Dopamine neuron activity encodes the length of upcoming contralateral movement sequences.

Dopaminergic neurons (DANs) in the substantia nigra pars compacta (SNc) have been related to movement speed, and loss of these neurons leads to bradykinesia in Parkinson's disease (PD). However, other aspects of movement vigor are also affected in PD; for example, movement sequences are typically shorter. However, the relationship between the activity of DANs and the length of movement sequences is unknown. We imaged activity of SNc DANs in mice trained in a freely moving operant task, which relies on individual forelimb sequences. We uncovered a similar proportion of SNc DANs increasing their activity before either ipsilateral or contralateral sequences. However, the magnitude of this activity was higher for contralateral actions and was related to contralateral but not ipsilateral sequence length. In contrast, the activity of reward-modulated DANs, largely distinct from those modulated by movement, was not lateralized. Finally, unilateral dopamine depletion impaired contralateral, but not ipsilateral, sequence length. These results indicate that movement-initiation DANs encode more than a general motivation signal and invigorate aspects of contralateral movements.

Dynamic behaviour restructuring mediates dopamine-dependent credit assignment.

Animals exhibit a diverse behavioural repertoire when exploring new environments and can learn which actions or action sequences produce positive outcomes. Dopamine release after encountering a reward is critical for reinforcing reward-producing actions1-3. However, it has been challenging to understand how credit is assigned to the exact action that produced the dopamine release during continuous behaviour. Here we investigated this problem in mice using a self-stimulation paradigm in which specific spontaneous movements triggered optogenetic stimulation of dopaminergic neurons. Dopamine self-stimulation rapidly and dynamically changes the structure of the entire behavioural repertoire. Initial stimulations reinforced not only the stimulation-producing target action, but also actions similar to the target action and actions that occurred a few seconds before stimulation. Repeated pairings led to a gradual refinement of the behavioural repertoire to home in on the target action. Reinforcement of action sequences revealed further temporal dependencies of refinement. Action pairs spontaneously separated by long time intervals promoted a stepwise credit assignment, with early refinement of actions most proximal to stimulation and subsequent refinement of more distal actions. Thus, a retrospective reinforcement mechanism promotes not only reinforcement, but also gradual refinement of the entire behavioural repertoire to assign credit to specific actions and action sequences that lead to dopamine release.

Criterion and construct validity of the Beck Depression Inventory (BDI-II) to measure depression in patients with cancer: The contribution of somatic items.

Background/Objective: Screening for depression in patients with cancer can be difficult due to overlap between symptoms of depression and cancer. We assessed validity of the Beck Depression Inventory (BDI-II) in this population. Method: Data was obtained in an outpatient neuropsychiatry unit treating patients with and without cancer. Psychometric properties of the BDI-II Portuguese version were assessed separately in 202 patients with cancer, and 376 outpatients with mental health complaints but without cancer. Results: Confirmatory factor analysis suggested a three-factor structure model (cognitive, affective and somatic) provided best fit to data in both samples. Criterion validity was good for detecting depression in oncological patients, with an area under the ROC curve (AUC) of 0.85 (95% confidence interval [CI], 0.76-0.91). A cut-off score of 14 had sensitivity of 87% and specificity of 73%. Excluding somatic items did not significantly change the ROC curve for BDI-II (difference AUCs = 0.002, p=0.9). A good criterion validity for BDI-II was also obtained in the non-oncological population (AUC = 0.87; 95% CI 0.81-0.91), with a cut-off of 18 (sensitivity=84%; specificity=73%). Conclusions: The BDI-II demonstrated good psychometric properties in patients with cancer, comparable to a population without cancer. Exclusion of somatic items did not affect screening accuracy.

Selective activation of striatal indirect pathway suppresses levodopa induced-dyskinesias.

Levodopa (L-DOPA) administration remains the gold standard therapy for Parkinson's disease (PD). Despite several pharmacological advances in the use of L-DOPA, a high proportion of chronically treated patients continues to suffer disabling involuntary movements, namely, L-DOPA-induced dyskinesias (LIDs). As part of the effort to stop these unwanted side effects, the present study used a rodent model to identify and manipulate the striatal outflow circuitry responsible for LIDs. To do so, optogenetic technology was used to activate separately the striatal direct (D1R- expressing) and indirect (D2R- expressing) pathways in a mouse model of PD. Firstly, D1-cre or A2a-cre animals received unilateral injections of neurotoxin 6-hydroxydopamine (6-OHDA) to simulate the loss of dopamine observed in PD patients. The effects of independently stimulating each pathway were tested to see if experimental dyskinesias could be induced. Secondly, dopamine depleted A2a-cre animals received systemic L-DOPA to evoke dyskinetic movements. The ability of indirect pathway optogenetic stimulation to suppress pre-established LIDs was then tested. Selective manipulation of direct pathway evoked optodyskinesias both in dopamine depleted and intact animals, but optical inhibition of these neurons failed to suppress LIDs. On the other hand, selective activation of indirect striatal projection neurons produced an immediate and reliable suppression of LIDs. Thus, a functional dissociation has been found here whereby activation of D1R- and D2R-expressing projection neurons evokes and inhibits LIDs respectively, supporting the notion of tight interaction between the two striatal efferent systems in both normal and pathological conditions. This points to the importance of maintaining an equilibrium in the activity of both striatal pathways to produce normal movement. Finally, the ability of selective indirect pathway optogenetic activation to block the expression of LIDs in an animal model of PD sheds light on intrinsic mechanisms responsible for striatal-based dyskinesias and identifies a potential therapeutic target for suppressing LIDs in PD patients.

Neuro-mesenchymal units control ILC2 and obesity via a brain-adipose circuit.

Signals from sympathetic neurons and immune cells regulate adipocytes and thereby contribute to fat tissue biology. Interactions between the nervous and immune systems have recently emerged as important regulators of host defence and inflammation1-4. Nevertheless, it is unclear whether neuronal and immune cells co-operate in brain-body axes to orchestrate metabolism and obesity. Here we describe a neuro-mesenchymal unit that controls group 2 innate lymphoid cells (ILC2s), adipose tissue physiology, metabolism and obesity via a brain-adipose circuit. We found that sympathetic nerve terminals act on neighbouring adipose mesenchymal cells via the ß2-adrenergic receptor to control the expression of glial-derived neurotrophic factor (GDNF) and the activity of ILC2s in gonadal fat. Accordingly, ILC2-autonomous manipulation of the GDNF receptor machinery led to alterations in ILC2 function, energy expenditure, insulin resistance and propensity to obesity. Retrograde tracing and chemical, surgical and chemogenetic manipulations identified a sympathetic aorticorenal circuit that modulates ILC2s in gonadal fat and connects to higher-order brain areas, including the paraventricular nucleus of the hypothalamus. Our results identify a neuro-mesenchymal unit that translates cues from long-range neuronal circuitry into adipose-resident ILC2 function, thereby shaping host metabolism and obesity.

Author Correction: Light-entrained and brain-tuned circadian circuits regulate ILC3s and gut homeostasis.

An Amendment to this paper has been published and can be accessed via a link at the top of the paper.

Light-entrained and brain-tuned circadian circuits regulate ILC3s and gut homeostasis.

Group 3 innate lymphoid cells (ILC3s) are major regulators of inflammation, infection, microbiota composition and metabolism1. ILC3s and neuronal cells have been shown to interact at discrete mucosal locations to steer mucosal defence2,3. Nevertheless, it is unclear whether neuroimmune circuits operate at an organismal level, integrating extrinsic environmental signals to orchestrate ILC3 responses. Here we show that light-entrained and brain-tuned circadian circuits regulate enteric ILC3s, intestinal homeostasis, gut defence and host lipid metabolism in mice. We found that enteric ILC3s display circadian expression of clock genes and ILC3-related transcription factors. ILC3-autonomous ablation of the circadian regulator Arntl led to disrupted gut ILC3 homeostasis, impaired epithelial reactivity, a deregulated microbiome, increased susceptibility to bowel infection and disrupted lipid metabolism. Loss of ILC3-intrinsic Arntl shaped the gut 'postcode receptors' of ILC3s. Strikingly, light-dark cycles, feeding rhythms and microbial cues differentially regulated ILC3 clocks, with light signals being the major entraining cues of ILC3s. Accordingly, surgically or genetically induced deregulation of brain rhythmicity led to disrupted circadian ILC3 oscillations, a deregulated microbiome and altered lipid metabolism. Our work reveals a circadian circuitry that translates environmental light cues into enteric ILC3s, shaping intestinal health, metabolism and organismal homeostasis.

The prevalence of late-life depression in a Portuguese community sample: A 10/66 Dementia Research Group study.

BACKGROUND: Late life depression is associated with a significant burden of disease. Estimating depression in older adults can be difficult and requires different methodological approaches from those fitting younger adults. As community prevalence data is scarce in Portugal, we estimated the prevalence of depression in a sample of older Portuguese adults. Moreover, we investigated the association between depression and disability. METHODS: A cross-sectional comprehensive one-phase survey was conducted of all residents aged 65 and over of one urban and one rural catchment area in Southern Portugal. Standardized 10/66 assessments include a comprehensive cognitive module and the Geriatric Mental State (GMS)-AGECAT. Information on demographics, non-communicable disease risk factors and disability/functioning (WHODAS 2.0) was also recorded. Depression was assessed using both ICD-10 and EURO-D criteria. RESULTS: We interviewed 1405 older people (mean age 74.9, SD = 6.7 years; 55.5% women) after 313 (18.2%) refusals to participate. The prevalence rate for ICD-10 depression was 4.4 (95% CI 3.5-5.6) and 18.0 (95% CI 16.0-20.1) using the EURO-D case definition. As compared with having no depression, ICD-10 depression was associated with a higher level of disability, even after adjusting for confounders (4.8, 95% CI 2.8-8.1). The same happened with subsyndromal depression ('EURO-D only') cases (2.2, 95% CI 1.4-3.5). LIMITATIONS: Non-generalisability of findings outside of catchment areas. CONCLUSIONS: In this sample of older Portuguese people, the prevalence of depression was high and so were the associated levels of disability. EURO-D diagnoses may provide a better picture of clinically significant old age depression as a basis for health and social service planning.

Hypomania Symptoms Across Psychiatric Disorders: Screening Use of the Hypomania Check-List 32 at Admission to an Outpatient Psychiatry Clinic.

Introduction: Hypomania symptoms are best described as a continuum, ranging beyond Bipolar Spectrum Disorders (BSD). Other nosological entities, such as major depressive disorder, schizoaffective disorder, or borderline personality disorder, may also share symptoms with BSD, raising challenges for differential diagnosis. While the Hypomania Checklist-32 is one of the most widely used tools for screening hypomania, there is limited evidence describing its use in a real-world outpatient psychiatric clinical setting. Methods: Here we tested the psychometric properties of a European Portuguese adaptation of the HCL-32, establishing its factor structure, reliability and construct validity. Furthermore, we analyzed differences in hypomanic symptoms among several clinical groups and in a non-clinical sample. Data was obtained retrospectively in an ecological setting from a clinical sample of an outpatient psychiatry and psychology clinic, comprising 463 Portuguese individuals, 326 of whom had a psychiatric diagnosis, namely BSD (n = 66), major depressive disorder (n = 116), or other psychiatric disorders (n = 144). A separate non-clinical sample was also collected among healthy volunteers (n = 62). A battery of self-report measures of affective symptoms was applied, and in a subset of patients, diagnosis was established using a structured diagnostic interview. Results: Psychometric properties of the HCL-32 were adequate, with good internal consistency (Cronbach's α = 0.86) and test-retest stability (ICC = 0.86), and two subscores ("active/elated" and "risk-taking/irritable") defined by Principal Component Analysis. Receiver Operating Characteristic curve analysis demonstrated that the test score discriminated moderately between patients with BSD and other clinical samples as well as healthy volunteers, with a cut-off score of 17 for the total score of the HCL-32 rendering the best combination of sensitivity and specificity. When compared to the HCL-32 total score, the risk-taking/irritable subscore seems to provide additional benefit in discriminating between different clinical groups, namely regarding specificity in the discrimination from patients with a diagnosis of major depressive disorder that was low for the full scale and the alternate subscale. Conclusions: HCL-32 can be used as a screening tool for BSD among adult patients presenting in an outpatient psychiatric clinical setting.

Platelet Tau Protein as a Potential Peripheral Biomarker in Alzheimer's Disease: An Explorative Study.

BACKGROUND: Cerebrospinal fluid (CSF) measures of tau and amyloid proteins have now been largely accepted to be a diagnostic tool to aid the clinical diagnosis of Alzheimer's disease (AD), but CSF is not routinely obtained in most clinical settings. There is a need, therefore, to uncover additional readily accessible peripheral biomarkers that will enable comprehensive detection of AD-specific proteins in blood and blood derivates. OBJECTIVES: Blood platelets contain proteins found in neuronal cell lines, including tau protein. Since tau protein is a characteristic of AD-neuropathology, platelet tau protein may be closely related to the central nervous process occurring in neurodegeneration. METHOD: Platelets from 25 AD and 26 control subjects were analysed for the microtubule-binding and C-terminal region, as well as two tau phosphorylation sites (Ser202/Thr205 and Thr181). RESULTS: Tau protein measures did not discriminate between AD and control individuals. However, subjects with MMSE 24-27 had elevated C-terminal end tau protein (p=0.049) compared to those with MMSE >27, whereas older AD subjects (>80 years) showed higher t-tau protein in comparison to younger AD (<80 years; p=0.009) and control (<80 years; p=0.011) participants. CONCLUSIONS: These initial findings not only confirm that platelet tau protein can be measured, but also indicate that platelet tau measures merit further study as they may be useful in indicating early stages of cognitive impairment. Further studies on larger number of participants are needed to confirm our findings.

Dopamine neuron activity before action initiation gates and invigorates future movements.

Deciding when and whether to move is critical for survival. Loss of dopamine neurons (DANs) of the substantia nigra pars compacta (SNc) in patients with Parkinson's disease causes deficits in movement initiation and slowness of movement. The role of DANs in self-paced movement has mostly been attributed to their tonic activity, whereas phasic changes in DAN activity have been linked to reward prediction. This model has recently been challenged by studies showing transient changes in DAN activity before or during self-paced movement initiation. Nevertheless, the necessity of this activity for spontaneous movement initiation has not been demonstrated, nor has its relation to initiation versus ongoing movement been described. Here we show that a large proportion of SNc DANs, which did not overlap with reward-responsive DANs, transiently increased their activity before self-paced movement initiation in mice. This activity was not action-specific, and was related to the vigour of future movements. Inhibition of DANs when mice were immobile reduced the probability and vigour of future movements. Conversely, brief activation of DANs when mice were immobile increased the probability and vigour of future movements. Manipulations of dopamine activity after movement initiation did not affect ongoing movements. Similar findings were observed for the initiation and execution of learned action sequences. These findings causally implicate DAN activity before movement initiation in the probability and vigour of future movements.

Psychiatric symptoms screening in the early stages of Parkinson's disease.

Psychiatric complaints are common in Parkinson's disease (PD), and have a significant influence in disease outcome and quality of life. Little attention has been paid to psychiatric symptoms at early stage disease. We aimed to screen a population of early stage PD patients for psychiatric symptoms and to study the relation with motor and cognitive function. Thirty-six early stage PD patients underwent motor [Hoehn and Yahr (HY), Unified Parkinson's Disease Rating Scale] and cognitive [Frontal Assessment Battery, Mini-Mental State Examination (MMSE)] assessment as well as general psychiatric [Symptom Check-List 90 (SCL-90-R)] and psychosis [Brief Psychiatric Rating Scale (BPRS)] screening. Relation between psychiatric domains scores was studied with principal component analysis. Relation between psychiatric, disease related, cognitive and motor function was assessed with bivariate correlation (Pearson). SCL-90-R scores were higher for somatization (significant scores in 66.7% of patients), depression (36.1%), anxiety (27%) and obsessive-compulsive symptoms (OCS) (52.8%). Scores were highly correlated, except for psychosis and phobia. Depression and anxiety were negatively correlated to MMSE score and dopaminergic doses, respectively. BPRS scores were higher for somatic concern, depression, anxiety and hallucinations. There was segregation between depression, anxiety, hallucinations, other positive psychotic symptoms and negative psychotic symptoms. Depression was related to MMSE score. We found a high prevalence of psychiatric complaints in PD patients, mostly related to depression, anxiety, somatization and OCS. Hallucinations were also frequent, but not associated to cognitive function or dopaminergic doses, suggesting a different physiopathological background.

Clinical features associated with REM sleep behavior disorder symptoms in the early stages of Parkinson's disease.

We aimed to characterize the clinical features associated with REM sleep behaviour disorder (RBD) in early stage Parkinson's disease (PD). Presence of clinical RBD was determined according to ICSD minimal clinical criteria and a validated RBD questionnaire. We registered time of appearance of RBD symptoms in relation to PD onset and the occurrence of RBD symptoms in the past in non-RBD patients. RBD and non-RBD groups were compared in terms of motor and cognitive dysfunction. The same comparisons were made between patients who reported RBD symptoms at some point in time (including those non-RBD patients that reported occurrence of RBD symptoms in the past) and those who did not (RBDS and non-RBDS, respectively). We assessed 75 patients. Forty-one (55%) patients presented with RBD, 19 beginning before PD onset. Five non-RBD patients reported having had RBD symptoms in the past. There were no significant differences between RBD and non-RBD patients. RBDS group presented a significantly higher proportion of non-tremor motor sub-type compared to non-RBDS patients. Our results suggest that RBD is very frequent in the early stages of PD. In some patients, RBD symptoms could have disappeared before or in the first years after motor disturbance onset. Non-tremor motor sub-type was related to RBD symptoms history, rather than to the presence of RBD clinical criteria at time of evaluation, suggesting that the physiopathological changes that cause the association with motor status could remain, in spite of symptom fluctuation.

[Club drugs]. / Club drugs: Um Novo Perfil de Abuso de Substâncias em Adolescentes e Jovens Adultos.

Club drugs are the following substances: Methylenedioxymethamphetamine (MDMA); Methamphetamine; Lysergic Acid Diethylamide (LSD); Ketamine; Gamma-hydroxybutyrate (GHB) and Flunitrazepam. These substances are mainly used by adolescents and young adults, mostly in recreational settings like dance clubs and rave parties. These drugs have diverse psychotropic effects, are associated with several degrees of toxicity, dependence and long term adverse effects. Some have been used for several decades, while others are relatively recent substances of abuse. They have distinct pharmacodynamic and pharmacokinetic properties, are not easy to detect and, many times, the use of club drugs is under diagnosed. Although the use of these drugs is increasingly common, few health professionals feel comfortable with the diagnosis and treatment. The authors performed a systematic literature review, with the goal of synthesising the existing knowledge about club drugs, namely epidemiology, mechanism of action, detection, adverse reactions and treatment. The purpose of this article is creating in Portuguese language a knowledge data base on club drugs, that health professionals of various specialties can use as a reference when dealing with individual with this kind of drug abuse.

Caregiving experiences and knowledge about dementia in Portuguese clinical outpatient settings.

BACKGROUND: Important public health and clinical issues remain unanswered concerning disease-related knowledge and caregiving experiences in dementia. The aim of this study is to describe these dimensions in Portuguese clinical settings and analyze the link between knowledge and burden, and also between knowledge and positive caregiving experiences. METHODS: We studied a non-randomized sample of 116 caregivers of outpatients with ICD10-DCR diagnosis of dementia. Comprehensive assessments included Dementia Knowledge Questionnaire (DKQ), Zarit Burden Interview (ZBI), Caregiving Activity Survey (CAS), Positive Aspects of Caregiving (PAC) and General Health Questionnaire-12 (GHQ). Portuguese translations for DKQ, ZBI and PAC scales had been developed; validity aspects were documented, as well as test-retest reliability coefficients for ZBI (ICC = 0.93) and PAC (ICC = 0.85). RESULTS: Most caregivers were close relatives, female and living with the patient. Although positive aspects of care were reported, burden and distress levels were moderate to high. Knowledge needs were not striking. Distress was moderately correlated to burden, but no associations were found between caregivers' knowledge and ZBI, PAC or GHQ. DKQ scores did not predict PAC nor ZBI scores. A relationship was found between ZBI, as dependent variable, and PAC, GHQ and CAS. CONCLUSIONS: A large proportion of caregivers in this sample, albeit informed about dementia, were at risk of high burden and distress. Knowledge about dementia may not be protective of burden per se, nor did it influence positive aspects of caregiving.

Munchausen syndrome mimicking psychiatric disease with concomitant genuine physical illness.

Munchausen syndrome is a disorder in which patients intentionally produce symptoms mimicking physical or psychiatric illnesses with the aim to assume the sick role and to gain medical attention. Once a patient receives a Munchausen syndrome diagnosis every complaint made thence tends to be regarded with scepticism by clinical staff. However, it is possible that a bona fide illness, which might be disregarded, may coexist in these patients. We report a case of MS mimicking psychiatric disease with concomitant genuine acute physical illness. Despite the initial doubts about the veracity of the latter, due to its prompt recognition, treatment was successful.

Acute psychotic episode in a patient with thyrotoxicosis factitia.

Psychotic syndromes in the context of hyperthyroidism are seldom mentioned in medical textbooks and only a few cases have been published. Typically, such cases present as an affective psychosis. Schizophrenia-like psychosis is a rare occurrence in hyperthyroidism and the link between these two conditions is still poorly understood.We report the case of a female patient with a known history of chronic lymphocytic thyroiditis. The patient presented to our emergency department with an acute schizophrenia-like psychosis. Elevated levels of T4 and free T4 were found. These resulted from the patient's voluntary intake of excess levothyroxine as an attempt to lose weight (thyrotoxicosis factitia). Normalisation of thyroid hormone levels and antipsychotic treatment led to prompt remission of the psychosis. Even though the patient stopped the antipsychotics, she remained free of symptoms during the follow-up. Similar cases are briefly reviewed and some of the data from basic research is also considered.