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La relazione tra la valenza e la semantica nell’elaborazione delle emozioni: correlati elettrofisiologici e di neuroimaging in popolazioni sane e cliniche.
No full textTra la miriade di input sensoriali nell'ambiente, il sistema attentivo automaticamente prioritizza gli stimoli in base al loro contenuto affettivo, in termini di valenza positiva o negativa. Oltre al contenuto affettivo di uno stimolo, altre due variabili entrano in gioco durante la sua elaborazione: la semantica, o significato, e il suo livello di attivazione, anche chiamato arousal. Lo scopo della tesi è di esaminare i correlati elettrofisiologici e di neuroimaging di questi elementi nell’elaborazione di stimoli emozionali sia nelle popolazioni sane che in quelle cliniche.
Inizialmente, gli Studi 1 (n=30) e 2 (n=34), già pubblicati, investigano i correlati comportamentali ed elettrofisiologici dell’elaborazione implicita di parole di dolore mediante un paradigma di priming affettivo in individui sani. Questo paradigma presuppone che la valenza di una parola sia elaborata diversamente se è preceduta da stimoli negativi di dolore rispetto a stimoli non legati a dolore. Questo rappresenta il primo tentativo di applicare l'analisi delle componenti dei potenziali evento-relati (ERP) nel priming affettivo su parole di dolore. I risultati mostrano tempi di reazione più rapidi quando parole negative erano precedute da quelle di dolore rispetto che positive. Le analisi ERP non hanno rivelato alcun effetto del dolore durante la fase iniziale (N400), ma una maggiore ampiezza durante la fase tardiva (LPP) quando parole negative erano precedute da quelle di dolore, sottolineando che per generare una risposta specifica al contenuto semantico il sistema cognitivo necessita di più tempo.
In seguito, lo Studio 3 (n=34), in corso, indaga il ruolo della valenza e dell’arousal nella produzione di parole in un compito di fluenza, che richiede agli individui di generare il maggior numero di parole emozionali in 60 secondi. I risultati mostrano una produzione maggiore di parole negative rispetto a quelle positive. Considerando l’arousal, le parole positive con alto arousal venivano prodotte più frequentemente sia rispetto alle parole positive con basso arousal che alle parole negative. Questo studio fornisce una prospettiva tridimensionale in cui l'organizzazione dei concetti emotivi nella memoria semantica si basa non solo sulla loro valenza e semantica, ma anche sull'intensità dell’esperienza emotiva.
Infine, lo Studio 4 (in prep) sfrutta la variabilità neuroanatomica e comportamentale unica della demenza semantica, un disturbo neurodegenerativo caratterizzato da atrofia nei lobi temporali anteriori (ATL). La demenza semantica si presenta in due forme cliniche: quella con atrofia emisferica sinistra e perdita di memoria semantica, e quella con atrofia emisferica destra e deficit socio-emotivi. Esaminando le cartelle cliniche di 228 individui, si è osservato che coloro con atrofia lateralizzata a destra mostrava più esperienze emotive positive rispetto a coloro con atrofia lateralizzata a sinistra, oltre ad altri cambiamenti comportamentali, un modello che abbiamo confermato con analisi di neuroimaging strutturale. Lo studio su questa popolazione fa luce sul ruolo dell'ATL destro nell’associare la conoscenza semantica alle esperienze affettive.
In conclusione, i risultati comportamentali ed ERP offrono preziosi spunti sul corso temporale dell’elaborazione di stimoli emozionali, identificando una finestra temporale critica per lo studio dell'interazione tra semantica e valenza. I risultati clinici e di neuroimaging forniscono un substrato anatomico, aprendo una nuova prospettiva sulla localizzazione delle emozioni. Pertanto, questo progetto di ricerca costituisce un contributo modesto ma significativo, rivelando il meccanismo attraverso il quale il cervello genera risposte specifiche a emozioni distinte per interpretare le esperienze emotive individuali.Amidst the multitude of sensory inputs competing in the environment, the attentional system automatically prioritizes stimuli based on their affective content— their evaluation in terms of positive and negative valence. Beyond the affective content of a stimulus, two other variables play a part during its processing: its semantics, or conveyed meaning, and its level of activation, also named arousal. The aim of this thesis is to examine the electrophysiological and neuroimaging correlates of these elements of emotion processing in both healthy and clinical populations.
First, Studies 1 (n=30, published) and 2 (n=34, published) delved into the behavioral and electrophysiological correlates of implicit processing of words with pain content using an affective priming paradigm in healthy subjects. This paradigm considered the potential difference in processing the valence of a word when preceded by negative stimuli related to pain compared to negative and positive stimuli unrelated to pain. Notably, this marked the first attempt to apply event-related potential (ERP) component analysis to an affective priming paradigm involving pain-related words. Results showed faster reaction times when a negative word was preceded by a pain word compared to a positive one. ERP analyses revealed no effect of pain during early-stage processing (N400) but a larger waveform when the negative word was preceded by a pain word rather than a positive one during late-stage processing (LPP), underscoring the longer time course required by the cognitive system to generate a response to specific semantic content.
Building upon this, Study 3 (ongoing) aimed to investigate valence and arousal in word generation using an emotion fluency task, which required individuals to generate as many emotional words as possible in 60 seconds. Results in a sample of 34 healthy subjects revealed a higher production of negative words compared to positive ones. However, upon considering arousal, it was found that positive words with high arousal were produced more frequently than both low arousal positive words and negative words. This study provides a three-dimensional perspective in which the organization of emotion concepts in semantic memory is not only based on their valence and semantics, but also on the intensity of an emotional experience.
Ultimately, Study 4 (in preparation) leveraged the unique neuroanatomical and behavioral variability found in semantic dementia, a neurodegenerative disorder characterized by atrophy in the anterior temporal lobes (ATLs). Semantic dementia presents in two clinical forms: those with predominantly left hemisphere atrophy and loss of semantic memory, and those with predominantly right hemisphere atrophy and socioemotional deficits. We reviewed medical records of a cohort of 228 individuals with SD which revealed that those with right-lateralized atrophy showed greater positive emotional experiences than those with left-lateralized atrophy as well as other changes in behaviors, a pattern we confirmed with structural neuroimaging analyses. This study in a clinical population shed light on the role of the right ATL in binding together semantic knowledge to affective experiences.
In conclusion, behavioral and ERP findings offered valuable insights into the time course of implicit emotion processing emphasizing a critical time window for studying the interplay between semantics and valence. The clinical and neuroimaging findings provide an anatomical substrate, opening a new perspective on the mapping of emotions. Consequently, this research project makes a meaningful contribution to the field by revealing the mechanism through which the brain generates responses tailored to distinct emotions to parse individual emotional experiences
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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