Changes in brain connectivity related to the treatment of depression measured through fMRI: a systematic review

Depression is a mental illness that presents alterations in brain connectivity in the Default Mode Network (DMN), the Affective Network (AN) and other cortical-limbic networks, and the Cognitive Control Network (CCN), among others. In recent years the interest in the possible effect of the different antidepressant treatments on functional connectivity has increased substantially. The goal of this paper is to conduct a systematic review of the studies on the relationship between the treatment of depression and brain connectivity. Nineteen studies were found in a systematic review on this topic. In all of them, there was improvement of the clinical symptoms after antidepressant treatment. In 18 out of the 19 studies, clinical improvement was associated to changes in brain connectivity. It seems that both DMN and the connectivity between cortical and limbic structures consistently changes after antidepressant treatment. However, the current evidence does not allow us to assure that the treatment of depression leads to changes in the CCN. In this regard, some papers report a positive correlation between changes in brain connectivity and improvement of depressive symptomatology, particularly when they measure cortical-limbic connectivity, whereas the changes in DMN do not significantly correlate with clinical improvement. Finally, some papers suggest that changes in connectivity after antidepressant treatment might be partly related to the mechanisms of action of the treatment administered. This effect has been observed in two studies with stimulation treatment (one with rTMS and one with ECT), and in two papers that administered three different pharmacological treatments. Our review allows us to make a series of recommendations that might guide future researchers exploring the effect of anti-depression treatments on brain connectivity

Effective connectivity of visual word recognition and homophone orthographic errors

The study of orthographic errors in a transparent language like Spanish is an important topic in relation to writing acquisition. The development of neuroimaging techniques, particularly functional magnetic resonance imaging (fMRI), has enabled the study of such relationships between brain areas. The main objective of the present study was to explore the patterns of effective connectivity by processing pseudohomophone orthographic errors among subjects with high and low spelling skills. Two groups of 12 Mexican subjects each, matched by age, were formed based on their results in a series of ad hoc spelling-related out-scanner tests: a high spelling skills (HSSs) group and a low spelling skills (LSSs) group. During the f MRI session, two experimental tasks were applied (spelling recognition task and visuoperceptual recognition task). Regions of Interest and their signal values were obtained for both tasks. Based on these values, structural equation models (SEMs) were obtained for each group of spelling competence (HSS and LSS) and task through maximum likelihood estimation, and the model with the best fit was chosen in each case. Likewise, dynamic causal models (DCMs) were estimated for all the conditions across tasks and groups. The HSS group's SEM results suggest that, in the spelling recognition task, the right middle temporal gyrus, and, to a lesser extent, the left parahippocampal gyrus receive most of the significant effects, whereas the DCM results in the visuoperceptual recognition task show less complex effects, but still congruent with the previous results, with an important role in several areas. In general, these results are consistent with the major findings in partial studies about linguistic activities but they are the first analyses of statistical effective brain connectivity in transparent languages

Effect of verbal task complexity in a working memory paradigm in patients with type 1 diabetes. A fMRI study.

Podeu consultar dades primàries associades a l'article a: http://hdl.handle.net/2445/109182Type 1 diabetes (T1D) is commonly diagnosed in childhood and adolescence, and the developing brain has to cope with its deleterious effects. Although brain adaptation to the disease may not result in evident cognitive dysfunction, the effects of T1D on neurodevelopment could alter the pattern of BOLD fMRI activation. The aim of this study was to explore the neural BOLD activation pattern in patients with T1D versus that of healthy matched controls while performing two visuospatial working memory tasks, which included a pair of assignments administered through a block design. In the first task (condition A), the subjects were shown a trial sequence of 3 or 4 white squares positioned pseudorandomly around a fixation point on a black background. After a fixed delay, a second corresponding sequence of 3 or 4 red squares was shown that either resembled (direct, 50%) or differed from (50%) the previous stimulation order. The subjects were required to press one button if the two spatial sequences were identical or a second button if they were not. In condition B, the participants had to determine whether the second sequence of red squares appeared in inverse order (inverse, 50%) or not (50%) and respond by pressing a button. If the latter sequence followed an order distinct from the inverse sequence, the subjects were instructed to press a different button. Sixteen patients with normal IQ and without diabetes complications and 16 healthy control subjects participated in the study. In the behavioral analysis, there were no significant differences between the groups in the pure visuo-spatial task, but the patients with diabetes exhibited poorer performance in the task with verbal stimuli (p < .001). However, fMRI analyses revealed that the patients with T1D showed significantly increased activation in the prefrontal inferior cortex, subcortical regions and the cerebellum (in general p < .001). These different activation patterns could be due to adaptive compensation mechanisms that are devoted to improving efficiency while solving more complex cognitive tasks

Neuroimage study on low orthographic competence group

Background: In this paper we studied the functional neural substrates underlying the performance of homophonic spelling error detecting tasks including frequent and infrequent Spanish words- through functional Magnetic Resonance Imaging (fMRI) procedure in subjects with low orthographic performance. Method: A block design was used to administer 2 visual tasks,with 2 experimental conditions each, to 8 healthy participants with low orthographic performance. In both tasks correct and misspelled Spanish words sequentially appeared. Participants were instructed to detect orthographic errorsin one task, as well as the presence of 1 specific vowel in the other. Image data were obtained from 32 axial contiguous slices and repetition time of 3 seconds. Results: Significant bilateral activations were found, especially inmedial temporal areas during the orthographic error recognition task performance, whereas upper right and left frontal regions were significantly activated while detecting a specific vowel. Conclusions: These data are consistent with the literature and suggest an association between orthographic processing and hyperactivation of bilateral cerebral areas in subjects with low orthographic skills, probably due to compensatory mechanism

Correlato neural de la lectura en bilingües

This paper does not intend to carry out a systematic or complete review of the literature, but rather aims to offer a critical view by the authors about the functional brain organization during reading in bilinguals. Firstly, a critical analysis of different theoretical proposals about the reading process is presented, with particular emphasis on the Dual-Route Cascade Model for being the most influential theory in the field. Then, we analize the main theoretical proposals about the neurobiological substrate based mainly on functional neuroimage studies. The main factors that influence this neural correlate during reading in bilinguals are extracted and the findings regarding them of the most recent studies are presented. Finally, a critical analysis is made about the main limitations of the research on this topic and challenges and future research lines in the field are discussed.Este artículo no pretende realizar una revisión sistemática ni completa de la literatura, sino que tiene como objetivo ofrecer una visión crítica por parte de los autores, acerca de la organización funcional cerebral durante la lectura en personas bilingües. Primeramente se presenta un análisis crítico de diferentes propuestas teóricas acerca del proceso lector, haciendo particular énfasis en el modelo de doble ruta en cascada por ser el más influyente. Luego se analizan las principales propuestas teóricas acerca del sustrato neurobiológico basado fundamentalmente en estudios de imágenes funcionales. Se extraen los principales factores que influyen sobre este correlato neural durante la lectura en bilingües y se presentan los hallazgos de los estudios más recientes. Finalmente, se hace un análisis crítico acerca de las principales limitaciones de las investigaciones en este tema y se describen los retos y líneas de investigación futuras que el campo tiene por delante

Complex systems representing effective connectivity in patients with Type One diabetes mellitus

Background Type 1 diabetes mellitus (T1D) affects the entire cellular network of the organism. Some patients develop cognitive disturbances due to the disease, but several authors have suggested that the brain develops compensatory mechanisms to minimize or prevent neuropsychological decline. The present study aimed to assess the effective connectivity underlying visuospatial working memory performance in young adults diagnosed with T1D using neuroimaging techniques (fMRI). Methods Fifteen T1D right-handed, young adults with sustained metabolic clinical stability and a control group matched by age, sex, and educational level voluntarily participated. All participants performed 2 visuospatial working memory tasks using a block design within an MRI scanner. Regions of interest and their signal values were obtained. Effective connectivity by means of structural equations models was evaluated for each group and task through maximum likelihood estimation, and the model with the best fit was chosen in each case. Results Compared to the control group, the patient group showed a significant reduction in brain activity in the two estimated networks (one for each group and task). The models of effective connectivity showed greater brain connectivity in healthy individuals, as well as a more complex network. T1D patients showed a pattern of connectivity mainly involving the cerebellum and the red nucleus. In contrast, the control group showed a connectivity network predominantly involving brain areas that are typically activated while individuals are performing working memory tasks. Conclusion Our results suggest a specific effective connectivity between the cerebellum and the red nucleus in T1D patients during working memory tasks, probably reflecting a compensatory mechanism to fulfill task demands

A massive experiment on choice blindness in political decisions : confidence, confabulation, and unconscious detection of self-deception

We implemented a Choice Blindness Paradigm containing political statements in Argentina to reveal the existence of categorical ranges of introspective reports, identified by confidence and agreement levels, separating easy from very hard to manipulate decisions. CBP was implemented in both live and web-based forms. Importantly, and contrary to what was observed in Sweden, we did not observe changes in voting intentions. Also, confidence levels in the manipulated replies where significantly lower than in non-manipulated cases even in undetected manipulations. We name this phenomenon unconscious detection of selfdeception. Results also show that females are more difficult to manipulate than men.Fil: Rieznik, Andrés. Universidad Torcuato Di Tella, Escuela de Negocios, Laboratorio de Neurociencia, Buenos Aires, Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina. El Gato y La Caja, Buenos Aires, Argentina.Fil: Moscovich, Lorena. Universidad de San Andrés, Buenos Aires, ArgentinaFil: Frieiro, Alan. Universidad de Vigo, Vigo, EspañaFil: Figini, Julieta. Universidad de San Andrés, Buenos Aires, ArgentinaFil: Catalano, Rodrigo. El Gato y La Caja, Buenos Aires, ArgentinaFil: Garrido, Juan Manuel. El Gato y La Caja, Buenos Aires, ArgentinaFil: Álvarez Heduan, Facundo. El Gato y La Caja, Buenos Aires, ArgentinaFil: Sigman, Mariano. CONICET, Buenos Aires, Argentina. Universidad Torcuato Di Tella, Escuela de Negocios, Laboratorio de Neurociencia, Buenos Aires, ArgentinaFil: González, Pablo A. El Gato y La Caja, Buenos Aires, Argentin

Analysis of Pseudohomophone Orthographic Errors through Functional Magnetic Resonance Imaging (fMRI)

The study of orthographic errors in a transparent language such as Spanish is an important topic in relation to writing acquisition because in Spanish it is common to write pseudohomophones as valid words. The main objective of the present study was to explore the possible differences in activation patterns in brain areas while processing seudohomophone orthographic errors between participants with high (High Spelling Skills (HSS)) and low (Low Spelling Skills (LSS)) spelling orthographic abilities. We hypothesize that (a) the detection of orthographic errors will activate bilateral inferior frontal gyri, and that (b) this effect will be greater in the HSS group. Two groups of 12 Mexican participants, each matched by age, were formed based on their results in a group of spelling-related ad hoc tests: HSS and LSS groups. During the fMRI session, two experimental tasks were applied involving correct and pseudohomophone substitution of Spanish words. First, a spelling recognition task and second a letter searching task. The LSS group showed, as expected, a lower number of correct responses (F(1, 21) = 52.72, p <.001, η2 = .715) and higher reaction times compared to the HSS group for the spelling task (F(1, 21) = 60.03, p <.001, η2 = .741). However, this pattern was reversed when the participants were asked to decide on the presence of a vowel in the words, regardless of spelling. The fMRI data showed an engagement of the right inferior frontal gyrus in HSS group during the spelling task. However, temporal, frontal, and subcortical brain regions of the LSS group were activated during the same task

Bioinformatics Discovery of Vertebrate Cathelicidins from the Mining of Available Genomes

Due to the worrying increase in antimicrobial resistance to conventional antibiotics, the search for alternatives is becoming increasingly important. Antimicrobial peptides (AMPs), originating from natural resources, have been recognised as a novel class of antibiotics. An advantage of peptides over antibiotics is that the resistance is more difficult to attain than for conventional antibiotics. With the increasing number of genomes sequenced and available in the public domain, one alternative methodology to obtain novel AMPs is to analyse genes and proteins from genomic databases to predict and identify amino acid sequences that share similarities and molecular features with natural bioactive antimicrobial peptides. In this chapter, we summarise some of our recent results on the production of antimicrobial peptides, particularly, how we managed to identify a family of antimicrobial peptides: cathelicidins, through bioinformatics tools, from the genomes of two lower vertebrates (a reptile and a bird) available in public databases. We hope that our preliminary investigation with these novel peptides could be useful for the design of future strategies that pursue the production of antimicrobial peptides through biotechnology

Seguridad y salud laboral en autopsias

Se presenta el resultado del análisis de las condiciones de trabajo de patólogos y técnicos de anatomía patológica, durante la realización de autopsias. El estudio se ha llevado a cabo analizando cada una de las etapas del proceso de la autopsia en el Hospital Infanta Margarita de Cabra, e identificando y valorando los peligros y riesgos ligados a cada fase. Entre los resultados obtenidos se han identificado riesgos higiénicos, ergonómicos y de seguridad, destacando entre ellos el riesgo biológico por la gravedad de sus consecuencias, los diversos peligros que lo originan y su continua presencia durante la autopsia. Para cada peligro se indican las medidas preventivas a adoptar, y se detallan las características que deben cumplir los equipos de protección individual necesarios