalamic circuit via the orbitofrontal cortex (OFC) is assumed to play a major role in the pathophysiology of OCD; however, its pathogenesis is not fully understood. Several reports have described the development of OCD after traumatic brain injury (TBI); however, the pathogenesis of post-TBI OCD remains unknown. Moreover, patients with TBI often have a variety of sequelae, including cognitive dysfunction and mood disorders, which make the diagnosis and treatment of OCD more complex.

Case presentation

We report the case of a 17-year-old Japanese male who developed OCD after traffic trauma. The patient developed a fear of contamination and checking compulsion after injuring his right OFC and left temporal lobe when he ran into a running truck during a suicide attempt. We believe that the patient's fear of contamination can be diagnosed as true post-TBI OCD. However, his memory impairment was significant, and we considered his checking compulsion to be strongly influenced by cognitive dysfunction due to TBI. We attempted behavioral therapy for OCD; however, sufficient results were not achieved because of the interference from the sequelae of TBI.

Conclusion

It is not rare for OCD symptoms to appear after TBI. Differentiating the OCD symptoms induced by brain injury or cognitive dysfunction associated with TBI is important to determine a treatment strategy.

An ecological approach to identify distinct neural correlates of disinhibition in frontotemporal dementia

Disinhibition is a core symptom of many neurodegenerative diseases, particularly frontotemporal dementia, and is a major cause of stress for caregivers. While a distinction between behavioural and cognitive disinhibition is common, an operational definition of behavioural disinhibition is still missing. Furthermore, conventional assessment of behavioural disinhibition, based on questionnaires completed by the caregivers, often lacks ecological validity. Therefore, their neuroanatomical correlates are non-univocal. In the present work, we used an original behavioural approach in a semi-ecological situation to assess two specific dimensions of behavioural disinhibition: compulsivity and social disinhibition. First, we investigated disinhibition profile in patients compared to controls. Then, to validate our approach, compulsivity and social disinhibition scores were correlated with classic cognitive tests measuring disinhibition (Hayling Test) and social cognition (mini-Social cognition & Emotional Assessment). Finally, we disentangled the anatomical networks underlying these two subtypes of behavioural disinhibition, taking in account the grey (voxel-based morphometry) and white matter (diffusion tensor imaging tractography). We included 17 behavioural variant frontotemporal dementia patients and 18 healthy controls. We identified patients as more compulsive and socially disinhibited than controls. We found that behavioural metrics in the semi-ecological task were related to cognitive performance: compulsivity correlated with the Hayling test and both compulsivity and social disinhibition were associated with the emotion recognition test. Based on voxel-based morphometry and tractography, compulsivity correlated with atrophy in the bilateral orbitofrontal cortex, the right temporal region and subcortical structures, as well as with alterations of the bilateral cingulum and uncinate fasciculus, the right inferior longitudinal fasciculus and the right arcuate fasciculus. Thus, the network of regions related to compulsivity matched the "semantic appraisal" network. Social disinhibition was associated with bilateral frontal atrophy and impairments in the forceps minor, the bilateral cingulum and the left uncinate fasciculus, regions corresponding to the frontal component of the "salience" network. Summarizing, this study validates our semi-ecological approach, through the identification of two subtypes of behavioural disinhibition, and highlights different neural networks underlying compulsivity and social disinhibition. Taken together, these findings are promising for clinical practice by providing a better characterisation of inhibition disorders, promoting their detection and consequently a more adapted management of patients.

Temporal variability of regional intrinsic neural activity in drug-naïve patients with obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) displays alterations in regional brain activity represented by the amplitude of low-frequency fluctuation (ALFF), but the time-varying characteristics of this local neural activity remain to be clarified. We aimed to investigate the dynamic changes of intrinsic brain activity in a relatively large sample of drug-naïve OCD patients using univariate and multivariate analyses. We applied a sliding-window approach to calculate the dynamic ALFF (dALFF) and compared the difference between 73 OCD patients and age- and sex-matched healthy controls (HCs). We also utilized multivariate pattern analysis to determine whether dALFF could differentiate OCD patients from HCs at the individual level. Compared with HCs, OCD patients exhibited increased dALFF mainly within regions of the cortical-striatal-thalamic-cortical (CSTC) circuit, including the bilateral dorsal anterior cingulate cortex, medial prefrontal cortex and striatum, and right dorsolateral prefrontal cortex (dlPFC). Decreased dALFF was identified in the bilateral inferior parietal lobule (IPL), posterior cingulate cortex, insula, fusiform gyrus, and cerebellum. Moreover, we found negative correlations between illness duration and dALFF values in the right IPL and between dALFF values in the left cerebellum and Hamilton Depression Scale scores. Furthermore, dALFF can distinguish OCD patients from HCs with the most discriminative regions located in the IPL, dlPFC, middle occipital gyrus, and cuneus. Taken together, in the current study, we demonstrated a characteristic pattern of higher variability of regional brain activity within the CSTC circuits and lower variability in regions outside the CSTC circuits in drug-naïve OCD patients.

Executive functions and insight in OCD: a comparative study

BACKGROUND

Around 25 to 30% of patients with obsessive-compulsive disorder (OCD) do not respond to treatment. These patients have the longest duration of disease and the worst prognosis. Following years of research on this topic, insight has emerged as a potential explanation for this therapeutic resistance. Therefore, it has become important to characterize OCD patients with poor insight. Few studies have focused on the neuropsychological and cognitive characteristics of these patients.

METHODS

To help fill this gap, we divided 57 patients into two groups, one with good insight and the other with poor insight, assessed their neuropsychological functions-through a Rey's figure test, a California verbal learning test, a Toulouse-Piéron test and a Wisconsin Card Sorting Test (WCST)-and compared the results with those of a paired control group.

RESULTS

The statistical analysis, with a significance level of 95%, revealed differences in the executive function tests, and particularly in the WCST (p ≤ 0.001) and trail-making-test (TMT A/B) (p = 0.002).

CONCLUSIONS

These differences suggest that the neuropsychological profile of poor-insight patients is different from their good-insight counterparts, emphasize the role played by the executive functions in insight and highlights the need for more accurate neurocognitive research and treatment.

Diogenes syndrome in dementia: a case report

BACKGROUND

Diogenes syndrome is a neurobehavioural syndrome characterised by domestic squalor, hoarding and lack of insight. It is an uncommon but high-mortality condition, often associated with dementia.

AIMS

To describe the clinical features and treatment of Diogenes syndrome secondary to behavioural variant frontotemporal dementia (bvFTD).

METHOD

We describe a case of bvFTD in a 77-year-old man presenting with Diogenes syndrome.

RESULTS

The patient's medical and psychiatric histories were unremarkable, but in recent years he had begun packing his flat with 'art pieces'. Mental state examination revealed confabulation and more structured delusions. Neuropsychological evaluation outlined an impairment in selective attention and letter verbal fluency, but no semantic impairment, in the context of an overall preserved mental functioning. Brain magnetic resonance imaging and positron emission tomography (PET) with fluorodeoxyglucose showed mild bilateral temporo-insular atrophy and hypometabolism in the left-superior temporal gyrus respectively. An amyloid PET scan and genetic analysis covering the dementia spectrum were normal. A diagnosis of bvFTD was made.

CONCLUSIONS

The clinical framing of behavioural symptoms of dementia such as hoarding poses a diagnostic challenge. This case illustrates the importance of a deeper understanding of Diogenes syndrome, leading to timelier diagnosis and effective therapeutic strategies.

Increased cerebellar-default-mode network connectivity at rest in obsessive-compulsive disorder

Abnormalities of the cerebellum and default-mode network (DMN) in patients with obsessive-compulsive disorder (OCD) have been widely reported. However, alterations of reciprocal functional connections between the cerebellum and DMN at rest in OCD remain unclear. Forty patients with OCD and 38 gender-, age-, and education-matched healthy controls (HCs) underwent resting-state functional magnetic resonance imaging scan. Seed-based functional connectivity (FC) and support vector machine (SVM) were applied to analyze the imaging data. Compared with HCs, patients with OCD exhibited increased FCs between the left Crus I-left superior medial prefrontal cortex (MPFC) and between the right Crus I-left superior MPFC, left middle MPFC, and left middle temporal gyrus (MTG). A significantly negative correlation was observed between the right Crus I-left MTG connectivity and the Yale-Brown Obsessive-Compulsive Scale compulsion subscale scores in the OCD group (r = - 0.476, p = 0.002, Bonferroni corrected). SVM classification analysis indicated that a combination of the left Crus I-left superior MPFC connectivity and the right Crus I-left middle MPFC connectivity can be used to discriminate patients with OCD from HCs with a sensitivity of 85.00%, specificity of 68.42%, and accuracy of 76.92%. Our study highlights the contribution of the cerebellar-DMN connectivity in OCD pathophysiology and provides new findings to OCD research.

The Psychopharmacology of Obsessive-Compulsive Disorder: A Preclinical Roadmap

This review evaluates current knowledge about obsessive-compulsive disorder (OCD), with the goal of providing a roadmap for future directions in research on the psychopharmacology of the disorder. It first addresses issues in the description and diagnosis of OCD, including the structure, measurement, and appropriate description of the disorder and issues of differential diagnosis. Current pharmacotherapies for OCD are then reviewed, including monotherapy with serotonin reuptake inhibitors and augmentation with antipsychotic medication and with psychologic treatment. Neuromodulatory therapies for OCD are also described, including psychosurgery, deep brain stimulation, and noninvasive brain stimulation. Psychotherapies for OCD are then reviewed, focusing on behavior therapy, including exposure and response prevention and cognitive therapy, and the efficacy of these interventions is discussed, touching on issues such as the timing of sessions, the adjunctive role of pharmacotherapy, and the underlying mechanisms. Next, current research on the neurobiology of OCD is examined, including work probing the role of various neurotransmitters and other endogenous processes and etiology as clues to the neurobiological fault that may underlie OCD. A new perspective on preclinical research is advanced, using the Research Domain Criteria to propose an adaptationist viewpoint that regards OCD as the dysfunction of a normal motivational system. A systems-design approach introduces the security motivation system (SMS) theory of OCD as a framework for research. Finally, a new perspective on psychopharmacological research for OCD is advanced, exploring three approaches: boosting infrastructure facilities of the brain, facilitating psychotherapeutic relearning, and targeting specific pathways of the SMS network to fix deficient SMS shut-down processes. SIGNIFICANCE STATEMENT: A significant proportion of patients with obsessive-compulsive disorder (OCD) do not achieve remission with current treatments, indicating the need for innovations in psychopharmacology for the disorder. OCD may be conceptualized as the dysfunction of a normal, special motivation system that evolved to manage the prospect of potential danger. This perspective, together with a wide-ranging review of the literature, suggests novel directions for psychopharmacological research, including boosting support systems of the brain, facilitating relearning that occurs in psychotherapy, and targeting specific pathways in the brain that provide deficient stopping processes in OCD.

Evidence for Distinct Forms of Compulsivity in the SAPAP3 Mutant-Mouse Model for Obsessive-Compulsive Disorder

The specific mechanisms underlying compulsive behavior in obsessive-compulsive disorder (OCD) are unknown. It has been suggested that such compulsivity may have its origin in cognitive dysfunction such as impaired processing of feedback information, received after the completion of goal-directed actions. The signal attenuation (SA) task models such a processing deficit in animals by attenuating the association strength between food reward and audiovisual feedback (signal) presented after performance of an operant response. The compulsive-like responding resulting from SA is well characterized in rats, but was so far not established in mice, a species for which powerful genetic OCD models exist. Thus, first, we demonstrate that the SA task can be implemented in mice and show that attenuation of reward-associated response feedback produces similar behavior in C57BL/6 mice as previously reported in rats. Second, we tested the hypothesis that SAPAP3 knock-out mice (SAPAP3^-/-), prone to exhibit several OCD-like abnormalities including excessive grooming, show enhanced compulsive-like behavior in the SA task compared with their wild-type (WT) littermates. However, task-related compulsivity measures in SAPAP3^-/- and WT did not yield significant differences, neither following SA nor during “regular” extinction of operant behavior. Thus, compulsive-like instrumental behavior following feedback distortion was not potentiated in compulsively grooming mice, implicating specifically that (1) a general deficit in feedback processing is not related to excessive grooming in SAPAP3^-/- and (2) different manifestations of compulsivity may be driven by independent mechanisms.

Differences in obsessive-compulsive symptom dimensions between patients with epilepsy with obsessive-compulsive symptoms and patients with OCD

Clinical correlates of obsessive-compulsive symptoms (OCS) were evaluated in 100 adult consecutive outpatients with epilepsy, using the Obsessive-Compulsive Inventory (OCI-R), Beck Depression Inventory (BDI), Dissociative Experiences Scale (DES-II), and the Schizotypal Personality Questionnaire (SPQ). Dimensional Yale-Brown Obsessive-Compulsive Scale (DY-BOCS) was applied to determine the types and severity of OCS to the 45 patients with epilepsy who were over 21 points on the OCI-R scale and 30 patients who were with diagnosed obsessive-compulsive disorder (OCD) among the patients in the psychiatry outpatient clinic, as a control group. As a result, it was found that patients with epilepsy with OCS tend to have more symmetry/exactness obsessions and compulsions, whereas patients with OCD had significantly more contamination/cleaning and aggressiveness obsessions and compulsions. In addition, OCS was found to be significantly higher in temporal lobe epilepsy (TLE) and extratemporal epilepsy than generalized epilepsy. However, OCS were correlated with depression, dissociation, and schizotypy in patients with epilepsy, while only depression was predictive when regression analysis was performed for OCS. This study is the first study to compare patients with OCD with patients with epilepsy in terms of the nature of OCS and first identified the differences in OCS dimensions between patients with epilepsy with OCS and patients with OCD.

Hoarding and obsessive-compulsive behaviours in frontotemporal dementia: Clinical and neuroanatomic associations

BACKGROUND

Hoarding and obsessive-compulsive behaviours (OCB) are well documented symptoms in frontotemporal dementia (FTD). While contemporary models consider hoarding and obsessive-compulsive disorder distinct, the related behaviours have not been separately examined in patients with FTD, and the neuroanatomical correlates of hoarding in patients with FTD have not been previously examined (American Psychiatric Association, 2013; Grisham and Baldwin, 2015; Mataix-Cols et al., 2010).

METHODS

Patients with FTD who were evaluated between 2004 and 2018 at our centre were included. Cortical thickness and subcortical volumetric analyses were completed on available T1 high resolution anatomic scans using FreeSurfer.

RESULTS

Eighty-seven patients met inclusion criteria, and 49 had scans available for quantitative MRI volumetric analysis. New hoarding behaviours were present in 29% of patients and were more common in the semantic variant subtype of FTD, while 49% of individuals had new or increased OCB. Hoarding behaviours were associated with decreased thickness in a factor comprised of left temporal, insular and anterior cingulate cortices. The presence of OCB was predicted by reduced cortical thickness and volumes in a factor comprised of the anterior cingulate and subcortical volumes in the bilateral amygdala and hippocampus. OCB were associated with greater right temporal cortical thickness in comparison to patients with hoarding.

DISCUSSION

The association of the semantic variant with hoarding, together with the observed associations between left temporal atrophy and hoarding indicate that degeneration of the left temporal lobe has a role in the emergence of hoarding in FTD. As in current models of Hoarding disorder and Obsessive-Compulsive disorder, our results suggest that in patients with FTD, hoarding and OCB are clinically and anatomically partially dissociable phenomenon. The results may also help to further elucidate the cognitive processes and neural networks contributing to Hoarding disorder and Obsessive-Compulsive disorder in persons without dementia.

Defining Compulsive Behavior

Compulsive tendencies are a central feature of problematic human behavior and thereby are of great interest to the scientific and clinical community. However, no consensus exists about the precise meaning of ‘compulsivity,’ creating confusion in the field and hampering comparison across psychiatric disorders. A vague conceptualization makes compulsivity a moving target encompassing a fluctuating variety of behaviors, which is unlikely to improve the new dimension-based psychiatric or psychopathology approach. This article aims to help progress the definition of what constitutes compulsive behavior, cross-diagnostically, by analyzing different definitions in the psychiatric literature. We searched PubMed for articles in human psychiatric research with ‘compulsive behavior’ or ‘compulsivity’ in the title that focused on the broader concept of compulsivity—returning 28 articles with nine original definitions. Within the definitions, we separated three types of descriptive elements: phenomenological, observational and explanatory. The elements most applicable, cross-diagnostically, resulted in this definition: Compulsive behavior consists of repetitive acts that are characterized by the feeling that one ‘has to’ perform them while one is aware that these acts are not in line with one’s overall goal. Having a more unified definition for compulsive behavior will make its meaning precise and explicit, and therefore more transferable and testable across clinical and non-clinical populations.

Diagnostic neuroimaging markers of obsessive-compulsive disorder: Initial evidence from structural and functional MRI studies

As of yet, no diagnostic biomarkers are available for obsessive-compulsive disorder (OCD), and its diagnosis relies entirely upon the recognition of behavioural features assessed through clinical interview. Neuroimaging studies have shown that various brain structures are abnormal in OCD patients compared to healthy controls. However, the majority of these results are based on average differences between groups, which limits diagnostic usage in clinical practice. In recent years, a growing number of studies have applied multivariate pattern analysis (MVPA) techniques on neuroimaging data to extract patterns of altered brain structure, function and connectivity typical for OCD. MVPA techniques can be used to develop predictive models that extract regularities in data to classify individual subjects based on their diagnosis. In the present paper, we reviewed the literature of MVPA studies using data from different imaging modalities to distinguish OCD patients from controls. A systematic search retrieved twelve articles that fulfilled the inclusion and exclusion criteria. Reviewed studies have been able to classify OCD diagnosis with accuracies ranging from 66% up to 100%. Features important for classification were different across imaging modalities and widespread throughout the brain. Although studies have shown promising results, sample sizes used are typically small which can lead to high variance of the estimated model accuracy, cohort-specific solutions and lack of generalizability of findings. Some of the challenges are discussed that need to be overcome in order to move forward toward clinical applications.

Compulsivity in Alcohol Use Disorder and Obsessive Compulsive Disorder: Implications for Neuromodulation

Alcohol use Disorder (AUD) is one of the leading causes of morbidity and mortality worldwide. The progression of the disorder is associated with the development of compulsive alcohol use, which in turn contributes to the high relapse rate and poor longer term functioning reported in most patients, even with treatment. While the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) defines AUD by a cluster of symptoms, parsing its heterogeneous phenotype by domains of behavior such as compulsivity may be a critical step to improve outcomes of this condition. Still, neurobiological underpinnings of compulsivity need to be fully elucidated in AUD in order to better design targeted treatment strategies. In this manuscript, we review and discuss findings supporting common mechanisms between AUD and OCD, dissecting the construct of compulsivity and focusing specifically on characteristic disruptions in habit learning and cognitive control in the two disorders. Finally, neuromodulatory interventions are proposed as a probe to test compulsivity as key pathophysiologic feature of AUD, and as a potential therapy for the subgroup of individuals with compulsive alcohol use, i.e., the more resistant stage of the disorder. This transdiagnostic approach may help to destigmatize the disorder, and suggest potential treatment targets across different conditions.

Deep Brain Stimulation Programming 2.0: Future Perspectives for Target Identification and Adaptive Closed Loop Stimulation

Deep brain stimulation has developed into an established treatment for movement disorders and is being actively investigated for numerous other neurological as well as psychiatric disorders. An accurate electrode placement in the target area and the effective programming of DBS devices are considered the most important factors for the individual outcome. Recent research in humans highlights the relevance of widespread networks connected to specific DBS targets. Improving the targeting of anatomical and functional networks involved in the generation of pathological neural activity will improve the clinical DBS effect and limit side-effects. Here, we offer a comprehensive overview over the latest research on target structures and targeting strategies in DBS. In addition, we provide a detailed synopsis of novel technologies that will support DBS programming and parameter selection in the future, with a particular focus on closed-loop stimulation and associated biofeedback signals.

Neurobehavioral Abnormalities Associated with Executive Dysfunction after Traumatic Brain Injury

Objective: This article will address how anomalies of executive function after traumatic brain injury (TBI) can translate into altered social behavior that has an impact on a person’s capacity to live safely and independently in the community.

Method: Review of literature on executive and neurobehavioral function linked to cognitive ageing in neurologically healthy populations and late neurocognitive effects of serious TBI. Information was collated from internet searches involving MEDLINE, PubMed, PyscINFO and Google Scholar as well as the authors’ own catalogs.

Conclusions: The conventional distinction between cognitive and emotional-behavioral sequelae of TBI is shown to be superficial in the light of increasing evidence that executive skills are critical for integrating and appraising environmental events in terms of cognitive, emotional and social significance. This is undertaken through multiple fronto-subcortical pathways within which it is possible to identify a predominantly dorsolateral network that subserves executive control of attention and cognition (so-called cold executive processes) and orbito-frontal/ventro-medial pathways that underpin the hot executive skills that drive much of behavior in daily life. TBI frequently involves disruption to both sets of executive functions but research is increasingly demonstrating the role of hot executive deficits underpinning a wide range of neurobehavioral disorders that compromise relationships, functional independence and mental capacity in daily life.

Deep Brain Stimulation of the H Fields of Forel Alleviates Tics in Tourette Syndrome

The current rationale for target selection in Tourette syndrome revolves around the notion of cortico-basal ganglia circuit involvement in the pathophysiology of the disease. However, despite extensive research, the ideal target for deep brain stimulation (DBS) is still under debate, with many structures being neglected and underexplored. Based on clinical observations and taking into account the prevailing hypotheses of network processing in Tourette syndrome, we chose the fields of Forel, namely field H1, as a target for DBS. The fields of Forel constitute the main link between the striatopallidal system and the thalamocortical network, relaying pallidothalamic projections from core anatomical structures to the thalamic ventral nuclear group. In a retrospective study we investigated two patients suffering from chronic, medically intractable Tourette syndrome who underwent bilateral lead implantation in field H1 of Forel. Clinical scales revealed significant alleviation of tics and comorbid symptoms, namely depression and anxiety, in the postoperative course in both patients.

Obsessive-Compulsive Disorder Associated with Posterior Cranial Fossa Meningioma

We report here a patient in whom the effects of a cerebellum mass may have led to development of obsessive-compulsive disorder (OCD). A 33-year-old woman showed symptoms of OCD, including obsessive worry about infection from tainted blood and repetitive confirmation, which worsened during pregnancy. She had comprehension in regard to her illness and no evidence of cognitive dysfunction and did not meet other DSM-5 criteria such as depression. One month after giving childbirth, the symptoms worsened, while headache and dizziness also developed. The Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) score was 34. The patient was examined for a headache and a posterior cranial fossa meningioma was found. Following resection of the meningioma, the OCD symptoms were remarkably reduced (Y-BOCS score 10). There is only one previous report of pure OCD associated with a cerebellar mass and the present findings should help to elucidate the mechanism.

Meta-analytic investigations of common and distinct grey matter alterations in youths and adults with obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) is a disabling illness with onset generally in childhood. OCD-youths differ from OCD-adults with regard to gender distribution, comorbidity patterns and treatment options. However, little is known about the neural correlate differences underpin those two populations. The current meta-analysis summarizes voxel based morphometry findings to elucidate whether differences of neural correlates exist between these two populations. Both OCD-youths and OCD-adults demonstrated greater striatal volume and smaller prefrontal grey matter volume (GMV). However, smaller GMV in left visual cortex was observed in OCD-youths only, while smaller GMV in anterior cingulate gyrus and greater GMV in cerebellum were demonstrated only in OCD-adults. Meta-regression showed greater GMV in left putamen was most prominent in samples with higher percentages of medicated OCD-adults. Our findings confirmed the most consistent GMV alterations in OCD were in prefrontal-striatal circuitry. Besides, other regions may involve at different developmental stages including deficits of visual cortex in OCD-youths and abnormalities of limbic-cerebellar circuit in OCD-adults. Medication effect may be more pronounced in the striatum, especially the putamen.

Validity of Quinpirole Sensitization Rat Model of OCD: Linking Evidence from Animal and Clinical Studies

Obsessive-compulsive disorder (OCD) is a neuropsychiatric disorder with 1–3% prevalence. OCD is characterized by recurrent thoughts (obsessions) and repetitive behaviors (compulsions). The pathophysiology of OCD remains unclear, stressing the importance of pre-clinical studies. The aim of this article is to critically review a proposed animal model of OCD that is characterized by the induction of compulsive checking and behavioral sensitization to the D2/D3 dopamine agonist quinpirole. Changes in this model have been reported at the level of brain structures, neurotransmitter systems and other neurophysiological aspects. In this review, we consider these alterations in relation to the clinical manifestations in OCD, with the aim to discuss and evaluate axes of validity of this model. Our analysis shows that some axes of validity of quinpirole sensitization model (QSM) are strongly supported by clinical findings, such as behavioral phenomenology or roles of brain structures. Evidence on predictive validity is contradictory and ambiguous. It is concluded that this model is useful in the context of searching for the underlying pathophysiological basis of the disorder because of the relatively strong biological similarities with OCD.

Computational Modeling and Neuroimaging Techniques for Targeting during Deep Brain Stimulation

Accurate surgical localization of the varied targets for deep brain stimulation (DBS) is a process undergoing constant evolution, with increasingly sophisticated techniques to allow for highly precise targeting. However, despite the fastidious placement of electrodes into specific structures within the brain, there is increasing evidence to suggest that the clinical effects of DBS are likely due to the activation of widespread neuronal networks directly and indirectly influenced by the stimulation of a given target. Selective activation of these complex and inter-connected pathways may further improve the outcomes of currently treated diseases by targeting specific fiber tracts responsible for a particular symptom in a patient-specific manner. Moreover, the delivery of such focused stimulation may aid in the discovery of new targets for electrical stimulation to treat additional neurological, psychiatric, and even cognitive disorders. As such, advancements in surgical targeting, computational modeling, engineering designs, and neuroimaging techniques play a critical role in this process. This article reviews the progress of these applications, discussing the importance of target localization for DBS, and the role of computational modeling and novel neuroimaging in improving our understanding of the pathophysiology of diseases, and thus paving the way for improved selective target localization using DBS.

Compulsivity in obsessive-compulsive disorder and addictions

Compulsive behaviors are driven by repetitive urges and typically involve the experience of limited voluntary control over these urges, a diminished ability to delay or inhibit these behaviors, and a tendency to perform repetitive acts in a habitual or stereotyped manner. Compulsivity is not only a central characteristic of obsessive-compulsive disorder (OCD) but is also crucial to addiction. Based on this analogy, OCD has been proposed to be part of the concept of behavioral addiction along with other non-drug-related disorders that share compulsivity, such as pathological gambling, skin-picking, trichotillomania and compulsive eating. In this review, we investigate the neurobiological overlap between compulsivity in substance-use disorders, OCD and behavioral addictions as a validation for the construct of compulsivity that could be adopted in the Research Domain Criteria (RDoC). The reviewed data suggest that compulsivity in OCD and addictions is related to impaired reward and punishment processing with attenuated dopamine release in the ventral striatum, negative reinforcement in limbic systems, cognitive and behavioral inflexibility with diminished serotonergic prefrontal control, and habitual responding with imbalances between ventral and dorsal frontostriatal recruitment. Frontostriatal abnormalities of compulsivity are promising targets for neuromodulation and other interventions for OCD and addictions. We conclude that compulsivity encompasses many of the RDoC constructs in a trans-diagnostic fashion with a common brain circuit dysfunction that can help identifying appropriate prevention and treatment targets.

From Thought to Action: How the Interplay Between Neuroscience and Phenomenology Changed Our Understanding of Obsessive-Compulsive Disorder

The understanding of obsessive-compulsive disorder (OCD) has evolved with the knowledge of behavior, the brain, and their relationship. Modern views of OCD as a neuropsychiatric disorder originated from early lesion studies, with more recent models incorporating detailed neuropsychological findings, such as perseveration in set-shifting tasks, and findings of altered brain structure and function, namely of orbitofrontal corticostriatal circuits and their limbic connections. Interestingly, as neurobiological models of OCD evolved from cortical and cognitive to sub-cortical and behavioral, the focus of OCD phenomenology also moved from thought control and contents to new concepts rooted in animal models of action control. Most recently, the proposed analogy between habitual action control and compulsive behavior has led to the hypothesis that individuals suffering from OCD may be predisposed to rely excessively on habitual rather than on goal-directed behavioral strategies. Alternatively, compulsions have been proposed to result either from hyper-valuation of certain actions and/or their outcomes, or from excessive uncertainty in the monitoring of action performance, both leading to perseveration in prepotent actions such as washing or checking. In short, the last decades have witnessed a formidable renovation in the pathophysiology, phenomenology, and even semantics, of OCD. Nevertheless, such progress is challenged by several caveats, not least psychopathological oversimplification and overgeneralization of animal to human extrapolations. Here we present an historical overview of the understanding of OCD, highlighting converging studies and trends in neuroscience, psychiatry and neuropsychology, and how they influenced current perspectives on the nosology and phenomenology of this disorder.

Hyper-influence of the orbitofrontal cortex over the ventral striatum in obsessive-compulsive disorder

Dysfunction of the fronto-striato-thalamic circuit routing through the orbitofrontal cortex (OFC) is thought to play the main role in the pathophysiology of obsessive-compulsive disorder (OCD). Repetitious stimulation of the OFC-ventral striatum (VS) projections in mice has been shown to increase the firing of the postsynaptic VS cells and the frequency of OCD-like symptoms. Moreover, increased functional connectivity (FC) between the OFC and the VS has been reported in patients with OCD. While FC is a synchronous, non-directed correlation, the directed influence between these brain regions remains unclear in patients with OCD. We obtained resting state functional magnetic resonance imaging scans from 37 non-medicated patients with OCD and 38 matched healthy volunteers, and calculated bivariative voxel-wise Granger Causality (GC) to and from three striatal regions of interest (ROI) using a blind deconvolution procedure. Additionally, we conducted multivariative GC analysis to determine if the effect revealed by the bivariative voxel-wise GCA is mediated by another seed ROI. We found a significant hyper-influence of the OFC over the VS of subjects with OCD (p<.05, corrected). Multivariative GC analysis confirmed this effect (p<.05, corrected) and that it was not mediated by another brain area within the striatum. This is the first study investigating the directed influence of the fronto-striato-thalamic loop in non-medicated patients with OCD. We confirmed the hyperactive connection from the OFC to the VS that is consistent with previous animal studies. These findings provide evidence for the more detailed pathophysiology of OCD.

Using Optogenetics to Dissect the Neural Circuits Underlying OCD and Related Disorders

Clinical and preclinical studies have uncovered substantial evidence that dysfunction in cortico-striatal-thalamo-cortical (CSTC) loops central to the selection of action strategies may underlie obsessive compulsive disorder (OCD) symptoms. In human OCD, data suggest that the balance between selections of habitual versus goal-directed action strategies is disrupted, with concomitant hyperactivation of CSTC regions associated with these strategies. Preclinical lesion and inactivation studies of homologous CSTC regions in rodents have shed light on how sub-regions of the frontal cortex and striatum can have dissociable effects on the exhibition of goal-directed or habitual behavior. However, these traditional methods lack the precision necessary to dissect the exact projections and cell types underlying these behaviors. It is essential to uncover this information to begin to determine how disruption in these circuits may lead to disease pathology. Here, we summarize several recent studies that utilize optogenetics, a technique that allows stimulation or inhibition of specific neural projections and cell types using light, to further understand the contribution of CSTC activity to both action selection and the OCD-relevant behavior of perseverative grooming. Based on these experiments and findings in human OCD patients, we argue that OCD symptoms may not only be associated with an enhancement of habitual behavior, but also with aberrant recruitment of goal-directed neural circuits. We also discuss the current status of translating optogenetic technology to primates, as well as how findings in rodents may help inform treatment of patients suffering from OCD and related disorders.

Late-onset obsessive-compulsive disorder associated with left cerebellar lesion

The onset of obsessive-compulsive disorder (OCD) after age 50 is rare and generally related to an organic etiology. An involvement of fronto-striatal circuits has been strongly suggested, whereas cerebellum remains so far scarcely explored. We present here the description of a "pure" late-onset OCD associated with a cerebellar lesion, neither comorbid with other mental disorders nor with neurological syndromes. To our knowledge, this condition was not previously described in literature. The patient is a 62-year-old woman who developed a late-onset OCD associated with a left cerebellar lesion due to an arachnoid cyst in the left posterior fossa. We debate the possible role of the cerebellar lesion in favoring a transition from a predisposing liability (namely an obsessive-compulsive personality disorder and a depressive status) to the onset of OCD in this woman.

A Prospective Longitudinal Study of Perceived Infant Outcomes at 18-24 Months: Neural and Psychological Correlates of Parental Thoughts and Actions Assessed during the First Month Postpartum

The first postpartum months constitute a critical period for parents to establish an emotional bond with their infants. Neural responses to infant-related stimuli have been associated with parental sensitivity. However, the associations among these neural responses, parenting, and later infant outcomes for mothers and fathers are unknown. In the current longitudinal study, we investigated the relationships between parental thoughts/actions and neural activation in mothers and fathers in the neonatal period with infant outcomes at the toddler stage. At the first month postpartum, mothers (n = 21) and fathers (n = 19) underwent a neuroimaging session during which they listened to their own and unfamiliar baby's cry. Parenting-related thoughts/behaviors were assessed by interview twice at the first month and 3-4 months postpartum and infants' socioemotional outcomes were reported by mothers and fathers at 18-24 months postpartum. In mothers, higher levels of anxious thoughts/actions about parenting at the first month postpartum, but not at 3-4 months postpartum, were associated with infant's low socioemotional competencies at 18-24 months. Anxious thoughts/actions were also associated with heightened responses in the motor cortex and reduced responses in the substantia nigra to own infant cry sounds. On the other hand, in fathers, higher levels of positive perception of being a parent at the first month postpartum, but not at 3-4 months postpartum, were associated with higher infant socioemotional competencies at 18-24 months. Positive thoughts were associated with heightened responses in the auditory cortex and caudate to own infant cry sounds. The current study provides evidence that parental thoughts are related to concurrent neural responses to their infants at the first month postpartum as well as their infant's future socioemotional outcome at 18-24 months. Parent differences suggest that anxious thoughts in mothers and positive thoughts in fathers may be the targets for parenting-focused interventions very early postpartum.

Neurobiological model of obsessive-compulsive disorder: evidence from recent neuropsychological and neuroimaging findings

Obsessive-compulsive disorder (OCD) was previously considered refractory to most types of therapeutic intervention. There is now, however, ample evidence that selective serotonin reuptake inhibitors and behavior therapy are highly effective methods for treatment of OCD. Furthermore, recent neurobiological studies of OCD have found a close correlation between clinical symptoms, cognitive function, and brain function. A large number of previous neuroimaging studies using positron emission tomography, single-photon emission computed tomography or functional magnetic resonance imaging (fMRI) have identified abnormally high activities throughout the frontal cortex and subcortical structures in patients with OCD. Most studies reported excessive activation of these areas during symptom provocation. Furthermore, these hyperactivities were decreased after successful treatment using either selective serotonin reuptake inhibitors or behavioral therapy. Based on these findings, an orbitofronto-striatal model has been postulated as an abnormal neural circuit that mediates symptomatic expression of OCD. On the other hand, previous neuropsychological studies of OCD have reported cognitive dysfunction in executive function, attention, nonverbal memory, and visuospatial skills. Moreover, recent fMRI studies have revealed a correlation between neuropsychological dysfunction and clinical symptoms in OCD by using neuropsychological tasks during fMRI. The evidence from fMRI studies suggests that broader regions, including dorsolateral prefrontal and posterior regions, might be involved in the pathophysiology of OCD. Further, we should consider that OCD is heterogeneous and might have several different neural systems related to clinical factors, such as symptom dimensions. This review outlines recent neuropsychological and neuroimaging studies of OCD. We will also describe several neurobiological models that have been developed recently. Advanced findings in these fields will update the conventional biological model of OCD.

Hungry for reward: How can neuroscience inform the development of treatment for Anorexia Nervosa?

Dysfunctional reward from the pursuit of thinness presents a major challenge to recovery from Anorexia Nervosa (AN). We explore the neuroscientific basis of aberrant reward in AN, with the aim of generating novel hypotheses for translational investigation, and elucidate disease mechanisms to inform the development of targeted interventions. Relevant neuroimaging and behavioural studies are reviewed. These suggest that altered eating in AN may be a consequence of aberrant reward processing combined with exaggerated cognitive control. We consider evidence that such aberrant reward processing is reflected in the compulsive behaviours characterising AN, with substantial overlap in the neural circuits implicated in reward processing and compulsivity. Drawing on contemporary neuroscientific theories of substance dependence, processes underpinning the shift from the initially rewarding pursuit of thinness to extreme and compulsive weight control behaviours are discussed. It is suggested that in AN, weight loss behaviour begins as overtly rewarding, goal-directed and positively reinforced, but over time becomes habitual and increasingly negatively reinforced. Excessive habit formation is suggested as one underlying mechanism perpetuating compulsive behaviour. Ongoing research into the behavioural and neural basis of aberrant reward in AN is required to further elucidate mechanisms. We discuss clinical and transdiagnostic implications, and propose that future treatment innovation may benefit from the development of novel interventions targeting aberrant reward processing in AN.

Obsessions appear after the removal a brain tumor in the right frontal lobe

A series of case reports and neuroimaging research points to the underlying neuropathological substrate for obsessive-compulsive disorder (OCD) and the underlying associations between OCD and areas of the frontal lobe. We report a patient wherein the onset of OCD occurred after resection of meningioma of the right frontal lobe and who was treated successfully with paroxetine hydrochloride. We suggest that the onset of secondary (organic) OCD is associated with the frontal lobe, and we propose that the origin of obsessions is located in the right frontal lobe.

New developments in human neurocognition: clinical, genetic, and brain imaging correlates of impulsivity and compulsivity

Impulsivity and compulsivity represent useful conceptualizations that involve dissociable cognitive functions, which are mediated by neuroanatomically and neurochemically distinct components of cortico-subcortical circuitry. The constructs were historically viewed as diametrically opposed, with impulsivity being associated with risk-seeking and compulsivity with harm-avoidance. However, they are increasingly recognized to be linked by shared neuropsychological mechanisms involving dysfunctional inhibition of thoughts and behaviors. In this article, we selectively review new developments in the investigation of the neurocognition of impulsivity and compulsivity in humans, in order to advance our understanding of the pathophysiology of impulsive, compulsive, and addictive disorders and indicate new directions for research.