Obsessive-compulsive and other behavioural changes with bilateral basal ganglia lesions. A neuropsychological, magnetic resonance imaging and positron tomography study

Reduction of N-acetylaspartate in the medial prefrontal cortex correlated with symptom severity in obsessive-compulsive disorder: meta-analyses of (1)H-MRS studies

Structural and functional neuroimaging findings suggest that disturbance of the cortico-striato-thalamo-cortical (CSTC) circuits may underlie obsessive-compulsive disorder (OCD). However, some studies with (1)H-magnetic resonance spectroscopy ((1)H-MRS) reported altered level of N-acetylaspartate (NAA), they yielded inconsistency in direction and location of abnormality within CSTC circuits. We conducted a comprehensive literature search and a meta-analysis of (1)H-MRS studies in OCD. Seventeen met the inclusion criteria for a meta-analysis. Data were separated by frontal cortex region: medial prefrontal cortex (mPFC), dorsolateral prefrontal cortex, orbitofrontal cortex, basal ganglia and thalamus. The mean and s.d. of the NAA measure were calculated for each region. A random effects model integrating 16 separate datasets with 225 OCD patients and 233 healthy comparison subjects demonstrated that OCD patients exhibit decreased NAA levels in the frontal cortex (P=0.025), but no significant changes in the basal ganglia (P=0.770) or thalamus (P=0.466). Sensitivity analysis in an anatomically specified subgroup consisting of datasets examining the mPFC demonstrated marginally significant reduction of NAA (P=0.061). Meta-regression revealed that NAA reduction in the mPFC was positively correlated with symptom severity measured by Yale-Brown Obsessive Compulsive Scale (P=0.011). The specific reduction of NAA in the mPFC and significant relationship between neurochemical alteration in the mPFC and symptom severity indicate that the mPFC is one of the brain regions that directly related to abnormal behavior in the pathophysiology of OCD. The current meta-analysis indicates that cortices and sub-cortices contribute in different ways to the etiology of OCD.

Caudate nucleus and social cognition: neuropsychological and SPECT evidence from a patient with focal caudate lesion

Most studies in social cognition have focused on developmental diseases or analyzed the consequences of acquired frontal lesions on the integrity of Theory of Mind (ToM), but, to our knowledge, none to date has addressed the eventual consequences of damage to the basal ganglia on ToM. To investigate the possible consequences of such lesions on social cognition, we tested a selected patient, MVG, a 44-year-old man with a focal caudate nucleus (CN) lesion following stroke. In the aftermath of this stroke, MVG shows loss of empathy and difficulties recognizing emotions in others. The dual aims of this study were first, to evaluate the implications of CN on ToM and recognition of emotion, and second, to discuss these results as a consequence of a disconnection of the sub-cortical orbito-frontal (OF) loop due to caudate damage. We performed a complete neuropsychological assessment of MVG, as well as different tasks evaluating social cognition, such as the Faux-Pas Test and the Reading the Eyes in the Mind Test. No deficits were found in the neuropsychological tests. However, on tasks assessing social cognition, MVG showed impairments in the "warm" or "affective" part of ToM as well as in the ability to recognize negative emotions (i.e., sadness and fear). These results indicate that damage to the head of the left CN can lead to impairment of ToM and emotion recognition. Furthermore, the data shows that, in MVG, such impairment appears to be due to a disconnection of the sub-cortical OF circuit resulting from damage to the CN. Neuro-imaging data tends to confirm this hypothesis by bringing out a hypo-perfusion in both, the territory of his left CN and prefrontal (i.e., ventromedial) brain areas.

The prevalence and clinical characteristics of punding in Parkinson's disease

BACKGROUND

Punding (the display of stereotyped, repetitive behaviors) is a relatively recently discovered feature of Parkinson's disease (PD). Little is known about the prevalence and clinical characteristics of punding in PD.

METHODS

In this review, four large scientific databases were comprehensively searched for literature in relation to punding prevalence and clinical correlates in the context of PD.

RESULTS

Prevalence was found to vary greatly (between 0.34 to 14%), although there were large disparities in study populations, assessment methods, and criteria. We observed an association between punding, dopaminergic medications, and impulse control disorder. Other characteristics, which may be more common among punders, include a higher severity of dyskinesia, younger age of disease onset, longer disease duration, and male gender.

DISCUSSION

More research in large clinical datasets is required in many areas before conclusions are drawn. The pathophysiology behind the punding phenomenon is also poorly understood at present, rendering it difficult to develop targeted therapy. The current mainstay of treatment is the reduction in the dose of dopaminergic medications, the evidence for other suggested therapies being purely empirical.

The Basal Ganglia as a Substrate for the Multiple Actions of Amphetamines

Amphetamines are psychostimulant drugs with high abuse potential. Acute and chronic doses of amphetamines affect dopamine (DA) neurotransmission in the basal ganglia. The basal ganglia are a group of subcortical nuclei that are anatomically positioned to integrate cognitive, motor and sensorimotor inputs from the cortex. Amphetamines can differentially alter the functioning of specific BG circuits to produce neurochemical changes that affect cognition, movement, and drug seeking behavior through their effects on DA neurotransmission. This review focuses on how alterations in dopaminergic neurotransmission within distinct basal ganglia pathways can modify their functional output to predict and explain the acute and long term behavioral consequences of amphetamine exposure.

Is there evidence of brain white-matter abnormalities in obsessive-compulsive disorder?: a narrative review

OBJECTIVE

Although several studies have confirmed the occurrence of gray-matter abnormalities in obsessive-compulsive disorder (OCD), the literature on white matter in OCD is more limited. In this study, we reviewed the role of white-matter abnormalities in the pathophysiology of OCD.

METHOD

We reviewed the PubMed studies investigating white-matter integrity in patients with OCD between 1980 and 2010.

RESULTS

Case studies of patients who developed obsessive-compulsive symptoms secondary to multiple sclerosis, cerebrovascular diseases, and paraneoplastic leucoencephalopathy and controlled studies of patients with OCD examined with neuroimaging techniques (eg, structural, diffusion, and spectroscopic magnetic resonance imaging) were all consistent with the existence of abnormalities in specific white-matter tracts (eg, internal capsule, cingulate bundle, and corpus callosum) of individuals with OCD.

CONCLUSIONS

Our review emphasizes that the reported white-matter alterations in OCD complement the broader gray-matter abnormalities identified and may well suggest that OCD is associated with large-scale disruption in brain systems or networks, as opposed to being a consequence of disturbances in isolated brain regions.

Effects of behavioral therapy or pharmacotherapy on brain glucose metabolism in subjects with obsessive-compulsive disorder as assessed by brain FDG PET

This prospective study investigated the effect of pharmacotherapy (PT) and cognitive behavioral therapy (CBT) on cerebral glucose metabolism in adults with obsessive-compulsive disorder (OCD). Dynamic positron emission tomography (PET) of the brain with F-18-fluorodeoxyglucose (FDG) was performed before and after treatment in 16 subjects diagnosed for OCD for at least 2 years (PT: n=7). Pre-to-post-treatment change of scaled local metabolic rate of glucose (SLMRGlc) was assessed separately in therapy responders and non-responders. Correlation was tested between SLMRGlc change and change of OCD, depression, or anxiety symptoms. SLMRGlc increased in the right caudate after successful therapy. The increase tended to correlate with the improvement of OCD symptom severity. The finding of increased local caudate activity after successful therapy is in contrast to most previous studies. Possible explanations include effects of therapy on concomitant depression symptoms and/or the large proportion of early-onset OCD in the present sample.

Brain activation during cognitive planning in twins discordant or concordant for obsessive-compulsive symptoms

Neuroimaging studies have indicated abnormalities in cortico-striatal-thalamo-cortical circuits in patients with obsessive–compulsive disorder compared with controls. However, there are inconsistencies between studies regarding the exact set of brain structures involved and the direction of anatomical and functional changes. These inconsistencies may reflect the differential impact of environmental and genetic risk factors for obsessive–compulsive disorder on different parts of the brain. To distinguish between functional brain changes underlying environmentally and genetically mediated obsessive–compulsive disorder, we compared task performance and brain activation during a Tower of London planning paradigm in monozygotic twins discordant (n = 38) or concordant (n = 100) for obsessive–compulsive symptoms. Twins who score high on obsessive–compulsive symptoms can be considered at high risk for obsessive–compulsive disorder. We found that subjects at high risk for obsessive–compulsive disorder did not differ from the low-risk subjects behaviourally, but we obtained evidence that the high-risk subjects differed from the low-risk subjects in the patterns of brain activation accompanying task execution. These regions can be separated into those that were affected by mainly environmental risk (dorsolateral prefrontal cortex and lingual cortex), genetic risk (frontopolar cortex, inferior frontal cortex, globus pallidus and caudate nucleus) and regions affected by both environmental and genetic risk factors (cingulate cortex, premotor cortex and parts of the parietal cortex). Our results suggest that neurobiological changes related to obsessive–compulsive symptoms induced by environmental factors involve primarily the dorsolateral prefrontal cortex, whereas neurobiological changes induced by genetic factors involve orbitofrontal–basal ganglia structures. Regions showing similar changes in high-risk twins from discordant and concordant pairs may be part of compensatory networks that keep planning performance intact, in spite of cortico-striatal-thalamo-cortical deficits.

Is there any role of Toxoplasma gondii in the etiology of obsessive-compulsive disorder?

Obsessive-compulsive disorder (OCD) is a common psychiatric illness. Although the aetiology of OCD is still unknown, the family-genetic data show that familial forms of OCD may be associated with a specific genetic susceptibility. Recent investigations have associated development of OCD with infectious illness. Toxoplasmic encephalitis (TE) is a common presentation of Toxoplasma gondii infection of the central nervous system (CNS). The most commonly affected CNS region in TE is the cerebral hemisphere, followed by the basal ganglia, cerebellum and brain stem. The basal ganglia has been implicated in the development of OCD. Therefore, in this study, it was aimed to investigate a possible association between Toxoplasma infection and OCD. We selected 42 patients with OCD and 100 healthy volunteers, and investigated the sero-positivity rate for anti-Toxoplasma IgG antibodies by Enzyme Linked Immunosorbent Assay (ELISA). The sero-positivity rate for anti-T. gondii IgG antibodies among OCD patients (47.62%) was found to be significantly higher than the rate in healthy volunteers (19%). This is the first report to examine a potential association between Toxoplasma infection and OCD. The main finding of the present study is an increased level of IgG antibodies to T. gondii in OCD patients when compared with the level in healthy controls. There might be a causal relationship between chronic toxoplasmosis and the aetiology of OCD.

Comorbidities of obsessive and compulsive symptoms in Huntington's disease

Although current reports document a high rate of obsessive and compulsive symptoms (O/Cs) in Huntington's disease (HD), there have been no studies published that have made an attempt to identify comorbidities of O/Cs in HD. We examined O/Cs in 1642 individuals with a diagnosis of HD. Of those endorsing significant O/Cs (27.2%), nearly one-quarter reported obtaining treatment for obsessive compulsive disorder. Individuals with HD and O/Cs were older, had poorer functioning, and a longer duration of illness than those without O/Cs. Individuals with HD and O/Cs endorsed significantly higher psychiatric comorbidities of depression, suicidal ideation, aggression, delusions, and hallucinations. Participants with the most severe O/Cs and worse performance on the Stroop task, a measure of executive function. Clinicians should be aware that patients with HD and O/Cs might have a somewhat different clinical picture from those without, and may require a specialized treatment plan.

The neurobiology of repetitive behavior: …and men

In young, typically developing children, repetitive behavior similar to that in certain neuropsychiatric syndromes is common. Whereas this behavior is adaptive in typical development, in many disorders it forms a core component of symptoms and causes prominent impairment in the daily life of affected individuals. Understanding the neurobiological mechanisms involved repetitive behavior will improve our understanding of the pathogenesis of developmental neuropsychiatric disorders, stimulating novel approaches to these conditions. However, studies on the neurobiology of human repetitive behavior have often been limited to distinct conditions and generalization has been hindered by inconsistent terminology. In this paper, we synthesize the 'disorder-driven' literature, building on findings from fundamental animal research and translational models. These findings suggest a model for classifying repetitive behavior by its neuroanatomical correlates.

Basal ganglia MR relaxometry in obsessive-compulsive disorder: T2 depends upon age of symptom onset

Dysfunction in circuits linking frontal cortex and basal ganglia (BG) is strongly implicated in obsessive-compulsive disorder (OCD). On MRI studies, neuropsychiatric disorders with known BG pathology have abnormally short T2 relaxation values (a putative biomarker of elevated iron) in this region. We asked if BG T2 values are abnormal in OCD. We measured volume and T2 and T1 relaxation rates in BG of 32 adults with OCD and 33 matched controls. There were no group differences in volume or T1 values in caudate, putamen, or globus pallidus (GP). The OCD group had lower T2 values (suggesting higher iron content) in the right GP, with a trend in the same direction for the left GP. This effect was driven by patients whose OCD symptoms began from around adolescence to early adulthood. The results suggest a possible relationship between age of OCD onset and iron deposition in the basal ganglia.

Frontal-striatal abnormalities underlying behaviours in the compulsive-impulsive spectrum

In this paper, we tentatively bring together the psychiatric, neurological and addiction perspectives on the impulsive-compulsive spectrum of neuropsychiatric disorders, in order to understand the pathophysiology of impulse control disorders (ICDs) in Parkinson's disease. In an attempt to try to pool the various levels of information we will therefore focus on three disorders within the impulse-compulsive spectrum, i.e., obsessive-compulsive disorder (OCD), ICDs in Parkinson's disease, and cocaine seeking behaviour. Whereas there are large differences between these three domains, each with their own nomenclature, hypotheses and study results, they share the focus on an imbalance within and between the frontal-striatal circuits as underlying substrate for the behaviours. For each disorder, we summarize the results from recent studies in order to describe in which way alterations in the frontal-striatal circuits contribute to the phenotype. The phenomenological overlap between ICDs in Parkinson's disease, addiction and OCD needs further investigation, since better understanding of the overlapping and differentiating characteristics will contribute to our understanding of the pathophysiology of the disturbances and treatment alternatives.

Brain changes in children and adolescents with obsessive-compulsive disorder before and after treatment: a voxel-based morphometric MRI study

The aim of this study is to determine whether children and adolescents with treatment-naïve obsessive-compulsive disorder (OCD) present brain structure differences in comparison with healthy subjects, and to evaluate brain changes after treatment and clinical improvement. Initial and 6 months' follow-up evaluations were performed in 15 children and adolescents (age range=9-17 years, mean=13.7, S.D.=2.5; 8 male, 7 female) with DSM-IV OCD and 15 healthy subjects matched for age, sex and estimated intellectual level. An evaluation with psychopathological scales and magnetic resonance imaging (MRI) was carried out at admission and after 6 months' follow-up. Axial three-dimensional T1-weighted images were obtained in a 1.5 T scanner and analysed using optimized voxel-based morphometry (VBM) and longitudinal VBM approaches. Compared with controls, OCD patients presented significantly less gray matter volume bilaterally in right and left parietal lobes and right parietal white matter (P=0.001 FWE corrected) at baseline evaluation. After 6 months of treatment, and with a clear clinical improvement, the differences between OCD patients and controls in the parietal lobes in gray and white matter were no longer statistically significant. During follow-up in the longitudinal study, an increase in gray matter volume in the right striatum of OCD patients was observed, though the difference was not statistically significant. Children and adolescents with untreated OCD present gray and white matter decreases in lateral parietal cortices, but this abnormality is reversible after clinical improvement.

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.

The globus pallidus sends reward-related signals to the lateral habenula

As a major output station of the basal ganglia, the globus pallidus internal segment (GPi) projects to the thalamus and brainstem nuclei thereby controlling motor behavior. A less well known fact is that the GPi also projects to the lateral habenula (LHb) which is often associated with the limbic system. Using the monkey performing a saccade task with positionally biased reward outcomes, we found that antidromically identified LHb-projecting neurons were distributed mainly in the dorsal and ventral borders of the GPi and that their activity was strongly modulated by expected reward outcomes. A majority of them were excited by the no-reward-predicting target and inhibited by the reward-predicting target. These reward-dependent modulations were similar to those in LHb neurons but started earlier than those in LHb neurons. These results suggest that GPi may initiate reward-related signals through its effects on the LHb, which then influences the dopaminergic and serotonergic systems.

The recognition of facial emotion expressions in Parkinson's disease

A limited number of studies in Parkinson's Disease (PD) suggest a disturbance of recognition of facial emotion expressions. In particular, disgust recognition impairment has been reported in unmedicated and medicated PD patients. However, the results are rather inconclusive in the definition of the degree and the selectivity of emotion recognition impairment, and an associated impairment of almost all basic facial emotions in PD is also described. Few studies have investigated the relationship with neuropsychiatric and neuropsychological symptoms with mainly negative results. This inconsistency may be due to many different problems, such as emotion assessment, perception deficit, cognitive impairment, behavioral symptoms, illness severity and antiparkinsonian therapy. Here we review the clinical characteristics and neural structures involved in the recognition of specific facial emotion expressions, and the plausible role of dopamine transmission and dopamine replacement therapy in these processes. It is clear that future studies should be directed to clarify all these issues.

An orbitofrontostriatopallidal pathway for morality: evidence from postlesion antisocial and obsessive-compulsive disorder

INTRODUCTION

A detailed proposal is made to the effect that nonlesional antisocial personality disorder (APD) is, among other things, a dysfunctional hypomoralism and that nonlesional obsessive-compulsive disorder (OCD) is, among other things, a dysfunctional hypermoralism.

METHOD

To provide an empirical test of this proposal, 25 previously published cases of acquired (post lesion) APD and 39 cases of acquired OCD are reviewed and compared with multivariate inference tests.

RESULTS

The acquired APD patients most often present putamenal or pallidal lesions.

CONCLUSION

The ensemble of neurobiological, endocrine, and behavioural traits in APD and OCD, as well as the distinct lesion sites in the acquired variants, support the notion of an orbitofrontostriatopallidal brain system underlying morality.

Behavioral symptoms after pallido-nigral lesions: a clinico-pathological case

A 59-year-old patient presented with compulsive behaviors and lasting apathy after carbon monoxide intoxication. The apathy could be overcome by external stimulation (self-activation deficit). There was severe neuronal loss bilaterally in the anterior part of the pallidum and in the substantia nigra, pars reticulata. This first clinico-pathological case of a self-activation deficit illustrates the dissociation between motor and behavioral symptoms in lesions of the pallido-nigral complex, with the behavioral symptoms being related to lesions of the substantia nigra, pars reticulata and of the anterior part of the pallidum.

Glutamatergic Synaptic Dysfunction and Obsessive-Compulsive Disorder

Obsessive-compulsive disorder (OCD) is a debilitating neuropsychiatric condition estimated to afflict 1-3% of the world population. The estimated financial impact in the treatment and management of OCD is in the billions of dollars annually in the US alone. At present there is a marked lack of evidence on the specific causes of OCD. Current hypotheses largely focus on the serotonin (5-HT) system on the basis of the effectiveness of selective serotonin reuptake inhibitors (SSRIs) in alleviating symptoms of patients with OCD, yet a considerable fraction of patients are non-responsive or minimally responsive to these agents. Despite this fact, SSRIs have remained the primary pharmacological treatment avenue for OCD. In recent years, multiple lines of evidence have implicated glutamatergic synaptic dysfunction within the cortico-striatal-thalamo-cortical (CSTC) brain circuit in the etiology of OCD and related disorders, thereby prompting intensified effort in the development and evaluation of agents that modulate glutamatergic neurotransmission for the treatment of OCD. With this in mind, here we review the following topics with respect to synaptic dysfunction and the neural circuitry underlying OCD: (1) evidence supporting the critical involvement of the CSTC circuit, (2) genetic studies supporting the involvement of glutamatergic dysfunction, (3) insights from genetic animal models of OCD, and (4) preliminary findings with glutamatergic neurotransmission-modulating agents in the treatment of OCD. Given the putative mechanistic overlap between OCD and the broader OC-spectrum of disorders, unraveling the synaptic basis of OCD has potential to translate into more effective treatments for an array of poorly understood human disorders.

A psychological and neuroanatomical model of obsessive-compulsive disorder

Imaging, surgical, and lesion studies suggest that the prefrontal cortex (orbitofrontal and anterior cingulate cortexes), basal ganglia, and thalamus are involved in the pathogenesis of obsessive-compulsive disorder (OCD). On the basis of these findings several models of OCD have been developed, but have had difficulty fully integrating the psychological and neuroanatomical findings of OCD. Recent research in the field of cognitive neuroscience on the normal function of these brain areas demonstrates the role of the orbitofrontal cortex in reward, the anterior cingulate cortex in error detection, the basal ganglia in affecting the threshold for activation of motor and behavioral programs, and the prefrontal cortex in storing memories of behavioral sequences (called "structured event complexes" or SECs). The authors propose that the initiation of these SECs can be accompanied by anxiety that is relieved with completion of the SEC, and that a deficit in this process could be responsible for many of the symptoms of OCD. Specifically, the anxiety can form the basis of an obsession, and a compulsion can be an attempt to receive relief from the anxiety by repeating parts of, or an entire, SEC. The authors discuss empiric support for, and specific experimental predictions of, this model. The authors believe that this model explains the specific symptoms, and integrates the psychology and neuroanatomy of OCD better than previous models.

Emerging anxiolytics

Anxiety disorders are the most common of the psychiatric disorders and are also associated with significant economic costs and impaired work productivity. The first-line pharmacotherapy of pharmatherapy for a number of anxiety disorders comprises selective serotonin re-uptake inhibitors (SSRIs) and serotonin and noradrenaline re-uptake inhibitors (SNRIs). Benzodiazepines are still widely used for the treatment of several anxiety disorders. Although these agents are effective, many patients are treatment-refractory and more effective, better tolerated medications are required. This paper discusses the understandings of mechanisms involved in the anxiety disorders and reviews emerging medications. Mechanisms underlying the use of d-cycloserine, second generation antipsychotics and beta-blockers are particularly exciting.

Integrating evidence from neuroimaging and neuropsychological studies of obsessive-compulsive disorder: the orbitofronto-striatal model revisited

Obsessive-compulsive disorder (OCD) is a common, heritable and disabling neuropsychiatric disorder. Theoretical models suggest that OCD is underpinned by functional and structural abnormalities in orbitofronto-striatal circuits. Evidence from cognitive and neuroimaging studies (functional and structural magnetic resonance imaging (MRI) and positron emission tomography (PET)) have generally been taken to be supportive of these theoretical models; however, results from these studies have not been entirely congruent with each other. With the advent of whole brain-based structural imaging techniques, such as voxel-based morphometry and multivoxel analyses, we consider it timely to assess neuroimaging findings to date, and to examine their compatibility with cognitive studies and orbitofronto-striatal models. As part of this assessment, we performed a quantitative, voxel-level meta-analysis of functional MRI findings, which revealed consistent abnormalities in orbitofronto-striatal and other additional areas in OCD. This review also considers the evidence for involvement of other brain areas outside orbitofronto-striatal regions in OCD, the limitations of current imaging techniques, and how future developments in imaging may aid our understanding of OCD.

Probability of obsessive and compulsive symptoms in Huntington's disease

BACKGROUND

The purpose of this study was to examine the probability of obsessive and compulsive (OC) symptoms across stages of Huntington's disease (HD) with both cross sectional and longitudinal data.

METHODS

We present the largest sample to date of individuals at risk for HD (N = 3964). Obsessive and compulsive symptoms were assessed with the Unified Huntington's Disease Rating Scale OC items.

RESULTS

The probability of meeting the threshold for obsessions and compulsions increased with greater disease severity. Those with no motor abnormalities ("at risk") had a 7% probability of obsessions and a 3.5% probability of compulsions; the peak probability for obsessions (24%) and compulsions (12%) occurred in patients with advanced disease with significant functional disability.

CONCLUSIONS

The probability of OC symptoms is more than three times greater by stages 3 and 4 (clearly manifest disease) than in our at-risk group with no apparent motor abnormalities.

The basal ganglia: an overview of circuits and function

The technique of electrical stimulation of brain tissue-known clinically as deep brain stimulation (DBS)-is at the fore of treatment of human neurological disease. Here we provide a general overview highlighting the anatomy and circuitry of the basal ganglia (BG). We introduce common disease states associated with BG dysfunction and current hypotheses of BG function. Throughout this introductory review we direct the reader to other reviews in this special issue of Neuroscience and Biobehavioral Reviews highlighting the interaction between basic science and clinical investigation to more fully understand the BG in both health and disease.

Fluvoxamine treatment and D2 receptors: a pet study on OCD drug-naïve patients

Changes in D(2) receptors during antidepressant therapy have been reported in patients with major depressive disorder using PET/SPET. The aim of this study was to evaluate modifications in D(2) receptors that might occur in patients affected by obsessive-compulsive disorder (OCD) during serotonin reuptake sites inhibitors (SSRIs). To this purpose, we measured the in vivo binding of [(11)C]raclopride ([(11)C]Rac)in the brain of a group of OCD naïve patients before and after the repeated administration of the inhibitor SSRI fluvoxamine. Eight patients with a Diagnostic and Statistical Manual of Mental Disorders IVth edition diagnosis of OCD completed the study undergoing a PET scan and a complete clinical evaluation before and during treatment with fluvoxamine. Patients have been compared also with a group of nine age-matched normal volunteers. Fluvoxamine treatment significantly improved clinical symptoms and increased [(11)C]Rac binding potential (BP) in the basal ganglia of OCD patients (7.5+/-5.2, 6.9+/-6.9, and 9.9+/-9.3% in dorsal caudate, dorsal putamen, and ventral basal ganglia, respectively; p<0.01) to values closer to those observed in the group of normal subjects. Chronic treatment with fluvoxamine induces a slight but significant increase in striatal [(11)C]Rac BP of previously drug-naïve OCD patients. The modifications in D(2) receptor availability might be secondary to fluvoxamine effects on serotoninergic activity.

Apathy and the basal ganglia

We should like to emphasize the following points: 1. Apathy is defined here as a quantified and observable behavioral syndrome consisting in a quantitative reduction of voluntary (or goal-directed) behaviors; 2. Therefore, apathy occurs when the systems that generate and control voluntary actions are altered; 3. These systems are mostly represented by the different subregions embedded in the Prefrontal cortex (PFC) and in the basal ganglia regions that are closely connected with the PFC; 4. In consequence, clinically, apathy is a prefrontal syndrome either due to direct lesions of the PFC or to lesions of basal ganglia areas that are closely related to the PFC; 5. Apathy is not a single entity but rather heterogeneous. Several different mechanisms may lead to apathy; Because there are several anatomical-functional prefrontal-basal ganglia circuits, the underlying mechanisms responsible for apathy may differ according to which prefrontal-basal ganglia circuit is affected; 6. In this context, apathy is the macroscopic results of the disruption of one or several elementary steps necessary for goal-directed behavior that are subserved by different prefrontal-basal ganglia circuits; 7. Intense apathy is related to caudate nucleus and GPi, disrupting associative and limbic pathways from/to the PFC; 8. in progressive supranuclear palsy (PSP) and focal lesions (caudate nuclei, GPi), apathy may be due to a loss of PFC activation; 9. In Parkinson's disease (PD), apathy may be due to a loss of signal focalization; 10. More globally, we propose that apathy may be explained by the impact of lesions or dysfunctions of the BG, because these lesions or dysfunctions lead to a loss of amplification of the relevant signal and/or to a loss of temporal and spatial focalization, both of which result in a diminished extraction of the relevant signal within the frontal cortex, thereby inhibiting the capacity of the frontal cortex to select, initiate, maintain and shift programs of action.

As bases neuroanatômicas do comportamento: histórico e contribuições recentes

Tendo em vista as mais recentes contribuições, as áreas corticais límbicas - originalmente denominadas em conjunto de grande lobo límbico -, além dos giros do cíngulo e parahipocampal, são constituídas pelas regiões mais posteriores do córtex fronto-orbitário e pelo córtex insular. Em contraposição ao restante do córtex cerebral, que se projeta sobre os gânglios da base (particularmente sobre as porções mais dorsais e mais extensas do striatum, constituídas fundamentalmente pelo núcleo caudado e pelo putame), as áreas corticais límbicas se caracterizam por se projetarem principalmente sobre o hipotálamo e também sobre a porção mais ventral do striatum (principalmente sobre o núcleo accumbens). Uma vez que todo o striatum se projeta para o globo pálido - e este para o tálamo, que se projeta para o córtex cerebral, constituindo-se, assim, circuitos córtico-subcorticais reentrantes -, tem-se que, enquanto as alças relacionadas com o striatum e o pallidum dorsais são responsáveis por atividades e rotinas motoras, as alças relacionadas com o striatum e o pallidum ventrais caracterizam circuitos córtico-subcorticais reentrantes e segregados que se relacionam particularmente com funções comportamentais. A amígdala estendida (amígdala centromedial, componente dorsal ou estria terminal, componente ventral e núcleo da estria terminal), por sua vez, também recebe aferências de todas as áreas corticais límbicas, é particularmente modulada pelas áreas corticais pré-frontais e, ao invés de se projetar sobre o striatum, projeta-se diretamente sobre o hipotálamo e o tronco encefálico. Ao receber também conexões diretas do tálamo, a amígdala estendida pode ainda desencadear respostas principalmente autonômicas, de forma inespecífica, porém rápida, através da ativação de centros do tronco encefálico. Os sistemas macro-anatômicos fronto-basais, estriatal-palidal ventral e amígdala estendida, em conjunto com o núcleo basal de Meynert e com o sistema septo-banda diagonal, constituem as principais estruturas e sistemas que possuem conexões com as áreas corticais límbicas e que, em conjunto com estas, atuam sobre o hipotálamo e o tronco encefálico que, por sua vez, geram os componentes autonômicos, endócrinos e somatomotores das experiências emocionais e que regulam as atividades básicas de beber, comer e pertinentes ao comportamento sexual.

Secondary mania of vascular origin in elderly patients: A report of two clinical cases

The concept of secondary mania continues to be debated together with unresolved or partially resolved issues such as lateralization, localization, age of onset, disinhibition syndromes, and others. We have described two patients with secondary mania following a stroke. One had a large left hemisphere cerebral infarction and the symptoms arose about 2.5 years later, possibly triggered by a transient ischemic attack involving the right hemisphere. The other had an infarction in the right posterior artery territory extending to the thalamus and internal capsule together with infarctions in the deep border zones of both hemispheres at the level of the centrum semiovale with the manic symptoms concomitant with the onset of the event. The clinical and neuro-anatomic mechanisms that underlie the diverse locations of secondary mania are discussed. The cerebral components of secondary mania and disinhibition syndromes are very similar and it is proposed that disinhibition syndromes, secondary hypomania and secondary mania with and without psychotic symptoms are simply a continuum of severity of mood disorder and secondary mania with psychotic symptoms may be an extreme form. The concept of secondary mania in the elderly is not likely to disappear although several unresolved issues remain. For the neurophysician, geriatrician, and the psychiatrist there is much to be attained by simplifying the issues and accepting the view that secondary mania is a discrete entity.

The roles of sequencing and verbal working memory in sentence comprehension deficits in Parkinson's disease

Studies of sentence comprehension deficits in Parkinson's disease (PD) patients suggest that language processing involves circuits connecting subcortical and cortical regions. Anatomically segregated neural circuits appear to support different cognitive and motor functions. To investigate which functions are implicated in PD comprehension deficits, we tested comprehension, verbal working memory span, and cognitive set-switching in a non-linguistic task in 41 PD patients; we also obtained speech measurements reflecting motor sequencing processes that may be involved in articulatory rehearsal within working memory. Comprehension of sentences with center-embedded or final relative clauses was impaired when they could not be understood from lexical semantic content alone. Overall comprehension error rates correlated strongly with impaired set-switching and significantly with reduced working memory span and speech motor sequencing deficits. Correlations with comprehension of different sentence structures indicate that these impairments do not represent a single deficit; rather, PD comprehension deficits appear to arise from several independent mechanisms. Deficits in cognitive set-switching or underlying inhibitory processes may compromise the ability to process relative clauses. Deficits in verbal working memory appear to impair comprehension of long-distance dependencies. Speech sequencing correlated with neither set-switching nor verbal working memory span, consistent with their being supported by independent, segregated cortico-subcortical circuits.

Apathy and the Functional Anatomy of the Prefrontal Cortex–Basal Ganglia Circuits

The clinical signs grouped under the concept of apathy are a common feature of prefrontal and basal ganglia lesions or dysfunctions and can therefore help to improve our understanding of the functional anatomy of the prefrontal-basal ganglia system. Apathy is here defined as a quantitative reduction of voluntary, goal-directed behaviors. The underlying mechanisms responsible for apathy can be divided into three subtypes of disrupted processing: 'emotional-affective', 'cognitive' and 'auto-activation'. Apathy due to the disruption of 'emotional-affective' processing refers to the inability to establish the necessary linkage between emotional-affective signals and the ongoing or forthcoming behavior. It may be related to lesions of the orbital-medial prefrontal cortex or to the related subregions (limbic territory) within the basal ganglia (e.g. ventral striatum, ventral pallidum). Apathy due to the disruption of 'cognitive' processing refers to difficulties in elaborating the plan of actions necessary for the ongoing or forthcoming behavior. It may be related to lesions of the dorsolateral prefrontal cortex and the related subregions (associative territory) within the basal ganglia (e.g. dorsal caudate nucleus). The disruption of 'auto-activation' processing refers to the inability to self-activate thoughts or self-initiate actions contrasting with a relatively spared ability to generate externally driven behavior. It is responsible for the most severe form of apathy and in most cases the lesions affect bilaterally the associative and limbic territories of the internal portion of the globus pallidus. It characterizes the syndrome of 'auto-activation deficit' (also known as 'psychic akinesia' or 'athymormia'). This syndrome implies that direct lesions of the basal ganglia output result in a loss of amplification of the relevant signal, consequently leading to a diminished extraction of this signal within the frontal cortex. Likewise, apathy occurring in Parkinson's disease could be interpreted as secondary to the loss of spatial and temporal focalization of the signals transferred to the frontal cortex. In both situations (direct basal ganglia lesions and nigro-striatal dopaminergic loss), the capacity of the frontal cortex to select, initiate, maintain and shift programs of actions is impaired.

Cognitive and behavioral aspects of PSP since Steele, Richardson and Olszewski's description of PSP 40 years ago and Albert's delineation of the subcortical dementia 30 years ago

Although researchers are now familiar with progressive supranuclear palsy (PSP) and its characteristic "subcortical" dementia, this was not the case prior to seminal descriptions by Steele, Richardson, Olszewski and Albert. In fact, the first three authors identified this disorder, and the last one introduced the classification of the dementias according to the anatomical involvement. This paper is in honor of their contributions, and will also outline the changes that have occurred since their seminal works.

Parkinsonism following bilateral lesions of the globus pallidus: performance on a variety of motor tasks shows similarities with Parkinson's disease

OBJECTIVES

The authors report the results of detailed investigations into the motor function of a patient who, after a heavy drinking binge and subsequent unconsciousness, respiratory acidosis, and initial recovery, developed parkinsonism characterised by hypophonic speech and palilalia, "fast micrographia", impaired postural reflexes, and brady/akinesia in proximal (but not distal) alternating upper limb movements.

METHODS

In addition to brain magnetic resonance imaging (MRI), different aspects of motor function were investigated using reaction time (RT) tasks, pegboard and finger tapping tasks, flex and squeeze tasks, movement related cortical potentials (MRCPs), and contingent negative variation (CNV). Cognitive function was also assessed. The results were compared to those previously reported in patients with Parkinson's disease (PD).

RESULTS

Brain MRI showed isolated and bilateral globus pallidus (GP) lesions covering mainly the external parts (GPe). These lesions were most probably secondary to respiratory acidosis, as other investigations failed to reveal an alternative cause. The results of the RT tasks showed that the patient had difficulties in preparing and maintaining preparation for a forthcoming movement. MRCP and CNV studies were in line with this, as the early component of the MRCP and CNV were absent prior to movement. The patient's performance on pegboard and finger tapping, and flex and squeeze tasks was normal when performed with one hand, but clearly deteriorated when using both hands simultaneously or sequentially.

CONCLUSIONS

In general, the present results were similar to those reported previously in patients with PD. This provides further indirect evidence that the output of globus pallidus is of major importance in abnormal motor function in PD. The possible similarities of the functional status of GP in PD and our case are discussed.