Action video games and posterior parietal cortex neuromodulation enhance both attention and reading in adults with developmental dyslexia.

The impact of action video games on reading performance has been already demonstrated in individuals with and without neurodevelopmental disorders. The combination of action video games and posterior parietal cortex neuromodulation by a transcranial random noise stimulation could enhance brain plasticity, improving attentional control and reading skills also in adults with developmental dyslexia. In a double blind randomized controlled trial, 20 young adult nonaction video game players with developmental dyslexia were trained for 15 h with action video games. Half of the participants were stimulated with bilateral transcranial random noise stimulation on the posterior parietal cortex during the action video game training, whereas the others were in the placebo (i.e. sham) condition. Word text reading, pseudowords decoding, and temporal attention (attentional blink), as well as electroencephalographic activity during the attentional blink, were measured before and after the training. The action video game + transcranial random noise stimulation group showed temporal attention, word text reading, and pseudoword decoding enhancements and P300 amplitude brain potential changes. The enhancement in temporal attention performance was related with the efficiency in pseudoword decoding improvement. Our results demonstrate that the combination of action video game training with parietal neuromodulation increases the efficiency of visual attention deployment, probably reshaping goal-directed and stimulus-driven fronto-parietal attentional networks interplay in young adults with neurodevelopmental conditions.

Perception of complex Glass patterns through spatial summation across unique frames.

When processing visual information from the surroundings, human vision depends on the constant integration of form and motion cues. Dynamic Glass patterns (GPs) may be used to study how such visual integration occurs in the human visual system. Dynamic GPs are visual stimuli composed of two or more unique frames consisting of different configurations of dot pairs, called dipoles, presented in rapid succession. Previous psychophysical studies showed that the discrimination of translational and circular dynamic GPs is influenced by both the number of unique frames and the pattern update rate. In this study, we manipulated these two variables to assess their influence on the discrimination threshold of circular, radial, and spiral GPs, partially replicating previous findings on circular GPs. Our results indicate that circular GPs are more easily perceived than radial and spiral GPs, showing lower discrimination thresholds. Furthermore, we found that discrimination thresholds vary as a function of the number of unique frames but not as a function of the pattern update rate. Specifically, coherence thresholds decreased with increasing the number of unique frames. In conclusion, our findings support the existence of spatial summation of form signals coming from the unique frames that generate complex GPs. On the other hand, they do not support temporal integration of local form-motion signals based on the pattern update rate.

Cognitive benefits of the attentional vs exergame training in older adults.

OBJECTIVE: The present study aimed at comparing the effectiveness of an Attentional Computerized Cognitive Training and a commercial Exergame Training. METHODS: Eighty-four healthy older adults took part in the study. They were randomly assigned to one of the following conditions: Attentional Computerized Cognitive Training (ATT-CCT), Exergame Training (EXERG-T), or passive Control Group (CG). Participants assigned to the experimental groups underwent 8 laboratory-based sessions-lasting approximately 45 min each-of the respective training activity. A battery of cognitive tests was assessed before, after, and 3 months following the intervention phase. RESULTS: The results showed that just the ATT-CCT improved participants' performance, specifically within attention, processing speed, verbal learning and memory. While both intervention groups revealed improved memory self-perception and decreased self-reported absent-mindedness, only the benefits following the ATT-CCT proved to be stable over time. CONCLUSIONS: The results suggested that our ATT-CCT may be an effective tool for enhancing cognitive abilities in older healthy adults.

The effects of bilateral posterior parietal cortex tRNS on reading performance.

According to established cognitive neuroscience knowledge based on studies on disabled and typically developing readers, reading is based on a dual-stream model in which a phonological-dorsal stream (left temporo-parietal and inferior frontal areas) processes unfamiliar words and pseudowords, whereas an orthographic-ventral stream (left occipito-temporal and inferior frontal areas) processes known words. However, correlational neuroimaging, causal longitudinal, training, and pharmacological studies have suggested the critical role of visuo-spatial attention in reading development. In a double blind, crossover within-subjects experiment, we manipulated the neuromodulatory effect of a short-term bilateral stimulation of posterior parietal cortex (PPC) by using active and sham tRNS during reading tasks in a large sample of young adults. In contrast to the dual-stream model predicting either no effect or a selective effect on the stimulated phonological-dorsal stream (as well as to a general multisensory effect on both reading streams), we found that only word-reading performance improved after active bilateral PPC tRNS. These findings demonstrate a direct neural connectivity between the PPC, controlling visuo-spatial attention, and the ventral stream for visual word recognition. These results support a neurobiological model of reading where performance of the orthographic-ventral stream is boosted by an efficient deployment of visuo-spatial attention from bilateral PPC stimulation.

Effects of exergames on mood and cognition in healthy older adults: A randomized pilot study.

The elderly population is increasing and the implementation of stimulating training to promote active aging has become a research issue. This study aimed at investigating the effects of a cognitive-motor exergame training on cognitive functions and mood, in healthy older adults. A randomized controlled pilot study was conducted to compare a cognitive-motor exergame training with a passive control group. The training consisted of 8 sessions of 45 min each, including 10 interactive activities focused on several cognitive functions such as memory, processing speed and executive functions, all requiring motor planning and execution. A total of 57 participants were administered a battery of cognitive tests before and after the training. A mixed-effect ANOVA with group (experimental vs. control) as between factor and time (pre-and post-test) as within factor, was performed to evaluate the effect of the exergame training on cognitive abilities and mood. Results showed significant interaction effects in processing speed [STROOPC: F (1,53.4) = 9.04, p = 0.004, R 2 = 0.82], inhibition [3backs' false alarms: F (1,47.5) = 5.5, p = 0.02, R 2 = 0.79], and mood [Beck Depression Inventory: F (1,55) = 4.15, p = 0.04, R 2 = 0.6]. Even though post-hoc analyses did not provide statistical evidence supporting the interactions, overall data showed a trend toward better scores only for the experimental group, suggesting a potential improvement in information processing speed, working memory and mood. Exergaming may be a motivating and enjoyable approach to healthy and active aging.

Mechanisms Underlying Directional Motion Processing and Form-Motion Integration Assessed with Visual Perceptual Learning.

Dynamic Glass patterns (GPs) are visual stimuli commonly employed to study form-motion interactions. There is brain imaging evidence that non-directional motion induced by dynamic GPs and directional motion induced by random dot kinematograms (RDKs) depend on the activity of the human motion complex (hMT+). However, whether dynamic GPs and RDKs rely on the same processing mechanisms is still up for dispute. The current study uses a visual perceptual learning (VPL) paradigm to try to answer this question. Identical pre- and post-tests were given to two groups of participants, who had to discriminate random/noisy patterns from coherent form (dynamic GPs) and motion (RDKs). Subsequently, one group was trained on dynamic translational GPs, whereas the other group on RDKs. On the one hand, the generalization of learning to the non-trained stimulus would indicate that the same mechanisms are involved in the processing of both dynamic GPs and RDKs. On the other hand, learning specificity would indicate that the two stimuli are likely to be processed by separate mechanisms possibly in the same cortical network. The results showed that VPL is specific to the stimulus trained, suggesting that directional and non-directional motion may depend on different neural mechanisms.

Visual Short-Term Memory for Coherent and Sequential Motion: A rTMS Investigation.

We investigated the role of the human medio-temporal complex (hMT+) in the memory encoding and storage of a sequence of four coherently moving random dot kinematograms (RDKs), by applying repetitive transcranial magnetic stimulation (rTMS) during an early or late phase of the retention interval. Moreover, in a second experiment, we also tested whether disrupting the functional integrity of hMT+ during the early phase impaired the precision of the encoded motion directions. Overall, results showed that both recognition accuracy and precision were worse in middle serial positions, suggesting the occurrence of primacy and recency effects. We found that rTMS delivered during the early (but not the late) phase of the retention interval was able to impair not only recognition of RDKs, but also the precision of the retained motion direction. However, such impairment occurred only for RDKs presented in middle positions along the presented sequence, where performance was already closer to chance level. Altogether these findings suggest an involvement of hMT+ in the memory encoding of visual motion direction. Given that both position sequence and rTMS modulated not only recognition but also the precision of the stored information, these findings are in support of a model of visual short-term memory with a variable resolution of each stored item, consistent with the assigned amount of memory resources, and that such item-specific memory resolution is supported by the functional integrity of area hMT+.

Speech Fluency Improvement in Developmental Stuttering Using Non-invasive Brain Stimulation: Insights From Available Evidence.

Developmental stuttering (DS) is a disturbance of the normal rhythm of speech that may be interpreted as very debilitating in the most affected cases. Interventions for DS are historically based on the behavioral modifications of speech patterns (e.g., through speech therapy), which are useful to regain a better speech fluency. However, a great variability in intervention outcomes is normally observed, and no definitive evidence is currently available to resolve stuttering, especially in the case of its persistence in adulthood. In the last few decades, DS has been increasingly considered as a functional disturbance, affecting the correct programming of complex motor sequences such as speech. Compatibly, understanding of the neurophysiological bases of DS has dramatically improved, thanks to neuroimaging, and techniques able to interact with neural tissue functioning [e.g., non-invasive brain stimulation (NIBS)]. In this context, the dysfunctional activity of the cortico-basal-thalamo-cortical networks, as well as the defective patterns of connectivity, seems to play a key role, especially in sensorimotor networks. As a consequence, a direct action on the functionality of "defective" or "impaired" brain circuits may help people who stutter to manage dysfluencies in a better way. This may also "potentiate" available interventions, thus favoring more stable outcomes of speech fluency. Attempts aiming at modulating (and improving) brain functioning of people who stutter, realized by using NIBS, are quickly increasing. Here, we will review these recent advancements being applied to the treatment of DS. Insights will be useful not only to assess whether the speech fluency of people who stutter may be ameliorated by acting directly on brain functioning but also will provide further suggestions about the complex and dynamic pathophysiology of DS, where causal effects and "adaptive''/''maladaptive" compensation mechanisms may be strongly overlapped. In conclusion, this review focuses future research toward more specific, targeted, and effective interventions for DS, based on neuromodulation of brain functioning.

Temporal characteristics of global form perception in translational and circular Glass patterns.

The human visual system is continuously exposed to a natural environment with static and moving objects that the visual system needs to continuously integrate and process. Glass patterns (GPs) are a class of visual stimuli widely used to study how the human visual system processes and integrates form and motion signals. GPs are made of pairs of dots that elicit a strong percept of global form. A rapid succession of unique frames originates dynamic GPs. Previous psychophysical studies showed that dynamic translational GPs are easier to detect than the static version because of the spatial summation across the unique frames composing the pattern. However, it is not clear whether the same mechanism is involved in dynamic circular GPs. In the present study, we psychophysically investigated the role of the temporal and spatial summation in the perception of both translational and circular GPs. We manipulated the number of unique frames in dynamic GPs and the update rate of the frames presentation. The results suggest that spatial and temporal summation across unique frames takes place for both translational and circular GPs. Moreover, the number of unique frames and the pattern update rate equally influence the discrimination thresholds of translational and circular GPs. These results show that form and motion integration is likely to be processed similarly for translational and circular GPs.

Spatial and Temporal Selectivity of Translational Glass Patterns Assessed With the Tilt After-Effect.

Glass patterns (GPs) have been widely employed to investigate the mechanisms underlying processing of global form from locally oriented cues. The current study aimed to psychophysically investigate the level at which global orientation is extracted from translational GPs using the tilt after-effect (TAE) and manipulating the spatiotemporal properties of the adapting pattern. We adapted participants to translational GPs and tested with sinewave gratings. In Experiment 1, we investigated whether orientation-selective units are sensitive to the temporal frequency of the adapting GP. We used static and dynamic translational GPs, with dynamic GPs refreshed at different temporal frequencies. In Experiment 2, we investigated the spatial frequency selectivity of orientation-selective units by manipulating the spatial frequency content of the adapting GPs. The results showed that the TAE peaked at a temporal frequency of ∼30 Hz, suggesting that orientation-selective units responding to translational GPs are sensitive to high temporal frequencies. In addition, TAE from translational GPs peaked at lower spatial frequencies than the dipoles' spatial constant. These effects are consistent with form-motion integration at low and intermediate levels of visual processing.

Cognitive exergame training and transcranial random noise stimulation effects on executive control in healthy young adults.

Objective: In the present study, we investigated the efficacy of transcranial random noise stimulation (tRNS) combined with an exergame training (physical exercise combined with a videogame) chosen as potential techniques to boost brain functioning and to promote plastic effects in healthy young adults. The aim was to improve the motor response speed and the response time when inhibition was required. Method: Forty-nine participants were randomly assigned to four conditions. The protocol consisted of eight sessions of exergame cognitive training (or no training) associated with the active or sham stimulation of the left dorsolateral prefrontal cortex (left-DLPFC). Results: The results indicated faster simple reaction times following the exergame training, and faster reaction times in Go trials (while the ratio of NoGo trials remained unaltered) following tRNS. No interactions were present between the two procedures. Conclusions: These findings reveal better performance in both tasks with independent effects of the two techniques. Using noninvasive brain stimulation and exergame training may be a viable strategy to increase motor response speed and improve executive control. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Investigating the Interaction Between Form and Motion Processing: A Review of Basic Research and Clinical Evidence.

A widely held view of the visual system supported the perspective that the primate brain is organized in two main specialized streams, called the ventral and dorsal streams. The ventral stream is known to be involved in object recognition (e.g., form and orientation). In contrast, the dorsal stream is thought to be more involved in spatial recognition (e.g., the spatial relationship between objects and motion direction). Recent evidence suggests that these two streams are not segregated but interact with each other. A class of visual stimuli known as Glass patterns has been developed to shed light on this process. Glass patterns are visual stimuli made of pairs of dots, called dipoles, that give the percept of a specific form or apparent motion, depending on the spatial and temporal arrangement of the dipoles. In this review, we show an update of the neurophysiological, brain imaging, psychophysical, clinical, and brain stimulation studies which have assessed form and motion integration mechanisms, and the level at which this occurs in the human and non-human primate brain. We also discuss several studies based on non-invasive brain stimulation techniques that used different types of visual stimuli to assess the cortico-cortical interactions in the visual cortex for the processing of form and motion information. Additionally, we discuss the timing of specific visual processing in the ventral and dorsal streams. Finally, we report some parallels between healthy participants and neurologically impaired patients in the conscious processing of form and motion.

The neural mechanisms underlying directional and apparent circular motion assessed with repetitive transcranial magnetic stimulation (rTMS).

Dynamic Glass patterns (GPs) are a class of visual stimuli that evoke apparent motion and are commonly used to investigate the interaction between global form and motion processing in the visual system. Neuroimaging studies showed that (complex) circular dynamic GPs mainly activate areas along both the ventral and the dorsal stream such as hMT+, V3b/KO, dorsal V4 and LOC, whereas directional motion from rotating random dot kinematograms (RDKs) mainly activates the human MT complex (hMT+) and area V6. However, despite the large number of correlational information from fMRI studies, there is scarce evidence about the causal involvement of these brain areas in the perception of dynamic circular GPs and rotating RDKs. The aim of this study is to compare the neural basis of dynamic circular GPs and rotating RDKs by temporarily interfering with repetitive transcranial magnetic stimulation (rTMS) delivered over two visual areas largely involved in form and motion processing, such as V1/V2 and hMT+. Our results showed that rTMS over hMT + interfered only with the processing of rotating RDKs but not with the processing of circular dynamic GPs. On the other hand, rTMS delivered over early visual areas (V1/V2) did not interfere with the processing of both visual stimuli. These results suggest that partially different neural substrates subtend the processing of circular directional motion and apparent non-directional motion.

Does physical exercise and congruent visual stimulation enhance perceptual learning?

PURPOSE: There is currently great interest in methods that can modulate brain plasticity, both in terms of understanding the basic mechanisms, and in the remedial application to situations of sensory loss. Recent work has focussed on how different manipulations might be combined to produce new settings that reveal synergistic actions. Here we ask whether a prominent example of adult visual plasticity, called perceptual learning, is modified by other environmental factors, such as visual stimulation and physical exercise. METHODS: We quantified the magnitude, rate and transfer of perceptual learning using a peripheral Vernier alignment task, in two groups of subjects matched for a range of baseline factors (e.g. age, starting Vernier threshold, baseline fitness). We trained subjects for 5 days on a Vernier alignment task. In one group, we introduced an exercise protocol with congruent visual stimulation. The control group received the same visual stimulation, but did not exercise prior to measurement of Vernier thresholds. RESULTS: Although the task generated large amounts of learning (~40%) and some transfer to untrained conditions in both groups, there were no specific benefits associated with either the addition of an exercise schedule or congruent visual stimulation. CONCLUSION: In adults, short periods of physical exercise and visual stimulation do not enhance perceptual learning.

Probabilistic rejection templates in visual working memory.

Our interactions with the visual world are guided by attention and visual working memory. Things that we look for and those we ignore are stored as templates that reflect our goals and the tasks at hand. The nature of such templates has been widely debated. A recent proposal is that these templates can be thought of as probabilistic representations of task-relevant features. Crucially, such probabilistic templates should accurately reflect feature probabilities in the environment. Here we ask whether observers can quickly form a correct internal model of a complex (bimodal) distribution of distractor features. We assessed observers' representations by measuring the slowing of visual search when target features unexpectedly match a distractor template. Distractor stimuli were heterogeneous, randomly drawn on each trial from a bimodal probability distribution. Using two targets on each trial, we tested whether observers encode the full distribution, only one peak of it, or the average of the two peaks. Search was slower when the two targets corresponded to the two modes of a previous distractor distribution than when one target was at one of the modes and another between them or outside the distribution range. Furthermore, targets on the modes were reported later than targets between the modes that, in turn, were reported later than targets outside this range. This shows that observers use a correct internal model, representing both distribution modes using templates based on the full probability distribution rather than just one peak or simple summary statistics. The findings further confirm that performance in odd-one out search with repeated distractors cannot be described by a simple decision rule. Our findings indicate that probabilistic visual working memory templates guiding attention, dynamically adapt to task requirements, accurately reflecting the probabilistic nature of the input.

Transcranial random noise stimulation (tRNS): a wide range of frequencies is needed for increasing cortical excitability.

Transcranial random noise stimulation (tRNS) is a recent neuromodulation protocol. The high-frequency band (hf-tRNS) has shown to be the most effective in enhancing neural excitability. The frequency band of hf-tRNS typically spans from 100 to 640 Hz. Here we asked whether both the lower and the higher half of the high-frequency band are needed for increasing neural excitability. Three frequency ranges (100-400 Hz, 400-700 Hz, 100-700 Hz) and Sham conditions were delivered for 10 minutes at an intensity of 1.5 mA over the primary motor cortex (M1). Single-pulse transcranial magnetic stimulation (TMS) was delivered over the same area at baseline, 0, 10, 20, 30, 45 and 60 minutes after stimulation, while motor evoked potentials (MEPs) were recorded to evaluate changes in cortical excitability. Only the full-band condition (100-700 Hz) was able to modulate excitability by enhancing MEPs at 10 and 20 minutes after stimulation: neither the higher nor the lower sub-range of the high-frequency band significantly modulated cortical excitability. These results show that the efficacy of tRNS is strictly related to the width of the selected frequency range.

Modulatory mechanisms underlying high-frequency transcranial random noise stimulation (hf-tRNS): A combined stochastic resonance and equivalent noise approach.

BACKGROUND: High-frequency transcranial random noise stimulation (hf-tRNS) is a neuromodulatory technique consisting of the application of alternating current at random intensities and frequencies. hf-tRNS induces random neural activity in the system that may boost the sensitivity of neurons to weak inputs. Stochastic resonance is a nonlinear phenomenon whereby the addition of an optimal amount of noise results in performance enhancement, whereas further noise increments impair signal detection or discrimination. OBJECTIVE: The aim of the study was to assess whether modulatory effects of hf-tRNS rely on the stochastic resonance phenomenon, and what is the specific neural mechanism producing stochastic resonance. METHOD: Observers performed a two-interval forced choice motion direction discrimination task in which they had to report whether two moving patches presented in two temporal intervals had the same or different motion directions. hf-tRNS was administered at five intensity levels (0.5, 0.75, 1.0, 1.5, and 2.25 mA). RESULTS: The results showed a significant improvement in performance when hf-tRNS was applied at 1.5 mA, representing the optimal level of external noise. However, stimulation intensity at 2.25 mA significantly impaired direction discrimination performance. An equivalent noise (EN) analysis, used to assess how hf-tRNS modulates the mechanisms underlying global motion processing, showed an increment in motion signal integration with the optimal current intensity, but reduced motion signal integration at 2.25 mA. CONCLUSION: These results indicate that hf-tRNS-induced noise modulates neural signal-to-noise ratio in a way that is compatible with the stochastic resonance phenomenon.

The effect of experience and of dots' density and duration on the detection of coherent motion in dogs.

Knowledge about the mechanisms underlying canine vision is far from being exhaustive, especially that concerning post-retinal elaboration. One aspect that has received little attention is motion perception, and in spite of the common belief that dogs are extremely apt at detecting moving stimuli, there is no scientific support for such an assumption. In fact, we recently showed that dogs have higher thresholds than humans for coherent motion detection (Kanizsar et al. in Sci Rep UK 7:11259, 2017). This term refers to the ability of the visual system to perceive several units moving in the same direction, as one coherently moving global unit. Coherent motion perception is commonly investigated using random dot displays, containing variable proportions of coherently moving dots. Here, we investigated the relative contribution of local and global integration mechanisms for coherent motion perception, and changes in detection thresholds as a result of repeated exposure to the experimental stimuli. Dogs who had been involved in the previous study were given a conditioned discrimination task, in which we systematically manipulated dot density and duration and, eventually, re-assessed our subjects' threshold after extensive exposure to the stimuli. Decreasing dot duration impacted on dogs' accuracy in detecting coherent motion only at very low duration values, revealing the efficacy of local integration mechanisms. Density impacted on dogs' accuracy in a linear fashion, indicating less efficient global integration. There was limited evidence of improvement in the re-assessment but, with an average threshold at re-assessment of 29%, dogs' ability to detect coherent motion remains much poorer than that of humans.