Black-white asymmetry in visual perception.

Faces that move contain rich information about facial form, such as facial features and their configuration, alongside the motion of those features. During social interactions, humans constantly decode and integrate these cues. To fully understand human face perception, it is important to investigate what information dynamic faces convey and how the human visual system extracts and processes information from this visual input. However, partly due to the difficulty of designing well-controlled dynamic face stimuli, many face perception studies still rely on static faces as stimuli. Here, we focus on evidence demonstrating the usefulness of dynamic faces as stimuli, and evaluate different types of dynamic face stimuli to study face perception. Studies based on dynamic face stimuli revealed a high sensitivity of the human visual system to natural facial motion and consistently reported dynamic advantages when static face information is insufficient for the task. These findings support the hypothesis that the human perceptual system integrates sensory cues for robust perception. In the present paper, we review the different types of dynamic face stimuli used in these studies, and assess their usefulness for several research questions. Natural videos of faces are ecological stimuli but provide limited control of facial form and motion. Point-light faces allow for good control of facial motion but are highly unnatural. Image-based morphing is a way to achieve control over facial motion while preserving the natural facial form. Synthetic facial animations allow separation of facial form and motion to study aspects such as identity-from-motion. While synthetic faces are less natural than videos of faces, recent advances in photo-realistic rendering may close this gap and provide naturalistic stimuli with full control over facial motion. We believe that many open questions, such as what dynamic advantages exist beyond emotion and identity recognition and which dynamic aspects drive these advantages, can be addressed adequately with different types of stimuli and will improve our understanding of face perception in more ecological settings.

This study aims to evaluate the sensitivity of the speech intelligibility index (SII) to the assumed speech dynamic range (DR) in different languages and with different types of stimuli. Intelligibility prediction uses the absolute transfer function (ATF) to map the SII value to the predicted intelligibility for a given stimuli. To evaluate the sensitivity of the predicted intelligibility to the assumed DR, ATF-transformed SII scores for English (words), Korean (sentences), and Mandarin (sentences) were derived for DRs ranging from 10 dB to 60 dB. Increasing the assumed DR caused steeper ATFs for all languages. However, high correlation coefficients between predicted and measured intelligibility scores were observed for DRs from 20 dB to 60 dB for ATFs in English, Korean, and Mandarin. Results of the present study indicate that the intelligibility computed from the SII is not sensitive to the assumed DR. The 30-dB DR commonly used in computing the SII is thus a reasonable assumption that produces accurate predictions for different languages and different types of stimuli.

Cell-Assembly Coding in Several Memory Processes

Recent evidence suggests that speech substantially changes in ageing. As a complex neurophysiological process, it can accurately reflect changes in the motor and cognitive systems underpinning human speech. Since healthy ageing is not always easily discriminable from early stages of dementia based on cognitive and behavioural hallmarks, speech is explored as a preclinical biomarker of pathological itineraries in old age. A greater and more specific impairment of neuromuscular activation, as well as a specific cognitive and linguistic impairment in dementia, unchain discriminating changes in speech. Yet, there is no consensus on such discriminatory speech parameters, neither on how they should be elicited and assessed. To provide a state-of-the-art on speech parameters that allow for early discrimination between healthy and pathological ageing; the aetiology of these parameters; the effect of the type of experimental stimuli on speech elicitation and the predictive power of different speech parameters; and the most promising methods for speech analysis and their clinical implications. A scoping review methodology is used in accordance with the PRISMA model. Following a systematic search of PubMed, PsycINFO and CINAHL, 24 studies are included and analysed in the review. The results of this review yieldthree key questions for the clinical assessment of speech in ageing. First, acoustic and temporal parameters are more sensitive to changes in pathological ageing and, of these two, temporal variables are more affected bycognitive impairment. Second, different types of stimuli can trigger speech parameters with different degree of accuracy for the discrimination of clinical groups. Tasks with higher cognitive load are more precise in eliciting higher levels of accuracy. Finally, automatic speech analysis for the discrimination of healthy and pathological ageing should be improved for both research and clinical practice. Speech analysis is a promising non-invasive tool for the preclinical screening of healthy and pathological ageing. The main current challenges of speech analysis in ageing are the automatization of its clinical assessment and the consideration of the speaker's cognitive background during evaluation. What is already known on the subject Societal aging goes hand in hand with the rising incidence of ageing-related neurodegenerations, mainly Alzheimer's disease (AD). This is particularly noteworthy in countries with longer life expectancies. Healthy ageing and early stages of AD share a set of cognitive and behavioural characteristics. Since there is no cure for dementias, developing methods for accurate discrimination ofhealthy ageing and early AD is currently a priority. Speech has been described as one of the most significantly impaired features in AD. Neuropathological alterations in motor and cognitive systems would underlie specific speech impairment in dementia. Since speech can be evaluated quickly, non-invasively and inexpensively, its value for the clinical assessment of ageing itineraries may be particularly high. What this paper adds to existing knowledge Theoretical and experimental advances in the assessment of speech as a marker of AD have developed rapidly over the last decade. Yet, they are not always known to clinicians. Furthermore, there is a need to provide an updated state-of-the-art on which speech features are discriminatory to AD, how they can be assessed, what kind of results they can yield, and how such results should be interpreted. This article provides an updated overview of speech profiling, methods of speech measurement and analysis, and the clinical power of speech assessment for early discrimination of AD as the most common cause of dementia. What are the potential or actual clinical implications of this work? This article provides an overview of the predictive potential of different speech parameters in relation to AD cognitive impairment. In addition, it discusses the effect that the cognitive state, the type of elicitation task and the type of assessment method may have on the results of the speech-based analysis in ageing.

Retinal visual processing constrains human ocular following response

Learning of supra-span sequences was assessed in a densely amnesic individual (SJ) who suffers from a substantial circumscribed bilateral lesion to the hippocampus. SJ's ability to lay down information originating from repetitive memory recall episodes was assessed using Hebb's supra-span procedure. After assessment of short-term memory span, 25 sequences of span +1 items were presented to SJ for immediate serial recall (ISR), one sequence being presented repeatedly eight times. Learning was deduced by the comparison of ISR scores on the repeated versus nonrepeated sequences of span +1 items. SJ's learning capacity was examined using four different types of stimuli: digits, spatial locations (Corsi block tapping test), words, and pseudowords. Implicit learning of sensorimotor sequences was also assessed in SJ using a serial reaction time (SRT) paradigm. Findings with the supra-span ISR task revealed evidence of learning in SJ with all four types of stimuli. The learning magnitude, as well as learning rate, observed in SJ were comparable to those observed in matched control participants. SJ showed evidence of implicit learning on the SRT paradigm. We conclude that the hippocampus is not required to learn certain types of recurrent information, and that the supra-span ISR task can be considered as an implicit-based learning paradigm. These findings have significant implications for our conceptualisation of implicit learning, and for understanding of the role of the hippocampus in learning.

Chemical logic gates can be fabricated by synthesizing molecules that have the ability to detect external stimuli (e.g., temperature or pH) and provide logical outputs. It is, however, challenging to fabricate a system that consists of many logic gates using this method: complex molecules can be difficult to synthesize and these logic gates typically cannot be integrated together. Here, we fabricated different types of logic gates by assembling a combination of different types of stimuli-responsive hydrogels that change their size under the influence of one type of stimulus. Importantly, the preparation of these stimuli-responsive hydrogels is widely reported and technically simple. Through designing the geometry of the systems, we fabricated the YES, NOT, OR, AND, NOR, and NAND gates. Although the hydrogels respond to different types of stimuli, their outputs are the same: a change in size of the hydrogel. Hence, we show that the logic gates can be integrated easily (e.g., by connecting an AND gate to an OR gate). In addition, we fabricated a standalone system with the size of a normal drug tablet (i.e., a "smart tablet") that can analyze (or diagnose) different stimuli and control the release of a chemical (or drug) via the logic gates.

Despite children with ADHD frequently experiencing difficulties in social perception, the mechanisms underlying this impairment have been poorly explored. In this study, we examined social perception in children with ADHD, comparing them with typically-developing (TD) children on semi-naturalistic tasks, and considering the effect of nonverbal signal recognition. Our aim was to ascertain whether the two groups’ social perception related to different types of stimulus (video, audio or combined/multimodal). The role of three higher-order cognitive skills (theory of mind, attention and pragmatic language) was also investigated. Thirty-six children with ADHD, and 36 TD controls were tested. Social perception was significantly associated with participants’ ability to recognize nonverbal signals, and with the stimulus presentation modality. Children with ADHD only performed less well than TD children with combined stimuli. As concerns the higher-order cognitive skills, theory of mind had a significant role in both groups, but only with the video and combined stimuli, while attention explained most of the variance in social perception for all types of stimulus. Better pragmatic language skills were only associated with a better social perception in TD children, whatever the type of stimulus presented. Semi-naturalistic tasks should be included when assessing social perception in ADHD, and both theory of mind and attention should be the object of efforts to enhance social perception in the ADHD population.

Aging effects on functional auditory and visual processing using fMRI with variable sensory loading

Direction discrimination of cyclopean (stereoscopic) and luminance motion

Normal cell growth requires a precisely controlled balance between cell death and survival. This involves activation of different types of intracellular signaling cascades within the cell. While some types of signaling proteins regulate apoptosis, or programmed cell death, other proteins within the cell can promote survival. The serine/threonine kinase PAK4 can protect cells from apoptosis in response to several different types of stimuli. As is the case for other members of the p21-activated kinase (PAK) family, one way that PAK4 may promote cell survival is by phosphorylating and thereby inhibiting the proapoptotic protein Bad. This leads in turn to the inhibition of effector caspases such as caspase 3. Here we show that in response to cytokines which activate death domain-containing receptors, such as the tumor necrosis factor and Fas receptors, PAK4 can inhibit the death signal by a different mechanism. Under these conditions, PAK4 inhibits apoptosis early in the caspase cascade, antagonizing the activation of initiator caspase 8. This inhibition, which does not require PAK4's kinase activity, may involve inhibition of caspase 8 recruitment to the death domain receptors. This role in regulating initiator caspases is an entirely novel role for the PAK proteins and suggests a new mechanism by which these proteins promote cell survival.

The microenvironment characteristics of solid tumors, renowned as barriers that harshly impeded many drug-delivery approaches, were precisely studied, investigated, categorized, divided, and subdivided into a complex diverse of barriers. These categories were further studied with a particular perspective, which makes all barriers found in solid-tumor micromilieu turn into different types of stimuli, and were considered triggers that can increase and hasten drug-release targeting efficacy. This review gathers data concerning the nature of solid-tumor micromilieu. Past research focused on the treatment of such tumors, the recent efforts employed for engineering smart nanoarchitectures with the utilization of the specified stimuli categories, the possibility of combining more than one stimuli for much-greater targeting enhancement, examples of the approved nanoarchitectures that already translated clinically as well as the obstacles faced by the use of these nanostructures, and, finally, an overview of the possible future implementations of smart-chemical engineering for the design of more-efficient drug delivery and theranostic systems and for making nanosystems with a much-higher level of specificity and penetrability features.

93 TOLERANCE AND OPIOID-INDUCED HYPERALGESIA IN CLINICAL POPULATIONS

Seven key elements describing the regulation of adult neurogenesis are proposed. (i) A distinction must be made between regulation and 'control' at the transcriptional level in order to appreciate the hierarchy of regulatory factors. (ii) The regulatory hierarchy comprises conceptual levels from behaviour to genes. Consequently, 'regulation' of neurogenesis can be confounded by confusing rather than integrating factors, levels and concepts. The immense spectrum of neurogenic regulators reflects the sensitivity of adult neurogenesis to many different types of stimuli, and provides a means of abstraction. (iii) Age per se does not seem to play a constant role in the modulation of this process, as the dramatic 'age-related' changes in adult neurogenesis only take place early in life. (iv) The regulatory hierarchy at any given time-point is corresponded by the directionality and sequential interdependence of different regulatory factors in the course of development. Regulation goes from non-specific to specific, and the following steps build on regulation at the previous ones. (v) This complexity is reflected at the genetic level in that adult neurogenesis is highly heritable and highly polygenic with single factors explaining little of the variance. (vi) As regulation is additive, there is an element of self-reinforcement in the regulation of adult neurogenesis, allowing the formation of regulatory reserves for situations of functional demand. (vii) The complexity of regulation makes adult neurogenesis sensitive to pathological disturbance at various levels, suggesting that different molecular events might result in similar and shared behavioural or functional phenotypes originating in the dentate gyrus.

This research examined the nature of the stimulus portion of the S-R term. Sixteen Ss were presented with a classical trace conditioning situation in which it was possible for them to demonstrate conditioning to four different types of stimuli: afterimages, pattern of color followed by darkness, the positive stimulus used to evoke an afterimage, and conditioning to the cotton pad used to collect salivation. Of the 7 Ss that showed conditioning, 3 showed indications of afterimage conditioning, 2 of trace conditioning, 1 of pattern conditioning, and 1 of pad conditioning. It may be concluded that under appropriate experimental conditions, a percept may be used as the conditioned stimulus in a classical conditioning situation. Implications for learning theories are presented and discussed.