Domain Specificity of Oculomotor Learning after Changes in Sensory Processing.

Cortical responses to auditory novelty across task conditions: An intracranial electrophysiology study

Latencies and peak-to-peak amplitudes of pattern-reversal evoked-potential (PREP) components of active and inactive community-dwelling healthy 61- to 77-year-olds were compared with those of active and inactive 18- to 31-year-olds to determine whether long-term physical activity involvement was associated with attenuation of age-related changes in sensory processes. Binocular PREPs were derived for each of 2 check sizes (22 × 15 ft and 41 × 30 ft of visual angle) to provide increasing challenge of spatial resolution. Analyses of the latencies revealed significant effects for age, gender, and check size such that latencies were longer for older than for young participants, men than for women, and small than for larger check sizes. Amplitudes were larger in older adults for the P100-N150 peak-to-peak difference, but physical activity history was not associated with reduction of the observed age-related increases in component latencies and amplitude. As such, physical activity does not appear to attenuate age-related decline in visual sensory processing.

Macular degeneration (MD) is one of the leading causes of vision impairment in the Western world. Patients with MD tend to develop spontaneous eye movement strategies to compensate for their vision loss, including adopting a preferred retinal locus, or PRL, a spared peripheral region that they use more frequently to replace the damaged fovea. However, not all patients are successful in developing a PRL, and even when they do, it might take them months. Currently, no gold standard rehabilitative therapy exists, and MD research is further hindered by issues of recruitment, compliance, and comorbidity. To help address these issues, a growing body of research has used eye tracking-guided, gaze-contingent displays in a simulated central vision loss paradigm in individuals with intact vision. While simulated vision loss is qualitatively different than pathological central vision loss, our framework provides for a highly controlled model through which to study compensatory eye movements and test possible rehabilitation interventions in low vision. By developing a comprehensive framework, rather than relying on isolated and disconnected tasks, we create a cohesive environment where we can test larger-scale hypotheses, allowing us to examine interactions between tasks, assess training effects across multiple measures, and establish a consistent methodology for future research. Furthermore, participants in simulated central vision loss studies show similarities in their oculomotor compensatory behaviors compared to patients with MD. Here, we present a framework for conducting gaze-contingent studies related to simulated central vision loss. We emphasize the utilization of the framework to test behavioral and oculomotor performance of healthy individuals on a wide range of perceptual tasks encompassing different levels of visual processing. We also discuss how this framework can be adapted for training MD patients.

The purpose of this review is to combine the results of existing literature on the natural history of occult choroidal neovascularisation (CNV) associated with age-related macular degeneration (AMD). Published reports evaluating eyes with occult CNV in AMD patients were selected for meta-analysis based on a computerised MEDLINE search. Pooled estimates of the proportions of eyes with a vision loss greater than 2 to 3 (moderate vision loss) or 6 lines (severe vision loss) at 1 year and 2 to 3 years, respectively, or developing a classic component on fluorescein angiography at 1 year were measured. There is no significant heterogeneity among published rates of visual loss and development of classic CNV. The overall pooled estimates (95% confidence limits) of the proportions of eyes with at least moderate or severe vision loss, respectively, were 59% (53% to 64.5%) and 34% (25% to 43%) at 1 year and 70% (64% to 76%) and 47% (40% to 54%) at 2 to 3 years; the overall pooled estimate of the percentage of eyes developing classic CNV at 1 year was 46% (39% to 54%). A substantial number of patients with occult CNV from AMD will develop at least moderate visual loss at 1 year and severe visual loss within 3 years. However, visual acuity may remain stable in up to 30% of patients. These results may help us to understand the exact role of new therapies and in planning future trials.

Older individuals with macular diseases, such as age-related macular degeneration, experience central vision loss (CVL) due to degeneration of their photoreceptors and retinal cells. Patients with CVL may experience various vision impairments, including of visual acuity, fixation stability, contrast sensitivity, and stereoacuity. After CVL, most patients develop a preferred retinal locus outside the affected macular region, which serves as a new visual reference. In this review, we provide an overview of the visual function and impairment in individuals with CVL. In addition, the important role of biofeedback training on the visual function and activity of individuals with CVL is also reviewed. Accordingly, the location and development of the preferred retinal loci are discussed. Finally, this review discusses how to conduct biofeedback training to treat individuals with CVL.

Autism spectrum disorder (ASD) is characterized by social interaction and communication impairments, as well as restrictive/repetitive patterns of behavior, interests or activities, which can coexist with intellectual disability and altered sensory processing. To study the mechanisms underlying these core features of ASD, preclinical research has developed animal models with manipulations in ASD-linked genes, such as CNTNAP2. In order to fully interpret the findings from mechanistic studies, the extent to which these models display behaviors consistent with ASD must be determined. Toward that goal, we conducted an investigation of the consequences of a functional loss of Cntnap2 on ASD-related behaviors by comparing the performance of rats with a homozygous or heterozygous knockout of Cntnap2 to their wildtype littermates across a comprehensive test battery. Cntnap2-/- rats showed deficits in sociability and social novelty, and they displayed repetitive circling and hyperlocomotion. Moreover, Cntnap2-/- rats demonstrated exaggerated acoustic startle responses, increased avoidance to sounds of moderate intensity, and a lack of rapid audiovisual temporal recalibration; indicating changes in sensory processing at both the pre-attentive and perceptual levels. Notably, sensory behaviors requiring learned associations did not reveal genotypic differences, whereas tasks relying on automatic/implicit behaviors did. Ultimately, because these collective alterations in social, stereotypic, and sensory behaviors are phenotypically similar to those reported in individuals with ASD, our results establish the Cntnap2 knockout rat model as an effective platform to study not only the molecular and cellular mechanisms associated with ASD, but also the complex relationship between altered sensory processing and other core ASD-related behaviors. LAY SUMMARY: Autism spectrum disorder (ASD) is characterized by social interaction differences, and restrictive/repetitive patterns of behavior. We studied the behavioral alterations caused by the loss of an autism-linked gene, Cntnap2, in the rat to determine how mutations in this gene contribute to autism-related behaviors. We show the loss of Cntnap2 leads to changes in social, stereotypic, and sensory behaviors, indicating this rat model can be used to better understand the brain changes underlying ASD. Autism Res 2020, 13: 1698-1717. © 2020 International Society for Autism Research and Wiley Periodicals LLC.

Purpose To analyze outcomes after multiple light redirection (MLR) by photoablation of a small paracentral portion of Bowman's layer in each corneal quadrant using standard myopic laser in situ keratomileusis (LASIK) software with non-customized fenestrated MLR corneal light shields (Excimer-MLR) without postoperative visual training or magnification in pseudophakic eyes with central visual loss from age-related macular degeneration (AMD) with geographic atrophy (GA). Methods Retrospective analysis of two cases. Results Outcomes after Excimer-MLR in the worse-seeing eyes of an 86-year-old and a 65-year-old pseudophakic man with AMD and GA revealed corrected distance/near visual acuity gains of 6.0/6.0 and 11.8/10.0 lines within 12 days and 5.0/5.0 and 12.2/9.8 lines at 9 months, respectively, with improved Amsler grids, no distance or near glasses change, no complications, and no adverse events related to Excimer-MLR. Contrast sensitivity and stereopsis, measured in case 2, improved postoperatively. Conclusions This first report showed that Excimer-MLR safely produced large improvements in visual function up to 9 months postoperatively in two eyes with central visual loss from AMD. [ Journal of Refractive Surgery Case Reports. 2024;4(4):e29–e35.]

The present experiment investigated the hypothesis that age-related declines in cognitive functioning are partly due to a decrease in peripheral sensory functioning. In particular, it was suggested that some of the decline in serial recall for verbal material might be due to even small amounts of degradation due to noise or hearing loss. Older and younger individuals identified and recalled nonsense syllables in order at a number of different speech-to-noise ratios. Performance on the identification task was significantly correlated with performance on a subsequent serial recall task. However, this was restricted to the case in which the stimuli were presented in a substantial amount of noise. These data show that even small changes in sensory processing can lead to real and measurable declines in cognitive functioning as measured by a serial recall task.

Because of their ex utero development, relatively simple nervous system, translucency, and availability of tools to investigate neural function, larval zebrafish are an exceptional model for understanding neurodevelopmental disorders and the consequences of environmental toxins. Furthermore, early in development, zebrafish larvae easily absorb chemicals from water, a significant advantage over methods required to expose developing organisms to chemical agents in utero. Bisphenol A (BPA) and BPA analogs are ubiquitous environmental toxins with known molecular consequences. All humans have measurable quantities of BPA in their bodies. Most concerning, the level of BPA exposure is correlated with neurodevelopmental difficulties in people. Given the importance of understanding the health-related effects of this common toxin, we have exploited the experimental advantages of the larval zebrafish model system to investigate the behavioral and anatomic effects of BPA exposure. We discovered that BPA exposure early in development leads to deficits in the processing of sensory information, as indicated by BPA’s effects on prepulse inhibition (PPI) and short-term habituation (STH) of the C-start reflex. We observed no changes in locomotion, thigmotaxis, and repetitive behaviors (circling). Despite changes in sensory processing, we detected no regional or whole-brain volume changes. Our results show that early BPA exposure can induce sensory processing deficits, as revealed by alterations in simple behaviors that are mediated by a well-defined neural circuit.

Objective The main aim of this study was to determine the impact of botulinum toxin A (BTX-A) on severity and frequency of drooling in children with Cerebral Palsy (CP) secondary to Congenital Zika Syndrome (CZS). Methods This is a prospective longitudinal observational study including 23 children who received bilateral injections of BTX in the parotid and submandibular glands. The Thomas-Stonell & Greenberg Drooling Severity and Frequency Scale was applied by a multidisciplinary team including Speech, Language and Hearing professionals. The Global Impression of Improvement (GII) Scale was also applied to assess parents’ subjective perceptions of therapeutic response. Swallowing was assessed using Doppler ultrasonography. Univariate logistic regression was used to analyse differences between responders and non-responders. Results Participant age varied from 27 to 38 months (mean 31.78, SD = 2.61) all presented with Gross Motor Function Classification System (GMFCS) V. Drooling Severity and Frequency Scale scores ranged from 7 to 9 points (median = 9) prior to BTX administration and from 4 to 6 (median = 6) after. Pre- and post-treatment reduction in drooling severity occurred (Z = −3.746; p < 0.001). No cases of drooling worsening were reported. Only two subjects presented adverse effects attributed to BTX administration. Correlation was only confirmed with GII. Discussion This article presents the safe and positive impact of BTX-A administration guided by anatomical references described in the literature, even on children with microcephaly. Further studies are needed to facilitate the use of Doppler ultrasonography as a tool to characterize changes in sensory processing and motor response following intraoral input in children with CP.

In addition to the core domains of social communication impairments (SCI) and patterns of restricted and repetitive behaviors and interests (RRBIs), autism is characterized by changes in sensory processing, including in the integration of information across the different sensory modalities. While there is significant evidence that audiovisual (AV) integration is altered in the temporal domain in autism-and that these differences are associated with presentation of SCI and RRBIs-very little is known about how autistic individuals integrate AV information in the domain of space. We conducted a free-response AV spatial localization task in autistic and non-autistic children aged 7-17 years to understand better AV localization abilities, as well as how these abilities relate to SCI, RRBIs, and other clinical features of autism. While we found no group differences in AV spatial performance, an exploratory analysis revealed three clusters of autism features that were significantly predictive of performance across groups: a motor/somatosensory cluster, a sensory responsivity cluster, and a social communication cluster. Although autistic children appear to have intact audiovisual spatial integration ability, we believe that specific autism features and their links to AV spatial integration need to be further explored in future research. Limitations and future research directions are discussed.

Few studies have investigated the mechanisms responsible for the symptoms of restless legs syndrome (RLS). However, these studies were mainly performed during the asymptomatic period and therefore their findings might not apply to changes in sensory processing that occur during the symptomatic period. The objective of this study was to investigate the function of sensory nerve fibres in RLS patients using the current perception threshold (CPT) test during the daytime and in the presence of symptoms. Ninety-three patients with RLS and 34 healthy controls were included in the study. RLS patients were further divided into two subgroups, those who were experiencing RLS symptoms during the CPT test (symptom+) and those without symptoms (symptom-). Demographic data, RLS rating scale score and visual analogue scale were collected. Of the 127 enrolled subjects, CPT values were significantly lower in RLS patients than in controls for all three frequencies. Among the control and RLS subgroups (53 symptom+, 40 symptom-), symptom+ patients showed lower CPT values than controls. This finding indicates a relative hyperaesthetic state in the sensory afferents of peripheral nerves in symptom+ patients. There were no significant differences between the symptom- group and controls. The significantly lower CPT values for all three frequencies in symptom+ patients suggest that central sensory processing disturbance of sensory nerve fibres' input may be involved in the development of symptoms in RLS patients.

To perceive the auditory and visual aspects of a physical event as occurring simultaneously, the brain must adjust for differences between the two modalities in both physical transmission time and sensory processing time. One possible strategy to overcome this difficulty is to adaptively recalibrate the simultaneity point from daily experience of audiovisual events. Here we report that after exposure to a fixed audiovisual time lag for several minutes, human participants showed shifts in their subjective simultaneity responses toward that particular lag. This 'lag adaptation' also altered the temporal tuning of an auditory-induced visual illusion, suggesting that adaptation occurred via changes in sensory processing, rather than as a result of a cognitive shift while making task responses. Our findings suggest that the brain attempts to adjust subjective simultaneity across different modalities by detecting and reducing time lags between inputs that likely arise from the same physical events.

SummaryPrior information about features of a stimulus is a strong modulator of perception. For instance, the prospect of more intense pain leads to an increased perception of pain, whereas the expectation of analgesia reduces pain, as shown in placebo analgesia and expectancy modulations during drug administration [1]. This influence is commonly assumed to be rooted in altered sensory processing and expectancy-related modulations in the spinal cord [2], are often taken as evidence for this notion. Contemporary models of perception, however, suggest that prior information can also modulate perception by biasing perceptual decision-making — the inferential process underlying perception in which prior information is used to interpret sensory information. In this type of bias, the information is already present in the system before the stimulus is observed [3]. Computational models can distinguish between changes in sensory processing and altered decision-making as they result in different response times for incorrect choices in a perceptual decision-making task (Figure S1A,B) [4]. Using a drift-diffusion model, we investigated the influence of both processes in two independent experiments. The results of both experiments strongly suggest that these changes in pain perception are predominantly based on altered perceptual decision-making.

In humans, there is evidence that sensory processing of novel or threatening stimuli is right hemisphere dominated, especially in people experiencing negative affective states. There is also evidence for similar lateralization in a number of non-human animal species. Here we investigate whether this is also the case in domestic cattle that may experience long-term negative states due to commonly occurring conditions such as lameness. Health and welfare implications associated with pain in lame cows are a major concern in dairy farming. Behavioural tests combining animal behaviour and cognition could make a meaningful contribution to our understanding of disease-related changes in sensory processing in animals, and consequently enhance their welfare. We presented 216 lactating Holstein-Friesian cows with three different unfamiliar objects which were placed either bilaterally (e.g. two yellow party balloons, two black/white checkerboards) or hung centrally (a Kong™) within a familiar area. Cows were individually exposed to the objects on three consecutive days, and their viewing preference/eye use, exploration behaviour/nostril use, and stop position during approach was assessed. Mobility (lameness) was repeatedly scored during the testing period. Overall, a bias to view the right rather than the left object was found at initial presentation of the bilateral objects. More cows also explored the right object rather than the left object with their nose. There was a trend for cows appearing hesitant in approaching the objects by stopping at a distance to them, to then explore the left object rather than the right. In contrast, cows that approached the objects directly had a greater tendency to contact the right object. No significant preference in right or left eye/nostril use was found when cows explored the centrally-located object. We found no relationship between lameness and lateralized behaviour. Nevertheless, observed trends suggesting that lateralized behaviour in response to bilaterally located unfamiliar objects may reflect an immediate affective response are discussed. Further study is needed to understand the impact of long-term affective states on hemispheric dominance and lateralized behaviour.