Functional magnetic resonance imaging study of frontal lobe activation during word generation in obsessive-compulsive disorder

Disruption of effective connectivity from the dorsolateral prefrontal cortex to the orbitofrontal cortex by negative emotional distraction in obsessive-compulsive disorder

BACKGROUND

Obsessive-compulsive disorder (OCD) has been associated with abnormal cognitive and emotional functions and these dysfunctions may be dependent on the disruption of dynamic interactions within neuronal circuits associated with emotion regulation. Although several studies have shown the aberrant cognitive-affective processing in OCD patients, little is known about how to characterize effective connectivity of the disrupted neural interactions. In the present study, we applied effective connectivity analysis using dynamic causal modeling to explore the disturbed neural interactions in OCD patients.

METHOD

A total of 20 patients and 21 matched healthy controls performed a delayed-response working memory task under emotional or non-emotional distraction while undergoing functional magnetic resonance imaging.

RESULTS

During the delay interval under negative emotional distraction, both groups showed similar patterns of activations in the amygdala. However, under negative emotional distraction, the dorsolateral prefrontal cortex (DLPFC) and the orbitofrontal cortex (OFC) exhibited significant differences between groups. Bayesian model averaging indicated that the connection from the DLPFC to the OFC was negatively modulated by negative emotional distraction in patients, when compared with healthy controls (p < 0.05, Bonferroni-corrected).

CONCLUSIONS

Exaggerated recruitment of the DLPFC may induce the reduction of top-down prefrontal control input over the OFC, leading to abnormal cortico-cortical interaction. This disrupted cortico-cortical interaction under negative emotional distraction may be responsible for dysfunctions of cognitive and emotional processing in OCD patients and may be a component of the pathophysiology associated with OCD.

A longitudinal, event-related potential pilot study of adult obsessive-compulsive disorder with 1-year follow-up

AIM

Earlier brain imaging research studies have suggested that brain abnormalities in obsessive-compulsive disorder (OCD) normalize as clinical symptoms improve. However, although many studies have investigated event-related potentials (ERPs) in patients with OCD compared with healthy control subjects, it is currently unknown whether ERP changes reflect pharmacological and psychotherapeutic effects. As such, the current study examined the neurocognitive components of OCD to elucidate the pathophysiological abnormalities involved in the disorder, including the frontal-subcortical circuits.

METHODS

The Yale-Brown Obsessive-Compulsive Scale was used to evaluate 14 adult patients with OCD. The present study also included ten age-, sex-, and IQ-matched controls. The P300 and mismatch negativity (MMN) components during an auditory oddball task at baseline for both groups and after 1 year of treatment for patients with OCD were measured.

RESULTS

Compared with controls, P300 amplitude was attenuated in the OCD group at Cz and C4 at baseline. Pharmacotherapy and psychotherapy treatment for 1 year reduced OCD symptomology. P300 amplitude after 1 year of treatment was significantly increased, indicating normalization compared with baseline at Fz, Cz, C3, and C4. We found no differences in P300 latency, MMN amplitude, or MMN latency between baseline and after one year of treatment.

CONCLUSION

ERPs may be a useful tool for evaluating pharmacological and cognitive behavioral therapy in adult patients with OCD.

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.

Neuromodulation for obsessive-compulsive disorder

This article describes the basis for neuromodulation procedures for obsessive-compulsive disorder (OCD) and summarizes the literature on the efficacy of these interventions. Discussion includes neural circuitry underlying OCD pathology, the history and types of ablative procedures, the targets and modalities used for neuromodulation, and future therapeutic directions.

Dynamic cooperation and competition between brain systems during cognitive control

The human brain is characterized by a remarkable ability to adapt its information processing based on current goals. This ability, which is encompassed by the psychological construct of cognitive control, involves activity throughout large-scale, specialized brain systems that support segregated functions at rest and during active task performance. Based on recent research, we propose an account in which control functions rely on transitory changes in patterns of cooperation and competition between neural systems. This account challenges current conceptualizations of control as relying on segregated or antagonistic activity of specialized brain systems. Accordingly, we argue that the study of transitory task-based interactions between brain systems is critical to understanding the flexibility of normal cognitive control and its disruption in pathological conditions.

The functional magnetic resonance imaging-based verbal fluency test in obsessive-compulsive disorder

Clinical use of functional magnetic resonance imaging (fMRI) in obsessive-compulsive disorder (OCD) is limited by a relative absence of fMRI task development, standardization, and normative performance databases. We investigated the fMRI-based verbal fluency test (f-VFT) by quantitatively evaluating brain activation patterns in OCD participants (8 females and 4 males) compared with a normative database (16 females and 16 males). At the group level, OCD participants and references had highly similar activation in left-hemisphere language regions, including the precentral/premotor cortex, thalamus, basal ganglia, and inferior frontal gyrus/frontal operculum. At the interindividual level, however, the OCD group had highly variable activation patterns in the dorsal and ventral regions of the pre-supplementary motor area (pre-SMA) that may correspond with differences in demographic and clinical variables. Further, there were significant correlations in the OCD participants between pre-SMA dorsal and ventral activation and between dorsal pre-SMA activation and perfectionism. Our findings suggest considerable functional anatomical overlap in left-hemisphere language regions between OCD participants and references but significantly higher pre-SMA interindividual variability in OCD compared to the reference group that may be relevant in clinical fMRI application and the theoretical understanding of OCD.

Functional neuroimaging in obsessive-compulsive disorder

BACKGROUND AND AIM

Obsessive-compulsive disorder (OCD) is a severe, highly prevalent and chronically disabling psychiatric disorder that usually emerges during childhood or adolescence. This paper aims to review the literature on functional neuroimaging in OCD, analysing the reported dysfunctional connectivity in the corticostriatothalamocortical circuitry.

METHOD

This study included papers published in peer-reviewed journals dealing with functional imaging in OCD.

RESULTS

Striatal dysfunction, mainly of the caudate nucleus, leads to inefficient thalamic gating, resulting in hyperactivity within the orbitofrontal cortex (intrusive thoughts) and the anterior cingulate cortex (non-specific anxiety). Compulsions consist of ritualistic behaviours performed to recruit the inefficient striatum and neutralise unwanted thoughts and anxiety. Functional neuroimaging findings are discussed against the background of specific cognitive impairments, mainly regarding visuospatial processing, executive functioning and motor speed. Cognitive deficits are partial and specific, matching imaging data.

CONCLUSIONS

Several studies have targeted brain regions hypothesised to be involved in the pathogenesis of OCD, showing the existence of dysfunctional connectivity in the corticostriatothalamocortical circuitry. Improvements in spatial resolution of neuroimaging techniques may contribute to a better understanding of the neurocircuitry of OCD and other anxiety disorders.

Enhanced brain responsiveness during active emotional face processing in obsessive compulsive disorder

OBJECTIVES. The abnormal processing of emotional stimuli is common to a variety of psychiatric disorders. Specifically, patients with prominent anxiety symptoms generally overreact to emotional cues, which has been linked to increased amygdala activation. However, in OCD, enhanced responses are predominantly obtained using disease-specific stimuli and preferentially involve frontostriatal systems. METHODS. We assessed 21 OCD patients and 21 healthy controls with fMRI during an emotional face-processing paradigm involving active response generation to test for alterations in both brain activation and task-induced functional connectivity of the frontal cortex, the amygdala and the fusiform face area. RESULTS. OCD patients showed significantly greater activation of "face-processing" regions including the amygdala, fusiform gyrus and dorsolateral prefrontal cortex. The reciprocal connectivity between face-processing regions was enhanced in OCD. Importantly, we detected significant correlations between patients' clinical symptom severity and both task-related region activation and network functional connectivity. CONCLUSIONS. The results suggest that OCD patients may show enhanced brain responsiveness during emotional face-processing when tasks involve active response generation. Our findings diverge from previously described alterations in anxiety disorders, as patients showed enhanced amygdala-prefrontal connectivity as opposed to negative reciprocal interaction. This pattern would appear to be disorder-specific and was significantly related to obsessive-compulsive symptom severity.

Functional alterations of large-scale brain networks related to cognitive control in obsessive-compulsive disorder

OBJECTIVES

Neuroimaging studies have consistently implicated alterations of the basal ganglia and orbitofrontal cortex in the pathophysiology of OCD, however, recent work also emphasizes more diffuse patterns of brain alteration as occurring in this disorder. The goal of this study was to extend such observations by investigating large-scale brain functional network correlates of cognitive-control performance in OCD patients.

EXPERIMENTAL DESIGN

We combined fMRI with a validated task of cognitive control and a multivariate statistical method to assess multiple functional networks encompassing broad task-relevant cortical regions in OCD patients and matched controls. Functional networks of interest were targeted a priori and the groups were compared in terms of the spatiotemporal profile of network responses (functional connectivity) during the task performance in a data-driven manner.

PRINCIPAL OBSERVATIONS

Task performance was equivalent in both groups and each distinct network demonstrated strong overlap in its general response during task. However, significant differences in functional connectivity were also observed between groups that appeared driven by specific phases of task performance. Such differences were most pronounced during rest-task transitions and mainly involved dorsal anterior cingulate and insular cortices within the paralimbic network. Relative heightened functional connectivity of insula in patients during task correlated with a measure of patients' state anxiety.

CONCLUSIONS

Our findings provide a novel functional imaging characterization of brain network alterations associated with cognitive-control in OCD. Additionally, these findings raise questions about the role of patients' arousal states on the performance of cognitive imaging tasks that are otherwise assumed to be emotionally neutral.

Evidence for specific cognitive deficits in visual information processing in patients with OCD compared to patients with unipolar depression

OBJECTIVE

Neuropsychological studies comparing cognitive performance in patients suffering from Obsessive-Compulsive Disorder (OCD) or Major Depressive Disorder (MDD) revealed deficits in the domains of verbal fluency and viso-motor speed/set shifting in both groups. Spatial working memory deficits, however, have been identified as specific markers of OCD. As yet, it has not been substantiated whether deficits in visual organization and complex visual memory are also specific to OCD and are not shared by MDD.

METHOD

Test performance in seven cognitive domains was assessed in 40 OCD patients, 20 MDD patients, and 40 healthy controls. Patient groups were matched according to severity of depressive symptoms.

RESULTS

Deficits shared by both patient groups, as compared to controls, were found in delayed spatial recall and verbal fluency while verbal memory was normal in both patient groups. Only patients with OCD, but not MDD patients were impaired in the domains visual memory, viso-motor speed/set shifting, visual organization, and problem solving. In addition, OCD patients differed significantly from MDD subjects in visual organization and problem solving. Visual organization scores correlated significantly with severity of current compulsions in the OCD group (r=-.324).

CONCLUSIONS

OCD patients demonstrate difficulties in visual organization and mental manipulation of complex visual material, which are not accounted for by depressive symptoms and which constitute a specific cognitive deficit of the disorder.

Variations in the shape of the frontobasal brain region in obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) emerges during childhood through young adulthood coinciding with the late phases of postnatal brain development when fine remodeling of brain anatomy takes place. Previous research has suggested the existence of subtle anatomical alterations in OCD involving focal volume variations in different brain regions including the frontal lobes and basal ganglia. We investigated whether anatomical changes might also involve variations in the shape of the frontobasal region. A total of 101 OCD patients and 101 control subjects were examined using magnetic resonance imaging. A cross-sectional image highly representative of frontal-basal ganglia anatomy was selected in each individual and 25 reliable anatomical landmarks were identified to assess shape changes. A pixel-wise morphing approach was also used to dynamically illustrate the findings. We found significant group differences for overall landmark position and for most individual landmarks delimiting the defined frontobasal region. OCD patients showed a deformation pattern involving shortening of the anterior-posterior dimension of the frontal lobes and basal ganglia, and enlargement of cerebrospinal fluid spaces around the frontal opercula. In addition, we observed significant correlation of brain tissue shape variation with frontal sinus size. Identification of a global change in the shape of the frontobasal region may further contribute to characterizing the nature of brain alterations in OCD. The coincidence of brain shape variations with morphological changes in the frontal sinus indicates a potential association of OCD to late development disturbances, as the frontal sinus macroscopically emerges during the transition between childhood and adulthood.

Working memory dysfunction in obsessive-compulsive disorder: a neuropsychological and functional MRI study

Previous neuropsychological studies indicate that OCD subtypes such as checking rituals might be associated with a working memory deficit. On the other hand, functional neuroimaging studies found functional abnormalities of the frontal cortex and subcortical structures in OCD. Combined with functional imaging method, we applied neuropsychological batteries to demonstrate a working memory deficit in OCD by comparison with normal controls. In addition, working memory and brain activation were further examined with symptom-based analysis. Forty patients with OCD and 25 normal controls were examined using neuropsychological tests including the WAIS-R, WCST, WMS-R, and R-OCFT and functional MRI (fMRI) during the N-back task including 0- and 2-back task. On fMRI, the brain regions activated during the performance and the differences in the activation between patients and controls were identified. Additional analyses of severity and subtypes were conducted by using Y-BOCS severity score, symptom-checklist and Leckman's four-factor model, respectively. On the neuropsychological tests, the OCD patients had significantly lower scores on the delayed recall section of the WMS-R and the immediate recall section of the R-OCFT compared to the controls. On fMRI, the patients showed greater activation in the right dorsolateral prefrontal cortex (DLPFC), left superior temporal gyrus (STG), left insula, and cuneus during two-back task compared to the controls. Right orbitofrontal cortex activity showed a significant positive correlation with Y-BOCS scores in OCD. Furthermore, patients with obsessions/checking rituals (n=10) showed severer memory deficits and decreased activity in the postcentral gyrus than patients with cleanliness/washing rituals (n=14). In conclusion, we found neuropsychological dysfunction and brain abnormalities in OCD. Furthermore, our results suggested that symptom severity and symptom subtype such as obsessions/checking might affect neuropsychological dysfunction and related brain activities.

The neural bases of obsessive-compulsive disorder in children and adults

Functional imaging studies have reported with remarkable consistency hyperactivity in the orbitofrontal cortex (OFC), anterior cingulate cortex (ACC), and caudate nucleus of patients with obsessive-compulsive disorder (OCD). These findings have often been interpreted as evidence that abnormalities in cortico-basal ganglia-thalamo-cortical loops involving the OFC and ACC are causally related to OCD. This interpretation remains controversial, however, because such hyperactivity may represent either a cause or a consequence of the symptoms. This article analyzes the evidence for a causal role of these loops in producing OCD in children and adults. The article first reviews the strong evidence for anatomical abnormalities in these loops in patients with OCD. These findings are not sufficient to establish causality, however, because anatomical alterations may themselves be a consequence rather than a cause of the symptoms. The article then reviews three lines of evidence that, despite their own limitations, permit stronger causal inferences: the development of OCD following brain injury, pediatric autoimmune neuropsychiatric disorders associated with streptococcal infection, and neurosurgical lesions that attenuate OCD. Converging evidence from these various lines of research supports a causal role for the cortico-basal ganglia-thalamo-cortical loops that involve the OFC and ACC in the pathogenesis of OCD in children and adults.

Cerebral activation in children and adolescents with obsessive-compulsive disorder before and after treatment: a functional MRI study

BACKGROUND

Structural and functional fronto-striatal abnormalities are involved in the pathophysiology of obsessive-compulsive disorder (OCD). The aims of the present study were: (a) to investigate possible regional brain dysfunction in premotor cortico-striatal activity in drug-naïve children and adolescents with OCD; (b) to correlate brain activation with severity of obsessive-compulsive symptomatology; and (c) to detect possible changes in brain activity after pharmacological treatment.

METHOD

Twelve children and adolescents (age range 7-18 years; seven male, five female) with DSM-IV obsessive-compulsive disorder and twelve healthy subjects matched for age, sex and intellectual level were studied. Functional magnetic resonance imaging data were obtained during the performance of simple and complex sequences.

RESULTS

Comparing the complex motor condition with the simple control condition, both patients and controls showed a pattern of cerebral activation involving the fronto-parietal cortex and basal ganglia. Compared with controls, OCD patients presented significantly higher brain activation bilaterally in the middle frontal gyrus. After 6 months of pharmacological treatment and with clear clinical improvement, activation in the left insula and left putamen decreased significantly.

CONCLUSION

In a paediatric OCD sample that was treatment naïve and without another psychiatric disorder we showed hyperactivation of the circuits that mediate symptomatic expression of OCD. The cerebral activation decreases after treatment and clinical improvement.

The differential impact of executive attention dysfunction on episodic memory in obsessive-compulsive disorder patients with checking symptoms vs. those with washing symptoms

Neuropsychological studies of obsessive-compulsive disorder (OCD) have pointed to memory and attention deficits among its sufferers, but these reports have largely ignored the possibility that cognitive disturbances may vary across OCD clinical subtypes, or that their interactions may differ between subtypes. The purpose of the present study was to determine whether "checkers" and "washers" demonstrate differences in their memory and executive attention function. Fifty-three outpatients with primary DSM-IV diagnosis of OCD with typical checking (n=27) or washing (n=26) rituals participated in the study. Patients were administered the Wechsler Memory Scale-Revised and a comprehensive neuropsychological battery to assess executive attention function. Various neuropsychological tests were then subjected to factor analysis. Neuropsychological test results and obtained factor scores were compared between "washers" and "checkers". Effects of these factor scores on memory by OCD subtypes were examined. No significant difference in terms of demographic and clinical variables was found between the two groups. Checkers displayed performance deficits on Stroop test, Trail Making Test, GO/NO GO test (commission errors) and category fluency. Three factors, inhibition, cognitive flexibility, and multi-tasking, were obtained. Statistically significant differences were observed between the two groups on the inhibition and the cognitive flexibility scores, but not on the general memory or the multi-tasking score. There was a statistically significant interaction between groups and the inhibition score. Only among "checkers", a significant correlation was noted between the inhibition factor and the general memory, while no such correlation was observed among "washers". Among "checkers", poor general memory was related to inhibition deficits.

Attention and cognition in patients with obsessive-compulsive disorder

Although a dysfunctional prefrontal-striatal system is presupposed in obsessive-compulsive disorder (OCD), this is not sustained by neuropsychological studies. The aim of this study was twofold: (i) to investigate the cognitive deficits in patients with OCD compared to matched healthy controls; and (ii) to relate cognitive performance to clinical characteristics in patients with OCD. In this study, 39 patients with primary OCD according to Diagnostic and Statistical Manual, fourth edition criteria were compared to 26 healthy control subjects on a battery measuring verbal memory and executive functioning. Patients with OCD showed slowed learning on the verbal memory task and made more errors on the Wisconsin Card Sorting Test. Errors were failures to maintain set, which were related to severity of OCD symptomatology. The results show that patients with OCD have cognitive deficits. The authors hypothesize that these deficits may be interpreted by attentional deficits caused by a dysfunctional anterior cingulate cortex.

Neuropsychological profiles of patients with obsessive-compulsive disorder: early onset versus late onset

In this study, we assess the neuropsychological profiles of both early and late symptom-onset obsessive-compulsive disorder (OCD) patients. The early and late-onset OCD patients are compared to the control group with a series of neuropsychological measurements. The late-onset OCD patients exhibited impaired performance on the immediate and the delayed recall conditions of the Rey-Osterrieth Complex Figure Test (RCFT) and the letter and category fluency of the Controlled Oral Word Association Test (COWA), compared to the normal controls and the early-onset OCD patients. The controls and early-onset OCD patients did not differ on any of the neuropsychological measurements taken in this study. These results suggest that different neurophysiological mechanisms are in play in early and late-onset OCD patients, and age of onset can serve as a potential marker for the subtyping of OCD.

Memantine augmentation for refractory obsessive-compulsive disorder

Glutamatergic hyperactivity hypothesis in obsessive-compulsive disorder (OCD) has been proposed but not tested. Memantine is an uncompetitive N-methyl-d-aspartate (NMDA) receptor antagonist. We report two cases of refractory obsessive-compulsive disorder treated with an augmentation of memantine at 15 mg/day. The first case did not benefit from such treatment, while the second showed immediate and substantial improvement. Contrasting results, reflecting different subtypes of OCD, are discussed. We hypothesized that in certain OCD subtypes an agent that enhances memory for actions may promote a reduction in orbitofrontal activation.

A functional MRI comparison of patients with obsessive-compulsive disorder and normal controls during a Chinese character Stroop task

Recent functional neuroimaging and neuropsychological studies have suggested that abnormal activity in the anterior cingulate cortex (ACC) might cause an action-monitoring dysfunction in obsessive-compulsive disorder (OCD). To identify the relationship between brain dysfunction and cognitive dysfunction, we examined regional brain changes in OCD with functional magnetic resonance imaging (fMRI) during the performance of a cognitive task. Participants comprised 24 patients with OCD and 14 normal controls. First, we compared the cognitive function in the two groups as assessed by several neuropsychological tests. Then we used fMRI to explore brain correlates of their performance during the Chinese character version of the Stroop test, a task that is strongly related to action-monitoring function. The two groups did not differ on the neuropsychological tests. Both groups also showed similar activation pattern on fMRI. The patients, however, showed weaker activation than the normal controls in the ACC and the right caudate nucleus.

Brain activation of patients with obsessive-compulsive disorder during neuropsychological and symptom provocation tasks before and after symptom improvement: a functional magnetic resonance imaging study

BACKGROUND

Functional neuroimaging studies have implicated hyperactivity of the frontal cortex in obsessive-compulsive disorder (OCD); however, relationships between abnormal brain activity, clinical improvement, and neuropsychological function have not been clarified in OCD. To clarify the pathophysiology of this disorder, regional changes in brain function were examined during administration of cognitive and symptom provocation tasks in patients with OCD before and after treatment.

METHODS

Ten outpatients with OCD participated in the study. Functional magnetic resonance imaging (fMRI) was performed before and after treatment. Stroop and symptom provocation tasks were administered during fMRI. Each patient was randomly allocated to receive either pharmacotherapy with fluvoxamine 200 mg/day (n = 4) or behavior therapy (n = 6) for 12 weeks.

RESULTS

After 12-week treatment, mean (+/- SD) total score on the Yale-Brown Obsessive-Compulsive Scale decreased from 29.00 +/- 3.59 to 14.60 +/- 9.22, representing symptomatic improvement from moderate to mild. After symptom improvement, symptom provocation-related activation in the orbitofrontal, dorsolateral-prefrontal, and anterior cingulate cortices decreased. Conversely, Stroop task-related activation in the parietal cortex and cerebellum increased.

CONCLUSIONS

After improvement of OCD with either fluvoxamine or behavioral therapy, hyperactivation of the frontal lobe related to a symptom-provocative state decreases, and posterior brain activity related to action-monitoring function increases.

A critical evaluation of obsessive-compulsive disorder subtypes: symptoms versus mechanisms

Recently, experts have suggested that obsessive-compulsive disorder (OCD), a highly heterogeneous condition, is actually composed of distinct subtypes. Research to identify specific subtypes of OCD has focused primarily on symptom presentation. Subtype models have been proposed using factor analyses that yield dimensional systems of symptom categories, but not necessarily distinct subtypes. Other empirical work has considered the role of neuropsychological functioning and comorbidity as part of a comprehensive scheme for subtyping OCD. The identified dimensions from all of these studies have implications for the treatment of OCD. In this article, we review the research on subtypes of OCD, focusing on subtype schemes based upon overt symptom presentation and neuropsychological profiles. We also review research pertinent to alternative subtyping schemes, both conceptually and methodologically. The research is critically examined and implications for treatment are discussed. Recommendations for future investigations are offered.

The molecular neuroimaging of anxiety disorders

This paper reviews the molecular neuroimaging of anxiety disorders, and attempts to put recent advances in the context of previous findings. Knowledge of the metabolic correlates of symptom severity and treatment response in obsessive-compulsive disorder has been significantly extended, particularly response to selective serotonin reuptake inhibitor medication. However, the first neuroreceptor studies of serotonin transporter availability in obsessive-compulsive disorder have proved inconclusive, and further studies are anticipated. Reduced 5-HT1A receptor binding has been reported in panic disorder. Recent findings have extended the knowledge of hippocampal abnormalities in post-traumatic stress disorder, and have highlighted the complexity of the association between cortisol and the hippocampus in this disorder.

[Functional magnetic resonance imaging in the determination of dominant language cerebral area]

Functional magnetic resonance imaging (fMRI) is a technique for detecting minimal changes in brain perfusion and oxygenation secondary to neuronal activation. Its application in the pre-surgical evaluation of epileptic patients with temporal mesial sclerosis is currently being under investigation in several centers. This study aims to describe an activation paradigm for the evaluation of language and memory functions, as an alternative to the worldwide used Wada test, which is an invasive procedure. In order to propose a paradigm adapted to the Portuguese language, we report our experience in determining the dominant cerebral area for language through fMRI with a verbal fluency task. The results of the fMRI from 19 patients studied in Curitiba in a period of approximately two years were studied. Sixteen of them presented with left hemispheric cerebral language dominance. In five patients, results from fMRI and Wada test could be compared and agreed in localization. Our results reinforce the view that fMRI may become an essential tool for medical practice, perhaps for the determination of eloquent areas in the evaluation of candidates for epilepsy surgery.

Neuropsychological performance in obsessive-compulsive disorder: a critical review

There is growing evidence for neuropsychological dysfunction in obsessive-compulsive disorder (OCD) related to an underlying frontal lobe and/or basal ganglia dysfunction. The following paper is a systematical review of the existing literature on cognitive impairment in OCD patients. Fifty studies were surveyed with regard to methodological aspects and cognitive impairments found in OCD patients. In addition, the impact of confounding variables such as psychotropic medication, co-morbidity or severity of symptoms on neuropsychological functioning as well as effects of treatment are discussed. OCD is often related to memory dysfunction that seems to be associated with impaired organization of information at the stage of encoding. Several other executive functions are also commonly disturbed, though results are inconsistent. The results of our study suggest that some cognitive deficits seem to be common in OCD, but future studies should focus more on possible confounding variables such as co-morbidity or psychotropic medication.

Pathophysiology of obsessive–compulsive disorder

Obsessive-compulsive disorder (OCD) is characterized by repetitive intrusive thoughts and compulsive time-consuming behaviors classified into three to five distinct symptom dimensions including: (1) aggressive/somatic obsessions with checking compulsions; (2) contamination concerns with washing compulsions; (3) symmetry obsessions with counting/ordering compulsions; (4) hoarding obsessions with collecting compulsions; and (5) sexual/religious concerns. Phenomenologically, OCD could be thought of as the irruption of internal signals centered on the erroneous perception that "something is wrong" in a specific situation. This generates severe anxiety, leading to recurrent behaviors aimed at reducing the emotional tension. In this paper, we examine how the abnormalities in brain activity reported in OCD can be interpreted in the light of physiology after consideration of various approaches (phenomenology, neuropsychology, neuroimmunology and neuroimagery) that contribute to proposing the central role of several cortical and subcortical regions, especially the orbitofrontal cortex (OFC), the anterior cingulate cortex (ACC), the dorsolateral prefrontal cortex (DLPC), the head of the caudate nucleus and the thalamus. The OFC is involved in the significance attributed to the consequences of action, thereby subserving decision-making, whereas the ACC is particularly activated in situations in which there are conflicting options and a high likelihood of making an error. The DLPC plays a critical part in the cognitive processing of relevant information. This cortical information is then integrated by the caudate nucleus, which controls behavioral programs. A dysfunction of these networks at one or several stages will result in the emergence and maintenance of repetitive thoughts and characteristic OCD behavior.

Neuropsychological correlates of P300 abnormalities in patients with schizophrenia and obsessive-compulsive disorder

The cognitive significance of P300 abnormalities in schizophrenia and obsessive-compulsive disorder (OCD) was investigated. P300 was measured by an auditory oddball paradigm, in which a series of standard tones (1000 Hz) and target tones (1500 Hz) were presented. The subject's task was to count the number of the presented target tones. Cognitive functions were evaluated by neuropsychological tests, which were chosen to be sensitive to frontal and temporal dysfunction. Twenty-two schizophrenic patients, 19 OCD patients and 21 healthy controls participated. Event-related potentials measured at 15 electrode sites, which consisted of five levels on the left-right dimension and three levels on the anterior-posterior dimension, were included in the statistical analysis. P300 amplitudes on all 15 electrode sites were significantly smaller in schizophrenic and OCD patients than in the controls. Schizophrenic patients performed poorly on almost all neuropsychological tests, while OCD patients showed impaired performance on the Rey-Osterrieth Complex Figure Test and on a controlled oral word association test. In schizophrenic patients, P300 amplitude was associated with performance on verbal memory and learning by the Luria-Nebraska Neuropsychological Battery, while for OCD patients, P300 amplitude was related to the Trail Making Test, Part B response time. These results indicate that schizophrenic patients have generalized cognitive impairments, which are substrated by a wide range of cortical dysfunctions. The major cognitive deficits observed in OCD patients were impairments of controlled attention and self-guided, flexible behavior, which are mediated by the fronto-striatal system. The neurophysiological mechanisms underlying P300 abnormalities observed in schizophrenic and OCD patients are discussed.

Neuropsychology of obsessive-compulsive disorder: a review and treatment implications

The existing literature examining neuropsychological features of obsessive-compulsive disorder (OCD) is reviewed. The accumulated research points to a deficit in organizational strategies in general, suggesting problems in executive functioning. The available research is inconsistent in identifying memory deficits in OCD. However, memory problems are most evident when tests are used that require an implicit organizational strategy. While the majority of the research reviewed involves adult samples, there is emerging evidence that these deficits are present in children as well. It is suggested here that the interaction between organizational strategy deficits and the effort to recall unstructured information contributes to doubting, an important feature of OCD. Implications of this body of research for behavior therapy are considered.

Neuropsychological profile in patients with obsessive-compulsive disorder over a period of 4-month treatment

This study investigated the changes of the neuropsychological functions over a 4-month period of treatment in patients with obsessive-compulsive disorder (OCD). Thirty-nine OCD patients and 31 healthy controls were evaluated with neuropsychological and clinical tests. The same tests were readministered 4-months after pharmacological treatment for the OCD patients. At the first series of tests, compared to the controls, the OCD patients were significantly impaired on the immediate and delayed recall of Rey-Osterrieth Complex Figure Test (RCFT), and on the letter and category of Controlled Oral Word Association Test (COWA). They also showed a prolonged response time on Trail Making Test (TMT), part A. The severity of OCD measured by Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) correlated well with the performance on the immediate and delayed recall of RCFT and the response time on TMT, part A. After 4-months' follow-up, the OCD patients still showed impairment on the immediate and delayed recall of RCFT and COWA category. This is despite the fact that they had improved significantly on these functions in comparison with the controls over the period of treatment. In addition, an association between OCD symptoms and the performance on the neuropsychological tests was not observed. The neuropsychological profile of the OCD patients found in the present study is consistent with current theories proposing that the frontal-striatal system is the possible pathophysiological mechanism underlying the development of OCD.

Frontal lobe dysfunction in pathological gambling patients

BACKGROUND

Limited data are available about the validity of the diagnosis of pathological gambling (PG) and about the etiology and the efficacy of different treatment strategies of this disorder; however, similarities in decision-making behavior between PG patients and patients with ventromedial prefrontal cortex lesions suggest a possible implication of these areas in the pathophysiology of this disorder, as in obsessive-compulsive disorder, in which the decision-making impairment is significantly associated with response to serotonin reuptake inhibitor treatment. Nevertheless, several studies have shown that decision-making functioning is also impaired in drug-addicted patients who have shown abnormalities in ventromedial prefrontal cortex during functional neuroimaging studies.

METHODS

We assessed the decision-making function mediated by the ventromedial prefrontal cortex in 20 PG patients and 40 healthy control (HC) subjects using the Gambling Task, which simulates real-life decision-making, testing the ability to balance immediate rewards against long-term negative consequence.

RESULTS

Significant differences were found in Gambling Task performance between HC subjects and PG patients, who showed a specific decision-making profile across the sequence of the game. The dissimilarity does not appear to depend on the basic cognitive function deficit of the PG group.

CONCLUSIONS

These data seem to suggest the existence of a link between PG and other disorders (i.e., obsessive-compulsive disorder and drug addiction) all having diminished ability to evaluate future consequences, which may be explained at least in part by an abnormal functioning of the orbitofrontal cortex.

The integration of primary anorexia nervosa and obsessive-compulsive disorder

This paper explores the relationship between primary anorexia nervosa (PAN) and obsessive-compulsive disorder (OCD) in both their concomitant and their sequential presentation. Their clinical descriptions demonstrate the presence of obsessionality and compulsiveness that seem to interface during their course and overlap in their symptomatologies has been noted for over sixty years. However, recent research in this regard is scant. Commonalities in pathophysiology indicate disturbances in neurotransmitters, notably serotonin. Biological challenges have failed to establish a definitive correlation with PAN and OCD, whether in combination or individually. We may postulate that, with limitations, they share some anatomical pathways. The areas affected are the amygdala, cingulum and orbito-frontal cortex. Few studies, however, have been devoted to the treatment of concomitant PAN and OCD.

Impairment of incidental memory for frequency in patients with obsessive-compulsive disorder

The aim of our study was to investigate whether patients with obsessive-compulsive disorder (OCD) have impaired incidental memory for frequency. Fifty-four subjects (27 OCD patients and 27 matched control subjects) performed a task assessing estimation of occurrence of previously heard words. Performance on this task was compared with other intentional verbal memory tasks (recognition, recall and learning of common words). We also correlated memory for frequency with frontal lobe tests (Wisconsin Card Sorting Test, Trail Making Tests A and B, and verbal fluency). Performance on incidental learning of frequency was significantly worse in the OCD group than in control subjects. Other verbal memory measures did not show significant differences. Performance in the frequency task correlated with verbal fluency. Although intentional verbal memories are normal in OCD patients, incidental memory for frequency is impaired, suggesting that prefrontal systems are involved in OCD.

Neurobiology and clinical pharmacology of obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) is a brain disorder with recognizable periods of onset, course, familial occurrence, epidemiology, phenomenology, and treatment response. Several manifestations of pathophysiology are beginning to be defined, although they may represent intermediate pathophysiology rather than primary etiology. Positron emission tomography studies have consistently identified hypermetabolism in the orbitofrontal cortex, caudate nucleus, and, sometimes, anterior cingulate cortex. Neuropsychologic testing frequently identifies abnormalities in visuospatial function. Abnormal levels of cerebrospinal fluid neurotransmitters and neuromodulators are identifiable in untreated patients with OCD and return toward normal levels after effective treatment. The most consistent pathophysiologic finding in OCD points toward an abnormality in serotonin neurotransmission. Therapeutic response to selective serotonin reuptake inhibitors and the absence of improvement with norepinephrine reuptake inhibitors and dopamine antagonists argue strongly for a role of serotonin in the pathophysiology and treatment of OCD. Despite this clear indication from treatment trials, probes and manipulations of the serotonin system and its specific receptors have not provided a useful understanding of specific abnormalities. Clomipramine or potent selective serotonin reuptake inhibitors are the pharmacotherapy of choice for OCD, with a more limited role reserved for monoamine oxidase inhibitors. If one selective serotonin reuptake inhibitor is ineffective, others may be beneficial, in addition to the different proserotonergic and nonserotonergic augmentation strategies that could be useful in treatment of resistant OCD patients. Nondrug therapies are also important in OCD: behavioral therapy is frequently helpful and neurosurgery is sometimes helpful when other treatments fail.

Beck Depression Inventory factors related to demyelinating lesions of the left arcuate fasciculus region

This study was conducted to further establish the significance of the previously reported association between depressive symptoms and demyelinating lesions in the region of the left arcuate fasciculus in multiple sclerosis patients. The Beck Depression Inventory (BDI) was broken down into its main symptom categories on the basis of well-established factor analyses from the literature, and the correlation pattern between the resulting BDI subscores and lesion measurements was analyzed. We found that lesions of the left arcuate fasciculus region were selectively associated with BDI items expressing patients' Affective Symptoms and Somatic Complaints. Specifically, lesion measurements from this brain location accounted for 26% of symptom score variance of the BDI part that includes only these two factors. Performance Difficulties and Cognitive Distortions were not consistently associated with the lesion measurement. Performance Difficulties, however, showed a high correlation with the neurologic deficit detected in the physical examination. These results show that lesions in the left arcuate fasciculus region are associated with the core of the depressive syndrome rather than marginal symptoms and, thus, further suggest that this left suprainsular brain region involves white matter tracts relevant to mood regulation.

Functional neuroimaging and the neuroanatomy of obsessive-compulsive disorder

Functional neuroimaging studies have advanced the understanding of the brain mediation of OCD by orbitofrontal-subcortical circuitry, but much is still unknown. Phenotypic heterogeneity could account for many of the inconsistencies among previous neuroimaging studies of OCD. Current studies are seeking to find the neurobiological basis of OCD symptom subtypes and predictors of treatment response. Future studies combining genetics and basic neuroanatomic research with neuroimaging may clarify the cause and pathophysiology of OCD. Although many lines of evidence point to dysfunction of orbitofrontal-subcortical circuitry in patients with OCD, many questions remain unanswered. Some have suggested that orbitofrontal-subcortical hyperactivity in OCD may be the result of abnormal neuroanatomic development of these structures or a failure of pruning of neuronal connections between them, as occurs in normal development, but no postmortem neuroanatomic studies of OCD exist to delineate its pathophysiology. Interventions that directly alter the indirect-direct pathway balance within frontal-subcortical circuits will allow for direct testing of the pathophysiologic hypotheses presented here. The roles of various neurochemical systems in OCD are similarly unclear. Although an abundance of indirect evidence suggests serotonergic abnormalities in patients with OCD, no direct evidence demonstrates what those abnormalities are or whether they are primary or secondary phenomena in patients with OCD. Ongoing studies of 5-HT synthesis in the brains of patients with OCD may shed light on this question.