Modulated Stimuli Research Articles

Evaluating the Effects of Three Anesthetic Regimens on Retinal Structure and Function in the Living Mouse Eye Using a Customized Bimodal OCT/ORG System

Abstract Optical coherence tomography (OCT) is a non-invasive imaging technique that generates cross-sectional images of biological tissues at millimeter-level penetration depth with micron-level resolution. In this study, we developed a custom spectral-domain OCT (SD-OCT) system equipped with a flash stimulus module for dual-modality imaging of mouse retinal structure and function. The axial resolution of the system reached ~2.7/2 μm in air/tissue following optimization and calibration. We deployed this system to conduct in vivo OCT structural imaging and Optoretinography (ORG) functional assessment of mouse retina to investigate the effects of three anesthesia regimens. Statistical analysis of the results indicates that anesthesia results in a smaller relative intensity of IS/OS and ELM and a thickening of the outer segment compared to an awake state. Meanwhile, significant differences were observed in the effects on retinal structure and function between isoflurane and tribromoethanol anesthesia, while differences between isoflurane and esketamine+xylazine groups were small. These findings suggest that the type of anesthetic should be considered when comparing imaging results across studies reported in the literature.

Low-Cost, High-Efficiency Aluminum Zinc Oxide Synaptic Transistors: Blue LED Stimulation for Enhanced Neuromorphic Computing Applications.

Neuromorphic devices are electronic devices that mimic the information processing methods of neurons and synapses, enabling them to perform multiple tasks simultaneously with low power consumption and exhibit learning ability. However, their large-scale production and efficient operation remain a challenge. Herein, we fabricated an aluminum-doped zinc oxide (AZO) synaptic transistor via solution-based spin-coating. The transistor is characterized by low production costs and high performance. It demonstrates high responsiveness under UV laser illumination. In addition, it exhibits effective synaptic behaviors under blue LED illumination, indicating high-efficiency operation. The paired-pulse facilitation (PPF) index measured from optical stimulus modulation was 179.6%, indicating strong synaptic connectivity and effective neural communication and processing. Furthermore, by modulating the blue LED light pulse frequency, an excitatory postsynaptic current gain of 4.3 was achieved, demonstrating efficient neuromorphic functionality. This study shows that AZO synaptic transistors are promising candidates for artificial synaptic devices.

Augmented Optoelectronic Quantum Dot‐Enhanced Heterogeneous IGZO‐Te Photodiode for Artificial Synaptic Image Processing Applications

AbstractThis study presents a novel photodiode technology with augmented optoelectronic capabilities through the incorporation of quantum dots (QDs). The photodiode, composed of Indium Gallium Zinc Oxide‐Tellurium (IGZO‐Te), is engineered for enhanced light sensitivity and tailored optoelectronic interactions. The primary application of this advanced photodiode lies in the domain of artificial intelligence and machine learning, where it plays a pivotal role in simulating synaptic connections for image processing tasks. Due to the exceptional optical and electrical properties of the IGZO‐Te‐QDs active material combination, the photodiode demonstrates consistent and dependable optical synaptic functions linked to learning. This is achieved through conduction modulation and time duration modulation of light stimulus. In addition, the opto‐synaptic functionalities such as short‐term and long‐term memory has also been successfully demonstrated not only on single device but also on 6 × 6 photodiodes array device. These findings underscore the significant potential of the hybrid structure of IGZO‐Te with QDs in optical artificial neuromorphic chips.

Programmable Optoelectronic Synaptic Transistors Based on MoS2/Ta2NiS5 Heterojunction for Energy-Efficient Neuromorphic Optical Operation.

The optoelectronic synaptic transistors with various functions, broad spectral perception, and low power consumption are an urgent need for the development of advanced optical neural network systems. However, it remains a great challenge to realize the functional diversification of the systems on a single device. 2D van der Waals (vdW) materials can combine unique properties by stacking with each other to form heterojunctions, which may provide a strategy for solving this problem. Herein, an all-2D vdW heterojunction-based programmable optoelectronic synaptic transistor based on MoS2/Ta2NiS5 heterojunctions is demonstrated. The device implements reconfigurable, multilevel non-volatile memory (NVM) states through sequential modulation of multiple optical and electrical stimuli to achieve broadband (532-808nm), energy-efficient (17.2 fJ), hetero-synaptic functionality in a bionic manner. The intrinsic working mechanisms of the photogating effect caused by band alignment and the interfacial trapping defect modulation induced by gate voltage are revealed by Kelvin-probe force microscopy (KPFM) measurements and carrier transport analysis. Overall, the (opto)electronic synaptic weight controllability for combined in-sensor and in-memory logic processors is realized by the heterojunction properties. The proposed findings facilitate the technical realization of generic all 2D hetero-synapses for future artificial vision systems, opto-logical systems, and Internet of Things (IoT) entities.

Electricity/light-heat-hygro multi-responsive soft luminescent systems for rewritable and programmable information display

Rewritable luminescent materials are attracting widespread attention for information storage and display as they can help to reduce environmental wastes caused by the abuse of single-use and transient systems. Nevertheless, since most reported systems are chemical-stimuli-responsive and single-stimuli-responsive, it remains challenging to achieve the rewritable and programmable display of multiple information in one single system, which is essential to enhance information richness and display intelligence. In this work, an ideal kind of multi-responsive soft luminescent display systems are reported, which consist of heat/humidity-responsive fluorescence-phosphorescence dual-emission film and stacked graphene assembly (SGA) film by using thin poly (dimethyl siloxane) (PDMS) as middle connecting layer. In such multilayer structure, the heat generated by electricity connection or light illumination of bottom SGA film can be instantly transferred across the middle PDMS layer to cause heat-triggered red-to-blue emission color change, or to evaporate water for blue-to-red emission color recovery. Owing to the “residual-free” nature of these electricity, light and water stimuli, multi-responsive rewritability is guaranteed to enable the reversible writing and complete erasure of various letter/pattern information. On this basis, robust electricity/light-heat-hygro multi-responsive soft luminescent display systems are demonstrated, in which diverse letter/pattern information could be facilely programmed to be successively displayed and then completely reset to enable another data writing/erasing cycle by sequential modulation of different environmental stimuli. This study brings programmable merit for rewritable luminescent display systems and is expected to inspire more intelligent ones.

Interstitial Cells of Cajal and P2X3 Receptors at Ureteropelvic Junction Obstruction and Their Relationship with Pain Response.

Introduction: Etiopathogenesis and the symptomatology of ureteropelvic junction obstruction (UPJO) in the pediatric population has not yet been definitely clarified, suggesting a multifactorial nature of the condition. The aim was to analyze the association between the number of Interstitial Cells of Cajal (ICCs), as well as P2X3 receptors in ureteropelvic junction (UPJ) and the pain response in pediatric patients with hydronephrosis. Methods: 50 patients with congenital hydronephrosis underwent open or laparoscopic pyeloplasty at one of two departments of pediatric surgery and urology in Poland. Patients were divided into two groups according to the pain symptoms before surgery. A total of 50 samples of UPJ were obtained intraoperatively and underwent histopathological and immunohistochemical (IHC) analysis. Quantitative assessment of ICCs was based on the number of CD117(+) cells of adequate morphology in the subepithelial layer and the muscularis propria. Expression of P2X3 receptors was evaluated as the intensity of IHC staining. Results: Patients with hydronephrosis and accompanying pain were on average 60 months older (77 vs. 17 months) than children with asymptomatic hydronephrosis (p = 0.017). Symptomatic children revealed higher numbers of ICCs in both the subepithelial layer and in the lamina muscularis propria. In particular, symptomatic patients aged 2 years or more exhibited significantly higher numbers of ICCs in the subepithelial layer. Significant differences in the distribution of ICCs between the subepithelial layer and the lamina muscularis propria were observed in both groups. Expression of P2X3 receptors was limited to the urothelium and the muscle layer and correlated between these structures. There was no relationship between pain response and the expression of P2X3 receptors. Conclusions: ICCs and P2X3 receptors may participate in the pathogenesis of UPJO and in the modulation of pain response to a dilatation of the pyelocaliceal system. Explanation of the role of ICCs and P2X3 receptors in propagation of ureteral peristaltic wave and the modulation of pain stimuli requires further studies.

Light-Responsive Hydrogel Microcrawlers, Powered and Steered with Spatially Homogeneous Illumination.

Sub-millimeter untethered locomoting robots hold promise to radically change multiple areas of human activity such as microfabrication/assembly or health care. To overcome the associated hurdles of such a degree of robot miniaturization, radically new approaches are being adopted, often relying on soft actuating polymeric materials. Here, we present light-driven, crawling microrobots that locomote by a single degree of freedom actuation of their light-responsive tail section. The direction of locomotion is dictated by the robot body design and independent of the spatial modulation of the light stimuli, allowing simultaneous multidirectional motion of multiple robots. Moreover, we present a method for steering such robots by reversibly deforming their front section, using ultraviolet (UV) light as a trigger. The deformation dictates the robot locomotion, performing right- or left-hand turning when the UV is turned on or off respectively. The robots' motion and navigation are not coupled to the position of the light sources, which enables simultaneous locomotion of multiple robots, steering of robots and brings about flexibility with the methods to deliver the light to the place of robot operation.

Emotion recognition with EEG-based brain-computer interfaces: a systematic literature review

Electroencephalography (EEG)-based Brain-Computer Interface (BCI) systems for emotion recognition have the potential to assist the enrichment of human–computer interaction with implicit information since they can enable understanding of the cognitive and emotional activities of humans. Therefore, these systems have become an important research topic today. This study aims to present trends and gaps on this topic by performing a systematic literature review based on the 216 published scientific literature gathered from various databases including ACM, IEEE Xplore, PubMed, Science Direct, and Web of Science from 2016 to 2020. This review gives an overview of all the components of EEG based BCI system from the signal stimulus module which includes the employed device, signal stimuli, and data processing modality, to the signal processing module which includes signal acquisition, pre-processing, feature extraction, feature selection, classification algorithms, and performance evaluation. Thus, this study provides an overview of all components of an EEG-based BCI system for emotion recognition and examines the available evidence in a clear, concise, and systematic way. In addition, the findings are aimed to inform researchers about the issues on what are research trends and the gaps in this field and guide them in their research directions.

High-Frequency Discrete-Interval Binary Sequence in Asynchronous C-VEP-Based BCI for Visual Fatigue Reduction.

In code-modulated visual evoked potential (c-VEP) based BCI systems, flickering visual stimuli may result in visual fatigue. Thus, we introduced a discrete-interval binary sequence (DIBS) as visual stimulus modulation, with its power spectrum optimized to emphasize high-frequency components (40 Hz-60 Hz). 8 and 17 subjects participated, respectively, in offline and online experiments on a 4-target asynchronous c-VEP-based BCI system designed to realize a high positive predictive value (PPV), a low false positive rate (FPR) during idle states, and a high true positive rate (TPR) in control states, while minimizing visual fatigue level. Two visual stimuli modulations were introduced and compared: a maximum length sequence (m-sequence) and the high-frequency discrete-interval binary sequence (DIBS). The decoding algorithm was compared among the canonical correlation analysis (CCA), the task-related component analysis (TRCA), and two approaches of sub-band component weight calculation (the traditional method and the proportional method) for FBCCA and FBTRCA. In the online experiments, the average PPV, FPR and TPR achieved, respectively [Formula: see text], [Formula: see text], [Formula: see text] with m-sequence, while [Formula: see text], [Formula: see text] and [Formula: see text] with DIBS. Estimated by objective eye-related metrics and a subjective questionnaire, the visual fatigue in DIBS cases is significantly smaller than that in m-sequence cases. In this study, the feasibility of a novel modulation approach for visual fatigue reduction was proved in an asynchronous c-VEP system, while maintaining comparable performance to existing methods, which provides further insights towards enhancing this field's long-term viability and user-friendliness.

Fibromyalgia is associated with hypersensitivity but not with abnormal pain modulation: evidence from QST trials and spinal fMRI.

Widespread pain and hyperalgesia are characteristics of chronic musculoskeletal pain conditions, including fibromyalgia syndrome (FM). Despite mixed evidence, there is increasing consensus that these characteristics depend on abnormal pain augmentation and dysfunctional pain inhibition. Our recent investigations of pain modulation with individually adjusted nociceptive stimuli have confirmed the mechanical and thermal hyperalgesia of FM patients but failed to detect abnormalities of pain summation or descending pain inhibition. Furthermore, our functional magnetic resonance imaging evaluations of spinal and brainstem pain processing during application of sensitivity-adjusted heat stimuli demonstrated similar temporal patterns of spinal cord activation in FM and HC participants. However, detailed modeling of brainstem activation showed that BOLD activity during "pain summation" was increased in FM subjects, suggesting differences in brain stem modulation of nociceptive stimuli compared to HC. Whereas these differences in brain stem activation are likely related to the hypersensitivity of FM patients, the overall central pain modulation of FM showed no significant abnormalities. These findings suggest that FM patients are hyperalgesic but modulate nociceptive input as effectively as HC.

Psychometric Assessment of the Romanian Version of the Index of Dental Anxiety and Fear (IDAF-4C+).

The goal of this study was to assess the validity of the Romanian version of the Index of Dental Anxiety and Fear (IDAF-4C+) questionnaire. This study was conducted on a convenience sample of past patients and their acquaintances through an online questionnaire administered on the Google Forms platform between May 2021 and September 2022. The sections of the survey were demographic characteristics, the dental anxiety scale questionnaire, the IDAF-4C+ questionnaire, a single question about dental fear, and previous dental treatments. In total, 239 participants were included in the study, and the mean age was 37. The IDAF-4C questionnaire had good internal validity (Cronbach alpha was 0.945). The IDAF-4C had good convergent validity, and it was positively correlated with the dental anxiety scale (r = 0.825, p < 0.001) and the question about the fear of going to the dentist (r = 0.738, p < 0.001). The questionnaire had good reliability, and the intraclass correlation was 0.985. Lower levels of dental anxiety were associated with scaling, orthodontic treatment, and dental implants. A confirmatory factor analysis was conducted after the removal of the first question from the phobia module, and residual covariance was added between items four and nine of the stimulus module, showing a good fit for the retained questions of the IDAF-4C+, grouped by module. The Romanian version of the IDAF-4C+ showed acceptable psychometric properties.

Next-Generation Auditory Steady-State Responses in Normal-Hearing Adults: A Pilot Test–Retest Reliability Study

The Auditory Steady-State Response (ASSR) provides objective and ear-specific information essential for early and appropriate intervention. Test–retest reliability is essential for audiological monitoring. The test–retest reliability of the ASSR has received limited attention. Only a handful of studies found in the literature investigated the test–retest reliability of old-generation ASSR using amplitude or mixed modulated stimuli. However, to our knowledge, no published reports have specifically examined the test–retest reliability of the next-generation ASSR using Chirp family stimuli as implemented in the Interacoustics Eclipse system. This pilot study investigated (a) the test–retest reliability of air conduction (AC) ASSR thresholds across two test sessions and (b) the relationship between differences in ASSR thresholds across two sessions to the residual noise levels in normal-hearing adults. Methods: Fifteen normal-hearing adults (12 females) (30 ears) with an average age of 28 years were recruited for the study. The ASSRs were recorded using a two-channel recording montage. The automatic default stimuli and recording protocol using 90 Hz ASSR, and the accuracy method (p &lt; 0.01) as implemented in the Eclipse system is used to measure ASSR. Results: The study demonstrated strong test–retest reliability for ASSR across frequencies (500 Hz, 1000 Hz, 2000 Hz, and 4000 Hz). Notably, the highest reliability was observed at 500 Hz. The mean test–retest reliability of ASSR was found to be comparable to pure-tone thresholds, but the intra-subject variability is higher for ASSR compared to pure-tone thresholds. Additionally, no significant correlation was found between the difference in ASSR residual noise levels at the threshold and the difference in ASSR thresholds at all tested frequencies. Conclusion: The next-generation system demonstrated strong test–retest reliability across the frequencies examined in this pilot study. Particularly, an improvement in reliability was observed at 500 Hz compared to the old-generation ASSR. This enhancement can be attributed to the utilization of narrow-band CE-chirp stimuli, which generate large amplitude responses, and the implementation of an improved detection paradigm involving multiple harmonics spectral and phase analysis. This pilot study only enrolled adults with normal hearing, and future investigations should include a larger sample size comprising both normal-hearing and hearing-impaired individuals, as well as the pediatric population.

Pre-emptive versus preventive analgesia for postoperative pain: a systematic review and meta-analysis

BackgroundPostoperative pain is a type of nociceptive pain that originates from tissue damage due to trauma caused by surgery. Pre-emptive analgesia is treatment that starts before surgery, to prevent or reduce the establishment of sensitization of dorsal horn neurons caused by tissue injury, the sensitized neurons being supposed to amplify postoperative pain. Pre-emptive analgesia consists of administering analgesic medication before tissue injury, that is, before the reception, transmission, modulation, and nociception of the aggressive stimulus, aiming to prevent hyperalgesia. This review aims to compare the efficacy of pre-emptive analgesia and preventive analgesia in postoperative pain. MethodsArticle searching was done on five databases (PubMed, ProQuest, Scopus, ScienceDirect, ClinicalKey). Hand-searching was also done to find additional articles. We have only included double-blind, randomized, controlled trials (RCT). A total of fifteen articles were included and all were RCT studies comparing pre-emptive analgesia with preventive analgesia. The quality of the included studies was evaluated with Cochrane risk-of-bias assessment tools. Quantitative analysis was performed by Review Manager 5.4. ResultsFifteen studies comprising 830 subjects were included in this study. Our analysis revealed that pre-emptive analgesia significantly improved visual analog scale (VAS)/numeric rating scale (NRS)/verbal rating scale (VRS) 4 hours postoperatively [mean difference (MD) = -0.25, 95% CI: [- 0.49, -0.02]; I2 = 94%]. Unfortunately, pain scoring at 6, 12 and 24 hours after surgery did not differ significantly between pre-emptive and preventive analgesia. Duration of analgesia was comparable between the two groups. Time to rescue analgesics was similar between the two groups, but the pre-emptive group was associated with less analgesic consumption postoperatively than the preventive group. ConclusionPre-emptive analgesia provided better pain relief than preventive analgesia during the short term. Time to rescue analgesics is comparable between both groups, but pre-emptive analgesia is associated with lower amounts of rescue analgesics postoperatively.

Higher amplitudes in steady-state visual evoked potentials driven by square-wave versus sine-wave contrast modulation - A dual-laboratory study.

Steady-state visual evoked potentials (ssVEPs) are an established tool for assessing visuocortical responses in visual perception and attention. They have the same temporal frequency characteristics as a periodically modulated stimulus (e.g., in contrast or luminance) that drives them. It has been hypothesized that the amplitude of a given ssVEP may depend on the shape of the stimulus modulation function, but the size and robustness of these effects is not well established. The current study systematically compared the effect of the two most common functions in the ssVEP literature, square-wave and sine-wave functions. Across two laboratories, we presented mid-complex color patterns to 30 participants with square-wave or sine-wave contrast modulation and at different driving frequencies (6Hz, 8.57 Hz, 15 Hz). When ssVEPs were analyzed independently for the samples, with each laboratory's standard processing pipeline, ssVEP amplitudes in both samples decreased at higher driving frequencies and square-wave modulation evoked higher amplitudes at lower frequencies (i.e., 6Hz, 8.57 Hz) compared to sine-wave modulation. These effects were replicated when samples were aggregated and analyzed with the same processing pipeline. In addition, when using signal-to-noise ratios as outcome measures, this joint analysis indicated a somewhat weaker effect of increased ssVEP amplitudes to square-wave modulation at 15 Hz. The present study suggests that square-wave modulation should be used in ssVEP research when the goal is to maximize signal amplitude or signal-to-noise ratio. Given effects of modulation function across laboratories, and data processing pipelines, the findings appear robust to differences in data collection and analysis.

Measurement of individual color space using a luminous vector field.

This study is intended to measure the geometry of the observer's color space when viewing a computer screen and to define individual variations from these data. A CIE photometric standard observer assumes that the eye's spectral efficiency function is constant, and photometry measurements correspond to vectors with fixed directions. By definition, the standard observer decomposes color space into planar surfaces of constant luminance. Using heterochromatic photometry with a minimum motion stimulus, we systematically measure the direction of luminous vectors for many observers and many color points. During the measurement process, the background and stimulus modulation averages are fixed to the given points to ensure that the observer is in a fixed adaptation mode. Our measurements result in a vector field or set of vectors (x,v), where x is the point's color space position, and v is the observer's luminosity vector. To estimate surfaces from vector fields, two mathematical hypotheses were used: (1)that surfaces are quadratic or, equivalently, that the vector field model is affine, and (2)that the metric of surfaces is proportional to a visual origin. Across 24 observers, we found that vector fields are convergent and the corresponding surfaces are hyperbolic. The equation of the surface in the display's color space coordinate system, and in particular the axis of symmetry, varied systematically from individual to individual. A hyperbolic geometry is compatible with studies that emphasize a modification of the photometric vector with changing adaptations.

Compressive thermal wave imaging for subsurface analysis

Subsurface detail extraction in active thermography demands high capturing rates, resulting in less exposure time, data redundancy, large bandwidth requirement, and wastage of sensing resources and memory. Compressive sensing (CS) is a data acquisition technique that overcomes these limitations by acquiring the signal at sub-Nyquist rates with fewer measurements considering the signal is sparse in some transformed domains and reconstructing the original response. This paper validates the application of CS in frequency modulated thermal wave imaging by experimenting on a quick responsive mild steel specimen with artificially simulated back hole defects. The discrete cosine transform is selected as sparsity prior and the orthogonal matching pursuit is used to reconstruct the original thermal response from the compressed measurements. The initial analysis is carried out on choosing the optimal sparsity parameter and the number of measurements, followed by the effect of the number of measurements on defect detection in various post-processing techniques used in frequency modulated stimulus. The defects detected and their qualitative analysis through assessing signal-to-noise ratio confirmed the suitability of CS for efficient reconstruction of thermal data and thereby enhancing the defect signature.

Emergency Braking Evoked Brain Activities during Distracted Driving

Electroencephalogram (EEG) was used to analyze the mechanisms and differences in brain neural activity of drivers in visual, auditory, and cognitive distracted vs. normal driving emergency braking conditions. A pedestrian intrusion emergency braking stimulus module and three distraction subtasks were designed in a simulated experiment, and 30 subjects participated in the study. The common activated brain regions during emergency braking in different distracted driving states included the inferior temporal gyrus, associated with visual information processing and attention; the left dorsolateral superior frontal gyrus, related to cognitive decision-making; and the postcentral gyrus, supplementary motor area, and paracentral lobule associated with motor control and coordination. When performing emergency braking under different driving distraction states, the brain regions were activated in accordance with the need to process the specific distraction task. Furthermore, the extent and degree of activation of cognitive function-related prefrontal regions increased accordingly with the increasing task complexity. All distractions caused a lag in emergency braking reaction time, with 107.22, 67.15, and 126.38 ms for visual, auditory, and cognitive distractions, respectively. Auditory distraction had the least effect and cognitive distraction the greatest effect on the lag.

A Redundant Cortical Code for Speech Envelope.

Animal communication sounds exhibit complex temporal structure because of the amplitude fluctuations that comprise the sound envelope. In human speech, envelope modulations drive synchronized activity in auditory cortex (AC), which correlates strongly with comprehension (Giraud and Poeppel, 2012; Peelle and Davis, 2012; Haegens and Zion Golumbic, 2018). Studies of envelope coding in single neurons, performed in nonhuman animals, have focused on periodic amplitude modulation (AM) stimuli and use response metrics that are not easy to juxtapose with data from humans. In this study, we sought to bridge these fields. Specifically, we looked directly at the temporal relationship between stimulus envelope and spiking, and we assessed whether the apparent diversity across neurons' AM responses contributes to the population representation of speech-like sound envelopes. We gathered responses from single neurons to vocoded speech stimuli and compared them to sinusoidal AM responses in auditory cortex (AC) of alert, freely moving Mongolian gerbils of both sexes. While AC neurons displayed heterogeneous tuning to AM rate, their temporal dynamics were stereotyped. Preferred response phases accumulated near the onsets of sinusoidal AM periods for slower rates (<8 Hz), and an over-representation of amplitude edges was apparent in population responses to both sinusoidal AM and vocoded speech envelopes. Crucially, this encoding bias imparted a decoding benefit: a classifier could discriminate vocoded speech stimuli using summed population activity, while higher frequency modulations required a more sophisticated decoder that tracked spiking responses from individual cells. Together, our results imply that the envelope structure relevant to parsing an acoustic stream could be read-out from a distributed, redundant population code.SIGNIFICANCE STATEMENT Animal communication sounds have rich temporal structure and are often produced in extended sequences, including the syllabic structure of human speech. Although the auditory cortex (AC) is known to play a crucial role in representing speech syllables, the contribution of individual neurons remains uncertain. Here, we characterized the representations of both simple, amplitude-modulated sounds and complex, speech-like stimuli within a broad population of cortical neurons, and we found an overrepresentation of amplitude edges. Thus, a phasic, redundant code in auditory cortex can provide a mechanistic explanation for segmenting acoustic streams like human speech.

Behavioral signatures of Y-like neuronal responses in human vision

Retinal ganglion cells initiating the magnocellular/Y-cell visual pathways respond nonlinearly to high spatial frequencies (SFs) and temporal frequencies (TFs). This nonlinearity is implicated in the processing of contrast modulation (CM) stimuli in cats and monkeys, but its contribution to human visual perception is not well understood. Here, we evaluate human psychophysical performance for CM stimuli, consisting of a high SF grating carrier whose contrast is modulated by a low SF sinewave envelope. Subjects reported the direction of motion of CM envelopes or luminance modulation (LM) gratings at different eccentricities. The performance on SF (for LMs) or carrier SF (for CMs) was measured for different TFs (LMs) or carrier TFs (CMs). The best performance for LMs was at lower TFs and SFs, decreasing systematically with eccentricity. However, performance with CMs was bandpass with carrier SF, largely independent of carrier TF, and at the highest carrier TF (20 Hz) decreased minimally with eccentricity. Since the nonlinear subunits of Y-cells respond better at higher TFs compared to the linear response components and respond best at higher SFs that are relatively independent of eccentricity, these results suggest that behavioral tasks employing CM stimuli might reveal nonlinear contributions of retinal Y-like cells to human perception.

ANALYSIS OF SCIENTIFIC RESEARCH ON THE SENSIMOTOR DEVELOPMENT OF CHILDREN WITH DISORDERS OF INTELLECTUAL DEVELOPMENT

The article provides a theoretical analysis of research on the problem of sensorimotor development with children with violation of intellectual development. Theoretical aspects of sensorimotor development of children with intellectual disabilities in the following areas are considered: vestibular-postural reactions and bilateral coordination. Motor mechanisms affect the general development of the child, his ability to work and master the curriculum. Studies have shown the effect of physical activity on mental activity and academic performance. Imperfections of the motor sphere of children with PIR are revealed. Children's gait is unstable, movements are chaotic, poorly coordinated, poorly regulated muscular effort, impaired visual-motor coordination, inability to imitate, underdevelopment of differentiated finger movements. The disadvantages of arbitrary movements are pronounced. Theoretical analysis of scientific research on the role of the central nervous system in the construction of movements. Spinal cord, medulla, diencephalon, cerebellum, large hemispheres perform their functions. Simple movements (reflective) provide normal performance of more complex movements performed due to the lower parts of the central nervous system (spinal, medulla, midbrain). More complex postures are regulated by the activity of the midbrain, the vestibular system, which obey the cerebellum. The cerebellum coordinates the proportionality of movement. To perform movement in space, it is necessary to combine all types of sensitive sphere (afferentation). This process occurs at the level of the diencephalon and subcortical nuclei. It is proved that part of the vestibular signals must be registered and modulated by the brain. The lack of modulation of vestibular stimuli will be noticeable in bilateral reactions, coordination of the two sides of the body. The postural response may go unnoticed because it is difficult for the child to adopt a particular posture. Sensorimotor development affects the functioning of the body of a child with violation of intellectual development.