395 research outputs found
Audiovisual bounce-inducing effect: attention alone does not explain why the discs are bouncing.
No full textTwo disks moving from opposite points in space, overlapping, and stopping at one another’s starting point
can be seen as either bouncing off one another or streaming through one another. With silent displays, observers
report streaming, whereas, if a sound is played when the disks are in the overlap region, observers report bouncing.
The change in perception is thought to be modulated by a lack of attention that inhibits the integration of
the motion signal when disks overlap and by the sound that increases the congruence of the display, in comparison
with a real elastic bounce. Here, we accompanied the disks’ motion with either a bounce-congruent sound (
a billiard ball) or with bounce-incongruent sounds (a water drop, a firework). When the sound was switched
on 200 msec before the disks’ overlap, (1) all the audiovisual displays induced more bounce responses than did
the silent display, but (2) the bounce-congruent sound induced more bounce responses than did the bounceincongruent
sounds. However, when the sound was switched on at the disks’ overlap, only the first result was
observed. These results highlight both the role of attention and that of sound congruence
Audiovisual bounce-inducing effect: when sound congruence affects grouping in vision.
No full textTwo disks moving from opposite points in space, overlapping, and stopping at one another’s starting point
can be seen as either bouncing off one another or streaming through one another. With silent displays, observers
report streaming, whereas, if a sound is played when the disks are in the overlap region, observers report bouncing.
The change in perception is thought to be modulated by a lack of attention that inhibits the integration of
the motion signal when disks overlap and by the sound that increases the congruence of the display, in comparison
with a real elastic bounce. Here, we accompanied the disks’ motion with either a bounce-congruent sound (
a billiard ball) or with bounce-incongruent sounds (a water drop, a firework). When the sound was switched
on 200 msec before the disks’ overlap, (1) all the audiovisual displays induced more bounce responses than did
the silent display, but (2) the bounce-congruent sound induced more bounce responses than did the bounceincongruent
sounds. However, when the sound was switched on at the disks’ overlap, only the first result was
observed. These results highlight both the role of attention and that of sound congruence
Streaming or bouncing? Attention does not explain the audiovisual bounce-inducing effect
No full textRevealing the origin of the audiovisual bounce-inducing effect
No full textThe audiovisual bounce inducing effect (ABE) is a bouncing percept induced by the presentation of a sound
in a motion display otherwise perceived as streaming. The literature suggests that the origin of the ABE is
double: the effect stems from the action of an attentional component and that of a non-attentional component.
However, the type of response classically gathered in ABE studies does not enable the disentanglement of
the two components. Here, we used the ABE stimuli in a detection task and observed the effect of the sound
on participants’ sensitivity (hypothesised to be linked to the attentional component) and on response bias
(hypothesised to be linked to the non-attentional component). The sound affected sensitivity and response
bias in a way that is consistent with that expected by a selective modulation of the attentional and nonattentional
component by the sound
Contextual influences in texture-segmentation: Distinct effects from elements along the edge and in the texture-region
No full textBoth neurophysiological and psychophysical evidence suggest a strong influence of context on texturesegmentation.
Here we extend and further analyse this issue, with a particular focus on the underlying
mechanism. Specifically, we use a texture-edge discrimination task and separately investigate the effect
of elements far from and along the edge. Consistent with previous studies, we report both an iso-near
contextual effect – whereby performance is better if elements along the edge are iso-oriented compared
to ortho-oriented to the edge – as well as an ortho-far effect – whereby discrimination is higher when
elements far from the edge are orthogonal to the edge. We found that backward mask, which is known
to interrupt re-entrant processing from extrastriate areas, only interferes with the iso-near effect whereas
perturbing orientation, position or contrast polarity of elements far from the edge only abolishes the
ortho-far effect. This suggests that feedback processes may be involved in the iso-near effect. Instead,
the ortho-far effect may be accounted for by recurrent interactions among 1st order filters
La Fine del Potere Ottomano. L’ultimo sultano, l’ultimo califfo, gli ultimi gran visir
No full textContrariamente alla fine dell’Impero zarista, dell’Impero asburgico e di quello germanico, la fine dell’Impero ottomano sopravvenne dopo lunga e tortuosa agonia, prodotta principalmente dalle confliggenti ambizioni delle potenze che avevano vinto la Grande Guerra. A cento anni dall’abolizione del califfato (3 marzo 1924), Fabio L. Grassi ripercorre la storia ben poco conosciuta degli uomini che ressero e rappresentarono l’impero in quegli anni. L’autore ne illustra la vita, la carriera, le propensioni politiche, l’opera, le posizioni di volta in volta assunte, la loro sorte successiva, oltre che la loro dimensione culturale, morale e psicologica. Ciò che fecero e non fecero l’ultimo sultano, l’ultimo califfo e gli ultimi gran visir, ovvero i massimi rappresentanti della «Turchia legale», nelle loro relazioni da una parte con gli Alleati dall’altra con la «Turchia ribelle», costituisce un insieme complesso, ambiguo e in parte ancora misterioso.Contrary to the end of the Tsarist Empire, of the Habsburg Empire and of the Germanic, Empire, the end of the Ottoman Empire came after a long and torturous agony, caused mainly by the conflicting ambitions of the powers that had won the Great War. One hundred years after the abolition of the caliphate (3 March 1924), Fabio L. Grassi traces the scarcely story
known of the men who ruled and represented the empire in those years. The author illustrates their life, career and political propensities policies, their acts, the positions taken from time to time, theirs subsequent fate, as well as their cultural, psychological and moral dimension. What the last sultan, the last caliph and the last grand viziers, i.e. the highest representatives of «legal Türkiye», did and did not do, in their relations on the one hand with the AlliedPowers on the other with "rebel Türkiye", constitutes a
complex, ambiguous and partly still mysterious whole
Improving drug efficacy and specificity by innovative drug delivery approaches
No full textThe limited efficacy of current therapeutic approaches for a number of socially relevant human diseases requires the exploration of alternative and more effective therapeutic strategies. In this regard, the researchers have pursued on one hand the identification of novel and more effective therapeutic molecules and on the other the optimization of drug delivery systems.
So far, many therapeutic molecules, especially those used as anticancer drugs, are plagued by a low therapeutic index being the efficacious dose very close to the lethal one; moreover, they often lack any specificity of action. This aspect can be improved by the use of drug delivery systems composed of different drug carriers including lipids and polymers. The carriers, often in the shape of nanoparticles , can be loaded by the therapeutic molecule and directed against the target cells via the presence of targeting moieties allocated on the nanoparticle surface.
The specificity of the complex carrier/drug can be further improved by the use of therapeutic molecules preferentially/exclusively active on the target diseased cells. Molecules active against diseased-associated target (oncogenes etc) may hit the diseased cells leaving healthy cells substantially unaffected. In this regard, in the last three decades, nucleic acid based drugs (NABDs) have emerged as an attractive and novel alternative with great therapeutic potential. NABDs, which include antisense oligonucleotides, decoys, aptamers, triple helix forming oligonucleotides, DNAzymes, Ribozymes and small interfering RNAs, have been shown to be able to efficiently and specifically counteract pathological gene expression in many different experimental systems. Notably as they can be engineered to hit virtually any cell target, their potential applicability is very broad.
Despite NABD broad potential applicability, their use in the clinic is limited by the lack of optimal delivery systems. Due to their hydrophilic nature, NABDs cannot efficiently cross cellular membrane for which appropriate carriers are needed. Moreover, their instability in serum requires a proper protection to prevent a fast degradation which would invariably lead to the abrogation of any significant therapeutic effect.
The present special issue will be focused on the critical description of some aspects related to the optimization of drug delivery with a particular emphasis on NABD; despite this, a discussion about the possibility to use/adapt NABD developed delivery systems for more conventional drugs, is also present.
The papers of Chan et al., of Marrache et al, of Schaffert et al., Jung et al. and Grassi et al. describe different delivery approaches for NABD and other commonly used therapeutic molecules for several pathological conditions. In the paper of Chan et al. attention is given to liposome and polymeric based delivery systems with regard to DNA enzymes; the described studies offer perspectives on future methodologies for improved DNAzyme delivery and utility as novel drugs. Marrache et al. describe the use of nanoparticles (made by polymer, liposome and other delivery agents), as delivery devices which can be engineered to load multiple drugs with varied physicochemical properties, contrast agents, and cellular or intracellular component targeting moieties. Schaffert et al draw their attention on the description of delivery systems based on the polycation linear polyethylenimine, where peptide based ligands are attached to the polycation via heterobifunctional polyethylene glycol linker molecules. Conjugate synthesis, in vitro testing and in vivo cancer models in rodents are discussed. Jung et al describe the employment of the thermo sensitive pluronic-based core/shell nanoparticles, formed using various strategies such as self-assembly and temperature induced-phase transition. Particular emphasis is given to the use of the nanoparticles for tumor targeting, stimulated release of proteins, and cancer imaging capabilities. Grassi et al, beside discussing the above mentioned delivery systems, for most of the different types of NABDs, draw their attention on the complex situation of NABD delivery to the arteries describing the advantages and dis-advantages of three different administration routes i.e. systemic, perivascular and intravascular.
The papers of Lico et al, Pagliari et al and Castronovo et al report the use of “living delivery systems” and describe the influences of nano-systems on NABD. Lico et al. focus their attention on the use of a different approach for NABD delivery based on plant viruses which have a size particularly suitable for nanoscale applications and can offer several advantages being structurally uniform, robust, biodegradable and easy to produce. Pagliari et al. continue the description of “living vector” reporting the possible and very innovative use of stem cells as delivery devices for therapeutic molecules to the injured myocardium. Finally, in the paper of Castronovo et al., a completely innovative point of view about NABD complexation in nano-carriers is provided. The author show that the functionality of NABD in nano-systems is highly dependent upon the local density, molecular flexibility and network of weak interactions between adjacent molecules. The understanding of these properties can enable the development of powerful molecular tools for nano-medicine.
In conclusion, whereas the developmental process of many delivery systems is still at the beginning, other delivery strategies are closer to possible applications. Regardless of the fact that the delivery systems are used for NABD or clinically available drugs, we believe the target tissue will mainly determine the nature of the optimal strategy. Despite the delivery issue can and should be further optimized, the encouraging results displayed so far in different experimental models using NABD or clinically used drugs, fully justify further economic and scientific efforts
Positional noise in Landolt-C stimuli reduces spatial resolution: A study with younger and older observers
No full textIn the present study we examined the effect of positional noise on spatial resolution in younger and older observers. We used a yes/no discrimination task in which observers indicated whether the size of two gaps in a Landolt-C-like contour was the same or not. The proportion of trials observers perceived one gap larger was measured when gaps-position was fixed (low positional noise) and random (high positional noise). Specifically, we compared, across conditions and groups, the values of threshold, lower and upper asymptote of the psychometric function. In the younger group, noise does not prevent detection of gap-size difference although sensitivity is lower, as revealed by higher threshold and lower upper asymptote, i.e., the proportion of responses “I see a larger gap” at the largest gap-size difference (asymptotic performance). In the older group detection is prevented, as revealed by threshold, lower and upper asymptote data. This may be because, at stimulus onset, high positional noise has associated coarse filter analysers averaging across the two gaps, which cannot be switched off
The origin of the audiovisual bounce inducing effect: A TMS study.
No full textThe audiovisual bounce inducing effect (ABE) is a bouncing percept induced by the presence of a sound at the moment of two moving objects intercepting in a motion display otherwise perceived as streaming. The origin of the ABE is still debated: the effect could arise from the subtraction of attentional resources caused by the sound (needed to favor the perception of streaming), and/or from the cross-modal integration (binding) of visual and auditory information: indeed bouncing-like sounds are best in inducing the ABE. The neural mechanism responsible for the ABE is still unknown. Here, by using offline TMS, we investigated the role of the posterior parietal cortex (PPC), thought to be involved in both attentional and binding processes, in the generation of the ABE.
Results show that disrupting the functional integrity of the right (but not the left) PPC has the effect of weakening the binding of cross-modal information, which reduces the magnitude of the ABE. Indeed, if the effect of parietal stimulation was merely to disrupt attention, we would expect an increase (not a decrease) of bouncing percepts.
The present study not only shows the involvement of the right PPC in the ABE, but also support the notion that cross-modal binding (and not attention) is at the origin of the ABE
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