Effective connectivity among the working memory regions during preparation for and during performance of the n-back task

Recent neuroimaging studies have shown that working memory (WM) task difficulty can be decoded from patterns of brain activation in the WM network during preparation to perform those tasks. The inter-regional connectivity among the WM regions during task preparation has not yet been investigated. We examined this question using the graph modeling methods IMaGES and LOFS, applied to the previously published fMRI data of Manelis and Reder (2013). In that study, subjects performed 1-, 2-, and 3-back tasks. Each block of n-back was preceded by a preparation period and followed by a rest period. The analyses of task-related brain activity identified a network of 18 regions that increased in activation from 1to 3-back (Increase network) and a network of 17 regions that decreased in activation from 1to 3-back (Decrease network). The graph analyses revealed two types of connectivity sub-networks within the Increase and Decrease networks: "default" and "preparation-related." The "default" connectivity was present not only during task performance, but also during task preparation and during rest. We propose that this sub-network may serve as a core system that allows one to quickly activate cognitive, perceptual and motor systems in response to the relevant stimuli. The "preparation-related" connectivity was present during task preparation and task performance, but not at rest, and depended on the n-back condition. The role of this sub-network may be to pre-activate a connectivity "road map" in order to establish a top-down and bottom-up regulation of attention prior to performance on WM tasks. © 2014 Manelis and Reder

White matter abnormalities in adults with bipolar disorder type-II and unipolar depression

Discerning distinct neurobiological characteristics of related mood disorders such as bipolar disorder type-II (BD-II) and unipolar depression (UD) is challenging due to overlapping symptoms and patterns of disruption in brain regions. More than 60% of individuals with UD experience subthreshold hypomanic symptoms such as elevated mood, irritability, and increased activity. Previous studies linked bipolar disorder to widespread white matter abnormalities. However, no published work has compared white matter microstructure in individuals with BD-II vs. UD vs. healthy controls (HC), or examined the relationship between spectrum (dimensional) measures of hypomania and white matter microstructure across those individuals. This study aimed to examine fractional anisotropy (FA), radial diffusivity (RD), axial diffusivity (AD), and mean diffusivity (MD) across BD-II, UD, and HC groups in the white matter tracts identified by the XTRACT tool in FSL. Individuals with BD-II (n = 18), UD (n = 23), and HC (n = 24) underwent Diffusion Weighted Imaging. The categorical approach revealed decreased FA and increased RD in BD-II and UD vs. HC across multiple tracts. While BD-II had significantly lower FA and higher RD values than UD in the anterior part of the left arcuate fasciculus, UD had significantly lower FA and higher RD values than BD-II in the area of intersections between the right arcuate, inferior fronto-occipital and uncinate fasciculi and forceps minor. The dimensional approach revealed the depression-by-spectrum mania interaction effect on the FA, RD, and AD values in the area of intersection between the right posterior arcuate and middle longitudinal fasciculi. We propose that the white matter microstructure in these tracts reflects a unique pathophysiologic signature and compensatory mechanisms distinguishing BD-II from UD

What is behind a summary-evaluation decision?

Research in psychology has reported that, among the variety of possibilities for assessment methodologies, summary evaluation offers a particularly adequate context for inferring text comprehension and topic understanding. However, grades obtained in this methodology are hard to quantify objectively. Therefore, we carried out an empirical study to analyze the decisions underlying human summary-grading behavior. The task consisted of expert evaluation of summaries produced in critically relevant contexts of summarization development, and the resulting data were modeled by means of Bayesian networks using an application called Elvira, which allows for graphically observing the predictive power (if any) of the resultant variables. Thus, in this article, we analyzed summary-evaluation decision making in a computational framewor

The effects of imaginal and verbal strategies on prose comprehension in adults

Includes bibliographical references (p. 12-13)Supported in part by the National Institute of Education under Contract No. US-NIE-C-400-76-011

Implicit and explicit memory tests reactivate common memory traces: support for a unitary memory system

The structure of human memory is heatedly debated. While some researchers claim that there are two or more memory systems (Graf & Schacter, 1985; Mitchell & Brown, 1988; Tulving, 1985), others believe that memory is unitary (Bentin et al., 1992; Roediger, 1990). Behavioral and neuroimaging research presented in this dissertation examines a unitary model of human memory using implicit and explicit memory tests for object locations. Specifically, the behavioral experiments tested a) if implicit memory could occur without explicit memory, b) if implicit memory correlated with explicit memory and c) if both tests were equally affected by the strength of memory traces. It appeared that implicit memory for object locations was greater for explicitly recalled, compared to not recalled, items. Implicit memory was correlated with explicit recall. Stronger memory traces were associated with higher recall and higher implicit memory for object locations. The fMRI experiment tested a) if increases in neural activity were related to enhancement of implicit memory and b) re-engagement of encoding-related brain regions during implicit memory test for locations. Consistent with the findings reported in the earlier studies of explicit memory, improvement of implicit memory for locations was associated with increased neural activity in task-specific and attentional networks. In addition, implicit spatial memory depended on the magnitude of reactivation in the encoding-related brain regions. These findings indicated that implicit and explicit memory may rely on similar facilitatory mechanisms. Taken together, behavioral and neuroimaging evidence supported a unitary model of human memory and suggested that both, implicit and explicit, spatial memory tests access common memory representations. It was proposed that reactivation of memory traces is a key factor for performance on implicit and explicit memory tests. Implicit and explicit tests may differ in their ability to reactivate memory representations. This difference may account for dissociation between performance on implicit and explicit memory tests observed in the previous studies.Ph.D.Includes bibliographical references (p. 100-113)by Anna Maneli

The motif of the queen of spades in A.S. Pu\u161kin and L.E. Ulickaja

Das Ziel der vorgelegten Arbeit ist es, das Motiv der Pik-Dame in der povest? von A.S. Pu?kin sowie der Erz\ue4hlung von L.E. Ulickaja vorzustellen und n\ue4her zu er\uf6rtern. Die Arbeit ist in zwei Teile gegliedert: Der erste Teil befasst sich einerseits mit dem aktuellen Stand der Erkenntnisse zur Motivtheorie, andererseits wird der Forschungsstand zur Phantastik mit dem Schwerpunkt der "Theorie der phantastischen Literatur" von Uwe Durst beleuchtet. Schlie flich wird dann die Pik-Dame bei A.S. Pu?kin mithilfe der Motiv- und Phantastiktheorie nach Durst unter die Lupe genommen. Bei der Analyse stellt sich heraus, dass die Symbolik in der Erz\ue4hlung eine wesentliche Rolle spielt und dass das Motiv der Pik-Dame nur aufgrund der Attribute und Charaktereigenschaften der alten Gr\ue4fin funktionieren kann. Schlie flich ist sie die Protagonistin und wirkt sozusagen wie ein Magnet, der alles an sich heranzieht, aber gleichzeitig auch alles von sich st\uf6 ft. Der zweite Teil der Arbeit pr\ue4sentiert die postmoderne Pik-Dame bei L.E. Ulickaja. Hierbei werden die verschiedenen Weiblichkeitsentw\ufcrfe analysiert und die Rolle der Pik-Dame als Femme Fatale dargelegt. F\ufcr die Untersuchung dieser wird auf die Beitr\ue4ge der Literaturwissenschaftler zum Thema Femme Fatale eingegangen. Als letzter Punkt dieser Arbeit wird zum Thema Intertextualit\ue4t Stellung bezogen. Die verschiedenen Intertextualit\ue4tstheorien und Formen der Intertextualit\ue4t werden herausgearbeitet und diskutiert. Schlie flich kann man anhand dieser diversen Intertextualit\ue4tsbez\ufcge zwischen den beiden Werken vermerken und untersuchen. Die Zusammenfassung der Forschungsergebnisse liefert die herausgearbeiteten Punkte der gesamten Analyse und bildet den Schlusspunkt dieser Diplomarbeit.The aim of this thesis is to portray and to further elaborate on the motif of the queen of spades by A.S. Pu?kin and L.E. Ulickaja, respectively. The thesis will be distinguished into two parts. The first part deals with the current state of research regarding the motif theory, as well as the state of research in the field of phantasm, with emphasis on Uwe Durst?s "Theorie der phantastischen Literatur". Furthermore, the queen of spades in A.S. Pu?kin is examined with the aid of the motif theory and Durst?s phantasm theory. In the course of the analysis it becomes evident that symbolism plays a vital role in the storytelling, and that the motif of the queen of spades can take effect only due to the characteristics and attributes of the old duchess. After all, she is the protagonist and functions like a magnet which attracts and simultaneously repulses everything around it. The second part of the thesis displays the postmodern queen of spades in L.E. Ulickaja. Here, the different concepts of femininity are analysed and the role of the queen of spades as femme fatale is pointed out. In order to examine the latter, a closer look at the contributions of different literary scholars and their contributions with respect to the term femme fatale will be taken. As a last point of this thesis an elaboration on the issue of intertextuality is made.The different theories and forms of intertextuality are then discussed and distinguished. Based on these theories, different intertextual references between the two discussed works may be distinguished and documented. The final conclusion delineates the major results and forms the final point of the thesis.vorgelegt von Polina ManelisAbweichender Titel laut cbersetzung der Verfasserin/des VerfassersGraz, Univ., Dipl.-Arb., 2014 2.0118Text \ufcberw. dt., teilw. russ. Teilw. in kyrill. Schr