1,720,959 research outputs found
TOWARD MORE NATURALISTIC APPROACHES TO INVESTIGATE THE MECHANISMS AND NEURAL CORRELATES OF PROSPECTIVE MEMORY
Full text linkLa memoria prospettica (MP) è l’abilità di ricordarsi di portare a termine un’intenzione nel futuro. Il presente progetto si propone di investigare la MP e i suoi correlati neurali attraverso l’implementazione di paradigmi più realistici e metodi di analisi innovativi, per raccogliere dati comportamentali e neurofisiologici più riconducibili al funzionamento della MP nella vita quotidiana. Per raggiungere questo obiettivo, nuove classi di stimoli (riferiti a variabili presenti nel contesto quotidiano) sono state validate ed investigate, e nuovi metodi di analisi delle oscillazioni neurali associate ai processi di MP introdotti. Nel dettaglio, è stato investigato l’effetto della modalità sensoriale sulla MP e sulle sue basi neurali, creando un paradigma composto da versioni acustiche e visive di diversi task prospettici (le cui richieste incentivavano o i processi di monitoraggio, o quelli di mantenimento). I risultati comportamentali indicano che il mantenimento di un’intenzione ha maggior effetto sulla performance quando gli stimoli sono presentati in modalità acustica, specialmente nei task che incentivano il monitoraggio. L’indagine di questi risultati con tecniche neurofisiologiche, d’altro lato, ha rivelato che i processi di MP sono associati a diminuita attività nelle bande di frequenza theta e alpha, in maniera simile nelle due modalità. In quella acustica, tuttavia, i cluster di ridotta attività in alpha erano più lunghi e diffusi, indice che in questa modalità risorse aggiuntive erano necessarie per monitorare la presentazione dello stimolo associato al recupero dell’intenzione. Inoltre, questo confronto ha permesso di rivelare informazioni sul significato funzionale di questi cluster, considerato che quelli in alfa sembravano riflettere processi di monitoraggio indipendenti dalla modalità, mentre l’inizio e la durata delle oscillazioni in theta associano i risultati in questa banda con una ridotta elaborazione del task ongoing. Una seconda variabile considerata, molto presente nelle nostre vite negli ultimi tre anni, è l’esposizione a informazioni riguardanti la pandemia da COVID-19. Per studiarla, abbiamo validato dei filmati con contenuti riferiti alla situazione pandemica, proponendoli all’interno di un paradigma di priming affettivo, subito prima dell’esecuzione di un task prospettico. I dati raccolti in questa condizione sono stati confrontati con dati raccolti dopo la presentazione di video con contenuti neutrali o negativi. Mentre il video negativo produceva una riduzione nell’accuratezza, il video COVID-relato risultava migliorare la performance, suggerendo che questo stimolo possa fungere da fattore stressante, aumentando il coinvolgimento nel task. Nell’ultimo studio abbiamo applicato delle analisi di connettività funzionale (CF) all’indagine dei network coinvolti nella fase di mantenimento di diverse condizioni prospettiche. Questo approccio ha rivelato differenze significative nei network sottesi al mantenimento dell’intenzione, a seconda delle richieste del task prospettico, che incentivavano o il monitoraggio o il mantenimento. Pertanto, l’analisi di CF è risultata un utile strumento per studiare le oscillazioni nell’intervallo prestimolo dei paradigmi prospettici, indipendentemente dall’attività elicitata dopo la presentazione dello stimolo. Nel suo complesso, questo progetto ha evidenziato l’importanza del coinvolgimento di paradigmi e stimoli più naturalistici per l’indagine della MP, per scoprire nuovi fattori che giocano un ruolo in questa capacità e per offrire nuove strategie per studiarne gli effetti nei contesti in cui avvengono. Infine, approcci di analisi come la CF hanno il potenziale di permettere l’indagine della MP con maggior flessibilità, permettendoci di esaminare il mantenimento delle intenzioni attraverso paradigmi sperimentali più naturalistici.Prospective Memory (PM) is the ability to remember to perform an intention at some point in the future. The present project aims to investigate PM and its neural correlates through the implementation of more life-like paradigms and innovative analysis methods, to collect behavioral and neurophysiological data more generalizable to everyday PM functioning. To reach this goal, novel classes of stimuli (referring to variables present in people’s everyday context) were validated and investigated, and new methods of analysis of the neural oscillations associated with PM processing were introduced. In detail, we investigated the effect of sensory modality on PM processing and neural bases, creating a paradigm composed of auditory and visual versions of different PM conditions (enhancing either the monitoring or the maintenance requests of the PM task). Behavioral results indicated that the maintenance of an intention has greater effects on performance when stimuli are presented in the auditory modality, especially for PM tasks enhancing monitoring processes. The investigation of such findings with neurophysiological techniques, on the other hand, revealed that PM processes were associated with clusters of decreased activity in the theta and alpha frequency bands, consistently between sensory modalities. In the auditory, however, the cluster of alpha decreases was longer and more widespread, indicating that in this modality additional resources were required to monitor for the stimulus associated with intention retrieval (the PM cue). Moreover, this comparison allowed to shed light on the functional meaning of these decreases, as alpha decreases seemed to reflect modality-independent monitoring processes (strategic monitoring), whereas the onset and duration of the theta oscillations associate the results in this band with a reduced elaboration of the ongoing task. A second variable that we considered, very present in our life in the last three years, was the exposition to information regarding the COVID-19 pandemic. To do so, we validated a movie excerpt with content referring to the pandemic situation and proposed it within an affective priming paradigm, right before the execution of a PM task. Data collected in this condition were compared with the ones collected after the presentation of either a neutral or a negative video clip. While the negative prime induced decreased accuracy, the pandemic-related stimulus was reflected in improved performance, suggesting that such stimuli may work as acute stressors, increasing the involvement in the task. In the last study, we applied functional connectivity analysis to the examination of the networks involved during the maintenance phase of different PM conditions. This approach revealed significant differences in the networks underlying intention retention, depending on the monitoring-enhancing or maintenance-enhancing nature of the requests of the PM task. Therefore, functional connectivity resulted to be a useful tool to investigate the oscillations in the prestimulus interval of a PM paradigm, independently from the activity occurring after the stimulus presentation. Overall, this project highlighted the importance of the involvement of more naturalistic paradigms and classes of stimuli in the investigation of prospective remembering, to discover new factors that play a role in this ability, and to offer new strategies to study their effects in the context in which they occur. Finally, analysis approaches such as functional connectivity have the potential to allow the investigation of PM with increased flexibility, allowing us to examine intention maintenance through more life-like experimental paradigms, such as conditions in which no stimuli are presented (and the intention must be maintained) for longer intervals
Thinking about it: the impact of COVID-19-related stimuli on prospective memory
Full text linkBackground
Since 2020, information regarding COVID-19 has been a constant presence in the news, in our conversations and thoughts. Continuous exposure to this type of stimuli could have an impact on cognitive processes essential for our everyday activities, such as prospective memory (PM). PM is the ability to remember to perform an intention at a specific point in the future, like remembering to take prescribed medicines at a specific time or to turn off the stove after cooking. Do COVID-related stimuli affect our ability to perform a PM task?
Methods
To answer this question, we proposed a novel version of the classical paradigm used to investigate PM. Namely, this paradigm includes a baseline condition, in which an ongoing task is presented alone, and a PM condition in which the same task is proposed again together with a second (prospective) task. In this study, a short video clip was presented between the baseline and the PM condition. The video clip displayed either neutral, negative, or COVID-related content. Additionally, participants were asked to respond to two questionnaires and a series of questions regarding their well-being and experience with the pandemic. Namely, the DASS-21 scale (evaluating depression, anxiety, and stress), and the COVID-19-PTSD questionnaire (a questionnaire evaluating post-traumatic stress disorder symptoms related to the pandemic experience) were administered. Participants’ performance and responses were analyzed using a linear mixed effect (LME) model approach, and correlation analyses were run to highlight possible correlations between participants’ scores in the DASS-21, the COVID-19-PTSD, and the additional questions on their personal experience with the pandemic.
Results
The LME models revealed significant effects of the displayed video on performance: in line with previous studies, the clip displaying standard negative contents led to impaired accuracy in the ongoing task in the PM condition, compared to the Baseline. In contrast, participants who saw the COVID-related clip showed improved accuracy in the ongoing task compared to the other participants, selectively in the block performed after the video clip was displayed (PM condition). Furthermore, the explanatory power of the LME model calculated on accuracy to the ongoing trials was enhanced by the inclusion of the scores in the anxiety subscale of the DASS-21, suggesting a detrimental role of anxiety. Altogether, these results indicate a different effect of the exposure to classical negative contents (associated with a cost in terms of accuracy in the ongoing task between the baseline and the PM condition) and the pandemic-related one, which was instead characterized by a higher accuracy to ongoing trials compared to the other video clips. This counterintuitive finding seems to suggest that COVID-related stimuli are processed as “acute stressors” rather than negative stimuli, thus inducing a state of increased alertness and responsivity
Listen to the beat: Behavioral and neurophysiological correlates of slow and fast heartbeat sounds
Full text linkBackground: Listening to heartbeat sounds have been found to affect cardiac activity and behavior. However, less is known about the effects of these stimuli on brain activity and cognition. Alpha oscillations (8–13 Hz) are considered markers of cortical activation. Frontal alpha Asymmetry (FαA) reflects the valence attributed to the
stimulus and the tendency to approach/avoid it.
Aim: This study investigates the effects of sounds mimicking heart pulsations at different rhythms on reaction times and neurophysiological activity.
Method: EEG data were collected during a resting-state condition and two Simple Reaction Time tasks (SRT), during which artificially generated heartbeat sounds at fast (120 bpm, FastBeat condition) or slow (60 bpm, SlowBeat condition) rhythms were administered. Alpha power was compared across the three conditions. Differences in the SRT and FαA values were examined between the FastBeat and SlowBeat conditions.
Results: Compared to the resting-state condition, decreased alpha activity over bilateral frontocentral regions was observed in both tasks. The comparison between the FastBeat and the SlowBeat conditions revealed faster response times, a pattern of alpha suppression over right frontal regions, and lower FαA values in the former.
Conclusions: The similarity of alpha reductions elicited in the comparison between the resting-state and the two task conditions suggests that these patterns were ascribable to processes common to both conditions (SRT task, auditory stimulation). In contrast, the differences between the two conditions suggest that fast heartbeat sounds are perceived as more adverse and stressful stimuli, inducing cortical activation over regions associated with
negative states and avoidant tendencies
The impact of sensory modality on prospective memory: Differences between visual and auditory processing
No full textProspective memory (PM) is the ability to perform an intended action when the appropriate conditions occur. Several features play a role in the successful retrieval of an intention: the activity we are concurrently engaged in, the number of intentions we are maintaining, where our attention is focused (outward vs. to inner states), and how outstanding the trigger of the intention is. Another factor that may play a crucial role is sensory modality: Do auditory and visual stimuli prompt PM processing in the same way? In this study, we explored for the first time the nature of PM for auditory stimuli and the presence of modality-dependent differences in PM processing. To do so, an identical paradigm composed of multiple PM tasks was administered in two versions, one with auditory stimuli and one with visual ones. Each PM task differed for features such as focality, salience, and number of intentions (factors that are known in literature to modulate the monitoring and maintenance requests of PM) to explore the impact of sensory modality on a broad variety of classical PM tasks. In general, PM processing showed similar patterns between modalities, especially for low demanding prospective instructions. Conversely, substantial differences were found when the prospective load was increased and monitoring requests enhanced, as participants were significantly slower and less accurate with acoustic stimuli. These results represent the first evidence that modality-dependent effects arise in PM processing, especially in its interaction with features such as the difficulty of the task and the increased monitoring load
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
Full text linkWe 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
- …
