Normal Visual Conditions Research Articles

Sensory experience steers representational drift in mouse visual cortex

Representational drift—the gradual continuous change of neuronal representations—has been observed across many brain areas. It is unclear whether drift is caused by synaptic plasticity elicited by sensory experience, or by the intrinsic volatility of synapses. Here, using chronic two-photon calcium imaging in primary visual cortex of female mice, we find that the preferred stimulus orientation of individual neurons slowly drifts over the course of weeks. By using cylinder lens goggles to limit visual experience to a narrow range of orientations, we show that the direction of drift, but not its magnitude, is biased by the statistics of visual input. A network model suggests that drift of preferred orientation largely results from synaptic volatility, which under normal visual conditions is counteracted by experience-driven Hebbian mechanisms, stabilizing preferred orientation. Under deprivation conditions these Hebbian mechanisms enable adaptation. Thus, Hebbian synaptic plasticity steers drift to match the statistics of the environment.

The Impact of Stroboscopic Visual Conditions on the Performance of Elite Curling Athletes.

In elite curling, precise time perception, speed control, and accuracy are critical components of performance. Stroboscopic training enhances visual processing speed, reaction time, motor skill control, and cognitive abilities by challenging the brain to make quick decisions with limited visual information. This study aimed to investigate the impact of stroboscopic visual conditions on the key performance aspects of elite athletes in curling to determine whether these effects can be leveraged in long-term training to enhance elite curling performance. This study involved the participation of 32 national-level male curling athletes (n = 32, age: 19.9 ± 2.2 years, height: 178.0 ± 6.2 cm, body mass: 71.9 ± 10.6 kg, and training age: 2.7 ± 0.9 years). A cross-over controlled experiment was conducted, with participants randomly assigned to either a stroboscopic-first group (n = 16) or a control-first group (n = 16). Each participant completed tests under both stroboscopic and normal visual conditions, including assessments of time perception error, speed control error, and curling accuracy. Paired sample t-tests were employed to analyse performance differences across conditions, and two-factor ANOVA was used to analyse sequence effects. Bonferroni post-hoc tests were used to compare differences if the main effect was significant. Cohen's d was used for two-group comparisons, whereas ηp2 and Cohen's f were used for comparisons involving three or more groups. under stroboscopic conditions, participants experienced increased errors in time perception (p < 0.001, Cohen's d = 1.143), delivery speed control (p = 0.016, Cohen's d = 0.448), and reduced accuracy (p = 0.029, Cohen's d = 0.404). The sequence main effect on speed control error was significant (p = 0.025, ηp2 = 0.081, Cohen's f = 0.297). Stroboscopic visual conditions negatively impacted cognition (especially time perception) and delivery performance focused on speed control and accuracy in elite curling, highlighting the potential and feasibility of using stroboscopic training to enhance elite curling performance.

Effects of six-week stroboscopic training program on visuomotor reaction speed in goal-directed movements in young volleyball players: a study focusing on agility performance

BackgroundIn team sports, deficits in visuomotor reaction speed are considered a significant and modifiable risk factor that can lead to decreased performance and an increased risk of injuries. Thus, identifying effective methods to enhance visuomotor abilities is crucial. The main objective of this research was to investigate the impact of a six-week stroboscopic intervention on visuomotor reaction speed in goal-directed specific movements based on agility among young volleyball players. Additionally, the study aimed to explore the impact of saccade dynamics on visuomotor reaction speed performance throughout the experiment.MethodsThere were 50 athletes (26 males and 24 females) with an average age of 16.5 years (± 0.6) who participated in this study. Over a six-week training period, athletes performed volleyball-specific training either wearing stroboscopic glasses (intervention) or under normal visual conditions (control). Prior to and after the training period, the agility tests based on change-of-direction speed (CODS) and reactive agility (RA) were used to identify visuomotor reaction speed performance. To measure agility performance a five-repetition shuttle run to gates was conducted. The REAC-INDEX, which represents visuomotor reaction speed, was analyzed as the resulting difference between the CODS test and the RA test. To elicit saccadic dynamics, a laboratory visual search task was performed.ResultsA significant GROUP×TIME interaction was observed for the REAC-INDEX (p = 0.012, ηp2 = 0.13). ANCOVA analyses revealed significant GROUP differences, indicating improved post-training REAC-INDEX results (p = 0.004, d = 0.87), regardless of gender. Training-induced modulations in saccade acceleration did not reach significance, but a significant relationship was observed between changes in saccade acceleration and changes in the REAC-INDEX (r = -0.281, p = 0.048), indicating that higher performance gains following training were associated with a stronger increase in saccade acceleration.ConclusionsThis study demonstrates that stroboscopic training effectively enhances visuomotor reaction speed in goal-directed movements based on agility. Furthermore, visuomotor reaction speed gains could potentially be mediated by saccade dynamics. These findings provide valuable insights into the effectiveness of stroboscopic eyewear for training sport-specific visuomotor skills among young volleyball players.

Measuring visually guided motor performance in ultra low vision using virtual reality.

Ultra low vision (ULV) refers to profound visual impairment where an individual cannot read even the top line of letters on an ETDRS chart from a distance of 0.5 m. There are limited tools available to assess visual ability in ULV. The aim of this study was to develop and calibrate a new performance test, Wilmer VRH, to assess hand-eye coordination in individuals with ULV. A set of 55 activities was developed for presentation in a virtual reality (VR) headset. Activities were grouped into 2-step and 5-step items. Participants performed a range of tasks involving reaching and grasping, stacking, sorting, pointing, throwing, and cutting. Data were collected from 20 healthy volunteers under normal vision (NV) and simulated ULV (sULV) conditions, and from 33 participants with ULV. Data were analyzed using the method of successive dichotomizations (MSD), a polytomous Rasch model, to estimate item (difficulty) and person (ability) measures. MSD was applied separately to 2-step and 5-step performance data, then merged to a single equal interval scale. The mean SD of completion rates were 98.6 1.8%, 78.2 12.5% and 61.1 34.2% for NV, sULV and ULV, respectively. Item measures ranged from -1.09 to 5.7 logits and - 4.3 to 4.08 logits and person measures ranged from -0.03 to 4.2 logits and -3.5 to 5.2 logits in sULV and ULV groups, respectively. Ninety percent of item infits were within the desired range of [0.5,1.5], and 97% of person infits were within that range. Together with item and person reliabilities of 0.94 and 0.91 respectively, this demonstrates unidimensionality of Wilmer VRH. A Person Item map showed that the items were well-targeted to the sample of individuals with ULV in the study. We present the development of a calibrated set of activities in VR that can be used to assess hand-eye coordination in individuals with ULV. This helps bridge a gap in the field by providing a validated outcome measure that can be used in vision restoration trials that recruit people with ULV, and to assess rehabilitation outcomes in people with ULV.

Up-regulation of scleral C5b-9 and its regulation of the NLRP3 inflammasome in a form-deprivation myopia mouse model

BackgroundMyopia has become a major public health problem worldwide. Although the involvement of the complement system in myopia progression has been reported, the underlying mechanism has not been well established. In this study, we induced a form deprivation (FD) myopia mouse model to investigate the mechanisms. MethodsBoth C6-knockout (KO) and wild-type (WT) mice were divided into FD and normal control (NC) groups. The FD myopia was induced in the right eyes of 24-day-old mice using a translucent balloon for 4 weeks. The left eye remained untreated and served as self-control. NC group received no treatment. Refractive error and axial length were measured at baseline, 2 weeks, and 4 weeks later under normal visual, 4 weeks after FD. Scleral transcriptome sequencing analysis was performed in in FD mice. The scleral levels of C5b-9, NLRP3, Caspase-1, IL-1β, MMP-2, and collagen I were evaluated using immunohistochemistry. ResultsRNA-seq analysis showed 1058 differentially expressed genes. The GO analysis showed these genes were mainly related to the extracellular matrix, and immune response. The KEGG enrichment analysis showed that complement cascades were upregulated. Under normal visual conditions, both genotypes of mice exhibited comparable refractive error and axial length. However, after four weeks of FD, C6-KO mice showed a significantly less myopic shift (−2.28 ± 0.28 D versus −5.40 ± 1.33 D, P = 0.003), and axial shift (0.043 ± 0.032 mm versus 0.083 ± 0.026 mm, P = 0.042) in comparison to WT mice. Furthermore, the levels of C5b-9, NLRP3, caspase-1, IL-1β, and MMP-2 were found to be elevated in the deprived eyes of WT mice in comparison to their fellow eyes, whereas the extent of this increase was significantly lower in C6-KO mice. ConclusionsComplement cascades are activated in FD myopia model. Upregulation of C5b-9 might participate in scleral remodeling during myopia progression via regulation of NLRP3 inflammasome activation.

Stroboscopic Eyewear Applied During Warm-Up Does Not Provide Additional Benefits to the Sport-Specific Reaction Speed in Highly Trained Table Tennis Athletes.

While long-term training with stroboscopic eyewear suggests performance-enhancing effects on visuomotor abilities, it remains unclear whether a short-term application, for example, during a warm-up, results in immediate performance gains. This study evaluated potential performance-enhancing effects of stroboscopic eyewear applied during warm-up on reaction speed that may provide athletes an edge in visuomotor-demanding sports. Twenty-eight international-level table tennis athletes participated in this study. Participants performed their individual 10-minute table-tennis-specific warm-up under normal visual conditions and with stroboscopic eyewear. Prior to and after the warm-up, visuomotor reaction time was assessed in a sport-specific reaction test where athletes had to return 30 table tennis balls played by a ball machine at high speed to their backhand side. Reaction time was determined as the interval between ball output and movement onset as triggered by a mechanical switch. Furthermore, the time between ball-table contact and ball-racket contact (hit time) was analyzed as an indicator of how early the athletes intercepted the ball. Reaction time significantly improved following the warm-up (P < .001, ηp2=.393). However, there was no additional benefit of the stroboscopic eyewear (P = .338, ηp2=.034). No changes after the warm-up were observed for hit time (P = .246, ηp2=.055). The results indicate that warm-up facilitated visuomotor reaction speed; however, stroboscopic eyewear did not provide additional positive effects when compared to a warm-up under normal visual conditions. While shutter glasses may be useful for training over longer periods, short-term positive effects were not supported in this study.

VBLC: Visibility Boosting and Logit-Constraint Learning for Domain Adaptive Semantic Segmentation under Adverse Conditions

Generalizing models trained on normal visual conditions to target domains under adverse conditions is demanding in the practical systems. One prevalent solution is to bridge the domain gap between clear- and adverse-condition images to make satisfactory prediction on the target. However, previous methods often reckon on additional reference images of the same scenes taken from normal conditions, which are quite tough to collect in reality. Furthermore, most of them mainly focus on individual adverse condition such as nighttime or foggy, weakening the model versatility when encountering other adverse weathers. To overcome the above limitations, we propose a novel framework, Visibility Boosting and Logit-Constraint learning (VBLC), tailored for superior normal-toadverse adaptation. VBLC explores the potential of getting rid of reference images and resolving the mixture of adverse conditions simultaneously. In detail, we first propose the visibility boost module to dynamically improve target images via certain priors in the image level. Then, we figure out the overconfident drawback in the conventional cross-entropy loss for self-training method and devise the logit-constraint learning, which enforces a constraint on logit outputs during training to mitigate this pain point. To the best of our knowledge, this is a new perspective for tackling such a challenging task. Extensive experiments on two normal-to-adverse domain adaptation benchmarks, i.e., Cityscapes to ACDC and Cityscapes to FoggyCityscapes + RainCityscapes, verify the effectiveness of VBLC, where it establishes the new state of the art. Code is available at https://github.com/BIT-DA/VBLC.

Effects of various hyperopia intervention levels on male college students' gait kinematics.

Background: Hyperopia is a common blurred vision phenomenon that affects postural control in gait; however, current research has focused on the alteration and correction of hyperopia's physiological characteristics, ignoring the effect of hyperopia on gait kinematic characteristics. The effect of hyperopia on the basic form of movement walking is a worthy concern. Objective: To investigate the gait kinematic characteristics of male college students with varying degrees of visual acuity (normal vision, hyperopia 150°, and hyperopia 450°), as well as to provide a theoretical foundation for the effect of visual acuity on gait and fall risk reduction. Methods: Twenty-two male college students with normal visual acuity were chosen. Their vision was tested using a standard visual acuity logarithm table at normal and with 150° and 450° concave lenses. Gait kinematic data were collected under normal vision and hyperopic conditions using the PN3 Pro advanced inertial motion capture system and Axis Studio application program. Results and conclusion: 1. The change of center of gravity in Pre-double support was smaller than normal vision; Late-single support and Late-swing was larger than normal vision; 2. The percentage of the double-leg support decreased; the percentage of the single-leg support and the Late-swing increased; 3. For the joints' range of motion, Trunk flexion and extension range of motion in Pre-single support, Late-double support and Pre-swing smaller than normal visual acuity, and Late-swing larger than normal; hip internal abduction and adduction and internal and external rotation are larger than normal vision in Late-single support; knee and ankle in abduction and adduction direction are larger than normal vision in the swing stage; hip flexion and extension, internal external rotation are larger than normal vision in the swing stage. Hyperopic interventions have an impact on the kinematic characteristics of gait in male college students, mainly in terms of altered balance, increased instability, increased difficulty in maintaining trunk stability, and increased risk of injury.

Virtual reality set-up for studying vestibular function during head impulse test.

Virtual reality (VR) offers an ecological setting and the possibility of altered visual feedback during head movements useful for vestibular research and treatment of vestibular disorders. There is however no data quantifying vestibulo-ocular reflex (VOR) during head impulse test (HIT) in VR. The main objective of this study is to assess the feasibility and performance of eye and head movement measurements of healthy subjects in a VR environment during high velocity horizontal head rotation (VR-HIT) under a normal visual feedback condition. The secondary objective is to establish the feasibility of VR-HIT recordings in the same group of normal subjects but under altered visual feedback conditions. Twelve healthy subjects underwent video HIT using both a standard setup (vHIT) and VR-HIT. In VR, eye and head positions were recorded by using, respectively, an imbedded eye tracker and an infrared motion tracker. Subjects were tested under four conditions, one reproducing normal visual feedback and three simulating an altered gain or direction of visual feedback. During these three altered conditions the movement of the visual scene relative to the head movement was decreased in amplitude by 50% (half), was nullified (freeze) or was inverted in direction (inverse). Eye and head motion recording during normal visual feedback as well as during all 3 altered conditions was successful. There was no significant difference in VOR gain in VR-HIT between normal, half, freeze and inverse conditions. In the normal condition, VOR gain was significantly but slightly (by 3%) different for VR-HIT and vHIT. Duration and amplitude of head impulses were significantly greater in VR-HIT than in vHIT. In all three altered VR-HIT conditions, covert saccades were present in approximatively one out of four trials. Our VR setup allowed high quality recording of eye and head data during head impulse test under normal and altered visual feedback conditions. This setup could be used to investigate compensation mechanisms in vestibular hypofunction, to elicit adaptation of VOR in ecological settings or to allow objective evaluation of VR-based vestibular rehabilitation.

The effects of using stroboscopic training on sports performance

Stroboscopic training is a form of athletic training during which the individual performs a motor task under intermittently opaque visual conditions. The purpose of this training is to enhance subsequent performance under normal visual conditions as a result of shifting attentional focus within the multisensory integration process. The training performed with the help of this technology that uses specially designed glasses increases the contribution of other somatosensory afferents to motor control by refocusing the individual’s attention on proprioceptive feedback. Other benefits of stroboscopic training include improved short-term visual memory, improved capacity for anticipation as well as increased ability to focus in general but particularly on the central visual field and thus produce coherent movements. The current paper is a metaanalysis of the literature on stroboscopic training and its benefits for professional sport. In sports using stroboscopic (strobe) glasses, for example in hockey, basketball, football, volleyball, baseball or tennis, positive effects on some skills have been identified and training and testing protocols have been described. The aim of this paper is to highlight some practical and methodological benchmarks resulting from the use of stroboscopic training in various sports, and then transfer them to climbing training in order to enhance performance in this sport.

Without low spatial frequencies, high resolution vision would be detrimental to motion perception.

A normally sighted person can see a grating of 30 cycles per degree or higher, but spatial frequencies needed for motion perception are much lower than that. It is unknown for natural images with a wide spectrum how all the visible spatial frequencies contribute to motion speed perception. In this work, we studied the effect of spatial frequency content on motion speed estimation for sequences of natural and stochastic pixel images by simulating different visual conditions, including normal vision, low vision (low-pass filtering), and complementary vision (high-pass filtering at the same cutoff frequencies of the corresponding low-vision conditions) conditions. Speed was computed using a biological motion energy-based computational model. In natural sequences, there was no difference in speed estimation error between normal vision and low vision conditions, but it was significantly higher for complementary vision conditions (containing only high-frequency components) at higher speeds. In stochastic sequences that had a flat frequency distribution, the error in normal vision condition was significantly larger compared with low vision conditions at high speeds. On the contrary, such a detrimental effect on speed estimation accuracy was not found for low spatial frequencies. The simulation results were consistent with the motion direction detection task performed by human observers viewing stochastic sequences. Together, these results (i) reiterate the importance of low frequencies in motion perception, and (ii) indicate that high frequencies may be detrimental for speed estimation when low frequency content is weak or not present.

Validation of the International Reading Speed Texts in a Canadian Sample.

The International Reading Speed Texts (IReST) is a valid measure of reading speed in a Canadian sample. However, if clinicians desire to assess reading comprehension using the IReST, this will significantly reduce reading speeds of individuals with normal vision or reduced visual acuity and therefore should use the values presented here. The purposes of this study are (1) to validate the IReST in an English-speaking Canadian sample and (2) to examine how reading comprehension questions and reduced visual acuity affect reading speed on the IReST. For study 1, Canadian English speakers (n = 25) read all 10 IReST following the procedures used in the original IReST validation. For study 2, Canadian English speakers (n = 50) read all 10 IReST, half with normal/corrected-to-normal vision and half with reduced visual acuity, and were asked reading comprehension questions. No significant differences were found between Canadian sample and the published IReST values (in all cases, P > .05; mean difference [Mdiff] = -5.30 to +11.43; Cohen d = -0.15 to +0.27; Bayes factors = 0.41, 0.09). Assessing reading comprehension with multiple-choice questions on the IReST significantly reduced reading speeds in the normal vision condition (Mdiff = 25.3; 95% confidence interval, -16.7 to -34.1) and in the simulated impairment condition (Mdiff = 59.3; 95% confidence interval, -47.7 to -71). The IReST is a valid measure that can be used to assess reading speed in a Canadian English-speaking sample. If researchers/clinicians wish to assess both reading speed and comprehension, using multiple-choice reading comprehension questions, then the values provided by the IReST will likely underestimate an individual's true reading speed in individuals with normal/corrected-to-normal vision or reduced visual acuity.

Balance assessment in healthy children and adolescents aged 6–18 years based on six tests collected on AMTI AccuSway force platform

The aim of the study was to compare the results of six balance tests collected on AMTI AccuSway Plus ACS force platform between healthy female and male children and adolescents. We also searched for possible correlation of the balance measures with subjects' age. 228 healthy 6- to 18-year-old subjects (111 boys and 117 girls) participated in the study. Six balance tests were performed with the use of AMTI AccuSway Plus ACS platform: quiet standing for 30s, maximal voluntary sways of the body in the sagittal plane (anterior-posterior - AP test) for 30 s, and in the frontal plane (left-right - ML test) for 30s. All tests were performed in two conditions: eyes open and eyes closed. During quiet standing with eyes open, most balance measures were lower in girls ( p < 0.05). In AP and ML tests with eyes open, a few balance parameters were different between boys and girls ( p < 0.05). In quiet standing, AP and ML tests with eyes closed, there were no between-gender differences ( p > 0.05). In quiet standing with eyes open and closed most balance parameters were negatively correlated with age ( p < 0.05). Quiet standing postural sway characteristics depended on gender under normal visual conditions and it was similar in boys and girls under visual deprivation conditions. The vision was differently used by females and males in balance tasks. Static postural stability improved with age regardless of visual conditions.

Optimisation of Lighting Parameters of Irradiation in Light Culture of Lettuce Plants Using LED Emitters

The results of the ending phase of photo biological studies of capacity of lettuce and basil grown in conditions of a phytotron with irradiation by radiation of different ratio of fractions in the red-blue and blue-green-red regions of photosynthetic active radiation (PAR) are presented. The spectral variants of PAR providing the maximum or near to maximum capacity of the specified cultures are found. The complex and multiple-valued nature of effect of main PAR spectral regions on photo energetic and photo regulatory processes in plants providing their capacity is highlighted, which makes it impossible to determine common unified requirements to optimal parameters of artificial irradiation for growing of plants. These requirements shall be defined on the basis of direct photo biological experiments with main species of agricultural plants and be the most important element of the general photo culture macro technology. The general principles of fulfilment of the specified requirements to PAR spectra of phytoemitters are reviewed, including with consideration of setting of normal vision conditions for personnel of greenhouses and other protected ground structures.

The Effect of 4-Week Stroboscopic Training on Visual Function and Sport-Specific Visuomotor Performance in Top-Level Badminton Players

Stroboscopic training is suggested to improve visuomotor abilities in sports. However, previous research has primarily focused on untrained participants and only considered behavioral data. Because visuomotor performance is substantially determined by neural visual processes, this study aimed to examine the effects of stroboscopic training on visuomotor performance and neural visual function of athletes. A total of 10 German top-level badminton players (intervention: n = 5 and control: n = 5) participated in this study. Over a 4-week training period, athletes performed badminton-specific visuomotor tasks either wearing shutter glasses (intervention) or under normal visual conditions (control). Prior to and after the training period, behavioral smash-defense tests and neurophysiologic investigations of the N2 motion onset visual evoked potential were used to identify modulations in the athletes' visuomotor performance and visual perception speed, respectively. Badminton training improved visuomotor performance in both groups; however, stroboscopic training resulted in superior posttraining performance compared with normal visual conditions (P = .007). Training-induced modulations in N2 latency did not reach significance, although a strong relationship was observed between changes in N2 latency and changes in visuomotor performance (r = -.55), indicating that higher performance gains following training were associated with a stronger reduction in N2 latency. The results indicate that stroboscopic training may be more effective than conventional visuomotor training for improving visuomotor abilities even in athletes performing at high skill levels. Furthermore, visuomotor performance gains could potentially be mediated by neural adaptations in the visual motion system. These findings should be confirmed for athletes from different disciplines.

Lack of cone mediated retinal function increases susceptibility to form-deprivation myopia in mice

Retinal photoreceptors are important in visual signaling for normal eye growth in animals. We used Gnat2cplf3/cplf3 (Gnat2−/−) mice, a genetic mouse model of cone dysfunction to investigate the influence of cone signaling in ocular refractive development and myopia susceptibility in mice. Refractive development under normal visual conditions was measured for Gnat2−/− and age-matched Gnat2+/+ mice, every 2 weeks from 4 to 14 weeks of age. Weekly measurements were performed on a separate cohort of mice that underwent monocular form-deprivation (FD) in the right eye from 4 weeks of age using head-mounted diffusers. Refraction, corneal curvature, and ocular biometrics were obtained using photorefraction, keratometry and optical coherence tomography, respectively. Retinas from FD mice were harvested, and analyzed for dopamine (DA) and 3,4-dihydroxyphenylacetate (DOPAC) using high-performance liquid chromatography. Under normal visual conditions, Gnat2+/+ and Gnat2−/− mice showed similar refractive error, axial length, and corneal radii across development (p > 0.05), indicating no significant effects of the Gnat2 mutation on normal ocular refractive development in mice. Three weeks of FD produced a significantly greater myopic shift in Gnat2−/− mice compared to Gnat2+/+ controls (−5.40 ± 1.33 D vs −2.28 ± 0.28 D, p = 0.042). Neither the Gnat2 mutation nor FD altered retinal levels of DA or DOPAC. Our results indicate that cone pathways needed for high acuity vision in primates are not as critical for normal refractive development in mice, and that both rods and cones contribute to visual signalling pathways needed to respond to FD in mammalian eyes.

How highlighted utensils influence consumption in a dark setting

Objective: Previous research has shown that people consume less food in the dark compared to normal vision conditions. While this effect is commonly attributed to increased attention to internal cues, it could also be caused by increased difficulty to maneuver in a dark setting. This study investigated this potential alternative explanation.Design: A 2 (dark versus normal vision setting) × 2 (highlighted versus non-highlighted utensils) between-subjects design was employed.Main outcome measures: Perceived difficulty of maneuvering and consumption of yoghurt were assessed as main outcome measures.Results: Participants consumed marginally less in dark compared to normal vision conditions, and experienced higher difficulty of maneuvering. Importantly, both effects were qualified by a significant interaction with highlighting, which increased consumption and reduced perceived difficulty compared to no highlights. Difficulty of maneuvering did not mediate the interactive effect of vision and highlighting on consumption.Conclusion: Difficulty to maneuver should be considered when investigating eating behaviour under dark conditions. In line with an embodied cognition account, results also reveal the necessity of visual information for interaction with objects in the environment and imply that detail-deprived object information may be sufficient for activation of the motor system.

Stroboscopic vision and sustained attention during coincidence-anticipation

We compared coincidence-anticipation performance in normal vision and stroboscopic vision as a function of time-on-task. Participants estimated the arrival time of a real object that moved with constant acceleration (−0.7, 0, +0.7 m/s2) in a pseudo-randomised order across 4 blocks of 30 trials in both vision conditions, received in a counter-balanced order. Participants (n = 20) became more errorful (accuracy and variability) in the normal vision condition as a function of time-on-task, whereas performance was maintained in the stroboscopic vision condition. We interpret these data as showing that participants failed to maintain coincidence-anticipation performance in the normal vision condition due to monotony and attentional underload. In contrast, the stroboscopic vision condition placed a greater demand on visual-spatial memory for motion extrapolation, and thus participants did not experience the typical vigilance decrement in performance. While short-term adaptation effects from practicing in stroboscopic vision are promising, future work needs to consider for how long participants can maintain effortful processing, and whether there are negative carry-over effects from cognitive fatigue when transferring to normal vision.

BDNF expression in cat striate cortex is regulated by binocular pattern deprivation

Deprivation of patterned visual information, as in early onset congenital cataract patients, results in a severe impairment in global motion perception. Previously we reported a delayed maturation of the peripheral visual field representation in primary visual area 17, based on a 2-D DIGE screen for protein expression changes and in situ hybridization for the activity reporter gene ZIF268. To corroborate these findings we here explore the binocular pattern deprivation (BD)-regulated expression of brain-derived neurotrophic factor (BDNF), a well-described neurotrophin precipitously regulated by early visual experience. To assess the timing of maturation-related BDNF expression we compared the central and the peripheral visual field representations of area 17 of 1, 2, 4 and 6-month-old and adult cats reared under normal visual conditions. To scrutinize the outcome of BD, four different deprivation strategies were compared, including early onset BD from birth and lasting for 2, 4 or 6 months (2BD, 4BD, 6BD), and late onset BD for 2 months upon 2 months of normal vision (2N2BD), as animal models of congenital and delayed onset cataract. During normal cortical development the BDNF transcript levels, measured by quantitative RT-PCR, remained stable. Higher BDNF mRNA levels were found in central area 17 of 2BD and 6BD animals compared to age-matched controls. In central area 17, the high BDNF mRNA levels at the end of the BD period may activate a mechanism by which plastic processes, halted by deprivation, may begin. We here confirm that the peripheral visual field representation of area 17 matures slower than its central counterpart. Only in central area 17 normal visual input upon BD could upregulate BDNF mRNA which may lead to a fast activation of local plastic adaptations.

Development of postural balance in Brazilian children aged 4-10 years compared to young adults

DOI: http://dx.doi.org/10.5007/1980-0037.2016v18n4p419 The aim of the present study was to analyze the development of postural balance in 4- to 10-year-old Brazilian children, compared to a group of young adults under normal and deprived visual conditions. Body sway was assessed through average velocity and sway range at the center of pressure (CoP) in the anteroposterior and medio-lateral directions, obtained on a force platform (AMTI, Inc.). Sample was composed of 153 children (of seven different age groups) and 47 adults. Inter-group comparisons were performed using one-way ANOVA and Tukey’s post-hoc test at 5% significance level. The results showed that starting at 9 and 10 years of age, CoP velocity and displacement values for children were similar to values for adults under restricted visual conditions; however, there were differences between children and adults. The findings suggest that visual stimulation plays a prominent role in the balance of individuals up to 10 years of age, with significant evidence that postural balance is not fully developed up to that age.