ABSTRACT Introduction: Structural and functional neuroimaging in schizophrenia has gained strength in recent years, so this review aims to describe neuroimaging findings that contribute to the physiopathological understanding, monitoring, and diagnosis of this pathology. Methods: A PubMed/Medline search was conducted for clinical studies addressing neuroimaging in schizophrenia. Results: The search yielded 2200 results, from which 13 studies were included, which provided findings, such as functional and structural alterations of the amygdala, which have shown to be associated with negative symptoms; morphometric reduction of the frontal region, alterations in the perfusion of the anterior cingulate gyrus and the lower-left parietal cortex, deregulation of the histone deacetylase enzyme, among others which translate clinically in neurocognitive deficits. Conclusions: This review provides an updated view on the findings of neuroimaging that can contribute to the understanding of the pathological mechanisms behind this psychotic disorder, its diagnostic usefulness, and its potential contribution to the prognosis and follow-up of this disease.

RESUMEN: Introducción: La neuroimagen estructural y funcional en la esquizofrenia ha tomado fuerza en los últimos años, por lo que esta revisión tiene por objetivo describir hallazgos de esta técnica que contribuyen a la fisiopatología, diagnóstico y pronóstico de esta patología. Métodos: Se realizó una búsqueda en PubMed/Medline de estudios clínicos que abordan el estudio con neuroimágenes en la esquizofrenia. Resultados: La búsqueda arrojó 2200 resultados, de los cuales fueron incluidos 13 estudios, los que arrojaron hallazgos que se tradujeron en alteraciones neurocognitivas, tales como alteraciones funcionales y estructurales de la amígdala asociada a síntomas negativos, reducción morfométrica de la región frontal, alteraciones en la perfusión del giro del cíngulo anterior y la corteza parietal inferior izquierda, desregulación de la enzima histona deacetilasa, entre otros. Conclusiones: Esta revisión brinda una visión actualizada sobre los hallazgos de la neuroimagenología que pueden aportar a la comprensión de los mecanismos patológicos detrás de este trastorno psicótico, así como su utilidad diagnóstica y potencial contribución al seguimiento de esta enfermedad.

While most patients with depression respond to pharmacotherapy and psychotherapy, about one-third will present treatment resistance to these interventions. For patients with treatment-resistant depression (TRD), invasive neurostimulation therapies such as vagus nerve stimulation, deep brain stimulation, and epidural cortical stimulation may be considered. We performed a narrative review of the published literature to identify papers discussing clinical studies with invasive neurostimulation therapies for TRD. After a database search and title and abstract screening, relevant English-language articles were analyzed. Vagus nerve stimulation, approved by the U.S. Food and Drug Administration as a TRD treatment, may take several months to show therapeutic benefits, and the average response rate varies from 15.2-83%. Deep brain stimulation studies have shown encouraging results, including rapid response rates (> 30%), despite conflicting findings from randomized controlled trials. Several brain regions, such as the subcallosal-cingulate gyrus, nucleus accumbens, ventral capsule/ventral striatum, anterior limb of the internal capsule, medial-forebrain bundle, lateral habenula, inferior-thalamic peduncle, and the bed-nucleus of the stria terminalis have been identified as key targets for TRD management. Epidural cortical stimulation, an invasive intervention with few reported cases, showed positive results (40-60% response), although more extensive trials are needed to confirm its potential in patients with TRD.

ABSTRACT Introduction: Post-traumatic stress disorder affects the mental health of pediatric patients; it is considered very common in these patients. Scientific studies supported by magnetic resonance imaging have established a close relationship between post-traumatic stress and structural changes in the brain. A bibliographic review was carried out in the period from April to May 2021, in the resources available in MEDLINE, SciELO, Pubmed and Elsevier. Of the total of consultations, 25 references were cited. Objective: To describe the radiological signs in the neuroimaging of pediatric patients with post-traumatic stress disorder. Development: Neuroimaging studies in children and adolescents with post-traumatic stress disorder have focused on abnormal structures and the functionality of some individual brain regions; these involve the brain regions associated with pathophysiology, they are: the medial and dorsolateral prefrontal cortex; the orbitofrontal cortex; insula; lentiform nucleus; amygdala; hippocampus and parahippocampus; the anterior and posterior cingulate cortex; the precuneus; cuneus; the fusiform and lingual gyrus and the white matter tracts that connect these brain regions. Conclusions: The radiological signs in the neuroimaging of pediatric patients with post-traumatic stress disorder are: reduction of the volumes of the hippocampus; brain and intracranial volume and amygdala volume, as well as a decrease in the total area of the corpus callosum. In addition, it is observed that the pituitary volume and the volumes of cerebral gray matter were lower in patients with post-traumatic stress.

RESUMEN Introducción: El trastorno por estrés postraumático afectan la salud mental de los pacientes pediátricos, se considera muy común en estos pacientes. Estudios científicos apoyados en la resonancia magnética han fundamentado una estrecha relación entre el estrés postraumático y cambios estructurales en el cerebro. Se realizó una revisión bibliográfica en el periodo de abril a mayo de 2021, en los recursos disponibles en MEDLINE, SciELO, Pubmed y Elsevier. Del total de consultas se citaron 25 referencias. Objetivo: Describir los signos radiológicos en la neuroimagen de pacientes pediátricos con estrés postraumático. Desarrollo: Los estudios de neuroimagen en niños y adolescentes con trastorno por estrés postraumático se han centrado en estructuras anormales y la funcionalidad de algunas regiones individuales del cerebro; estas implican las regiones cerebrales asociadas con la fisiopatología, ellas son: la corteza prefrontal medial y dorsolateral; la corteza orbitofrontal; ínsula; núcleo lentiforme; amígdala; hipocampo y el parahipocampo; la corteza cingulada anterior y posterior; el precúneo; cúneo; el giro fusiforme y lingual y los tractos de materia blanca que conectan estas regiones cerebrales. Conclusiones: Los signos radiológicos en la neuroimagen de pacientes pediátricos con trastorno por estrés postraumático son: reducción de los volúmenes del hipocampo; del volumen cerebral e intracraneal y del volumen de la amígdala, así como una disminución del área total del cuerpo calloso. Además se observa que el volumen hipofisario y los volúmenes de materia gris cerebral fueron menores en los pacientes con estrés postraumático.

RESUMEN Introducción: El tratamiento del trastorno afectivo bipolar (TAB) con litio se ha relacionado con menos deterioro cognitivo y menores cambios en la anatomía estructural cerebral comparado con otros tratamientos. Sin embargo, los estudios son heterogéneos y son pocos los que evalúan si estos efectos están relacionados. El objetivo de este estudio es evaluar y relacionar el desempeno cognitivo y la neuroanatomía estructural en pacientes tratados con y sin litio. Métodos: Estudio de corte trasversal que incluyó a 48 sujetos con TAB I: 22 tratados con litio y 26 sin litio. Se evaluó el desempeno en las pruebas neuropsicológicas Wechsler III (WAIS III), TMTAyB (Trial Making Test), prueba de aprendizaje verbal de California (TAVEC), prueba de Figura compleja de Rey y prueba de clasificación de tarjetas de Wisconsin. Se evaluaron estructuras cerebrales obtenidas por resonancia magnétiva (RM) cerebral. Se calculó la diferencia de medias estandarizada (DME) entre ambos grupos, con ajuste por variables de confusión mediante puntuación de propensión, y se empleó el coeficiente de correlación de Spearman (p) para evaluar la relación existente entre el desempeno cognitivo y las regiones neuroanatómicas. Resultados: Respecto al grupo sin litio, el grupo con litio tuvo menos errores perseverativos en el Wisconsin (DME = -0,69) y mayores áreas corticales derecha e izquierda (DME = 0,85 y DME = 0,92); mayor superficie en el cíngulo anterior izquierdo (DME = 1,32), la corteza orbi-tofrontal medial derecha (DME = 1,17), el giro frontal superior derecho (DME = 0,82), los giros precentrales derecho e izquierdo (DME = 1,33 y DME = 0,98); mayor volumen de la amígdala derecha (DME = 0,57), el hipocampo derecho (DME = 0,66), el putamen derecho (DME = 0,87) y el tálamo derecho (DME = 0,67). En el grupo con litio, se encontró una correlación con dichos errores y el espesor del giro precentral izquierdo (p = -0,78), el volumen del tálamo derecho (p = -0,44) y la amígdala derecha (p = 0,6). Conclusiones: El grupo con litio tuvo mejor flexibilidad cognitiva y mayor dimensión en algunas regiones corticales frontales y subcorticales. Además, hubo correlación moderada a alta entre el desempeno en esta función ejecutiva y el espesor del giro precentral derecho, y los volúmenes del tálamo y la amígdala derecha. Estos hallazgos podrían indicar un efecto neuroprotector del litio

ABSTRACT Introduction: Lithium treatment of bipolar disorder (BD) has been associated with less impairment and fewer changes in structural brain anatomy compared to other treatments. However, the studies are heterogeneous and few assess whether these effects are related. The objective of this study was to evaluate and relate cognitive performance and structural neuroanatomy in patients treated with and without lithium. Methods: Cross-sectional study that included 48 subjects with BD-I, of which 22 were treated with lithium and 26 without lithium. Performance was assessed on Wechsler III (WAIS III), TMT A and B (Trial Making Test) neuropsychological tests, California verbal learning test (CVLT), Rey complex figure test and Wisconsin card sorting test. Brain structures obtained by magnetic resonance imaging (MRI) were evaluated. The standardised mean difference (SMD) between both groups was calculated, adjusted for confounding variables using a propen-sity score, and the Spearman correlation coefficient (p) was used to assess the relationship between cognitive performance and neuroanatomical regions. Results: Compared to the group without lithium, the group with lithium had fewer perse-verative errors in the Wisconsin test (SMD = -0.69) and greater left and right cortical areas (SMD = 0.85; SMD = 0.92); greater surface area in the left anterior cingulate (SMD = 1.32), right medial orbitofrontal cortex (SMD = 1.17), right superior frontal gyrus (SMD = 0.82), and right and left precentral gyrus (SMD = 1.33; SMD = 0.98); greater volume of the right amyg-dala (SMD = 0.57), right hippocampus (SMD = 0.66), right putamen (SMD = 0.87) and right thalamus (SMD=.67). In the lithium group, a correlation was found with these errors and the thickness of the left precentral gyrus (p = -0.78), the volume of the right thalamus (p =-0.44), and the right amygdala (p = 0.6). Conclusions: Thelithium group had better cognitive flexibility and greater dimension in some frontal and subcortical cortical regions. Furthermore, there was a moderate to high correlation between performance in this executive function and the thickness of the right precentral gyrus, and the volumes of the thalamus and the right amygdala. These findings could suggest a neuroprotective effect of lithium.

Abstract Objective To investigate associations between body mass index (BMI), white matter fractional anisotropy (FA), and C-reactive protein (CRP) in a group of individuals with bipolar disorder (BD) during euthymia and compare them with a control group of healthy subjects (CTR). Methods The sample consisted of 101 individuals (BD n = 35 and CTR n = 66). Regions of interest (ROI) were defined using a machine learning approach. For each ROI, a regression model tested the association between FA and BMI, controlling for covariates. Peripheral CRP levels were assayed, correlated with BMI, and included in a mediation analysis. Results BMI predicted the FA of the right cingulate gyrus in BD (AdjR2 = 0.312 F(3) = 5.537 p = 0.004; β = -0.340 p = 0.034), while there was no association in CTR. There was an interaction effect between BMI and BD diagnosis (F(5) = 3.5857 p = 0.012; Fchange = 0.227 AdjR2 = 0.093; β = -1.093, p = 0.048). Furthermore, there was a positive correlation between BMI and CRP in both groups (AdjR2 = 0.170 F(3) = 7.337 p < 0.001; β = 0.364 p = 0.001), but it did not act as a mediator of the effect on FA. Conclusion Higher BMI is associated with right cingulate microstructure in BD, but not in CTR, and this effect could not be explained by inflammatory mediation alone.

Abstract Introduction Persistent postural-perceptual dizziness (PPPD) is a functional vestibular disorder characterized by chronic dizziness, unsteadiness, and hypersensitivity to motion. Preexisting anxiety disorders and neurotic personality traits confer vulnerability to PPPD. High anxiety during acute vertigo or dizziness incites it. A functional magnetic resonance imaging (fMRI) study of chronic subjective dizziness found unexpectedly hypoactive responses to vestibular stimulation in cortical regions that integrate threat assessment and spatial perception. Objective This fMRI study used non-moving, but emotionally charged visual stimuli to investigate the brain's activity of PPPD patients and control subjects. Methods The participants included 16 women with PPPD and 16 age-matched women who recovered completely from acute episodes of vertigo or dizziness capable of triggering PPPD. Brain responses to positive, neutral, and negative figures from the International Affective Picture System were measured with fMRI and compared between the groups. Dizziness handicap, anxiety, and depression were assessed with validated questionnaires. Results Between group analyses: Participants with PPPD showed reduced activity in anterior cingulate cortex and increased activity in left angular gyrus in response to negative versus positive stimuli, which was not observed in recovered individuals. Within group analyses: Participants with PPPD had increased activity in visuospatial areas (parahippocampal gyrus, intraparietal sulcus) in negative versus positive and negative versus neutral contrasts, whereas recovered individuals had increased activity in anxiety regions (amygdala, orbitofrontal cortex). Conclusion Patients with PPPD may be more attuned to spatial elements than to the content of emotionally charged visual stimuli.

Resumo Objetivo: Nós avaliamos se os pacientes HIV-positivos com e sem déficits de memória clinicamente significativos e controles saudáveis diferem na espectroscopia de prótons do giro do cíngulo posterior, por ressonância magnética (RM) cerebral. Materiais e Métodos: Vinte e um pacientes HIV-positivos com déficit de memória foram comparados com 15 pacientes HIV-positivos sem déficit de memória e 22 controles, pareados por sexo, idade e escolaridade. As deficiências de memória foram classificadas por meio do desempenho no Teste de Aprendizagem Auditivo-Verbal de Rey. A espectroscopia de prótons foi realizada com tempo de eco curto (30 ms), por voxel único, no giro do cíngulo posterior, utilizando aparelho de RM de 1,5 T. Resultados: Os pacientes HIV-positivos com e sem déficit de memória apresentaram aumento da relação colina/creatina no giro do cíngulo posterior, comparados aos controles. Não houve diferenças significativas nas relações metabólicas no grupo HIV-positivo com déficit de memória, em relação ao grupo de pacientes HIV-positivo sem déficit. Conclusão: Pacientes HIV-positivos com e sem déficits de memória apresentaram relações colina/creatina significativamente aumentadas em relação aos controles, no giro do cíngulo posterior, o que pode refletir inflamação cerebral, alteração do metabolismo da membrana celular, microgliose e/ou astrocitose.

Abstract Objective: We aimed to evaluate whether human immunodeficiency virus (HIV)-positive patients with and without clinically significant memory deficits and healthy control participants differ on in vivo hydrogen-1 magnetic resonance spectroscopy (H-MRS) in the posterior cingulate gyri. Materials and Methods: In total, 21 HIV-positive patients with memory deficit (HIV+wMD) were compared with 15 HIV-positive patients without memory deficit (HIV+wOMD) and 22 sex-, age-, and education-matched control participants. Memory impairments were classified based on the participants’ performance on the Rey Auditory Verbal Learning Test. Short echo time (30 ms), single-voxel H-MRS was performed using a 1.5-T magnetic resonance scanner. Results: The HIV+wMD and HIV+wOMD groups had higher choline/creatine ratio in the posterior cingulate gyri than the control group. There were no significant metabolite ratio differences between the HIV+wMD and HIV+wOMD groups. Conclusion: HIV-positive patients with and without memory deficits had significantly higher choline/creatine ratios than controls in the posterior cingulate gyri, which may reflect cerebral inflammation, altered cell membrane metabolism, microgliosis, and/or astrocytosis.

Abstract Background Chronic low back pain (CLBP) represents a problem in the occupational environment, often associated with disability, sick-leave demands, loss of productivity, anxiety, depression and high socioeconomic cost. The emergence of functional neuroimaging allowed new insights into brain structure and physiology in normality and chronic pain. While occupational related aspects are recognized as important risk factors for chronicity there have not been thus far evaluated by fMRI experiments. The overall objective of this study is to compare the neuronal correlates between groups of individuals CLBP with or without sick-leave demands. Methods A total of 74 individuals were divided into three groups: chronic low back pain with sick-leave demands [CLBP_L]; chronic low back pain without sick-leave demands [CLBP_NL]; individuals without pain or sick-leave demands [Control]. Functional magnetic resonance imaging was used to assess brain function during moderate acute pain stimulation task (thumb controlled pressure). Results After acute painful stimulation, a higher brain response was found in the anterior cingulate and superior and medium frontal gyrus was observed in CLBP_NL vs. CLBP_L ( p < 0,001) and increased brain response in the frontal pole and paracingulate region in control vs. CLBP_L ( p < 0.001) during acute pain stimulation. Conclusion The modulation of acute pain participates in the mechanism propagating chronic pain perception. The lower activation in the superior frontal gyrus observed in the CLBP_L group compared to CLBP_NL, reinforces the idea of an already existing activation in this area.

This study aimed to explore the structural and functional characteristics of the neural network of resting-state brain activities in patients with amnestic mild cognitive impairment (aMCI) by functional magnetic resonance imaging (fMRI) technology. Resting state fMRI scanning was performed on 10 clinically diagnosed aMCI patients and 10 healthy volunteers, and the difference in the resting-state brain activities between aMCI patients and healthy volunteers was compared using the brain function network regional homogeneity (ReHo) analysis method. Results of the ReHo analysis of aMCI patients and healthy volunteers revealed that the ReHo value significantly increased in the posterior cingulate gyrus region, medial frontal lobe, medial cortex of the prefrontal lobe, and part of the parietal lobe. Compared with the normal elderlies, ReHo decreased in aMCI patients in the left temporal lobe (middle temporal gyrus and inferior temporal gyrus), left parahippocampal gyrus, occipital lobe, lingual gyrus, precuneus, and other regions while ReHo increased in regions of the right frontal lobe (inferior frontal gyrus), left superior temporal gyrus, precentral gyrus (frontal lobe), right thalamus, left fusiform gyrus, and other regions. In the resting state, there may be regional abnormalities in brain functional areas in aMCI patients, which may be associated with cognitive impairment.

Abstract Repetitive Transcranial Magnetic Stimulation (rTMS) has shown the potential to reduce craving to smoke and the amount of cigarettes smoked. When low frequency rTMS is preceded by a priming session the cortical inhibitory effects are enhanced provoking a lasting performance. In this study we evaluate the brain regional activations and self-reported mood effect of one session of primed low frequency rTMS over the left dorsolateral prefrontal cortex (DLPFC) in response to smoking- related cues during temporary nicotine abstinence. Ten moderate nicotine dependent subjects participated in a crossover design, comparing a single session of active versus sham stimulation. After treatment, a functional Magnetic Resonance Imaging (fMRI) study was performed in all participants while completing a block-design cue reactivity paradigm. Our measures also included self-reported craving and mood score before and after every rTMS session. The number of daily smoked cigarette in a one week around period was also recorded. The results show that self-reported cravings were lower following the active stimulation; significant activation was found in areas associated with emotion control (anterior cingulate gyrus and subgenual area) and episodic memory (precuneus and posterior cingulate gyrus) as a result of the stimulation. No significant difference was found in the number of cigarettes smoked and mood scores between the sham and active condition during the one week period records. This study confirms the previous evidence that rTMS can reduce cigarette cravings and provides evidence of the neural mechanism of action that take place in order to achieve these neuromodulation effects.

Resumen La Estimulación Magnética Transcranea repetitiva (EMTr) ha demostrado ser capaz de reducir el deseo por fumar y el consume de cigarrillos. Cuando una baja frecuencia de EMTr es precedida por una sesión de primado, los efectos inhibidores de la corteza cerebral aumentan y también su duración. En este estudio se evalúan las activaciones regionales del cerebro y el efecto en el estado de ánimo auto-reportado de una sesión de EMTr de baja frecuencia primada sobre la corteza dorsolateral prefrontal izquierda en respuesta a estímulos visuales relacionados con el tabaco durante una abstinencia temporal a la nicotina. Diez sujetos con dependencia moderada a la nicotina participaron en un experimento de diseño cruzado, comparando una sola sesión de estimulación activa contra una simulada. Después del tratamiento, se llevó a cabo un estudio de Imagen por Resonancia Magnética funcional (IRMf) en todos los participantes mientras llevaban a cabo un paradigma visual de bloques. Las mediciones incluyeron una puntuación auto-reportada del deseo por fumar y estado de ánimo antes y después de cada sesión de EMTr. Los resultados muestran que el deseo por fumar era menor luego de una sesión activa de estimulación; se encontraron activaciones significativas en áreas asociadas con el control emocional (giro del cíngulo anterior) y memoria episódica (precúneo y giro del cíngulo posterior) como resultado de la estimulación. No se encontró diferencia significativa en el número de cigarros fumados entre la sesión activa y simulado durante el periodo evaluado. Tampoco se registraron diferencias en las evaluaciones de estado de ánimo luego del tratamiento. Este estudio confirma la evidencia previa de que la EMTr puede reducir el deseo por fumar y proporciona evidencia del mecanismo de acción neural que se lleva a cabo para lograr estos efectos neuromoduladores.

Comparative study based on 565 adolescent school children coming from four schools in the metropolitan area of Santiago, Chile. All were interviewed in order to select a sample that was stratified for sex, class and condition of consumer or non-consumer. The variables of intellectual coefficient and socioeconomical level were maintained constant. With this selection we conformed two groups: 40 consumers exclusively of marihuana and 40 non-consumers. We compared the results obtained in both groups in the neuropsychological tests while the neuroSPECT studies of consumers were compared against a normal database for the same age group. The adolescent consumers of marihuana demonstrate less cognitive capacity related to the process of learning such as attention, concentration, ranking, viso-spatial integration, immediate retention and visual memory. The differences between both groups are statistically significant. The findings of neuroSPECT demonstrate subgenual hypoperfusion bilaterally, more marked on the left side, in area 25 of Brodmann. This area controls mood. There is also frontal bilateral hypoperfusion (area 10 and area 32 of Brodmann). Area 32 is pre-anterior cingulate gyrus. Also hypoperfusion of the anterior cingulate gyrus (area 24 of Brodmann) and hypoperfusion of area 36 of Brodmann that projects over the hippocampus. Students that were consumers exclusively of marihuana demonstrate coincident abnormal findings of neuroimages and neuropsychological tests in areas of the brain related with learning and also significant differences between consumers with non-consumers in the neuropsychological tests.

Estudio comparativo basado en 565 escolares adolescentes pertenecientes a cuatro colegios de Santiago, Chile. Fueron encuestados todos para seleccionar una muestra estratificada por sexo, curso y condición de consumidores o no consumidores, manteniendo constante las variables coeficiente intelectual y nivel socioeconómico. Se conforman dos grupos: 40 consumidores exclusivos de marihuana y 40 no consumidores. Se comparan los resultados obtenidos en ambos grupos en los Test Neuropsicológios y del NeuroSPECT de consumidores con una base de datos considerados normales para el mismo grupo etario. Los adolescentes consumidores de marihuana evidencian menores habilidades cognitivas asociadas al proceso de aprendizaje, tales como atención, concentración, jerarquización, integración visoespacial, retención inmediata y memoria visual. Las diferencias entre ambos grupos son estadísticamente significativas. Los hallazgos del NeuroSPECT muestran hipoperfusión subgenual bilateral, más marcada en el hemisferio izquierdo (área 25 de Brodmann), hipoperfusión frontal bilateral (areas 10 y 32 de Brodmann), hipoperfusión del gyrus cingulado anterior (área 24 de Brodmann) e hipoperfusión del área 36 de Brodmann que proyecta sobre el hipocampo. Los estudiantes consumidores exclusivamente de marihuana muestran compromiso coincidente en neuroimágenes y test neuropsicológicos en áreas del cerebro relacionadas con el aprendizaje y se diferencian significativamente de los no-consumidores en las pruebas neuropsicológicas.

Resumo Estudos anteriores demostraram redução do volume hipocampal, redução da concentração de N- Acetilaspartato (NAA) e aumento da concentração de mio-inositol (mI) em pacientes com doença de Alzheimer (DA). O objetivo deste trabalho foi de avaliar os volumes hipocampais de pacientes com DA e correlacioná-los com as alterações metabólicas detectadas pela espectroscopia de próton das formações hipocampais e da região do cíngulo posterior. Material e Métodos: 22 pacientes com provável DA (18 leve, 4 moderada) e 14 controles sem sintomas cognitivos foram incluídos neste estudo . Medidas volumétricas hipocampais, espectroscopia de próton de voxel único das formações hipocampais e da região do cíngulo foram obtidos. As seguintes razões de metabólitos foram avaliadas NAA/Cr, mI/Cr, mI/NAA. Análise estatística foi realizada para detectar as diferenças e correlações entre estes parâmetros nos pacientes e nos controles. Resultados: Os volumes das formações hipocampais dos pacientes e dos controles não foram significativamente diferentes. Os resultados da espectroscopia de próton foram significativamente diferentes nas das formações hipocampais dos pacientes e controles (mI/Cr, mI/NAA) e na região do cíngulo posterior (NAA/Cr, mI/Cr, mI/NAA). O melhor indicador para DA foi a razão NAA/Cr na região do cíngulo posterior com sensibilidade de 0,899 e especificidade de 0,800. Não houve correlação entre os volumes das formações hipocampais e os resultados da espectroscopia de próton nos pacientes com DA. Conclusões: Os resultados da espectroscopia de próton foram significativamente diferentes entre pacientes e controles das formações hipocampais e na região do cíngulo posterior, sendo NAA/Cr o melhor indicador para DA. Não houve correlação entre os volumes das formações hipocampais e os resultados da espectroscopia de próton nos pacientes com DA.

Abstract Prior studies have reported hippocampal volume loss, decrease in N-Acetylaspartate (NAA) concentration and increased myo-inositol (mI) concentration in patients with Alzheimer's disease (AD). The purpose of this study was to evaluate hippocampal volumes of AD patients and their correlation with metabolic changes detected by proton spectroscopy (1H MRS) of hippocampal formations and the posterior cingulate region. Materials and Methods: 22 patients with probable AD (18 mild, 4 moderate) and 14 elderly controls without cognitive symptoms, were enrolled in the study. Hippocampal volumetric measurements, single-voxel 1H MRS of the posterior cingulate region and of hippocampal formations were obtained. The following metabolite ratios were evaluated: NAA/Cr, mI/Cr, mI/NAA. Statistical analysis was performed to detect differences and correlations between these parameters in patients and controls. Results: The hippocampal volume of patients and controls did not differ significantly. The results of 1H MRS differed significantly between patients and controls in the hippocampal formations (mI/Cr, mI/NAA) and posterior cingulate region (NAA/Cr, mI/Cr, mI/NAA). The best predictor of AD diagnosis was NAA/Cr in the posterior cingulate region, having a sensitivity of 0.899 and specificity of 0.800. There was no correlation between hippocampal volumes and the results of 1H MRS in patients with AD. Conclusions: The results of 1H MRS differed significantly between patients and controls in hippocampal formations and the posterior cingulate region, with NAA/Cr proving to be the best predictor for AD. No correlation between hippocampal volumes and the results of 1H MRS in patients with AD was observed.

The obsessive compulsive disorder (OCD) is a diverse and multidimensional psychiatric syndrome, characterized by obsessions and compulsions, where anxiety is considered to be a key clinical component. Imaging studies have shown brain abnormalities in patients with OCD involving mainly the frontotemporal circuits, the orbitofrontal and the anterior cingulate cortex. These techniques have a high spatial resolution to identify brain alterations in this disorder but have less time resolution and are more expensive than electrophysiological studies. The electroencephalogram (EEG) and event-related potentials (ERPs) are the most common electrophysiological techniques used in the research of OCD. The EEG represents the electrical activity of the brain as recorded by electrodes placed on the scalp. The ERPs are voltage fluctuations that are temporarily linked to the presence of a physical or mental event. The best-known type of EEG is the <<traditional EEG>> (analyzed by visual inspection), which is characterized by the presence and topographic distribution of four frequency bands: delta (δ),theta (θ), alfa (α), and beta (β). The δ and θ bands are identified as slow activities while the α and β bands are known as fast activities. The slow activity has been referred to as the most common abnormality in OCD, specially in the θ band. Moreover, the Broad Band Spectral Parameters (BBSPs) have contributed, for more than two decades, to the study of psychiatric patients and their values can be presented in a compact form as a topographic map on the scalp (Brain Mapping in the frequency domain). The Absolute Power (AP) and the Relative Power (RP) are the most common BBSPs used. Is difficult to determine if AP is abnormal at certain age due to the fact that AP values vary with age. To solve it, it is suggested to transform AP's values, in every band, into Z values which indicate how close is the subject to the average values of normal individuals of the same age. Since abnormal increases and decreases have been described in the anterior brain regions by the slow bands (δ and θ) and the fast bands (α and β), some authors have considered inconsistent the alterations that have been observed with the BBSPs. Nevertheless, in accordance with traditional EEG studies, other authors have confirmed the excess of theta activity in patients with OCD. Of special interest for the clinical practice is that some authors have demonstrated, using the BBSPs, the existence of two OCD patients subgroups, which were homogeneous from the clinical point of view: one group with an excess of θ in the RP values, specially in the frontal and fronto-temporal regions, and a significative increase of α RP values for the other group. Eighty per cent of the patients of the first subgroup did not improved with selective serotonine reuptake inhibitors treatment, whereas 82.4 % of the patients of the second group improved. These results were confirmed ten years later and the α RP excess, present in those patients who improved, decreased after three months of treatment. However, it must be reminded that the generator of abnormal brain electrical activity, could be originate in a distant place to the location shown by the scalp electrodes. LORETA and VARETA are two methods used to calculate the origin of the generators above mentioned. The first investigation using LORETA was published in 2005, and it was observed that compared to controls, the OCD group showed an excess of β activity in the cingulate gyrus (mainly in the middle cingulate gyrus), as well as in the adjacent frontal, parietal and occipital regions. Two years later, in another EEG sources study, but using VARETA, has been found an excess of α activity with abnormal EEG sources located in the striatum and in the orbito-frontal and temporo-frontal regions, which decreased after successful treatment with paroxetine. Therefore, it is also heartening to confirm, through the study of generators of the EEG, a result of great clinical value previously proved with BBSPs. The ERPs are divided into two types: exogenous and endogenous. In this paper we shall refer to the endogenous or cognitive type which depends on the nature of the interaction between the subject and the stimulus, so it will vary with attention, relevance of the task and the processing required. The ERPs are small voltage fluctuations that are identified by their latency (time of appearance in milliseconds), its amplitude (voltage in microvolts) and its polarity (positive or negative voltage). Among the most characteristic ERPs components are the N200 and the P300. In most cases these components are elicited through a classical <<oddball>> paradigm, in which an infrequent stimulus (<<target>>) is randomly interspersed within an ongoing train of a different repeating stimulus (<<standard>>). There are at least two subcomponents of the P300: a frontal/central maximum amplitude component, the P3a that appears after the occurrence of unexpected distracters, regardless of its relevance for the task and represents an orienting response. The other one is the P3b, which has been more studied, it has a central/parietal distribution and evaluates attention and working memory.

El Trastorno Obsesivo Compulsivo (TOC) es un trastorno psiquiátrico crónico, clínicamente heterogéneo, multidimensional, caracterizado por la presencia de obsesiones y compulsiones, en el cual la ansiedad es un componente fundamental del cuadro clínico. Los estudios de imágenes tienen una gran resolución espacial que permite la identificación de las alteraciones presentes en esta entidad pero tienen menor resolución temporal y son de mayor costo que los estudios electrofisiológicos. Entre las técnicas electrofisiológicas más utilizadas para investigar el TOC se encuentran el electroencefalograma (EEG) y los potenciales relacionados con eventos (PREs). El EEG es el registro de la actividad eléctrica cerebral, es decir, de las diferencias de voltaje entre dos electrodos situados sobre el cuero cabelludo, en función del tiempo. Los PREs son las fluctuaciones de voltaje que están asociadas temporalmente a la presencia de un evento físico o mental. El tipo de EEG más conocido es aquél que se analiza por inspección visual (EEG tradicional: EEG-T) y que se describe mediante la presencia y distribución topográfica de cuatro tipos de actividades electroencefalográficas: delta (δ), theta (θ), alfa (α) y beta (β). Las bandas δ y θ se identifican como actividades lentas mientras que las bandas α y β se conocen como actividades rápidas. En el TOC se ha referido la actividad lenta como la anormalidad más común en el EEG-T, especialmente la actividad de tipo θ, aunque también se han descrito EEGs normales. Por otra parte, las medidas espectrales de banda ancha (MEBAs) han comprobado este exceso de actividad lenta además de anormalidades en las bandas rápidas, particularmente en la α. Entre las MEBAs más utilizadas se encuentran la potencia absoluta y la potencia relativa. Se ha demostrado, tanto con las MEBAs como con el análisis de generadores del EEG, que aquellos pacientes que tienen un exceso de a en regiones anteriores y medias responden mejor a los inhibidores de la recaptura de serotonina, lo cual es de gran utilidad clínica. Los PREs se dividen en dos tipos: exógenos y endógenos. En este trabajo se hará referencia a los endógenos o cognitivos. Entre los componentes de los PREs cognitivos más característicos están el N200 y el P300. En los pacientes con TOC se han descrito amplitudes mayores y latencias más cortas en los componentes P3b y N200, lo cual se ha atribuido a hiperalertamiento cortical y sobrefocalización de la atención. También se han observado correlaciones positivas entre la amplitud del componente N200 y la cronicidad del trastorno y entre la amplitud del componente P300 y la severidad de la sintomatología del TOC. Los pacientes con este trastorno tienen la sensación de que <<algo no está bien>> y se <<enganchan>> en respuestas de verificación excesiva. Esto se ha asociado con una alteración en el proceso de monitorización de la acción, que representa una de las funciones ejecutivas a cargo de las regiones frontales, particularmente del cíngulo anterior, el cual posiblemente se <<hiperactive>> en los pacientes con TOC cuando tienen la sensación de haber cometido un error. La <<negatividad relacionada al error>> (NRE) es una onda negativa, alrededor de los 50-150 ms, posterior a que el sujeto cometió un error o cuando está seguro de haberlo cometido. Se ha encontrado que los pacientes con TOC (niños y adultos) muestran un incremento de la negatividad de este componente en comparación a sujetos controles y se ha propuesto que pudiera considerarse como un marcador biológico del TOC. El EEG y los PREs pueden contribuir de manera importante, junto con los estudios clínicos e imagenológicos, a la identificación de las estructuras y circuitos involucrados en la fisiopatología del TOC. Además, hay evidencias que apoyan la utilidad de estas técnicas electrofisiológicas como estudios complementarios en la evaluación clínica y terapéutica de los pacientes con TOC.

OBJETIVOS: Em pacientes com primeiro episódio de esquizofrenia, estudos com ressonância magnética funcional (RMf) têm demonstrado disfunção pré-frontoparietal durante estimulação acústica e visual. O objetivo do presente estudo foi investigar a rede pré-frontoparietal em pacientes idosos com esquizofrenia utilizando o mesmo paradigma. Adicionalmente, foram presumidos efeitos favoráveis na ativação cerebral pelo antipsicótico atípico clozapina em comparação a neurolépticos típicos. MÉTODOS: Foram investigados 18 pacientes com esquizofrenia crônica e 21 controles saudáveis idosos. Nove pacientes com esquizofrenia haviam sido medicados com clozapina e nove haviam recebido neurolépticos típicos por décadas. Concomitantemente às avaliações com escalas psicopatológicas e neuropsicológicas foi utilizado um paradigma de estimulação auditiva e visual em um aparelho de ressonância magnética de 1,5 Tesla para investigar a resposta BOLD em diferentes áreas cerebrais. RESULTADOS: Comparados a controles saudáveis, os pacientes com esquizofrenia apresentaram diminuição na ativação cerebral nos córtices pré-frontal e parietal, assim como no giro do cíngulo anterior medial. Nessas regiões, os pacientes medicados com clozapina apresentaram resposta BOLD aumentada em comparação aos pacientes tratados com neurolépticos típicos. DISCUSSÃO: O presente estudo confirmou a presença de distúrbios na rede pré-frontoparietal em pacientes idosos com esquizofrenia, apontando assim para a preservação de déficits de ativação cerebrais e a influência de distúrbios do desenvolvimento neural em esquizofrenia crônica até a velhice. CONCLUSÃO: O antipsicótico atípico clozapina parece facilitar a ativação de áreas cerebrais mesmo em pacientes idosos com esquizofrenia crônica.

OBJECTIVES: In first-episode schizophrenia patients, functional magnetic resonance imaging (fMRI) has shown prefronto-parietal dysfunction during acoustic and visual stimulation. The aim of this study was to investigate the prefronto-parietal network in elderly schizophrenia patients using the same paradigm. Additionally, we hypothesized favourable effects on brain activation by the atypical antipsychotic clozapine compared to typical neuroleptics. METHODS: We investigated 18 elderly, chronic schizophrenia patients and 21 elderly healthy controls. Nine schizophrenia patients had been medicated with clozapine and 9 had been receiving typical neuroleptics over decades. In addition to assessments with psychopathological and neuropsychological rating scales we used an acoustic and visual stimulation paradigm in a 1.5 Tesla MRI scanner to investigate BOLD-response in different brain areas. RESULTS: Compared to healthy controls schizophrenia patients showed decreased brain activation in the prefrontal and parietal cortex as well as medial anterior cingulate gyrus compared to healthy controls. In these regions, patients medicated with clozapine showed increased BOLD-response compared to patients treated with typical neuroleptics. DISCUSSION: Our study confirmed prefronto-parietal network disturbances in elderly schizophrenia patients thus pointing to the preservation of brain activation deficits and the influence of neurodevelopmental disturbances in chronic schizophrenia until old-age. CONCLUSION: The atypical antipsychotic clozapine seems to facilitate brain activation even in elderly, chronic schizophrenia patients.

Happy emotional states have not been extensively explored in functional magnetic resonance imaging studies using autobiographic recall paradigms. We investigated the brain circuitry engaged during induction of happiness by standardized script-driven autobiographical recall in 11 healthy subjects (6 males), aged 32.4 ± 7.2 years, without physical or psychiatric disorders, selected according to their ability to vividly recall personal experiences. Blood oxygen level-dependent (BOLD) changes were recorded during auditory presentation of personal scripts of happiness, neutral content and negative emotional content (irritability). The same uniform structure was used for the cueing narratives of both emotionally salient and neutral conditions, in order to decrease the variability of findings. In the happiness relative to the neutral condition, there was an increased BOLD signal in the left dorsal prefrontal cortex and anterior insula, thalamus bilaterally, left hypothalamus, left anterior cingulate gyrus, and midportions of the left middle temporal gyrus (P < 0.05, corrected for multiple comparisons). Relative to the irritability condition, the happiness condition showed increased activity in the left insula, thalamus and hypothalamus, and in anterior and midportions of the inferior and middle temporal gyri bilaterally (P < 0.05, corrected), varying in size between 13 and 64 voxels. Findings of happiness-related increased activity in prefrontal and subcortical regions extend the results of previous functional imaging studies of autobiographical recall. The BOLD signal changes identified reflect general aspects of emotional processing, emotional control, and the processing of sensory and bodily signals associated with internally generated feelings of happiness. These results reinforce the notion that happiness induction engages a wide network of brain regions.