Manipulation of Pre-Target Activity on the Right Frontal Eye Field Enhances Conscious Visual Perception in Humans

The right Frontal Eye Field (FEF) is a region of the human brain, which has been consistently involved in visuo-spatial attention and access to consciousness. Nonetheless, the extent of this cortical site’s ability to influence specific aspects of visual performance remains debated. We hereby manipulated pre-target activity on the right FEF and explored its influence on the detection and categorization of low-contrast near-threshold visual stimuli. Our data show that pre-target frontal neurostimulation has the potential when used alone to induce enhancements of conscious visual detection. More interestingly, when FEF stimulation was combined with visuo-spatial cues, improvements remained present only for trials in which the cue correctly predicted the location of the subsequent target. Our data provide evidence for the causal role of the right FEF pre-target activity in the modulation of human conscious vision and reveal the dependence of such neurostimulatory effects on the state of activity set up by cue validity in the dorsal attentional orienting network

New approaches to the study of human brain networks underlying spatial attention and related processes

Cognitive processes, such as spatial attention, are thought to rely on extended networks in the human brain. Both clinical data from lesioned patients and fMRI data acquired when healthy subjects perform particular cognitive tasks typically implicate a wide expanse of potentially contributing areas, rather than just a single brain area. Conversely, evidence from more targeted interventions, such as transcranial magnetic stimulation (TMS) or invasive microstimulation of the brain, or selective study of patients with highly focal brain damage, can sometimes indicate that a single brain area may make a key contribution to a particular cognitive process. But this in turn raises questions about how such a brain area may interface with other interconnected areas within a more extended network to support cognitive processes. Here, we provide a brief overview of new approaches that seek to characterise the causal role of particular brain areas within networks of several interacting areas, by measuring the effects of manipulations for a targeted area on function in remote interconnected areas. In human participants, these approaches include concurrent TMS-fMRI and TMS-EEG, as well as combination of the focal lesion method in selected patients with fMRI and/or EEG measures of the functional impact from the lesion on interconnected intact brain areas. Such approaches shed new light on how frontal cortex and parietal cortex modulate sensory areas in the service of attention and cognition, for the normal and damaged human brain

Neural representations of the sense of self

The brain constructs representations of what is sensed and thought about in the form of nerve impulses that propagate in circuits and network assemblies (Circuit Impulse Patterns, CIPs). CIP representations of which humans are consciously aware occur in the context of a sense of self. Thus, research on mechanisms of consciousness might benefit from a focus on how a conscious sense of self is represented in brain. Like all senses, the sense of self must be contained in patterns of nerve impulses. Unlike the traditional senses that are registered by impulse flow in relatively simple, pauci-synaptic projection pathways, the sense of self is a system- level phenomenon that may be generated by impulse patterns in widely distributed complex and interacting circuits. The problem for researchers then is to identify the CIPs that are unique to conscious experience. Also likely to be of great relevance to constructing the representation of self are the coherence shifts in activity timing relations among the circuits. Consider that an embodied sense of self is generated and contained as unique combinatorial temporal patterns across multiple neurons in each circuit that contributes to constructing the sense of self. As with other kinds of CIPs, those representing the sense of self can be learned from experience, stored in memory, modified by subsequent experiences, and expressed in the form of decisions, choices, and commands. These CIPs are proposed here to be the actual physical basis for conscious thought and the sense of self. When active in wakefulness or dream states, the CIP representations of self act as an agent of the brain, metaphorically as an avatar. Because the selfhood CIP patterns may only have to represent the self and not directly represent the inner and outer worlds of embodied brain, the self representation should have more degrees of freedom than subconscious mind and may therefore have some capacity for a free-will mind of its own. S everal lines of evidence for this theory are reviewed. Suggested new research includes identifying distinct combinatorially coded impulse patterns and their temporal coherence shifts in defined circuitry, such as neocortical microcolumns. This task might be facilitated by identifying the micro-topography of field-potential oscillatory coherences among various regions and between different frequencies associated with specific conscious mentation. Other approaches can include identifying the changes in discrete conscious operations produced by focal trans-cranial magnetic stimulation

Scrivere per sé. Scritture prossime al parlato nella Roma del Quattrocento

Il contributo propone una prima analisi della lingua delle annotazioni contabili del notaio Evangelista de Bistusciis quale testimonianza del romanesco di tipo medio di fine Quattrocento, interrogandosi criticamente rispetto al livello di prossimità al parlato di queste scritture e delle caratteristiche linguistiche in esse documentat

Impegno politico e parodia linguistica. La campagna elettorale in dialetto di Borazio

Il contributo fornisce l’edizione critica e l’analisi linguistica delle Lettere dalla Sguizzera di Francesco Paolo Borazio (1918-1953), già noto come autore di composizioni poetiche nel dialetto della sua città natale, San Marco in Lamis (Foggia). Borazio, ex scalpellino con un basso livello di istruzione, compensato da molte appassionate letture personali, immagina di essere un emigrante all’estero e scrive quattro fittizie lettere semi-dialettali per sostenere la campagna elettorale del partito socialista, in vista delle vicine elezioni politiche italiane del 1953. In queste lettere originali, in bilico tra aspetto scherzoso e fondamentale serietà, il ricorso prevalente a un dialetto caratterizzato con precisione ed efficacia si alterna alla parodia dell’italiano approssimativo dei semicolti.Political Activism and Linguistic Parody. The Electoral Campaign in Dialect by Borazio · The contribution provides the critical edition and linguistic analysis of the Lettere dalla Sguizzera by Francesco Paolo Borazio (1918-1953), already known as the author of poetic compositions in the dialect of his native town, San Marco in Lamis (Foggia). Borazio, an ex-stonemason with a low level of education compensated by many passionate personal readings, imagines to be an emigrant abroad and write four fictitious semidifferential letters to support the electoral campaign of the Socialist Party, in view of the nearby Italian political elections of 1953. In these original letters, poised between joking appearance and fundamental seriousness, the prevailing recourse to a dialect characterized with precision and effectiveness alternates with the parody of the approximate semi-illiterate’s Italian

Three-dimensional speckle tracking echocardiography in the assessment of right ventricular dysfunction after surgical repair of tetralogy of Fallot.

Background: The combined effects of preoperative hypertrophy and hypoxia, possible intraoperative myocardial damage, type of reconstruction, and acquired postoperative lesions such as pulmonary regurgitation may result in impaired RV deformation in post-operative tetralogy of Fallot (TF). Recently 3D speckle tracking echocardiography (3DSTE) has been proposed to assess mechanical dyssynchrony in these patients but the role of electromechanical dysfunction is not completely clear. Methods: Sixteen patients after TF repair (aged 17-53years) with dilated right ventricle, right bundle branch block (QRS >120ms), and NYHA class I or greater were studied with twodimensional and three-dimensional speckle tracking echocardiography. Right ventricular enddiastolic and end-systolic volumes were measured from three-dimensional datasets and right ventricular ejection fraction (3D-RVEF) was obtained. Right intraventricular dyssynchrony was determined as the difference between the longest and shortest electromechanical coupling times in the basal septal and lateral RV segments. Interventricular dyssynchrony was determined as the difference between electromechanical coupling times in the basal lateral LV segment and the most delayed RV segment. Sixteeen age-matched healthy subjects were selected as controls. Results: Right intraventricular dyssynchrony (77.1+/-24.2ms vs 13.1+/-8.9ms) and interventricular dyssynchrony (74.7+/-22.2ms vs 11.4+/-7.9ms) were shown in patients compared to normal controls. Right intraventricular dyssynchrony correlated with RV longitudinal strain (r=0.62, p<0.005), 3D RV end-systolic volume (r=0.47, p=0.02), and QRS duration (r=0.39, p=0.03). Interventricular dyssynchrony correlated with RV longitudinal strain (r=0.73, p<0.001), RV systolic pressure (r=0.59, p<0.005), 3D-RVEF (r=0.53, p=0.003), and QRS duration (r=-0.44, p=0.031). Reduced RV strain, 3D-RVEF and prolonged QRS duration were the main determinant factors predicting RV dyssynchrony by multivariate analysis. On ROC curves RV strain and 3DRVEF had optimal predictive accuracy of the NYHA functional class and a larger area under the receiver operating characteristic curve than the QRS duration. Conclusions: In patients with repaired TF RV dyssynchrony is associated with reduced 3D-RVEF and RV 3DSTE parameters