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Abstract Cognitive impairment and symptoms of psychiatric disorders have been reported frequently as features of post-acute sequelae of SARS-CoV-2 infection. This study aims to investigate subjective memory complaints in COVID-19 survivors and determine if these are more strongly associated with objective cognitive impairment related to sequelae of SARS-CoV-2 infection or with symptoms of psychiatric conditions. A total of 608 COVID-19 survivors were evaluated in-person 6–11 months after hospitalization, with 377 patients assigned to a “no subjective memory complaint (SMC)” group and 231 patients assigned to an SMC group based on their Memory Complaint Scale scores. Follow-up evaluations included an objective cognitive battery and scale-based assessments of anxiety, depression, and post-traumatic stress symptoms. We found the perception of memory impairment in COVID-19 survivors to be more strongly associated to core symptoms of psychiatric conditions rather than to primary objective cognitive impairment. Univariate analysis indicated significant differences between the “no SMC” and SMC groups, both for the psychiatric symptom evaluations and for the cognitive evaluations (p

IntroductionThe COVID-19 pandemic has prompted global research efforts to reduce infection impact, highlighting the potential of cross-disciplinary collaboration to enhance research quality and efficiency.MethodsAt the FMUSP-HC academic health system, we implemented innovative flow management routines for collecting, organizing and analyzing demographic data, COVID-related data and biological materials from over 4,500 patients with confirmed SARS-CoV-2 infection hospitalized from 2020 to 2022. This strategy was mainly planned in three areas: organizing a database with data from the hospitalizations; setting-up a multidisciplinary taskforce to conduct follow-up assessments after discharge; and organizing a biobank. Additionally, a COVID-19 curated collection was created within the institutional digital library of academic papers to map the research output.ResultsOver the course of the experience, the possible benefits and challenges of this type of research support approach were identified and discussed, leading to a set of recommended strategies to enhance collaboration within the research institution. Demographic and clinical data from COVID-19 hospitalizations were compiled in a database including adults and a minority of children and adolescents with laboratory confirmed COVID-19, covering 2020–2022, with approximately 350 fields per patient. To date, this database has been used in 16 published studies. Additionally, we assessed 700 adults 6 to 11 months after hospitalization through comprehensive, multidisciplinary in-person evaluations; this database, comprising around 2000 fields per subject, was used in 15 publications. Furthermore, thousands of blood samples collected during the acute phase and follow-up assessments remain stored for future investigations. To date, more than 3,700 aliquots have been used in ongoing research investigating various aspects of COVID-19. Lastly, the mapping of the overall research output revealed that between 2020 and 2022 our academic system produced 1,394 scientific articles on COVID-19.DiscussionResearch is a crucial component of an effective epidemic response, and the preparation process should include a well-defined plan for organizing and sharing resources. The initiatives described in the present paper were successful in our aim to foster large-scale research in our institution. Although a single model may not be appropriate for all contexts, cross-disciplinary collaboration and open data sharing should make health research systems more efficient to generate the best evidence.

Objectives To develop a Brazilian public hospital, Sao Paulo University Medical School Clinics Hospital, HCFMUSP, informational model to link and improve multiple patients' health data, care pathways and outcomes, to build a living real world ecosystem aiming to subsidize policy decision-making, support research and promote patients' engagement and involvement. Methods Policy-relevant linkage data including demography, diagnostics, outpatient and emergency room visits, hospitalizations, intensive care evolution, assisted mechanical ventilation or special equipment’s uses, electronic prescriptions, imaging and clinical laboratory tests results, surgery records, blood components use, and medical and multidisciplinary teams’ evolutions. Telemedicine-based hub developed for patient’s access to his own visits or procedures schedule, comprehensive data and results temporal series, and specific communications channels. Anonymized data sharing for Sao Paulo State Health Secretariat policy decision-making and SP Research Agency multicenter Data Lake for Covid-19 pandemic research. Stratified impact and economic analysis regarding clinical and co-morbid conditions research were published. Results Since March 2020, this informational model example comprises over 10,000 Covid-19 patient’s related data with more than 100,000 events registered. During the first pandemic trimester, upon SP Health Secretariat policy, the HCFMUSP Central Institute’s 900 ward and 300 ICU beds were the SP central reference for severe and critical admissions. In this first evaluation 88.4% had co-morbidities (e.g. 48.1% hypertension, 30.5% diabetes), 51.7% required ICU admission and 28.9% died. Average hospital length of stay was 10.7 days, mean cost per admission was US$12,637.42, and the overall daily cost was US$919.24. Age strata >69 years confirmed COVID-19, ICU, elevated C-reactive protein (inflammation) adjusted by D-dimer levels (thrombosis biomarker), higher mSOFA, mechanical ventilation, dialysis, surgery and comorbidities, remained significantly associated with higher (24%-200%) costs and poorer outcomes. Conclusion The informational model is proving to be beneficial for all stakeholders. Technology-based organized systems increased management accuracy and efficiency, emergency preparedness, facilitates patient’s involvement and participation, promote medical and multi-professionals teams’ knowledge development, and permits to subsidize policy decisions and to improve public health.

Objective: Positron emission tomography (PET) allows in vivo evaluation of molecular targets in neurodegenerative diseases, such as Alzheimer’s disease. Mild cognitive impairment is an intermediate stage between normal cognition and Alzheimer-type dementia. In vivo fibrillar amyloid-beta can be detected in PET using [11C]-labeled Pittsburgh compound B (11C-PiB). In contrast, [18F]fluoro-2-deoxy-d-glucose (18F-FDG) is a neurodegeneration biomarker used to evaluate cerebral glucose metabolism, indicating neuronal injury and synaptic dysfunction. In addition, early cerebral uptake of amyloid-PET tracers can determine regional cerebral blood flow. The present study compared early-phase 11C-PiB and 18F-FDG in older adults without cognitive impairment, amnestic mild cognitive impairment, and clinical diagnosis of probable Alzheimer’s disease. Methods: We selected 90 older adults, clinically classified as healthy controls, with amnestic mild cognitive impairment, or with probable Alzheimer’s disease, who underwent an 18F-FDG PET, early-phase 11C-PiB PET and magnetic resonance imaging. All participants were also classified as amyloid-positive or -negative in late-phase 11C-PiB. The data were analyzed using statistical parametric mapping. Results: We found that the probable Alzheimer’s disease and amnestic mild cognitive impairment group had lower early-phase 11C-PiB uptake in limbic structures than 18F-FDG uptake. The images showed significant interactions between amyloid-beta status (negative or positive). However, early-phase 11C-PiB appears to provide different information from 18F-FDG about neurodegeneration. Conclusions: Our study suggests that early-phase 11C-PiB uptake correlates with 18F-FDG, irrespective of the particular amyloid-beta status. In addition, we observed distinct regional distribution patterns between both biomarkers, reinforcing the need for more robust studies to investigate the real clinical value of early-phase amyloid-PET imaging.

Objective: People with Alzheimer’s disease (AD) dementia have impaired sleep. However, the characteristics of sleep in the early stages of AD are not well known, and studies with the aid of biomarkers are lacking. We assessed the subjective sleep characteristics of non-demented older adults and compared their amyloid profiles. Methods: We enrolled 30 participants aged ≥ 60 years, with no dementia or major clinical and psychiatric diseases. They underwent [11C]PiB-PET-CT, neuropsychological evaluations, and completed two standardized sleep assessments (Pittsburgh Sleep Quality Inventory and Epworth Sleep Scale). Results: Comparative analysis of subjective sleep parameters across the two groups showed longer times in bed (p = 0.024) and reduced sleep efficiency (p = 0.05) in individuals with positive amyloid. No differences in other subjective sleep parameters were observed. We also found that people with multiple-domain mild cognitive impairment (MCI) had shorter self-reported total sleep times (p = 0.034) and worse overall sleep quality (p = 0.027) compared to those with single-domain MCI. Conclusions: Older adults testing positive for amyloid had a longer time in bed and lower sleep efficiency, regardless of cognitive status. In parallel, individuals with multiple-domain MCI reported shorter sleep duration and lower overall sleep quality.

Changes in brain structure asymmetry have been reported in autism spectrum disorder. Here the authors investigate this issue using a large-scale sample consisting of 54 data sets.

We organized 10Kin1day, a pop-up scientific event with the goal to bring together neuroimaging groups from around the world to jointly analyze 10,000+ existing MRI connectivity datasets during a 3-day workshop. In this report, we describe the motivation and principles of 10Kin1day, together with a public release of 8,000+ MRI connectome maps of the human brain.

Objective: To compare results of positron emission tomography (PET) with carbon-11-labeled Pittsburgh compound B (11C-PIB) obtained with cerebellar or global brain uptake for voxel intensity normalization, describe the cortical sites with highest tracer uptake in subjects with mild Alzheimer’s disease (AD), and explore possible group differences in 11C-PIB binding to white matter. Methods: 11C-PIB PET scans were acquired from subjects with AD (n=17) and healthy elderly controls (n=19). Voxel-based analysis was performed with statistical parametric mapping (SPM). Results: Cerebellar normalization showed higher 11C-PIB uptake in the AD group relative to controls throughout the cerebral cortex, involving the lateral temporal, orbitofrontal, and superior parietal cortices. With global uptake normalization, greatest cortical binding was detected in the orbitofrontal cortex; decreased 11C-PIB uptake in white matter was found in the posterior hippocampal region, corpus callosum, pons, and internal capsule. Conclusion: The present case-control voxelwise 11C-PIB PET comparison highlighted the regional distribution of amyloid deposition in the cerebral cortex of mildly demented AD patients. Tracer uptake was highest in the orbitofrontal cortex. Decreased 11C-PIB uptake in white-matter regions in this patient population may be a marker of white-matter damage in AD.

Objective: To analyze the differences in psychopathic traits between offender and non-offender youths with similar socioeconomic backgrounds. Method: The Psychopathy Checklist Revised (PCL-R) scale was used to identify whether 39 young offenders with no history of mental disorders or criteria for psychopathy exhibited differences in its total score, and specifically for factor 1 or factor 2 of this scale, when compared with 32 other young people, living in similar socioeconomic conditions, who had not committed offenses. Results: We observed statistically significant between-group differences (p < 0.01) in mean PCL-R scores, with a mean score of 13.4 in the offender group vs. 2.1 in the non-offender group. We also detected significant between-group differences when we analyzed mean factor 1 (p < 0.01) and factor 2 (p < 0.01) scores separately. Although the groups exhibited statistically significant difference in educational attainment, between-group comparison of mean PCL-R scores controlling for educational attainment by analysis of covariance (ANCOVA) showed that the difference in PCL-R scores remained statistically significant (p < 0.01). Conclusions: We conclude that, in this sample, the presence of both primary (interpersonal/affective characteristics) and secondary (lifestyle/antisocial behavior) psychopathic traits differed between offender and non-offender youths, even when excluding psychopathy and other mental disorders from the assessments. These results suggest a need for wide-ranging interventions, not restricted to socioeconomic aspects, for the management of juvenile delinquency.

The relationship between depression and epilepsy has been known since ancient times, however, to date, it is not fully understood. The prevalence of psychiatric disorders in persons with epilepsy is high compared to general population. It is assumed that the rate of depression ranges from 20 to 55% in patients with refractory epilepsy, especially considering those with temporal lobe epilepsy caused by mesial temporal sclerosis. Temporal lobe epilepsy is a good biological model to understand the common structural basis between depression and epilepsy. Interestingly, mesial temporal lobe epilepsy and depression share a similar neurocircuitry involving: temporal lobes with hippocampus, amygdala and entorhinal and neocortical cortex; the frontal lobes with cingulate gyrus; subcortical structures, such as basal ganglia and thalamus; and the connecting pathways. We provide clinical and brain structural evidences that depression and epilepsy represent an epiphenomenon sharing similar neural networks.

The relationship between depression and epilepsy has been known since ancient times, however, to date, it is not fully understood. The prevalence of psychiatric disorders in persons with epilepsy is high compared to general population. It is assumed that the rate of depression ranges from 20 to 55% in patients with refractory epilepsy, especially considering those with temporal lobe epilepsy caused by mesial temporal sclerosis. Temporal lobe epilepsy is a good biological model to understand the common structural basis between depression and epilepsy. Interestingly, mesial temporal lobe epilepsy and depression share a similar neurocircuitry involving: temporal lobes with hippocampus, amygdala and entorhinal and neocortical cortex; the frontal lobes with cingulate gyrus; subcortical structures, such as basal ganglia and thalamus; and the connecting pathways. We provide clinical and brain structural evidences that depression and epilepsy represent an epiphenomenon sharing similar neural networks.A relação entre depressão e epilepsia é conhecida desde a antiguidade; entretanto, até o momento, não é completamente compreendida. A prevalência de transtornos psiquiátricos nas pessoas com epilepsia é elevada quando comparada à população em geral. A taxa de depressão varia de 20 a 55% nos pacientes com epilepsia refratária, especialmente considerando-se aqueles com epilepsia do lobo temporal causada por esclerose mesial temporal. A epilepsia do lobo temporal é um bom modelo biológico para compreender as bases estruturais comuns entre a epilepsia e a depressão. É relevante ressaltar que a epilepsia do lobo mesial e a depressão apresentam circuitos similares envolvendo: os lobos temporais com o hipocampo, a amigdala, o córtex entorrinal e o neocortex; os lobos frontais com o giro cíngulo; estruturas subcorticais, como os núcleos da base e o tálamo, e suas vias de conexão. Postulamos por meio de evidências clínicas e estruturais que a depressão e a epilepsia representam um epifenômeno com redes neuronais similares.

OBJECTIVE: To make individual assessments using automated quantification methodology in order to screen for perfusion abnormalities in cerebral SPECT examinations among a sample of subjects with OCD. METHODS: Statistical parametric mapping (SPM) was used to compare 26 brain SPECT images from patients with OCD individually with an image bank of 32 normal subjects, using the statistical threshold of p < 0.05 (corrected for multiple comparisons at the level of individual voxels or clusters). The maps were analyzed, and regions presenting voxels that remained above this threshold were sought. RESULTS: Six patients from a sample of 26 OCD images showed abnormalities at cluster or voxel level, considering the criteria described above, which represented 23.07%. However, seven images from the normal group of 32 were also indicated as cases of perfusional abnormality, representing 21.8% of the sample. CONCLUSION: The automated quantification method was not considered to be a useful tool for clinical practice, for analyses complementary to visual inspection.

INTRODUCTION: Visual analysis is widely used to interpret regional cerebral blood flow (rCBF) SPECT images in clinical practice despite its limitations. Automated methods are employed to investigate between-group rCBF differences in research studies but have rarely been explored in individual analyses. OBJECTIVES: To compare visual inspection by nuclear physicians with the automated statistical parametric mapping program using a SPECT dataset of patients with neurological disorders and normal control images. METHODS: Using statistical parametric mapping, 14 SPECT images from patients with various neurological disorders were compared individually with a databank of 32 normal images using a statistical threshold of p

A maconha é a droga ilícita mais utilizada. Apesar disto, apenas um pequeno número de estudos investigaram as conseqüências neurotóxicas de longo prazo do uso de cannabis. As técnicas de neuroimagem se constituem em poderosos instrumentos para investigar alterações neuroanatômicas e neurofuncionais e suas correlações clínicas e neuropsicológicas. Uma revisão computadorizada da literatura foi conduzida nos indexadores MEDLINE e PsycLIT entre 1966 e novembro de 2004 com os termos 'cannabis', 'marijuana', 'neuroimaging', 'magnetic resonance', 'computed tomography', 'positron emission tomography', 'single photon emission computed tomography", 'SPET', 'MRI' e 'CT'. Estudos de neuroimagem estrutural apresentam resultados conflitantes, com a maioria dos estudos não relatando atrofia cerebral ou alterações volumétricas regionais. Contudo, há uma pequena evidência de que usuários de longo prazo que iniciaram um uso regular no início da adolescência apresentam atrofia cerebral assim como redução na substância cinzenta. Estudos de neuroimagem funcional relatam aumento na atividade neural em regiões que podem estar relacionadas com intoxicação por cannabis e alteração do humor (lobos frontais mesial e orbital) e redução na atividade de regiões relacionadas com funções cognitivas prejudicadas durante a intoxicação aguda. A questão crucial se efeitos neurotóxicos residuais ocorrem após o uso prolongado e regular de maconha permanece obscura, não existindo até então estudo endereçando esta questão diretamente. Estudos de neuroimagem com melhores desenhos, combinados com avaliação cognitiva, podem ser elucidativos neste aspecto.Cannabis is the most widely used illicit drug. Despite this, only a small number of studies have investigated the long-term neurotoxic consequences of cannabis use. Structural and functional neuroimaging techniques are powerful research tools to investigate possible cannabis-induced pathophysiological changes. A computer literature review was conducted in the MEDLINE and PsycLIT databases between 1966 and November of 2004 with the search terms 'cannabis', 'marijuana', 'neuroimaging', 'magnetic resonance', 'computed tomography', 'positron emission tomography', 'single photon emission computed tomography", 'SPET', 'MRI' and 'CT'. Structural neuroimaging studies have yielded conflicting results. Most studies report no evidence of cerebral atrophy or regional changes in tissue volumes, and one study suggested that long-term users who started regular use on early adolescence have cerebral atrophy as well as reduction in gray matter. However, several methodological shortcomings limit the interpretation of these results.Functional neuroimaging studies have reported increases in neural activity in regions that may be related with cannabis intoxication or mood-change effects (orbital and mesial frontal lobes, insula, and anterior cingulate) and decreases in activity of regions related with cognitive functions impaired during acute intoxication.The important question whether residual neurotoxic effects occur after prolonged and regular use of cannabis remains unclear, with no study addressing this question directly. Better designed neuroimaging studies, combined with cognitive evaluation, may be elucidative on this issue.

Contemporary neuroanatomical models for obsessive-compulsive disorder (OCD) propose that abnormalities of specific cortico-subcortical circuits mediate the disorder's symptoms. This paper focuses on the basal ganglia, believed to play a critical role in the functioning of those brain circuits. Clinical and experimental studies investigating the presence of abnormalities of basal ganglia structures in OCD are reviewed, with particular emphasis on the neuroimaging literature. Despite controversies in the area, a considerable amount of data has accumulated suggesting that abnormalities of the caudate and putamen nuclei can be associated with OCD. These abnormalities may be particularly relevant to specific subtypes of the disorder, such as early-onset OCD. With the continuing sophistication of neuroimaging technologies, future studies may be able to further clarify the role of each basal ganglia component in the pathophysiology of the various clinical features of OCD.

INTRODUÇÃO: Estudos que utilizam as técnicas de PET, SPECT e ressonância magnética funcional têm permitido o mapeamento dos circuitos cerebrais ativados durante diversas tarefas cognitivas. O campo da memória declarativa tem sido um dos mais intensamente estudados. No presente estudo, usa-se a técnica de mapeamento do fluxo sangüíneo cerebral regional (FSCr) por SPECT para investigar mudanças na atividade cerebral durante uma tarefa de memória episódica, em voluntários idosos sadios (n=15). MÉTODOS: Duas avaliações de SPECT foram realizadas na mesma sessão, usando a técnica de dose dividida do traçador 99 m-Tc-HMPAO. Medidas de FSCr foram registradas durante uma tarefa de reconhecimento de material verbal previamente aprendido e durante uma tarefa-controle mais simples. Comparações de FSCr foram realizadas automaticamente, utilizando o programa Statistical Parametric Mapping (SPM). RESULTADOS: Observou-se aumento de FSCr durante a tarefa de memória em várias regiões cerebrais, incluindo: córtex pré-frontal lateral bilateralmente (mais acentuadamente à esquerda); porções posteriores e mediais de córtex parieto-occipital à esquerda; hemisférios cerebelares bilateralmente; e córtex temporal lateral bilateralmente (pINTRODUCTION: PET, SPECT and functional magnetic resonance imaging studies have allowed the delineation of brain circuits activated during several types of cognitive tasks. The field of declarative memory has been one of the most extensively investigated. In the present study, the regional cerebral blood flow (rCBF) SPECT technique was used to investigate changes in brain activity during a verbal memory task in a group of elderly healthy volunteers (n=15). METHODS:Two SPECT acquisitions were performed in the same session, using the split-dose 99mTc-HMPAO technique. Measures of rCBF were taken during a recognition memory task and a simpler control task. Between-task comparisons were performed automatically using the Statistical Parametric Mapping (SPM) program. RESULTS: Increased rCBF during the memory task was seen in several brain regions, including: the lateral prefrontal cortex on both hemispheres (more intensely on the left side); posterior and medial portions of the left occipital and parietal cortices; the right and left cerebellar hemispheres; and the right and left lateral temporal cortex (p

The relationship between structural changes in grey matter and treatment response in patients with late-life depression remains an intriguing area of research. This magnetic resonance imaging (MRI) study compares the baseline grey matter volume of elderly people with and without major depression (according to the DSM-IV-TR criteria) and assesses its association with antidepressant treatment response. Brain MRI scans were processed using statistical parametric mapping and voxel-based morphometry. The sample consisted of 30 patients with depression and 22 healthy controls. We found a significant volumetric reduction in the orbitofrontal cortex bilaterally in patients in comparison with controls. According to their remission status after antidepressant treatment, patients were classified as remitted or not remitted. Compared with controls, remitted patients showed a volumetric reduction in the orbitofrontal cortex bilaterally and in another cluster in the right middle temporal pole. Non-remitted patients showed an even greater volumetric reduction in the orbitofrontal cortex bilaterally compared with controls. To investigate predictive factors of remission after antidepressant treatment, we used a logistic regression. Both baseline Mini Mental State Examination score and baseline left superior lateral orbitofrontal cortex volume (standardized to the total grey matter volume) were associated with remission status. Our findings support the use of regional brain atrophy as a potential biomarker for depression. In addition, baseline cognitive impairment and regional grey matter abnormalities predict antidepressant response in patients with late-life depression.

OBJECTIVE: To investigate the influence of brain-derived neurotrophic factor (BDNF) gene variations on cognitive performance and clinical symptomatology in first-episode psychosis (FEP). METHODS: We performed BDNF val66met variant genotyping, cognitive testing (verbal fluency and digit spans) and assessments of symptom severity (as assessed with the PANSS) in a population-based sample of FEP patients (77 with schizophreniform psychosis and 53 with affective psychoses) and 191 neighboring healthy controls. RESULTS: There was no difference in the proportion of Met allele carriers between FEP patients and controls, and no significant influence of BDNF genotype on cognitive test scores in either of the psychosis groups. A decreased severity of negative symptoms was found in FEP subjects that carried a Met allele, and this finding reached significance for the subgroup with affective psychoses (p < 0.01, ANOVA). CONCLUSIONS: These results suggest that, in FEP, the BDNF gene Val66Met polymorphism does not exert a pervasive influence on cognitive functioning but may modulate the severity of negative symptoms.OBJETIVO: Investigar a influência da variação do gene do fator neurotrófico derivado do cérebro (BDNF) no desempenho cognitivo e na sintomatologia clínica durante o primeiro episódio psicótico (PEP). MÉTODOS: Foram realizados a genotipificação das variantes Val66met do BDNF, o teste cognitivo (fluência verbal e repetição de dígitos) e as avaliações da gravidade dos sintomas (conforme avaliado pela Positive and Negative Syndrome Scale [PANSS]) em uma amostra de pacientes com PEP de base populacional (77 com psicose esquizofreniforme e 53 com psicose afetiva) e 191 vizinhos controle saudáveis. RESULTADOS: Não houve diferença na proporção de portadores do alelo Met entre pacientes com PEP e o grupo controle. Não houve influência significativa do genótipo do BDNF sobre a pontuação de cada um dos grupos psicóticos. Foi encontrada uma diminuição da gravidade dos sintomas negativos em sujeitos com PEP portadores do alelo Met, e essa descoberta mostrou-se significativa para o subgrupo com psicose afetiva (p < 0,01, ANOVA). CONCLUSÕES: Os resultados sugerem que, no PEP, o polimorfismo Val66Met do gene do BDNF não exerce uma influência importante sobre o funcionamento cognitivo, mas pode modular a gravidade dos sintomas negativos.

The pathophysiology of neurodegenerative diseases (ND) such as Alzheimer's disease (AD) and Parkinson's disease (PD) has not yet been completely elucidated. However, in the past few years, there have been great knowledge advances about intra-and extracellular proteins that may display impaired function or expression in AD, PD and other ND, such as amyloid beta (Aβ), α-synuclein, tau protein and neuroinflammatory markers. Recent developments in the imaging techniques of positron emission tomography (PET) and single photon emission computed tomography (SPECT) now allow the non-invasive tracking of such molecular targets of known relevance to ND in vivo. This article summarizes recent findings of PET and SPECT studies using these novel methods, and discusses their potential role in the field of drug development for ND as well as future clinical applications in regard to differential diagnosis of ND and monitoring of disease progression.A fisiopatologia das doenças neurodegenerativas (DN), tais como a doença de Alzheimer (DA) e a doença de Parkinson (DP), ainda não é completamente compreendida. No entanto, nos últimos anos, houve grandes avanços em termos do conhecimento sobre proteínas intra e extracelulares, tais como beta-amiloide (Aβ), α-sinucleína, proteína tau e marcadores neuroinflamatórios, que podem ter sua função ou expressão prejudicada na DA, DP ou em outras DN. Progressos recentes nas técnicas de tomografia por emissão de pósitrons (PET) e tomografia computadorizada por emissão de fóton único (SPECT) permitem hoje em dia a identificação não invasiva de tais alvos moleculares in vivo. Este artigo resume descobertas recentes de estudos de PET e SPECT cerebral usando esses alvos moleculares inovadores e discute o papel potencial dessas técnicas no campo do desenvolvimento de novos medicamentos para as DN, bem como futuras aplicações clínicas em relação ao diagnóstico diferencial e monitoramento da progressão dessas doenças.

ABSTRACT Voxel-based morphometry (VBM) is a useful approach for investigating neurostructural brain changes in dementia. We systematically reviewed VBM studies of Alzheimer's disease (AD) and mild cognitive impairment (MCI), specifically focusing on grey matter (GM) atrophy in the frontal lobe. Methods: Two searches were performed on the Pubmed database. A set of exclusion criteria was applied to ensure the selection of only VBM studies that directly investigated GM volume abnormalities in AD and/or MCI patients compared to cognitively normal controls. Results: From a total of 46 selected articles, 35 VBM studies reported GM volume reductions in the frontal lobe. The frontal subregions, where most of the volume reductions were reported, included the inferior, superior and middle frontal gyri, as well as the anterior cingulate gyrus. We also found studies in which reduced frontal GM was detected in MCI patients who converted to AD. In a minority of studies, correlations between frontal GM volumes and behavioural changes or cognitive deficits in AD patients were investigated, with variable findings. Conclusion: Results of VBM studies indicate that the frontal lobe should be regarded as an important brain area when investigating GM volume deficits in association with AD. Frontal GM loss might not be a feature specific to late AD only. Future VBM studies involving large AD samples are warranted to further investigate correlations between frontal volume deficits and both cognitive impairment and neuropsychiatric symptoms.

The last four decades have witnessed tremendous growth in research studies applying neuroimaging methods to evaluate pathophysiological and treatment aspects of psychiatric disorders around the world. This article provides a brief history of psychiatric neuroimaging research in Brazil, including quantitative information about the growth of this field in the country over the past 20 years. Also described are the various methodologies used, the wealth of scientific questions investigated, and the strength of international collaborations established. Finally, examples of the many methodological advances that have emerged in the field of in vivo neuroimaging are provided, with discussion of the challenges faced by psychiatric research groups in Brazil, a country of limited resources, to continue incorporating such innovations to generate novel scientific data of local and global relevance.