scholarly journals The orientation selectivity of face identification

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Valerie Goffaux ◽  
John A. Greenwood
Keyword(s):  
Tuning Curve ◽  
Gaussian Function ◽  
Face Identification ◽  
Identification Performance ◽  
Orientation Sensitivity ◽  
Match To Sample ◽  
High Level ◽  
Insight Into ◽  
Inverted Face ◽  
Sensitivity Profile

Abstract Recent work demonstrates that human face identification is most efficient when based on horizontal, rather than vertical, image structure. Because it is unclear how this specialization for upright (compared to inverted) face processing emerges in the visual system, the present study aimed to systematically characterize the orientation sensitivity profile for face identification. With upright faces, identification performance in a delayed match-to-sample task was highest for horizontally filtered images and declined sharply with oblique and vertically filtered images. Performance was well described by a Gaussian function with a standard deviation around 25°. Face inversion reshaped this sensitivity profile dramatically, with a downward shift of the entire tuning curve as well as a reduction in the amplitude of the horizontal peak and a doubling in bandwidth. The use of naturalistic outer contours (vs. a common outline mask) was also found to reshape this sensitivity profile by increasing sensitivity to oblique information in the near-horizontal range. Altogether, although face identification is sharply tuned to horizontal angles, both inversion and outline masking can profoundly reshape this orientation sensitivity profile. This combination of image- and observer-driven effects provides an insight into the functional relationship between orientation-selective processes within primary and high-level stages of the human brain.

scholarly journals Quantifying the signals contained in heterogeneous neural responses and determining their relationships with task performance

2014 ◽  
Vol 112 (6) ◽  
pp. 1584-1598 ◽  
Author(s):  
Marino Pagan ◽  
Nicole C. Rust
Keyword(s):  
Task Performance ◽  
Single Neuron ◽  
Weighted Sums ◽  
Neural Responses ◽  
Signal Modulation ◽  
Neural Data ◽  
Match To Sample ◽  
Neural Populations ◽  
Different Types ◽  
High Level

The responses of high-level neurons tend to be mixtures of many different types of signals. While this diversity is thought to allow for flexible neural processing, it presents a challenge for understanding how neural responses relate to task performance and to neural computation. To address these challenges, we have developed a new method to parse the responses of individual neurons into weighted sums of intuitive signal components. Our method computes the weights by projecting a neuron's responses onto a predefined orthonormal basis. Once determined, these weights can be combined into measures of signal modulation; however, in their raw form these signal modulation measures are biased by noise. Here we introduce and evaluate two methods for correcting this bias, and we report that an analytically derived approach produces performance that is robust and superior to a bootstrap procedure. Using neural data recorded from inferotemporal cortex and perirhinal cortex as monkeys performed a delayed-match-to-sample target search task, we demonstrate how the method can be used to quantify the amounts of task-relevant signals in heterogeneous neural populations. We also demonstrate how these intuitive quantifications of signal modulation can be related to single-neuron measures of task performance ( d′).

Insight into the formation of a continuous sheath structure for the PS phase in tri-continuous PVDF/PS/HDPE blends

RSC Advances ◽  
2016 ◽  
Vol 6 (1) ◽  
pp. 439-447 ◽  
Author(s):  
Rui Dou ◽  
Shuanglin Li ◽  
Yan Shao ◽  
Bo Yin ◽  
Mingbo Yang
Keyword(s):  
Ternary Blends ◽  
Continuous Structure ◽  
High Level ◽  
Very High ◽  
Insight Into ◽  
Sheath Structure

A hierarchical tri-continuous structure is formed and controlled in PVDF/PS/HDPE ternary blends. A very high level of PS continuity, about 80%, is achieved only with a PS volume composition as low as 11 vol%.

scholarly journals Reconstructing feedback representations in ventral visual pathway with a generative adversarial autoencoder

2020 ◽  
Author(s):  
Haider Al-Tahan ◽  
Yalda Mohsenzadeh
Keyword(s):  
Neural Network ◽  
Visual Information ◽  
Visual Pathway ◽  
Functional Magnetic Resonance ◽  
Low Level ◽  
Ventral Visual Pathway ◽  
High Level ◽  
Feedback Connections ◽  
The Brain ◽  
Insight Into

AbstractWhile vision evokes a dense network of feedforward and feedback neural processes in the brain, visual processes are primarily modeled with feedforward hierarchical neural networks, leaving the computational role of feedback processes poorly understood. Here, we developed a generative autoencoder neural network model and adversarially trained it on a categorically diverse data set of images. We hypothesized that the feedback processes in the ventral visual pathway can be represented by reconstruction of the visual information performed by the generative model. We compared representational similarity of the activity patterns in the proposed model with temporal (magnetoencephalography) and spatial (functional magnetic resonance imaging) visual brain responses. The proposed generative model identified two segregated neural dynamics in the visual brain. A temporal hierarchy of processes transforming low level visual information into high level semantics in the feedforward sweep, and a temporally later dynamics of inverse processes reconstructing low level visual information from a high level latent representation in the feedback sweep. Our results append to previous studies on neural feedback processes by presenting a new insight into the algorithmic function and the information carried by the feedback processes in the ventral visual pathway.Author summaryIt has been shown that the ventral visual cortex consists of a dense network of regions with feedforward and feedback connections. The feedforward path processes visual inputs along a hierarchy of cortical areas that starts in early visual cortex (an area tuned to low level features e.g. edges/corners) and ends in inferior temporal cortex (an area that responds to higher level categorical contents e.g. faces/objects). Alternatively, the feedback connections modulate neuronal responses in this hierarchy by broadcasting information from higher to lower areas. In recent years, deep neural network models which are trained on object recognition tasks achieved human-level performance and showed similar activation patterns to the visual brain. In this work, we developed a generative neural network model that consists of encoding and decoding sub-networks. By comparing this computational model with the human brain temporal (magnetoencephalography) and spatial (functional magnetic resonance imaging) response patterns, we found that the encoder processes resemble the brain feedforward processing dynamics and the decoder shares similarity with the brain feedback processing dynamics. These results provide an algorithmic insight into the spatiotemporal dynamics of feedforward and feedback processes in biological vision.

scholarly journals Exploring citizen science in post-socialist space: Uncovering its hidden character in the Czech Republic

2019 ◽  
Vol 27 (4) ◽  
pp. 241-253 ◽  
Author(s):  
Barbora Duží ◽  
Robert Osman ◽  
Jiří Lehejček ◽  
Eva Nováková ◽  
Pavel Taraba ◽  
...  
Keyword(s):  
Czech Republic ◽  
Citizen Science ◽  
The Czech Republic ◽  
The Public ◽  
Public Representation ◽  
Science Projects ◽  
Definition Of ◽  
High Level ◽  
Search Approach ◽  
Insight Into

Abstract Citizen science is a relatively new phenomenon in the Czech Republic and currently a general overview of existing citizen science projects is not available. This presents the challenge to uncover the ‘hidden’ citizen science landscapes. The main objective of this paper is to explore the (public) representation of citizen science (CS) projects and to describe their heterogeneity. The study aims to answer the question of what type of projects in the Czech Republic meet the definition of citizen science. Based on a specific methodological data-base search approach, we compiled a set of CS projects (N = 73). During the classification process, two general citizen science categories were identified. The first group (N = 46) consists of “pure” CS projects with a prevalence towards the natural sciences, principally ornithology, and thus corresponding to general European trends. Citizens usually participate in such research in the form of data collection and basic interpretation, and a high level of cooperation between academia and NGOs was detected. The second group of “potential” CS projects (N = 27) entails various forms of public participation in general, frequently coordinated by NGOs. Based on these results, we discuss the position of citizen science in the Czech Republic, including socially-oriented citizen science. Further research is strongly encouraged to achieve a more in-depth insight into this social phenomenon.

scholarly journals Developing cybersecurity education and awareness programmes for small- and medium-sized enterprises (SMEs)

2019 ◽  
Vol 27 (3) ◽  
pp. 393-410 ◽  
Author(s):  
Maria Bada ◽  
Jason R.C. Nurse
Keyword(s):  
Best Practices ◽  
Research Literature ◽  
Content Type ◽  
Security Education ◽  
Education And Awareness ◽  
The One ◽  
High Level ◽  
And Training ◽  
Insight Into

PurposeThe purpose of this study is to focus on organisation’s cybersecurity strategy and propose a high-level programme for cybersecurity education and awareness to be used when targeting small- and medium-sized enterprises/businesses (SMEs/SMBs) at a city-level. An essential component of an organisation’s cybersecurity strategy is building awareness and education of online threats and how to protect corporate data and services. This programme is based on existing research and provides a unique insight into an ongoing city-based project with similar aims.Design/methodology/approachTo structure this work, a scoping review was conducted of the literature in cybersecurity education and awareness, particularly for SMEs/SMBs. This theoretical analysis was complemented using a case study and reflecting on an ongoing, innovative programme that seeks to work with these businesses to significantly enhance their security posture. From these analyses, best practices and important lessons/recommendations to produce a high-level programme for cybersecurity education and awareness were recommended.FindingsWhile the literature can be informative at guiding education and awareness programmes, it may not always reach real-world programmes. However, existing programmes, such as the one explored in this study, have great potential, but there can be room for improvement. Knowledge from each of these areas can, and should, be combined to the benefit of the academic and practitioner communities.Originality/valueThe study contributes to current research through the outline of a high-level programme for cybersecurity education and awareness targeting SMEs/SMBs. Through this research, literature in this space was examined and insights into the advances and challenges faced by an on-going programme were presented. These analyses allow us to craft a proposal for a core programme that can assist in improving the security education, awareness and training that targets SMEs/SMBs.

scholarly journals Cochlear compound action potentials from high-level tone bursts originate from wide cochlear regions that are offset toward the most sensitive cochlear region

2019 ◽  
Vol 121 (3) ◽  
pp. 1018-1033 ◽  
Author(s):  
C. Lee ◽  
J. J. Guinan ◽  
M. A. Rutherford ◽  
W. A. Kaf ◽  
K. M. Kennedy ◽  
...  
Keyword(s):  
High Frequency ◽  
Action Potentials ◽  
Tuning Curve ◽  
Low Frequency ◽  
Sound Level ◽  
Frequency Tone ◽  
Compound Action Potentials ◽  
High Level ◽  
Level Tone ◽  
Compound Action

Little is known about the spatial origins of auditory nerve (AN) compound action potentials (CAPs) evoked by moderate to intense sounds. We studied the spatial origins of AN CAPs evoked by 2- to 16-kHz tone bursts at several sound levels by slowly injecting kainic acid solution into the cochlear apex of anesthetized guinea pigs. As the solution flowed from apex to base, it sequentially reduced CAP responses from low- to high-frequency cochlear regions. The times at which CAPs were reduced, combined with the cochlear location traversed by the solution at that time, showed the cochlear origin of the removed CAP component. For low-level tone bursts, the CAP origin along the cochlea was centered at the characteristic frequency (CF). As sound level increased, the CAP center shifted basally for low-frequency tone bursts but apically for high-frequency tone bursts. The apical shift was surprising because it is opposite the shift expected from AN tuning curve and basilar membrane motion asymmetries. For almost all high-level tone bursts, CAP spatial origins extended over 2 octaves along the cochlea. Surprisingly, CAPs evoked by high-level low-frequency (including 2 kHz) tone bursts showed little CAP contribution from CF regions ≤ 2 kHz. Our results can be mostly explained by spectral splatter from the tone-burst rise times, excitation in AN tuning-curve “tails,” and asynchronous AN responses to high-level energy ≤ 2 kHz. This is the first time CAP origins have been identified by a spatially specific technique. Our results show the need for revising the interpretation of the cochlear origins of high-level CAPs-ABR wave 1. NEW & NOTEWORTHY Cochlear compound action potentials (CAPs) and auditory brain stem responses (ABRs) are routinely used in laboratories and clinics. They are typically interpreted as arising from the cochlear region tuned to the stimulus frequency. However, as sound level is increased, the cochlear origins of CAPs from tone bursts of all frequencies become very wide and their centers shift toward the most sensitive cochlear region. The standard interpretation of CAPs and ABRs from moderate to intense stimuli needs revision.

scholarly journals Assessing the sociability of former pet and entertainment chimpanzees by using multiplex networks

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Dietmar Crailsheim ◽  
Toni Romani ◽  
Miquel Llorente ◽  
Elfriede Kalcher-Sommersguter
Keyword(s):  
Social Interaction ◽  
Information Gain ◽  
Life Experiences ◽  
Multiplex Networks ◽  
The Social ◽  
Close Proximity ◽  
Potential Benefits ◽  
Interaction Types ◽  
High Level ◽  
Insight Into

AbstractAdvances in the field of social network analysis facilitate the creation of multiplex networks where several interaction types can be analysed simultaneously. In order to test the potential benefits of this approach, we investigated the sociability of atypically raised chimpanzees by constructing and analysing 4-layered multiplex networks of two groups of former pet and entertainment chimpanzees (Pan troglodytes). These networks are based on four social interaction types (stationary vicinity, affiliative behaviour, allogrooming, passive close proximity) representing low- to high-level interaction types in terms of sociability. Using the tools provided by the MuxViz software, we could assess and compare the similarity and information gain of each these social interaction types. We found some social interaction types to be more similar than other ones. However, each social interaction type imparted different information. We also tested for a possible impact of the chimpanzees’ biographical background on the social interaction types and found affiliative behaviour as well as allogrooming to be affected by adverse early life experiences. We conclude that this multiplex approach provides a more realistic framework giving detailed insight into the sociability of these chimpanzees and can function as a tool to support captive care management decisions.

scholarly journals Protection from lethal malaria in transgenic mice expressing sickle hemoglobin

Blood ◽  
1996 ◽  
Vol 87 (4) ◽  
pp. 1600-1603 ◽  
Author(s):  
AT Hood ◽  
ME Fabry ◽  
F Costantini ◽  
RL Nagel ◽  
HL Shear
Keyword(s):  
Transgenic Mice ◽  
Red Blood Cells ◽  
Cerebral Malaria ◽  
Falciparum Malaria ◽  
Blood Cells ◽  
Virulent Strain ◽  
Plasmodium Chabaudi ◽  
Sickle Hemoglobin ◽  
High Level ◽  
Insight Into

Previous studies from our laboratories have shown that transgenic mice expressing high levels of beta S globin are well-protected from Plasmodium chabaudi adami and partially protected against P berghei (Shear et al, Blood 81:222, 1993). We have now infected transgenic mice expressing low (39%), intermediate (57%), and high (75%) levels of beta S with the virulent strain of P yoelii (17XL) that appears to cause cerebral malaria. We find that the level of protection in these three groups of mice correlates positively with the level of beta S chain expression in the mice. Seven of nine mice expressing the high level of beta S recovered from infection, as did 7 of 9 mice expressing the intermediate level of beta S. Control mice and mice expressing the lower level of beta S all succumbed to infection. In mice expressing high and intermediate levels of beta S, parasites were found almost exclusively in reticulocytes during recovery, suggesting that mature red blood cells expressing beta S are more resistant than reticulocytes. These studies confirm epidemiologic data and offer insight into the mechanism of protection of sickle trait individuals against falciparum malaria.

Ubiquitous Communication Via Residential Gateways

2011 ◽  
pp. 655-669
Author(s):  
Alex De Smedt
Keyword(s):  
Broadband Access ◽  
Access Points ◽  
Gateway System ◽  
Residential Gateway ◽  
Broadband Network ◽  
High Level ◽  
Technical Solutions ◽  
Media Data ◽  
Insight Into ◽  
Fixed Network

This chapter focuses on the equipment in the home, providing broadband access to the users into the home, called residential gateway. The chapter shows how such a device evolves from a simple modem to an advanced gateway system that contributes to: • The access inside the home of any data on any compatible device • The ubiquity of access points for the broadband network • The ubiquity of media data in the home from remote devices • The communication of mobile handsets via the fixed network. The objective of this chapter is to give the reader a technical insight into the enabling mechanisms and technologies dealing with such functionalities. The text indicates particular technical solutions, but explanations are kept high-level in order to allow nontechnical readers to understand the basics and concepts of the solutions. A number of references show that the technical exposé is becoming a reality.

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