Stimulus Variables Research Articles

COMPLEXITY-BASED ANALYSIS OF THE INFLUENCE OF VISUAL STIMULUS COLOR ON HUMAN EYE MOVEMENT

Analysis of eye movement due to different visual stimuli always has been one of the major research areas in vision science. An important category of works belongs to decoding of eye movement due to variations of color of visual stimuli. In this research, for the first time, we employ fractal analysis in order to investigate the variations of complex structure of eye movement time series in response to variations of color of visual stimuli. For this purpose, we applied two different images in three different colors (red, green, blue) to subjects. The result of our analysis showed that eye movement has the greatest complexity in case of green visual stimulus. On the other hand, the lowest complexity of eye movement was observed in case of red stimulus. In addition, the results showed that except for red visual stimulus, applying the visual stimulus with greater complexity causes the lower complexity in eye movements. The employed methodology in this research can be further applied to analyze the influence of other variations of visual stimuli on human eye movement.

Unravelling purinergic regulation in the epididymis: activation of V-ATPase-dependent acidification by luminal ATP and adenosine.

In the epididymis, elaborate communication networks between epithelial cells are important with respect to establishing an optimal acidic luminal environment for the maturation and storage of spermatozoa, which is essential for male fertility. Proton secretion by epididymal clear cells is achieved via the proton pumping V-ATPase located in their apical membrane. In the present study, we dissect the molecular mechanisms by which clear cells respond to luminal ATP and adenosine to modulate their acidifying activity via the adenosine receptor ADORA2B and the pH-sensitive ATP receptor P2X4. We demonstrate that the hydrolysis of ATP to produce adenosine by ectonucleotidases plays a key role in V-ATPase-dependent proton secretion, and is part of a feedback loop that ensures acidification of the luminal compartment These results help us better understand how professional proton-secreting cells respond to extracellular cues to modulate their functions, and how they communicate with neighbouring cells. Cell-cell cross-talk is crucial for the dynamic function of epithelia, although how epithelial cells detect and respond to variations in extracellular stimuli to modulate their environment remains incompletely understood. In the present study, we used the epididymis as a model system to investigate epithelial cell regulation by luminal factors. In the epididymis, elaborate communication networks between the different epithelial cell types are important for establishing an optimal acidic luminal environment for the maturation and storage of spermatozoa. In particular, clear cells (CCs) secrete protons into the lumen via the proton pumping V-ATPase located in their apical membrane, a process that is activated by luminal alkalinization. However, how CCs detect luminal pH variations to modulate their function remains uncharacterized. Purinergic regulation of epithelial transport is modulated by extracellular pH in other tissues. In the present study, functional analysis of the mouse cauda epididymis perfused in vivo showed that luminal ATP and adenosine modulate the acidifying activity of CCs via the purinergic ADORA2B and P2X4 receptors, and that luminal adenosine content is itself regulated by luminal pH. Altogether, our observations illustrate mechanisms by which CCs are activated by pH sensitive P2X4 receptor and ectonucleotidases, providing a feedback mechanism for the maintenance of luminal pH. These novel mechanisms by which professional proton-secreting cells respond to extracellular cues to modulate their functions, as well as how they communicate with neighbouring cells, might be translatable to other acidifying epithelia.

Cognitively Inspired Feature Extraction and Speech Recognition for Automated Hearing Loss Testing

Hearing loss, a partial or total inability to hear, is one of the most commonly reported disabilities. A hearing test can be carried out by an audiologist to assess a patient’s auditory system. However, the procedure requires an appointment, which can result in delays and practitioner fees. In addition, there are often challenges associated with the unavailability of equipment and qualified practitioners, particularly in remote areas. This paper presents a novel idea that automatically identifies any hearing impairment based on a cognitively inspired feature extraction and speech recognition approach. The proposed system uses an adaptive filter bank with weighted Mel-frequency cepstral coefficients for feature extraction. The adaptive filter bank implementation is inspired by the principle of spectrum sensing in cognitive radio that is aware of its environment and adapts to statistical variations in the input stimuli by learning from the environment. Comparative performance evaluation demonstrates the potential of our automated hearing test method to achieve comparable results to the clinical ground truth, established by the expert audiologist’s tests. The overall absolute error of the proposed model when compared with the expert audiologist test is less than 4.9 dB and 4.4 dB for the pure tone and speech audiometry tests, respectively. The overall accuracy achieved is 96.67% with a hidden Markov model (HMM). The proposed method potentially offers a second opinion to audiologists, and serves as a cost-effective pre-screening test to predict hearing loss at an early stage. In future work, authors intend to explore the application of advanced deep learning and optimization approaches to further enhance the performance of the automated testing prototype considering imperfect datasets with real-world background noise.

Consistent meal times improve performance on a daily time-place learning task

The ability of an animal to learn the spatiotemporal variability of stimuli is known as time-place learning (TPL). The present study investigated the role of the food-entrainable oscillator (FEO) in TPL. Rats were trained in an operant conditioning chamber which contained two levers that distributed a food reward, such that one lever provided food rewards in morning sessions, while the other lever provided food rewards in afternoon sessions. We expected that having access to the FEO would provide rats with more accurate depictions of time of day, leading to better performance. Rats received either one meal per day (1M group), which permitted FEO access, or many meals per day (MM group), which prevented FEO access. As predicted, 1M rats had a significantly higher percentage of correct first presses than MM rats. Once rats successfully learned the task, probe tests were conducted to determine the timing strategy used. Of the 10 rats that successfully learned the time-place discrimination, six used a circadian timing strategy. Future research should determine whether the advantage in learning seen in the rats having access to the FEO is specific to the daily TPL task used in this study, or to learning and memory tasks more generally.

Effect of ADHD medication in male C57BL/6J mice performing the rodent Continuous Performance Test.

The rodent Continuous Performance Test (rCPT) is a novel rodent paradigm to assess attention and impulsivity that resembles the human CPT. This task measures the rodents' ability to discriminate between target and non-target stimuli. The effect of attention-deficit/hyperactivity disorder (ADHD) medication on rCPT performance in mice remains to be fully characterized. To investigate the predictive validity of the mouse rCPT by studying the effects of ADHD medication methylphenidate, atomoxetine, amphetamine, guanfacine, and modafinil in four behavioral subgroups based on performance and impulsivity levels. Two cohorts of male C57BL/6J mice were used, and the effect of treatment was tested in a variable stimulus duration probe. Performance and impulsive subgroups were made based on discriminability and percentage premature responses, respectively. Methylphenidate, atomoxetine, and amphetamine improved performance in the low-performing animals, with no effect in the high-performers. These improvements were a result of increased hit rate and/or decreased false-alarm rate. Furthermore, these drugs decreased percentage premature responses in the high-impulsive group. Methylphenidate, guanfacine, and modafinil increased premature responses in the low-impulsive group. Modafinil impaired performance in the high-performers by increasing false-alarm rate. The effect of ADHD treatment was dependent on baseline, as seen by increases in performance for the low-performers and decreases in impulsivity for the high-impulsive animals. These results agree with clinical data and may support the inverted U-shaped arousal-performance theory. The rCPT combined with behavioral separation into subgroups has high predictive validity, and our study is a step forward towards establishing the clinical translatability of the rCPT.

Application of Logistic Differential Equation to Investigate The Extent of Emphasizing Stimulus Variation in Mathematics Instruction

The knowledge and skills in mathematics processes can be provided in an effective and systematic manner only by teaching mathematics in schools. Stimulus variation as a teaching skill is used to stimulate students’ interest and attract their attention to the lesson presentation. Therefore, this study investigated the extent of emphasizing stimulus variation in mathematics instruction using logistic differential equation. The study adopted a developmental survey design where a cross-section of in-service mathematics teachers in Imo State numbering 94 were continuously observed and surveyed to decipher their extent of emphasizing stimulus variation in the classroom to promote teaching excellence. The observations were carried out for 14 days and the data were generated based on direct observational technique (using observation schedule). The result revealed inadequate and inconsistent emphasis of stimulus variation teaching skill in mathematics instruction. This implies that pre-service mathematics teachers seldom emphasize stimulus variation when teaching mathematics. It was recommended that mathematics teachers should always employ the skill of stimulus variation in class during instructional delivery so as to enhance students’ learning experience and satisfaction thereby promoting teaching excellence. DOI: https://doi.org/10.31235/osf.io/rthj2

How experimental procedures influence estimates of metacognitive ability.

It is becoming widely appreciated that higher stimulus sensitivity trivially increases estimates of metacognitive sensitivity. Therefore, meaningful comparisons of metacognitive ability across conditions and observers necessitates equating stimulus sensitivity. To achieve this, one common approach is to use a continuous staircase that runs throughout the duration of the experiment under the assumption that this procedure has no influence on the estimated metacognitive ability. Here we critically examine this assumption. Using previously published data, we find that, compared to using a single level of stimulus contrast, staircase techniques lead to inflated estimates of metacognitive ability across a wide variety of measures including area under the type 2 ROC curve, the confidence-accuracy correlation phi, meta-d′, meta-d′/d′, and meta-d′–d′. Furthermore, this metacognitive inflation correlates with the degree of stimulus variability experienced by each subject. These results suggest that studies using a staircase approach are likely to report inflated estimates of metacognitive ability. Furthermore, we argue that similar inflation likely occurs in the presence of variability in task difficulty caused by other factors such as fluctuations in alertness or gradual improvement on the task. We offer practical solutions to these issues, both in the design and analysis of metacognition experiments.

Differential effects of chemogenetic inhibition of dopamine and norepinephrine neurons in the mouse 5-choice serial reaction time task

Attention-deficit/hyperactivity disorder (ADHD) is a psychiatric disorder characterized by inattention, aberrant impulsivity, and hyperactivity. Although the underlying pathophysiology of ADHD remains unclear, dopamine and norepinephrine signaling originating from the ventral tegmental area (VTA) and locus coeruleus (LC) is thought to be critically involved. In this study, we employ Designer Receptor Exclusively Activated by Designer Drugs (DREADDs) together with the mouse 5-Choice Serial Reaction Time Task (5-CSRTT) to investigate the necessary roles of these catecholamines in ADHD-related behaviors, including attention, impulsivity, and motivation. By selective inhibition of tyrosine hydroxylase (TH)-positive VTA dopamine neurons expressing the Gi-coupled DREADD (hM4Di), we observed a marked impairment of effort-based motivation and subsequently speed and overall vigor of responding. At the highest clozapine N-oxide (CNO) dose tested (i.e. 2 mg/kg) to activate hM4Di, we detected a reduction in locomotor activity. DREADD-mediated inhibition of LC norepinephrine neurons reduced attentional performance in a variable stimulus duration test designed to increase task difficulty, specifically by increasing trials omissions, reducing mean score, and visual processing speed. These findings show that VTA dopamine and LC norepinephrine neurons differentially affect attention, impulsive and motivational control. In addition, this study highlights how molecular genetic probing of selective catecholamine circuits can provide valuable insights into the mechanisms underlying ADHD-relevant behaviors.

Linear and Nonlinear Analysis of the Traditional and Differential Strength Training

Training methods are commonly studied using lineal and quantitative research, limiting the possibilities to proof new ways of optimizing the training process. The aim of the study was to compare the classical strength training appro-ach, based on repetitions, with differential training for the improvement of diffi culty elements in aerobic gymnastics applying a linear and a nonlinear tool for analyzing the interaction between load and performance.Two female national standard aerobic gymnasts followed three periods of training (TTa: 5 weeks of traditional training; DT: 8 weeks of differential training; TTb: 5 weeks of traditional training). Load applied to the gymnasts was expressed quantitatively (quantitative load) with an equation including time of execution (t), number of series (N), number of exercises in each series (Rp) and relative intensity, and qualitatively (qualitative load) defi ning the number of different exercises performed. Performance was defi ned through 6 tests based on the execution of three different push-ups. Quantitative and qualitative load, the time of execution of the push ups and the time of fl ight of the jumps were determined weekly during the 17 weeks. The interaction between the load applied to upper limbs and performance of push ups, and the interaction between the load applied to lower limbs and performance of jumps were analyzed using a non-linear metamodel (PerPot) and cross correlations. Push ups results show that the increase in load quantifi ed qualitatively correlates more positively with the increase in performance than with the increase in load measured quantitatively. This suggests that subjects respond better to an increase in the variation of training stimulus than to an increase in the number of repetitions. Nevertheless, PerPot proposes a reduction in the number of varied exercises in the DT period. Regarding jumping tests, the performance of both subjects remained constant, suggesting that four months of training was not enough to improve the time of fl ight in experienced gymnasts, or the training methods were not the most adequate.This study suggests that (1) differential training seems to lead to a greater increase in performance than traditional training, but (2) the same results could be achieved by reducing the number of varied exercises or combining both approaches.Keywords: non-linear metamodel, qualitative load, performance.

Modeling Fish Movement Trajectories in Relation to Hydraulic Response Relationships in an Experimental Fishway

This study developed an IBM (individual-based model) to model fish movement trajectories integrating hydraulic stimulus variables (turbulent kinetic energy (TKE), velocity (V) and strain rate (SR)) to which fish responded, and the rules for individual fish movement. The fish movement trajectories of the target fish, silver carp (Hypophthalmichthys molitrix), were applied to model fish trajectories in a 1% vertical slot fishway at a discharge of 13.5 L/s. Agreement between measured and simulated trajectories implied the plausibility of the movement rules, which illustrated that the fish movement trajectories model has the preliminary ability to track individual fish trajectories for this fishway.

Test–retest reliability of subjective supra-threshold scaling of multiple pressure-pain sensations among healthy individuals: a study using hydraulic pressure algometry

Background: Supra-threshold scaling of multiple pressure-pain sensations involves delivery of varied stimulus intensities, either via stimulus-dependent or response-dependent manner, and recording of subjective pain ratings by participants. The focus of this study was to determine the intra- and inter-session reliability of pain intensity and pain unpleasantness ratings related to pressure-pain thresholds (PPTs) of just noticeable pain (JNP), weak pain (WP) and moderate pain (MP) among healthy individuals.Methods: Fourteen healthy participants (eight women, six men) participated in three sessions of testing at varied intervals over the course of 72 h. In session one, a multiple random staircase method using hydraulic pressure algometry was used to measure PPT of JNP, WP and MP on thumbnail bed. In session 2, ratings of pain intensity and pain unpleasantness were recorded when stimuli at levels corresponding to PPT of JNP, WP and MP were repeatedly applied before and after 20 min of no intervention.Results: Interclass correlation coefficient (ICC) values for pain ratings of JNP, WP and MP in intra-session reliability were 0.810, 0.826 and 0.881, respectively, whereas the values were 0.817, 0.792 and 0.910, respectively, for inter-session reliability. ICC values for pain unpleasantness were also highly consistent and repeatable. Temporal summation of pain intensity and pain unpleasantness were not related to the repeated application of pressure stimuli.Conclusions: The findings indicate that the pain intensity and pain unpleasantness ratings for stimuli at levels equal to the thresholds of JNP, WP and MP have good intra- and inter-session reliability.Significance: This study showed that both pain intensity and pain unpleasantness of JNP, WP and MP have good intra- and inter-session reliability and agreement. Furthermore, the temporal summation of pain or unpleasantness is not related to repeated application of pressure stimuli.Abbreviations: JNP: Just noticeable pain; WP: Weak pain; MP: Moderate pain; PPTs: pressure-pain thresholds; HPA: Hydraulic pressure algometry; MRSM: multiple random staircase method

How Many Clocks, How Many Times? On the Sensory Basis and Computational Challenges of Circadian Systems.

A vital task for every organism is not only to decide what to do but also when to do it. For this reason, “circadian clocks” have evolved in virtually all forms of life. Conceptually, circadian clocks can be divided into two functional domains; an autonomous oscillator creates a ~24 h self-sustained rhythm and sensory machinery interprets external information to alter the phase of the autonomous oscillation. It is through this simple design that variations in external stimuli (for example, daylight) can alter our sense of time. However, the clock’s simplicity ends with its basic concept. In metazoan animals, multiple external and internal stimuli, from light to temperature and even metabolism have been shown to affect clock time. This raises the fundamental question of cue integration: how are the many, and potentially conflicting, sources of information combined to sense a single time of day? Moreover, individual stimuli, are often detected through various sensory pathways. Some sensory cells, such as insect chordotonal neurons, provide the clock with both temperature and mechanical information. Adding confusion to complexity, there seems to be not only one central clock in the animal’s brain but numerous additional clocks in the body’s periphery. It is currently not clear how (or if) these “peripheral clocks” are synchronized to their central counterparts or if both clocks “tick” independently from one another. In this review article, we would like to leave the comfort zones of conceptual simplicity and assume a more holistic perspective of circadian clock function. Focusing on recent results from Drosophila melanogaster we will discuss some of the sensory, and computational, challenges organisms face when keeping track of time.

An optimal protocol for measurement of corticospinal excitability, short intracortical inhibition and intracortical facilitation in the rectus femoris

The study aimed to determine the optimal application of single- and paired-pulse transcranial magnetic stimulation (TMS) in the rectus femoris. Twenty-nine male adults participated in the study, which involved 5 separate experiments. Experiments 1 to 3 assessed the effect of conditioning stimulus (CS) intensity (60, 70, 80 and 90% active motor threshold, AMT), contraction strength (5, 10, 20 and 50% maximum voluntary contraction, MVC), and inter-stimulus interval (ISI, 2–5 ms for short-interval intracortical inhibition, SICI and 10–15 ms for intracortical facilitation, ICF) on SICI and ICF. In Experiment 4, 30 measurements of corticospinal excitability (CSE), SICI and ICF were recorded, with the minimum number of consecutive measurements required as a probability of falling within the 95% CI determined. In Experiment 5, within- and between-day reliability of CSE, SICI and ICF was assessed. The results suggest that for SICI, a CS of 70% AMT, ISI of 2 ms, and contraction strength of 5 or 10% MVC induces the greatest level of inhibition. Negligible differences in ICF were seen across stimulus variables. The minimum number of measurements required to obtain an accurate estimate of CSE, SICI and ICF was 21, 18 and 17, respectively. Using the optimal stimulus variables and number of measurements, CSE, SICI and ICF can be measured reliably both within- and between-days (intraclass correlation coefficient, ICC ≥ 0.87, ≥0.74, and ≥0.61, respectively). The current findings can be used to guide future investigations using single- and paired-pulse TMS to elicit responses in the rectus femoris.

Distal tubule basolateral potassium channels: cellular and molecular mechanisms of regulation.

Multiple clinical and translational evidence support benefits of high potassium diet; however, there many uncertainties underlying the molecular and cellular mechanisms determining effects of dietary potassium. Kir4.1 and Kir5.1 proteins form a functional heteromer (Kir4.1/Kir5.1), which is the primary inwardly rectifying potassium channel on the basolateral membrane of both distal convoluted tubule (DCT) and the collecting duct principal cells. The purpose of this mini-review is to summarize latest advances in our understanding of the evolution, physiological relevance and mechanisms controlling these channels. Kir4.1 and Kir5.1 channels play a critical role in determining electrolyte homeostasis in the kidney and blood pressure, respectively. It was reported that Kir4.1/Kir5.1 serves as potassium sensors in the distal nephron responding to variations in dietary intake and hormonal stimuli. Global and kidney specific knockouts of either channel resulted in hypokalemia and severe cardiorenal phenotypes. Furthermore, knock out of Kir5.1 in Dahl salt-sensitive rat background revealed the crucial role of the Kir4.1/Kir5.1 channel in salt-induced hypertension. Here, we focus on reviewing novel experimental evidence of the physiological function, expression and hormonal regulation of renal basolateral inwardly rectifying potassium channels. Further investigation of molecular and cellular mechanisms controlling Kir4.1 and Kir4.1/Kir5.1-mediating pathways and development of specific compounds targeting these channels function is essential for proper control of electrolyte homeostasis and blood pressure.

Cross-dimensional magnitude interactions arise from memory interference

Magnitudes from different dimensions (e.g., space and time) interact with each other in perception, but how these interactions occur remains unclear. In four experiments, we investigated whether cross-dimensional magnitude interactions arise from memory interference. In Experiment 1, participants perceived a constant-length line consisting of two line segments of complementary lengths and presented for a variable stimulus duration; then they received a cue about which of the two segment lengths to later reproduce. Participants were to first reproduce the stimulus duration and then the cued length. Reproduced durations increased as a function of the cued length if the cue was given before duration was retrieved from memory for reproduction (i.e. before duration reproduction; Experiment 1) but not if it was given after the duration memory had been retrieved from memory (i.e. after the start of duration reproduction; Experiment 2). These findings demonstrate that space-time interaction arises as a result of memory interference when length and duration information co-exist in working memory. Experiment 3 further demonstrated spatial interference on duration memories from memories of filled lengths (i.e. solid line segments) but not from noisier memories of unfilled lengths (demarcated empty spatial intervals), thus highlighting the role of memory noise in space-time interaction. Finally, Experiment 4 showed that time also exerted memory interference on space when space was presented as (relatively noisy) unfilled lengths. Taken together, these findings suggest that cross-dimensional magnitude interactions arise as a result of memory interference and the extent and direction of the interaction depend on the relative memory noises of the target and interfering dimensions. We propose a Bayesian model whereby the estimation of a magnitude is based on the integration of the noisily encoded percept of the target magnitude and the prior knowledge that magnitudes co-vary across dimensions (e.g., space and time). We discuss implications for cross-dimensional magnitude interactions in general.

Rhythm and Synchrony in a Cortical Network Model.

We studied mechanisms for cortical gamma-band activity in the cerebral cortex and identified neurobiological factors that affect such activity. This was done by analyzing the behavior of a previously developed, data-driven, large-scale network model that simulated many visual functions of monkey V1 cortex (Chariker et al., 2016). Gamma activity was an emergent property of the model. The model's gamma activity, like that of the real cortex, was (1) episodic, (2) variable in frequency and phase, and (3) graded in power with stimulus variables like orientation. The spike firing of the model's neuronal population was only partially synchronous during multiple firing events (MFEs) that occurred at gamma rates. Detailed analysis of the model's MFEs showed that gamma-band activity was multidimensional in its sources. Most spikes were evoked by excitatory inputs. A large fraction of these inputs came from recurrent excitation within the local circuit, but feedforward and feedback excitation also contributed, either through direct pulsing or by raising the overall baseline. Inhibition was responsible for ending MFEs, but disinhibition led directly to only a small minority of the synchronized spikes. As a potential explanation for the wide range of gamma characteristics observed in different parts of cortex, we found that the relative rise times of AMPA and GABA synaptic conductances have a strong effect on the degree of synchrony in gamma.SIGNIFICANCE STATEMENT Canonical computations used throughout the cerebral cortex are performed in primary visual cortex (V1). Providing theoretical mechanisms for these computations will advance understanding of computation throughout cortex. We studied one dynamical feature, gamma-band rhythms, in a large-scale, data-driven, computational model of monkey V1. Our most significant conclusion is that the sources of gamma band activity are multidimensional. A second major finding is that the relative rise times of excitatory and inhibitory synaptic potentials have strong effects on spike synchrony and peak gamma band power. Insight gained from studying our V1 model can shed light on the functions of other cortical regions.

ECT: a new look at an old friend.

Electroconvulsive therapy (ECT) as a treatment option in psychiatry is advancing day by day. This review discusses new advancements in ECT with regards to anesthetic variables, stimulus, and response variables along with their impact on clinical outcomes. Anesthetic variables influence clinical efficacy and patient tolerance of ECT. Although etomidate or a ketamine-propofol combination may be the first choice for many clinicians, the search for ideal induction agent continues. Dexmedetomidine, remifentanil, or ketamine may aid in augmentation of ECT; however, they are not recommended routinely. A systematic procedure for hyperventilation of the patient has been shown to have clinical repercussions. Optimizing anesthesia-ECT time interval (ASTI) has a significant impact on the success of the procedure. BIS monitoring alone cannot be relied upon for timing stimulus. High-dose brief pulse right unilateral ECT represents an acceptable first-line form of treatment, though there is currently no 'gold standard'. Other stimulus variations such as focal electrically administered seizure therapy, individualized low-amplitude seizure therapy, magnetic seizure therapy, left unilateral and left anterior right temporal electrode placements are explored to reduce memory effects. EEG ictal indices may be relied upon for seizure adequacy, and therefore may be used to both guide treatment and predict the outcome of the procedure. Modern ECT is streamlined by augmentation with drugs, hyperventilation, optimizing anesthesia-ECT time interval, and various stimulus parameters guided by seizure adequacy markers.

Students Awareness and Utilization of Educational Broadcasts to Learn in Ogbomoso, Oyo State

Radio and Television are broadcast media meant to disseminate audio and video signal, messages, information or programs to wide range of audience. Radio and television are already playing a role in educating the populace non-formally through various educational channels and programs, but there is significant potential to capitalize on their ability to enhance development and learning curriculum content among secondary school students. This study: 1) Find out the awareness of educational radio and television programs by secondary school students in Ogbomoso 2) Investigate secondary school students access to educational radio and television programs in Ogbomoso and 3) Investigate problems militating against students’ use of educational radio and television programs for learning. Questionnaire was used as instrument to elicit responses from 100 secondary school students on their awareness-on and access to seven educational radio and television programs. The findings revealed that the students were not aware of the educational radio and television programs even though they have access to it. The study recommends that teachers in secondary schools should include educational broadcasts as forms of stimulus variation that they could apply to their classes and educational programs producers on both radio and television should create enough awareness about the programs to enable students follow the programs at appropriate time.

Discrimination of spatial phase: The roles of luminance distribution and attention

We can easily discriminate certain phase relations in spatial patterns but not others. Phase perception has been found different in the fovea vs. periphery, and for single patterns vs. textures. Different numbers of mechanisms have been proposed to account for the regularities of phase perception.In this study, I attempt to better understand the mechanisms behind discrimination of spatial phase. In order to reveal the role of luminance cues, I use histogram matching of patterns with different phases. Possible effects of attention were studied using visual search experiments with varied stimulus set size. Simple and compound Gabor patches, broadband lines and edges, and textures composed of those patterns were used as stimuli.The experiments indicate that phase discrimination is mediated by two mechanisms. The first uses luminance differences and operates pre-attentively, in parallel across the visual field. The second compares relative positions of dark and bright segments within an image, and is strictly limited by capacity of attention.

Not-So-CLEVR: learning same-different relations strains feedforward neural networks.

The advent of deep learning has recently led to great successes in various engineering applications. As a prime example, convolutional neural networks, a type of feedforward neural network, now approach human accuracy on visual recognition tasks like image classification and face recognition. However, here we will show that feedforward neural networks struggle to learn abstract visual relations that are effortlessly recognized by non-human primates, birds, rodents and even insects. We systematically study the ability of feedforward neural networks to learn to recognize a variety of visual relations and demonstrate that same-different visual relations pose a particular strain on these networks. Networks fail to learn same-different visual relations when stimulus variability makes rote memorization difficult. Further, we show that learning same-different problems becomes trivial for a feedforward network that is fed with perceptually grouped stimuli. This demonstration and the comparative success of biological vision in learning visual relations suggests that feedback mechanisms such as attention, working memory and perceptual grouping may be the key components underlying human-level abstract visual reasoning.