295 research outputs found
On the âblindnessâ of blindsight: What is the evidence for phenomenal awareness in the absence of primary visual cortex (V1)?
Blindsight has been central to theories of phenomenal awareness; that a lesion to primary visual cortex (V1) abolishes all phenomenal awareness while unconscious visual functions can remain has led to the views that this region plays in generating visual consciousness. However, since the early 20th century, there have been reports, many of which controversial, of phenomenal awareness in patients with V1 lesions. These reports include selective sparing of motion awareness, hemianopic completion and visual aftereffects. More recently, there have been successful attempts of inducing visual qualia with noninvasive brain stimulation. Here we critically review this evidence and discuss their implications to theoretical understanding of phenomenal awareness
Partner selection in indoor-to-outdoor cooperative networks: an experimental study
In this paper, we develop a partner selection protocol for enhancing the
network lifetime in cooperative wireless networks. The case-study is the
cooperative relayed transmission from fixed indoor nodes to a common outdoor
access point. A stochastic bivariate model for the spatial distribution of the
fading parameters that govern the link performance, namely the Rician K-factor
and the path-loss, is proposed and validated by means of real channel
measurements. The partner selection protocol is based on the real-time
estimation of a function of these fading parameters, i.e., the coding gain. To
reduce the complexity of the link quality assessment, a Bayesian approach is
proposed that uses the site-specific bivariate model as a-priori information
for the coding gain estimation. This link quality estimator allows network
lifetime gains almost as if all K-factor values were known. Furthermore, it
suits IEEE 802.15.4 compliant networks as it efficiently exploits the
information acquired from the receiver signal strength indicator. Extensive
numerical results highlight the trade-off between complexity, robustness to
model mismatches and network lifetime performance. We show for instance that
infrequent updates of the site-specific model through K-factor estimation over
a subset of links are sufficient to at least double the network lifetime with
respect to existing algorithms based on path loss information only.Comment: This work has been submitted to IEEE Journal on Selected Areas in
Communications in August 201
Cooperative Regions For Coded Cooperation Over Time-Varying Fading Channels
The performance analysis of coded cooperation has been mainly focused on two extreme cases of channel variability, i.e. the block-fading (BF) and the fast-fading (FF) model. In more practical propagation environments the fading correlation across time depends on the level of user mobility. This paper analyzes the effects of time-selective fading on the performance of coded cooperation by providing an analytical framework for the error rate evaluation as a function of the mobility degree of the mobile station (MS) and of the quality of the inter-MS channel. The purpose is to evaluate the conditions on the propagation settings where the additional exploitation of spatial diversity (when time-diversity is available) provided by cooperative transmission is able to enhance substantially the performance of the non-cooperative transmission. We show that coded cooperation can outperform the non-cooperative (coded and bit-interleaved) transmission only up to a certain degree of mobility. The cooperative region is defined as the collection of mobility settings for which coded cooperation can be regarded as a competitive strategy compared to non-cooperative transmission. Contrary to what has been previously shown for BF channels, we demonstrate that the inter-MS channel quality plays a key role in the definition of the cooperative region
Prestimulus EEG power predicts conscious awareness but not objective visual performance
Prestimulus oscillatory neural activity has been linked to perceptual outcomes during performance of psychophysical
detection and discrimination tasks. Specifically, the power and phase of low frequency oscillations have been found
to predict whether an upcoming weak visual target will be detected or not. However, the mechanisms by which
baseline oscillatory activity influences perception remain unclear. Recent studies suggest that the frequently reported
negative relationship between power and stimulus detection may be explained by changes in detection criterion (i.e.,
increased target present responses regardless of whether the target was present/absent) driven by the state of neural
excitability, rather than changes in visual sensitivity (i.e., more veridical percepts). Here, we recorded EEG while human
participants performed a luminance discrimination task on perithreshold stimuli in combination with single-trial ratings
of perceptual awareness. Our aim was to investigate whether the power and/or phase of prestimulus oscillatory activity
predict discrimination accuracy and/or perceptual awareness on a trial-by-trial basis. Prestimulus power (3â28 Hz) was
inversely related to perceptual awareness ratings (i.e., higher ratings in states of low prestimulus power/high excitability)
but did not predict discrimination accuracy. In contrast, prestimulus oscillatory phase did not predict awareness
ratings or accuracy in any frequency band. These results provide evidence that prestimulus power influences the
level of subjective awareness of threshold visual stimuli but does not influence visual sensitivity when a decision has
to be made regarding stimulus features. Hence, we find a clear dissociation between the influence of ongoing neural
activity on conscious awareness and objective performance
Confident texture-based laryngeal tissue classification for early stage diagnosis support
Early stage diagnosis of laryngeal squamous cell carcinoma (SCC) is of primary importance for lowering patient mortality or after treatment morbidity. Despite the challenges in diagnosis reported in the clinical literature, few efforts have been invested in computer-assisted diagnosis. The objective of this paper is to investigate the use of texture-based machine-learning algorithms for early stage cancerous laryngeal tissue classification. To estimate the classification reliability, a measure of confidence is also exploited. From the endoscopic videos of 33 patients affected by SCC, a well-balanced dataset of 1320 patches, relative to four laryngeal tissue classes, was extracted. With the best performing feature, the achieved median classification recall was 93% [interquartile range Ă°IQRĂ ÂŒ 6%]. When excluding low-confidence patches, the achieved median recall was increased to 98% (IQR ÂŒ 5%), proving the high reliability of the proposed approach. This research represents an important advancement in the state-of-the-art computer-assisted laryngeal diagnosis, and the results are a promising step toward a helpful endoscope-integrated processing system to support early stage diagnosis
Confident texture-based laryngeal tissue classification for early stage diagnosis support
none8siopenMoccia, Sara; De Momi, Elena; Guarnaschelli, Marco; Savazzi, Matteo; Laborai, Andrea; Guastini, Luca; Peretti, Giorgio; Mattos, Leonardo S.Moccia, Sara; De Momi, Elena; Guarnaschelli, Marco; Savazzi, Matteo; Laborai, Andrea; Guastini, Luca; Peretti, Giorgio; Mattos, Leonardo S
Boring bivalve traces in modern reef and deeper-water macroid and rhodolith beds
Macroids and rhodoliths, made by encrusting acervulinid foraminifera and coralline algae, are widely recognized as
bioengineers providing relatively stable microhabitats and increasing biodiversity for other species. Macroid and
rhodolith beds occur in different depositional settings at various localities and bathymetries worldwide. Six case
studies of macroid/rhodolith beds from 0 to 117m water depth in the Pacific Ocean (northern Central Ryukyu
Islands, French Polynesia), eastern Australia (Fraser Island, One Tree Reef, Lizard Island), and the Mediterranean Sea
(southeastern Spain) show that nodules in the beds are perforated by small-sized boring bivalve traces
(Gastrochanolites). On average, boring bivalve shells (gastrochaenids and mytilids) are more slender and smaller than
those living inside shallow-water rocky substrates. In the Pacific, Gastrochaena cuneiformis, Gastrochaena sp., Leiosolenus
malaccanus, L. mucronatus, L. spp., and Lithophaga/Leiosolenus sp., for the first time identified below 20m water depth,
occur as juvenile forms along with rare small-sized adults. In deep-water macroids and rhodoliths the boring bivalves
are larger than the shallower counterparts in which growth of juveniles is probably restrained by higher overturn rates
of host nodules. In general, most boring bivalves are juveniles that grew faster than the acervulinid foraminiferal and
coralline red algal hosts and rarely reached the adult stage. As a consequence of phenotypic plasticity, small-sized
adults with slow growth rates coexist with juveniles. Below wave base macroids and rhodoliths had the highest
amounts of bioerosion, mainly produced by sponges and polychaete worms. These modern observations provide
bases for paleobiological inferences in fossil occurrences.Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT)
Japan Society for the Promotion of Science
Grants-in-Aid for Scientific Research (KAKENHI)
25247083Erasmus+FAR2012-2017FIR2016FIR2018PRIN "Biotic resilience to global change: biomineralization of planktonic and benthic calcifiers in the past, present and future"
2017RX9XXXYBioMed Central-Prepay Membership at the University of FerraraJunta de AndalucĂa
RNM 190Committee on ResearchMuseum of PaleontologyDepartment of Integrative Biology, UC BerkeleyUC Pacific Rim Projec
Fast Visuomotor Processing of Redundant Targets: The Role of the Right Temporo-Parietal Junction
Parallel processing of multiple sensory stimuli is critical for efficient, successful interaction with the environment. An experimental approach to studying parallel processing in sensorimotor integration is to examine reaction times to multiple copies of the same stimulus. Reaction times to bilateral copies of light flashes are faster than to single, unilateral light flashes. These faster responses may be due to âstatistical facilitationâ between independent processing streams engaged by the two copies of the light flash. On some trials, however, reaction times are faster than predicted by statistical facilitation. This indicates that a neural âcoactivationâ of the two processing streams must have occurred. Here we use fMRI to investigate the neural locus of this coactivation. Subjects responded manually to the detection of unilateral light flashes presented to the left or right visual hemifield, and to the detection of bilateral light flashes. We compared the bilateral trials where subjects' reaction times exceeded the limit predicted by statistical facilitation to bilateral trials that did not exceed the limit. Activity in the right temporo-parietal junction was higher in those bilateral trials that showed coactivation than in those that did not. These results suggest the neural coactivation observed in visuomotor integration occurs at a cognitive rather than sensory or motor stage of processing
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