1,720,963 research outputs found
Overt and covert effects of cognitive fatigue on attention networks
Full text linkBackground and aims
Cognitive fatigue refers to a variation of the psychophysiological state during or after prolonged periods of mental activity that requires work efficiency, and could lead to temporary deterioration of attentional functioning, especially top-down attention and cognitive control. The present study aims to verify the effects of cognitive fatigue on attention in the context of the three attentional networks described by Posner, by using behavioral and psychophysiological measures, to detect variations in overt and covert responses respectively.
Methods
Thirty young healthy subjects were enrolled in the study, 15 in the “fatigue” and 15 in the control group. Cognitive fatigue was provoked by a continuous arithmetic task lasting 1 h, and the EEG recordings were conducted before and after the task, while subjects were performing the attention network test. The N1, N2 and P3 components were analyzed for the alerting, orienting and conflict networks, in conformity with behavioral analysis.
Results
No difference emerged between groups in networks' efficiency scores and in N1 and P3 amplitudes related to the alerting network. As regards the orienting network, P3 amplitude was significantly reduced in the fatigue group alone (p = 0.02), while no differences emerged in N1 amplitude. As regards the conflict network, both N2 and P3 amplitudes were significantly reduced in the fatigue group alone and selectively for the incongruent target (p < 0.001; p = 0.001 respectively).
Conclusions
Our results suggest that, in young healthy subjects, cognitive fatigue interferes with goal-driven attention especially when the task demand is higher, sparing the bottom-up attention control mechanisms and in absence of any overt observable effect
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
Cerebellum’s Contribution to Attention, Executive Functions and Timing: Psychophysiological Evidence from Event-Related Potentials
No full textSince 1998, when Schmahmann first proposed the concept of the “cognitive affective syndrome” that linked cerebellar damage to cognitive and emotional impairments, a substantial body of literature has emerged. Anatomical, neurophysiological, and functional neuroimaging data suggest that the cerebellum contributes to cognitive functions through specific cerebral–cerebellar connections organized in a series of parallel loops. The aim of this paper is to review the current findings on the involvement of the cerebellum in selective cognitive functions, using a psychophysiological perspective with event-related potentials (ERPs), alone or in combination with non-invasive brain stimulation techniques. ERPs represent a very informative method of monitoring cognitive functioning online and have the potential to serve as valuable biomarkers of brain dysfunction that is undetected by other traditional clinical tools. This review will focus on the data on attention, executive functions, and time processing obtained in healthy subjects and patients with varying clinical conditions, thus confirming the role of ERPs in understanding the role of the cerebellum in cognition and exploring the potential diagnostic and therapeutic implications of ERP-based assessments in patients
Serotonergic central tone in Parkinson's disease with fatigue: Evidence from the loudness dependence of auditory evoked potentials (LDAEP)
Full text linkCentral fatigue in Parkinson's disease (PD) is a common and disabling symptom that further worsens the patients’ quality of life. A deficit in the serotonergic system may be implicated in the occurrence of fatigue in patients with PD as well as in those with other chronic conditions characterized by fatigue. The loudness dependence of auditory evoked potentials (LDAEP) is a neurophysiological tool that has proved to be effective in measuring the serotonergic central function in vivo. The aim of the present study was to assess central serotonergic activity in PD patients and to explore its possible association with the presence of fatigue. LDAEP was recorded in 38 PD patients (26 without fatigue – PDnF and 12 with fatigue – PDF) and 34 healthy controls. A significant difference between parkinsonian patients and controls emerged, with patients displaying stronger LDAEP values (which reflect a lower serotonergic central tone) than controls. By contrast, no differences in LDAEP emerged between PDF and PDnF. Our electrophysiological data confirmed the presence of a deficit in serotonergic central transmission in PD. An association between this deficit and fatigue was not demonstrated. It is likely that an altered dopamine/serotonin balance, rather than a serotonin deficit alone, is involved in the genesis of central fatigue. This complex and multifaceted symptom is related above all to a dysfunction in the striato-thalamo-cortical loop that connects the neostriatum to the frontal lobe and is strongly affected by motivation
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
Behavioral Addictions Questionnaire (BAQ): Validation of a New Tool for the Screening of Multiple Addictive Behaviors in the Italian Population
No full textThis study deals with the uncertainty in defining behavioral addictions (BAs). BAs are characterized by specific compulsive behaviors, regardless of potential negative consequences. However, to differentiate a behavior from a leisure activity to an addictive one is still an object of debate in the literature. Accordingly, this study aimed to assess the psychometric properties of the Behavioral Addictions Questionnaire (BAQ) as a possible screening tool for multiple BAs (i.e., shopping, food addiction, gambling, sex, work, exercise, Internet, videogames, and smartphone). BAQ aims to give a dimensional and quantitative assessment of addictive behaviors in a continuum, including both the adaptive and maladaptive features of the behaviors. Five hundred and seventy-six healthy adults (age range: 18–88) participated in the study, completing a survey including the BAQ questionnaire. Considering both exploratory and confirmatory factor analyses, statistical examination suggested good psychometric properties, with adequate validity in all its subscales (i.e., the goodness of fit). Moreover, also higher reliability was confirmed for each dimension detected (i.e., all alpha over 0.65). The BAQ represents a comprehensive screening instrument that benefits from appropriate validity and reliability for assessing BAs. Therefore, it can be used in clinical fields and research. Moreover, the feature of BAs on a continuum, and the severity index adopted by the study, can help from a preventive perspective. However, further validation of the BAQ is needed in other countries and contexts
124. Pearl and pitfalls in brain functional analysis by event–related potentials: a narrative review by Italian Psychophysiology and Cognitive Neuroscience Society on methodological limits and clinical reliability- Part II.
No full textMental flexibility in Parkinson's disease with central fatigue: Data from the frontal assessment battery
Full text linkBackground and aims
Central fatigue is defined as a reduced energy level or an
increased perception of effort, often associated to a failure in
initiating and maintaining tasks that require self-motivation. It is
common in Parkinson's disease population and it has been
hypothesized to be related to a dysfunction in the striato-talamo-
prefrontal loop. The aim of the present study was to explore the
association between fatigue and executive functions as index of
integrity of the striato-thalamo-prefrontal loop.
Methods
Twenty-nine non-demented PD patients without fatigue - PDnF,
28 non-demented PD patients with fatigue - PDF and 26 age and sex-
matched controls underwent an evaluation with the Frontal
Assessment Battery (FAB), MMSE, PSQI, BDI, STAI Y1-2, PDQ-39.
Differences between groups in FAB scores (total and subitems) were
analyzed by means of Kruskal-Wallis test. Moreover, a correlation
between fatigue and FAB was also analyzed.
Results
Overall parkinsonian population displayed worse performance
than controls in frontal scores especially inhibitory control (p =
0.008) and sensitivity to interference (p = 0.014). PDF displayed
significantly worse than PDnF in verbal fluency (p = 0.05). Fatigue
severity inversely correlated with executive performance (p b 0.001).
Conclusions
Phonemic fluency tasks are thought to reflect the simultaneous
engagement of several executive functions such as attention,
working memory, retrieval, information processing. The association
of central fatigue with a deficit in mental flexibility, could support
the hypothesis that central fatigue is a reliable index of the
impairment of higher executive functions needed in order to
effectively assess costs and benefits related to adaptive decision-
making behavior
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