Visual Neuropsychology in Development: Anatomo-Functional Brain Mechanisms of Action/Perception Binding in Health and Disease

A study on the difference between functional connectivity in elbow flexion and extension according to object weight

In this study, the results of functional connectivity between various areas were extracted when flexion and extension of the elbow were repeatedly performed with 500 g and 1000 g balls in hand. All subjects performed elbow bending and stretching at an angle of 90 degrees with the right back of their hand facing down. A total of 30 bending and stretching exercises were performed for 1 minute. At this time, the experiment was carried out under 2 conditions: (500 g motion) when performing the exercise with a 500-g object in the right hand and a 1000 g object (1000 g motion). To process functional magnetic resonance imaging data, we used the Functional Connectivity (CONN) toolbox, which was implemented in Statistical Parametric Mapping software version 12. Visual.lateral (right, R)-Visual.medial, Visual.medical-Visual.occipital, SensoriMotor.superior-SensoriMotor.lateral (left, L), FrontoParital.lateral prefrontal cortex (R)-FrontoParital.posterior cingulate cortex (R), and DorsalAttention.intraparietal sulcus (R)-SensoriMotor.superior connection reduced the effect size when flexion and extension of the elbow joint with 1000 g objects more than 500 g objects were carried out. On the other hand, when the task was performed with 1000 g objects rather than 500 g, the effect size of Visual.lateral (L)-Visual.medial, Salience.supramarginal gyrus (L)-DorsalAttention.intraparietal sulcus (R), Language.posterior superior temporal gyrus (L)-Language.inferior frontal gyrus (L), and Salience.AInsula (L)-Salience.AInsula (R) connection increased. The connection that showed the highest correlation coefficient when performing elbow exercise with a 500 g object was DorsalAttention.frontal eye fields (L)-SensoriMotor.superior, Language.inferior frontal gyrus (L)-Language.inferior frontal gyrus (R), and DorsalAttention.intraparietal sulcus (R)-SensoriMotor.lateral. On the other hand, when performing elbow exercises with 1000 g of objects, the highest correlation coefficients were Language.posterior superior temporal gyrus (L)-Language.posterior superior temporal gyrus (R), and Salience.supramarginal gyrus (R)-DorsalAttention.intraparietal sulcus (R). In conclusion, these findings suggest that the brain adapts its functional connectivity patterns in response to changes in physical load during motor tasks, potentially implicating different cognitive and sensorimotor processes depending on the exertion level required by the task. This has implications for understanding the neural mechanisms underlying motor control and could inform rehabilitation strategies for motor impairments.

Body-Related Visual Biasing Affects Accuracy of Reaching

Background: Many daily activities depend on visual inputs to improve motor accuracy and minimize errors. Reaching tasks present an ecological framework for examining these visuomotor interactions, but our comprehension of how different amounts of visual input affect motor outputs is still limited. The present study fills this gap, exploring how hand-related visual bias affects motor performance in a reaching task (to draw a line between two dots). Methods: Our setup allowed us to show and hide the visual feedback related to the hand position (cursor of a computer mouse), which was further disentangled from the visual input related to the task (tip of the line). Results: Data from 53 neurotypical participants indicated that, when the hand-related visual cue was visible and disentangled from the task-related visual cue, accommodating movements in response to spatial distortions were less accurate than when the visual cue was absent. Conclusions: We interpret these findings with reference to the concepts of motor affordance of visual cues, shifts between internally- and externally-oriented cognitive strategies to perform movements, and body-related reference frames.

Neuroscientific insights about computer vision models: a concise review

The development of biologically-inspired computational models has been the focus of study ever since the artificial neuron was introduced by McCulloch and Pitts in 1943. However, a scrutiny of literature reveals that most attempts to replicate the highly efficient and complex biological visual system have been futile or have met with limited success. The recent state-of the-art computer vision models, such as pre-trained deep neural networks and vision transformers, may not be biologically inspired per se. Nevertheless, certain aspects of biological vision are still found embedded, knowingly or unknowingly, in the architecture and functioning of these models. This paper explores several principles related to visual neuroscience and the biological visual pathway that resonate, in some manner, in the architectural design and functioning of contemporary computer vision models. The findings of this survey can provide useful insights for building futuristic bio-inspired computer vision models. The survey is conducted from a historical perspective, tracing the biological connections of computer vision models starting with the basic artificial neuron to modern technologies such as deep convolutional neural network (CNN) and spiking neural networks (SNN). One spotlight of the survey is a discussion on biologically plausible neural networks and bio-inspired unsupervised learning mechanisms adapted for computer vision tasks in recent times.

Dyslexia Due to Visual Impairments

Reading involves many different abilities that are necessary or sufficient conditions for fluent and flawless reading. The absence of one necessary or of all sufficient conditions is a cause of dyslexia. The present study investigates whether too short fixation times and an impaired ability to recognize a string of letters simultaneously are causes of dyslexia. The frequency and types of reading mistakes were investigated in a tachistoscopic pseudoword experiment with 100 children with dyslexia to test the impact of too short fixation times and the attempts of children with dyslexia to recognize more letters simultaneously than they can when reading pseudowords. The experiment demonstrates that all types of reading mistakes disappear when the fixation time increases and/or the number of letters that the children try to recognize simultaneously is reduced. The results cannot be interpreted as being due to altered visual crowding, impaired attention, or impaired phonological awareness, but can be regarded as an effect of impaired temporal summation and a dysfunction in the ventral stream of the visual system.

Effects of school indoor visual environment on children's health outcomes: A systematic review

Children's visual perceptions are critical for their comfort and health. This review explores the impacts of school indoor visual environment on children's health outcomes. A systematic search yielded 5704 articles, of which 32 studies were reviewed. Five environmental themes were identified: lighting, access to nature, window characteristics, art/environmental aesthetics, and ergonomics/spatial arrangement. Results affirm that visual environment affects children's health. There are disparities across environmental themes, with more extensive evidence for lighting and access to nature, but relatively limited in other areas. This study suggests a need for multi-disciplinary collaboration to develop a holistic perspective.

Gut Microbiome Dysbiosis as a Potential Risk Factor for Idiopathic Toe-Walking in Children: A Review

Idiopathic toe walking (ITW) occurs in about 5% of children. Orthopedic treatment of ITW is complicated by the lack of a known etiology. Only half of the conservative and surgical methods of treatment give a stable positive result of normalizing gait. Available data indicate that the disease is heterogeneous and multifactorial. Recently, some children with ITW have been found to have genetic variants of mutations that can lead to the development of toe walking. At the same time, some children show sensorimotor impairment, but these studies are very limited. Sensorimotor dysfunction could potentially arise from an imbalanced production of neurotransmitters that play a crucial role in motor control. Using the data obtained in the studies of several pathologies manifested by the association of sensory-motor dysfunction and intestinal dysbiosis, we attempt to substantiate the notion that malfunction of neurotransmitter production is caused by the imbalance of gut microbiota metabolites as a result of dysbiosis. This review delves into the exciting possibility of a connection between variations in the microbiome and ITW. The purpose of this review is to establish a strong theoretical foundation and highlight the benefits of further exploring the possible connection between alterations in the microbiome and TW for further studies of ITW etiology.

Visual Motor Reaction Times Predict Receptive and Expressive Language Development in Early School-Age Children

Proficiency of multisensory processing and motor skill are often associated with early cognitive, social, and language development. However, little research exists regarding the relationship between multisensory motor reaction times (MRTs) to auditory, visual and audiovisual stimuli, and classical measures of receptive language and expressive vocabulary development in school-age children. Thus, this study aimed to examine the concurrent development of performance in classical tests of receptive (Peabody Picture Vocabulary Test; abbreviated as PPVT) and expressive vocabulary (Expressive Vocabulary Test; abbreviated as EVT), nonverbal intelligence (NVIQ) (determined with the aid of Raven's Colored Progressive Matrices; abbreviated as RCPM), speed of visual-verbal processing in the Rapid Automatic Naming (RAN) test, Eye-Hand Co-ordination (EHC) in the SLURP task, and multisensory MRTs, in children (n = 75), aged between 5 and 10 years. Bayesian statistical analysis showed evidence for age group differences in EVT performance, while PPVT was only different for the youngest group of children aged 5-6, supporting different developmental trajectories in vocabulary acquisition. Bayesian correlations revealed evidence for associations between age, NVIQ, and vocabulary measures, with decisive evidence and a higher correlation (r = 0.57 to 0.68) between EVT, MRT tasks, and EHC visuomotor processing. This was further supported by regression analyses indicating that EVT performance was the strongest unique predictor of multisensory MRTs, EHC, and RAN time. Additionally, visual MRTs were found to predict both receptive and expressive vocabulary. The findings of the study have important implications as accessible school-based assessments of the concurrent development of NVIQ, language, and multisensory processing; and hence as rapid and timely measures of developmental and neurodevelopmental status.

Reliability of a Smooth Pursuit Eye-Tracking System (EyeGuide Focus) in Healthy Adolescents and Adults

Mild traumatic brain injury (mTBI) is the most common brain injury, seen in sports, fall, vehicle, or workplace injuries. Concussion is the most common type of mTBI. Assessment of impairments from concussion is evolving, with oculomotor testing suggested as a key component in a multimodality diagnostic protocol. The aim of this study was to evaluate the reliability of one eye-tracking system, the EyeGuide Focus. A group of 75 healthy adolescent and adult participants (adolescents: n = 28; female = 11, male = 17, mean age 16.5 ± 1.4 years; adults n = 47; female = 22; male = 25, mean age 26.7 ± 7.0 years) completed three repetitions of the EyeGuide Focus within one session. Intraclass correlation coefficient (ICC) analysis showed the EyeGuide Focus had overall good reliability (ICC 0.79, 95%CI: 0.70, 0.86). However, a familiarization effect showing improvements in subsequent trials 2 (9.7%) and 3 (8.1%) was noticeable in both cohorts (p < 0.001) with adolescent participants showing greater familiarization effects than adults (21.7% vs. 13.1%). No differences were observed between sexes (p = 0.69). Overall, this is the first study to address the concern regarding a lack of published reliability studies for the EyeGuide Focus. Results showed good reliability, suggesting that oculomotor pursuits should be part of a multimodality assessment protocol, but the observation of familiarization effects suggests that smooth-pursuit testing using this device has the potential to provide a biologically-based interpretation of the maturation of the oculomotor system, as well as its relationship to multiple brain regions in both health and injury.

Electrophysiological Evidence for Interhemispheric Connectivity and Communication in Young Human Infants

Little is known empirically about connectivity and communication between the two hemispheres of the brain in the first year of life, and what theoretical opinion exists appears to be at variance with the meager extant anatomical evidence. To shed initial light on the question of interhemispheric connectivity and communication, this study investigated brain correlates of interhemispheric transmission of information in young human infants. We analyzed EEG data from 12 4-month-olds undergoing a face-related oddball ERP protocol. The activity in the contralateral hemisphere differed between odd-same and odd-difference trials, with the odd-different response being weaker than the response during odd-same trials. The infants' contralateral hemisphere "recognized" the odd familiar stimulus and "discriminated" the odd-different one. These findings demonstrate connectivity and communication between the two hemispheres of the brain in the first year of life and lead to a better understanding of the functional integrity of the developing human infant brain.

Electrophysiological Evidence Reveals the Asymmetric Transfer from the Right to Left Hemisphere as Key to Reading Proficiency

The present investigation aimed to explore the interhemispheric interactions that contribute to changes in reading proficiency by examining the processing of visual word recognition in relation to word familiarity. A lexical decision task was administered to 25 participants, and their electrophysiological activity was recorded. A behavioral analysis showed the faster and more accurate processing of highly familiar words compared to less familiar ones. An event-related potential analysis uncovered an asymmetric familiarity effect over the N100 and N400 components across the two hemispheres, indicating an asymmetrical word familiarity processing. Granger causality analyses demonstrated a stronger transfer of information from the right hemisphere (RH) to the left hemisphere (LH) during the N100 processing and a weaker transfer from the LH to the RH during the N400 processing for highly familiar word recognition. These findings suggest that the asymmetric coordination between the RH and LH occurs early in visual word recognition and highlight the importance of interhemispheric interactions in efficient visual word recognition and proficient reading.

The Contribution of Visual and Auditory Working Memory and Non-Verbal IQ to Motor Multisensory Processing in Elementary School Children

Although cognitive abilities have been shown to facilitate multisensory processing in adults, the development of cognitive abilities such as working memory and intelligence, and their relationship to multisensory motor reaction times (MRTs), has not been well investigated in children. Thus, the aim of the current study was to explore the contribution of age-related cognitive abilities in elementary school-age children (n = 75) aged 5-10 years, to multisensory MRTs in response to auditory, visual, and audiovisual stimuli, and a visuomotor eye-hand co-ordination processing task. Cognitive performance was measured on classical working memory tasks such as forward and backward visual and auditory digit spans, and the Raven's Coloured Progressive Matrices (RCPM test of nonverbal intelligence). Bayesian Analysis revealed decisive evidence for age-group differences across grades on visual digit span tasks and RCPM scores but not on auditory digit span tasks. The results also showed decisive evidence for the relationship between performance on more complex visually based tasks, such as difficult items of the RCPM and visual digit span, and multisensory MRT tasks. Bayesian regression analysis demonstrated that visual WM digit span tasks together with nonverbal IQ were the strongest unique predictors of multisensory processing. This suggests that the capacity of visual memory rather than auditory processing abilities becomes the most important cognitive predictor of multisensory MRTs, and potentially contributes to the expected age-related increase in cognitive abilities and multisensory motor processing.

Preschool Children’s Processing of Events during Verb Learning: Is the Focus on People (Faces) or Their Actions (Hands)?

Verbs are central to the syntactic structure of sentences, and, thus, important for learning one’s native language. This study examined how children visually inspect events as they hear, and do not hear, a new verb. Specifically, there is evidence that children may focus on the agent of the action or may prioritize attention to the action being performed; to date, little evidence is available. This study used an eye tracker to track 2-, 3-, and 4-year-olds’ looking to the agent (i.e., face) vs. action (i.e., hands) while viewing events linked to a new verb as well as distractor events. A Tobii X30 eye tracker recorded children’s fixations to AOIs (head/face and hands) as they watched three target events and two distractor events in different orders during the learning phase, and pointed to one of two events in two test trials. This was repeated for a second novel verb. Pointing results show that children in all age groups were able to learn and extend the new verbs to new events at test. Additionally, across age groups, when viewing target events, children increased their looking to the hands (where the action is taking place) as those trials progressed and decreased their looking to the agents’ face, which is less informative for learning a new verb’s meaning. In contrast, when viewing distractor events, children decreased their looking to hands over trials and maintained their attention to the face. In summary, children’s visual attention to agents’ faces and hands differed depending on whether the events cooccurred with the new verb. These results are important as this is the first study to show this pattern of visual attention during verb learning, and, thus, these results help reveal underlying attentional strategies children may use when learning verbs.

Neuro-Behavioral Correlates of Executive Dysfunctions in Dyslexia Over Development From Childhood to Adulthood

Dyslexia is a neurobiological learning disability in the reading domain that has symptoms in early childhood and persists throughout life. Individuals with dyslexia experience difficulties in academia and cognitive and emotional challenges that can affect wellbeing. Early intervention is critical to minimize the long-term difficulties of these individuals. However, the behavioral and neural correlates which predict dyslexia are challenging to depict before reading is acquired. One of the precursors for language and reading acquisition is executive functions (EF). The present review aims to highlight the current atypicality found in individuals with dyslexia in the domain of EF using behavioral measures, brain mapping, functional connectivity, and diffusion tensor imaging along development. Individuals with dyslexia show EF abnormalities in both behavioral and neurobiological domains, starting in early childhood that persist into adulthood. EF impairment precedes reading disability, therefore adding an EF assessment to the neuropsychological testing is recommended for early intervention. EF training should also be considered for the most comprehensive outcomes.