Hypothesis of subcortical visual pathway impairment in schizophrenia

Schizophrenia is a severe mental disease involving both neurological and psychiatric abnormalities. Previous studies mainly focus on damage to high-order cognitive dysfunction, which is related to high-level cortical regions such as the prefrontal and temporal lobes. Recent research reveals that impairment of low-level sensory processing occurs in the early stage of schizophrenia, which may be due to impairment of the subcortical magnocellular visual pathway. Moreover, the structure and function of some important nuclei in a subcortical visual pathway are reported to be abnormal in patients with schizophrenia. Inspired by the above evidence, we propose a hypothesis that impairment of the Superior Colliculus-Pulvinar-Amygdala subcortical visual pathway may be involved in the pathological mechanisms of early stages of schizophrenia. And we propose a possible method to detect dysfunction of this subcortical pathway through examining topological processing, which may help early diagnosis of schizophrenia.

Individual Subject Approaches to Mapping Sensory-Biased and Multiple-Demand Regions in Human Frontal Cortex

Sensory modality, widely accepted as a key factor in the functional organization of posterior cortical areas, also shapes the organization of human frontal lobes. 'Deep imaging,' or the practice of collecting a sizable amount of data on individual subjects, offers significant advantages in revealing fine-scale aspects of functional organization of the human brain. Here, we review deep imaging approaches to mapping multiple sensory-biased and multiple-demand regions within human lateral frontal cortex. In addition, we discuss how deep imaging methods can be transferred to large public data sets to further extend functional mapping at the group level. We also review how 'connectome fingerprinting' approaches, combined with deep imaging, can be used to localize fine-grained functional organization in individual subjects using resting-state data. Finally, we summarize current 'best practices' for deep imaging.

The effectiveness of cognitive rehabilitation in improving visual and auditory attention in ischemic stroke patients

The present study aimed to investigate the effectiveness of a cognitive rehabilitation program in improving the visual and auditory attention performance in stroke patients. The research method was quasi-experimental with a pre-intervention, post-intervention and follow-up design and control group. Twenty ischemic stroke patients with attention disorder were randomly classified into experimental and control groups. Cognitive evaluation of patients, including pre-intervention, immediately and 6 weeks after the intervention, was performed by the IVA + Plus (Integrated Visual and Auditory Continuous Performance Test). The experimental group received a cognitive rehabilitation program as 1-h sessions per week for 8 weeks, but the control group received no intervention. The results indicated significant effects of a cognitive rehabilitation program on the auditory (p = 0.002) and visual (p = 0.009) attention as well as the 6-week follow-up after the intervention, and it improved visual and auditory attention in stroke patients in the experimental group. The effectiveness of a cognitive rehabilitation program improved attention performance in stroke patients and had a positive effect on visual and auditory attention performance in ischemic stroke patients.

Sinusoidal analysis reveals a non-linear and dopamine-dependent relationship between ambient illumination and motor activity in larval zebrafish

Larval zebrafish show stereotyped motor responses to changes in ambient illumination. The responses can be evaluated in 96-well plates, and are used widely to assess neurological function in zebrafish models. However, the square-wave (on/off) light stimuli commonly employed in these studies do not allow analysis of the relationship between motor activity and illumination intensity or its rate of change. To address this limitation, we measured larval zebrafish motor function while ambient illumination was modulated sinusoidally. Motor activity varied robustly and reproducibly in antiphase with illumination. The relationship between mean swimming speed (dependent variable) and illuminance (independent variable) was described most closely by a power function, and was influenced dynamically by the proportional rate of change of illuminance. Several predictions from this model were verified experimentally by testing responses to sinusoidal illumination waveforms that were amplitude-, phase-, or offset-modulated, or transformed by a power function. At concentrations ≤5 μM, the dopamine D2 receptor inverse agonist haloperidol selectively abrogated the motor response to decreasing Illuminance without altering baseline activity in bright light, suggesting that dopamine is essential for illuminance-dependent motor function. These data contribute to understanding the environmental determinants of motor activity in zebrafish larvae, suggest experimental opportunities to elucidate underlying neural mechanisms, and potentially provide an assay of dopaminergic function for chemical and genetic screening applications.

Benefits and pitfalls of data compression in visual working memory

Data compression in memory is a cognitive process allowing participants to cope with complexity to reduce information load. However, previous studies have not yet considered the hypothesis that this process could also lead to over-simplifying information due to haphazard amplification of the compression process itself. For instance, we could expect that the over-regularized features of a visual scene could produce false recognition of patterns, not because of storage capacity limits but because of an errant compression process. To prompt memory compression in our participants, we used multielement visual displays for which the underlying information varied in compressibility. The compressibility of our material could vary depending on the number of common features between the multi-dimensional objects in the displays. We measured both accuracy and response times by probing memory representations with probes that we hypothesized could modify the participants' representations. We confirm that more compressible information facilitates performance, but a more novel finding is that compression can produce both typical memory errors and lengthened response times. Our findings provide clearer evidence of the forms of compression that participants carry out.

A colorimetric sensing platform for azodicarbonamide detection in flour based on MnO2 nanosheets oxidative system

Azodicarbonamide (ADA), as a dough conditioner food additive in flour, can be turned into toxic biurea and semicarbazide after high temperature processing. Hence, the using of ADA in food material should be strictly controlled, and the detection of ADA is very important for consumers' safety and health. Herein, a simple and fast colorimetric strategy has been developed for ADA detection based on the MnO₂ nanosheets-3,3',5,5'-tetramethylbenzidine (TMB)-glutathione (GSH) as oxidative sensing system (MnO₂-TMB-GSH). Since the ADA can selectively react with GSH via oxidizing the sulfydryl (-SH) group of GSH to disulfide bond (S-S), which makes GSH unable to reduce MnO₂ nanosheets and restore its oxidase-like activity. The absorbance changes of the TMB solution depended on ADA content. The MnO₂-TMB-GSH colorimetric platform can detect the ADA with a linear range of 10 μmol L^-1 (11.6 ppm) to 400 μmol L^-1 (464 ppm), and the limit of detection (LOD) is 3.3 μmol L^-1 (3.51 ppm). Some potential interferences in real sample were tested and did not affect the MnO₂-TMB-GSH colorimetric platform for ADA detection. Furthermore, the sensing platform was applied for detecting ADA in real flour sample with a recovery of 96%-105% (RSD < 5%). This colorimetric method can effectively and rapidly detect ADA additives in flour less than the prescribed standard (45 mg kg^-1), which shows a great potential for visualization analysis and on-site detection of ADA in flour. A simple and fast colorimetric strategy has been developed for azodicarbonamide (ADA) detection based on the MnO₂ nanosheets-3,3',5,5'-tetramethylbenzidine (TMB)-glutathione (GSH) as oxidative sensing system (MnO₂-TMB-GSH).

Neurosurgical experience of managing optic pathway gliomas

BACKGROUND

Optic pathway gliomas (OPGs), also known as visual pathway gliomas, are debilitating tumors that account for 3-5% of all pediatric brain tumors. They are most commonly WHO grade 1 pilocytic astrocytomas and frequently occur in patients with neurofibromatosis type 1. The location of these tumors results in visual loss and blindness, endocrine and hypothalamic dysfunction, hydrocephalus, and premature death. Their involvement of the visual pathways and proximity to other eloquent brain structures typically precludes complete resection or optimal radiation dosing without incurring significant neurological injury. There are various surgical interventions that can be performed in relation to these lesions including biopsy, cerebrospinal fluid diversion, and partial or radical resection, but their role is a source of debate. This study catalogues our surgical experience and patient outcomes in order to support decision-making in this challenging pathology.

METHODS

A retrospective review of all cases of OPGs treated in a single center from July 1990 to July 2020. Data was collected on patient demographics, radiographic findings, pathology, and management including surgical interventions. Outcome data included survival, visual function, endocrine, and hypothalamic dysfunction.

RESULTS

One hundred twenty-one patients with OPG were identified, and 50 of these patients underwent a total of 104 surgical procedures. These included biopsy (31), subtotal or gross total resection (20 operations in 17 patients), cyst drainage (17), Ommaya reservoir insertion (9), or cerebrospinal fluid diversion (27). During the study period, there was 6% overall mortality, 18% hypothalamic dysfunction, 20% endocrine dysfunction, and 42% had some cognitive dysfunction. At diagnosis 75% of patients had good or moderate visual function in at least one eye, and overall, this improved to 83% at the end of the study period. In comparison the worst eye had good or moderate visual function in 56%, and this reduced to 53%. Baseline and final visual function were poorer in patients who had a surgical resection, but improvements in vision were still found-particularly in the best eye.

DISCUSSION/CONCLUSION

OPG are debilitating childhood tumor that have lifelong consequences in terms of visual function and endocrinopathies/hypothalamic dysfunction; this can result in substantial patient morbidity. Decisions regarding management and the role of surgery in this condition are challenging and include cerebrospinal fluid diversion, biopsy, and in highly select cases cystic decompression or surgical resection. In this paper, we review our own experience, outcomes, and surgical philosophy.

Subthalamic deep brain stimulation affects heading perception in Parkinson's disease

Parkinson's disease (PD) presents with visuospatial impairment and falls. It is critical to understand how subthalamic deep brain stimulation (STN DBS) modulates visuospatial perception. We hypothesized that DBS has different effects on visual and vestibular perception of linear motion (heading), a critical aspect of visuospatial navigation; and such effects are specific to modulated STN location. Two-alternative forced-choice experiments were performed in 14 PD patients with bilateral STN DBS and 19 age-matched healthy controls (HC) during passive en bloc linear motion and 3D optic-flow in immersive virtual reality measured vestibular and visual heading. Objective measure of perception with Weibull psychometric function revealed that PD has significantly lower accuracy [L: 60.71 (17.86)%, R: 74.82 (17.44)%] and higher thresholds [L: 16.68 (12.83), R: 10.09 (7.35)] during vestibular task in both directions compared to HC (p < 0.05). DBS significantly improved vestibular discrimination accuracy [81.40 (14.36)%] and threshold [4.12 (5.87), p < 0.05] in the rightward direction. There were no DBS effects on the slopes of vestibular psychometric curves. Visual heading perception was better than vestibular and it was comparable to HC. There was no significant effect of DBS on visual heading response accuracy or discrimination threshold (p > 0.05). Patient-specific DBS models revealed an association between change in vestibular heading perception and the modulation of the dorsal STN. In summary, DBS may have different effects on vestibular and visual heading perception in PD. These effects may manifest via dorsal STN putatively by its effects on the cerebellum.

Selection history modulates the limit of visual awareness in color perception

Among studies on the limit of conscious representation of color at a given instant, some have shown evidence of momentary awareness of only a single color, while others have not, leading to uncertainty about the factors that influence the limit. In two experiments, we explored the role of selection history, or recent experience with a trial, which is known to influence the representations of task stimuli and responses. Two color patches were briefly displayed either simultaneously or sequentially. In Experiment 1, we presented the two types of trials either in separate blocks or in interleaved couplets. In the former case, participants could deploy optimal attentional control setting in response to different types of trials with little cost by using recent experience with a preceding trial and prior knowledge. In the latter case, reconfiguring attentional control setting after each trial would be costly. In Experiment 2, we mixed the two types of trials randomly within a block during testing, but re-grouped them in data analyses such that the same type of trials was either repeated or not repeated. The results show that accuracy was comparable between the simultaneous and sequential trials in the block condition in Experiment 1 and in the repeat condition in Experiment 2, suggesting that two colors were perceived at a time. These results indicate that selection history plays an important role in the limit of visual awareness in color perception and that the finding of single-color perception reported in previous research might not be a general phenomenon.

Atypical neural processing during the execution of complex sensorimotor behavior in autism

Stereotyped behavior is rhythmic, repetitive movement that is essentially invariant in form. Stereotypy is common in several clinical disorders, such as autism spectrum disorders (ASD), where it is considered maladaptive. However, it also occurs early in typical development (TD) where it is hypothesized to serve as the foundation on which complex, adaptive motor behavior develops. This transition from stereotyped to complex movement in TD is thought to be supported by sensorimotor integration. Stereotypy in clinical disorders may persist due to deficits in sensorimotor integration. The present study assessed whether differences in sensorimotor processing may limit the expression of complex motor behavior in individuals with ASD and contribute to the clinical stereotypy observed in this population. Adult participants with ASD and TD performed a computer-based stimulus-tracking task in the presence and absence of visual feedback. Electroencephalography was recorded during the task. Groups were compared on motor performance (root mean square error), motor complexity (sample entropy), and neural complexity (multiscale sample entropy of the electroencephalography signal) in the presence and absence of visual feedback. No group differences were found for motor performance or motor complexity. The ASD group demonstrated greater neural complexity and greater differences between feedback conditions than TD individuals, specifically in signals relevant to sensorimotor processing. Motor performance and motor complexity correlated with clinical stereotypy in the ASD group. These findings support the hypothesis that individuals with ASD have differences in sensorimotor processing when executing complex motor behavior and that stereotypy is associated with low motor complexity.

Auditory cues facilitate object movement processing in human extrastriate visual cortex during simulated self-motion: A pilot study

Visual segregation of moving objects is a considerable computational challenge when the observer moves through space. Recent psychophysical studies suggest that directionally congruent, moving auditory cues can substantially improve parsing object motion in such settings, but the exact brain mechanisms and visual processing stages that mediate these effects are still incompletely known. Here, we utilized multivariate pattern analyses (MVPA) of MRI-informed magnetoencephalography (MEG) source estimates to examine how crossmodal auditory cues facilitate motion detection during the observer's self-motion. During MEG recordings, participants identified a target object that moved either forward or backward within a visual scene that included nine identically textured objects simulating forward observer translation. Auditory motion cues 1) improved the behavioral accuracy of target localization, 2) significantly modulated the MEG source activity in the areas V2 and human middle temporal complex (hMT+), and 3) increased the accuracy at which the target movement direction could be decoded from hMT+ activity using MVPA. The increase of decoding accuracy by auditory cues in hMT+ was significant also when superior temporal activations in or near auditory cortices were regressed out from the hMT+ source activity to control for source estimation biases caused by point spread. Taken together, these results suggest that parsing object motion from self-motion-induced optic flow in the human extrastriate visual cortex can be facilitated by crossmodal influences from auditory system.

When two worlds collide: the influence of an obstacle in peripersonal space on multisensory encoding

Multisensory coding of the space surrounding our body, the peripersonal space, is crucial for motor control. Recently, it has been proposed that an important function of multisensory coding is that it allows anticipation of the tactile consequences of contact with a nearby object. Indeed, performing goal-directed actions (i.e. pointing and grasping) induces a continuous visuotactile remapping as a function of on-line sensorimotor requirements. Here, we investigated whether visuotactile remapping can be induced by obstacles, e.g. objects that are not the target of the grasping movement. In the current experiment, we used a cross-modal obstacle avoidance paradigm, in which participants reached past an obstacle to grasp a second object. Participants indicated the location of tactile targets delivered to the hand during the grasping movement, while a visual cue was sometimes presented simultaneously on the to-be-avoided object. The tactile and visual stimulation was triggered when the reaching hand passed a position that was drawn randomly from a continuous set of predetermined locations (between 0 and 200 mm depth at 5 mm intervals). We observed differences in visuotactile interaction during obstacle avoidance dependent on the location of the stimulation trigger: visual interference was enhanced for tactile stimulation that occurred when the hand was near the to-be-avoided object. We show that to-be-avoided obstacles, which are relevant for action but are not to-be-interacted with (as the terminus of an action), automatically evoke the tactile consequences of interaction. This shows that visuotactile remapping extends to obstacle avoidance and that this process is flexible.

Older adults rely on somatosensory information from the effector limb in the planning of discrete movements to somatosensory cues

While younger and older adults can perform upper-limb reaches to spatial targets with comparable endpoint accuracy (i.e., Helsen et al., 2016; Goodman et al., 2020), movement planning (i.e., reaction time) is significantly longer in older versus younger adults (e.g., Pohl et al., 1996; Goodman et al., 2020). Critically relevant to the current study, age-related differences in reaction time are even greater when older adults plan movement towards somatosensory versus visual or bimodal targets in the absence of vision of the moving limb (e.g., Goodman et al., 2020). One proposed explanation of these lengthened reaction times to somatosensory targets is that older adults may be experiencing challenges in implementing sensorimotor transformations when planning discrete movements of their unseen limb. To test this idea and assess the contributions of somatosensory information to these motor planning processes, tendon vibration was applied to the muscles of the effector limb between reaching movements made towards visual, somatosensory, or bimodal targets. The results revealed that older adults show the greatest increases in reaction times when vibration was applied during the preparation of movements to somatosensory targets. Further, both older and younger adults exhibited decreased movement endpoint precision when tendon vibration was applied. However, only older adults showed significantly lower movement endpoint precision due to tendon vibration when making movements to somatosensory targets, versus both visual and bimodal targets. These results corroborate previous evidence that older adults have difficulties planning upper-limb movements to somatosensory targets. As well, these results yielded novel evidence that such motor planning processes in older adult rely on somatosensory cues from the effector limb.

A multisensory perspective onto primate pulvinar functions

Perception in ambiguous environments relies on the combination of sensory information from various sources. Most associative and primary sensory cortical areas are involved in this multisensory active integration process. As a result, the entire cortex appears as heavily multisensory. In this review, we focus on the contribution of the pulvinar to multisensory integration. This subcortical thalamic nucleus plays a central role in visual detection and selection at a fast time scale, as well as in the regulation of visual processes, at a much slower time scale. However, the pulvinar is also densely connected to cortical areas involved in multisensory integration. In spite of this, little is known about its multisensory properties and its contribution to multisensory perception. Here, we review the anatomical and functional organization of multisensory input to the pulvinar. We describe how visual, auditory, somatosensory, pain, proprioceptive and olfactory projections are differentially organized across the main subdivisions of the pulvinar and we show that topography is central to the organization of this complex nucleus. We propose that the pulvinar combines multiple sources of sensory information to enhance fast responses to the environment, while also playing the role of a general regulation hub for adaptive and flexible cognition.

Do infants represent human actions cross-modally? An ERP visual-auditory priming study

Recent findings indicate that 7-months-old infants perceive and represent the sounds inherent to moving human bodies. However, it is not known whether infants integrate auditory and visual information in representations of specific human actions. To address this issue, we used ERPs to investigate infants' neural sensitivity to the correspondence between sounds and images of human actions. In a cross-modal priming paradigm, 7-months-olds were presented with the sounds generated by two types of human body movement, walking and handclapping, after watching the kinematics of those actions in either a congruent or incongruent manner. ERPs recorded from frontal, central and parietal electrodes in response to action sounds indicate that 7-months-old infants perceptually link the visual and auditory cues of human actions. However, at this age these percepts do not seem to be integrated in cognitive multimodal representations of human actions.

Sensory cue reactivity: Sensitization in alcohol use disorder and obesity

Neuroimaging techniques to measure the function of the human brain such as electroencephalography (EEG), positron emission tomography (PET), and functional magnetic resonance imaging (fMRI), are powerful tools for understanding the underlying neural circuitry associated with alcohol use disorder (AUD) and obesity. The sensory (visual, taste and smell) paradigms used in neuroimaging studies represent an ideal platform to investigate the connection between the different neural circuits subserving the reward/executive control systems in these disorders, which may offer a translational mechanism for novel intervention predictions. Thus, the current review provides an integrated summary of the recent neuroimaging studies that have applied cue-reactivity paradigms and neuromodulation strategies to explore underlying alterations in neural circuitry as well in treatment strategies in AUD and obesity. Finally, we discuss literature on mechanisms associated with increased alcohol sensitivity post-bariatric surgery (BS) which offers guidance for future research to use sensory percepts in elucidating the relation of reward signaling in AUD development post-BS.

Extending the study of visual attention to a multisensory world (Charles W. Eriksen Special Issue)

Charles W. Eriksen (1923-2018), long-time editor of Perception & Psychophysics (1971-1993) - the precursor to the present journal - undoubtedly made a profound contribution to the study of selective attention in the visual modality. Working primarily with neurologically normal adults, his early research provided both theoretical accounts for behavioral phenomena as well as robust experimental tasks, including the well-known Eriksen flanker task. The latter paradigm has been used and adapted by many researchers over the subsequent decades. While Eriksen's research interests were primarily focused on situations of unimodal visual spatially selective attention, here I review evidence from those studies that have attempted to extend Eriksen's general approach to non-visual (i.e., auditory and tactile) selection and the more realistic situations of multisensory spatial attentional selection.

Visual symptoms, Neck/shoulder problems and associated factors among surgeons performing Minimally Invasive Surgeries (MIS): A comprehensive survey

PURPOSE

Minimally Invasive Surgery (MIS) is demanding on the musculoskeletal and visual systems. Prevalence, severity and association of neck/shoulder problems and visual symptoms were examined among MIS surgeons. The associations of workplace and individual factors with these symptoms independently and combined were also examined.

METHODS

MIS surgeons completed a comprehensive online survey inclusive of 52 questions about individual and workplace physical factors, neck/shoulder problems and visual symptoms. Binary logistic regression models were conducted to determine the associations of the neck/shoulder problems, visual symptoms and combined symptoms with workplace and individual factors.

RESULTS

290 surgeons completed the survey. Neck/shoulder problems and visual symptoms were reported by 31.0% and 29.0%, respectively, 15.5% reported both problems. The prevalence and severity of neck/shoulder problems and visual symptoms were significantly associated (p < 0.001). Several workplace and individual factors were associated with these symptoms (p ≤ 0.05).

CONCLUSIONS

Several factors in the workplace environment (temperature, asymmetrical weight bearing and forward head movement) and individual (being female and wearing vision correction glasses) were significantly associated with neck/shoulder problems and visual symptoms. Evaluation of different strategies to minimise the strain on the neck/shoulder region and the visual system is required.

Efficacy of augmented visual environments for reducing sickness in autonomous vehicles

The risk of motion sickness is considerably higher in autonomous vehicles than it is in human-operated vehicles. Their introduction will therefore require systems that mitigate motion sickness. We investigated whether this can be achieved by augmenting the vehicle interior with additional visualizations. Participants were immersed in motion simulations on a moving-base driving simulator, where they were backward-facing passengers of an autonomous vehicle. Using a Head-Mounted Display, they were presented either with a regular view from inside the vehicle, or with augmented views that offered additional cues on the vehicle's present motion or motion 500ms into the future, displayed on the vehicle's interior panels. In contrast to the hypotheses and other recent studies, no difference was found between conditions. The absence of differences between conditions suggests a ceiling effect: providing a regular view may limit motion sickness, but presentation of additional visual information beyond this does not further reduce sickness.

Evidence for visual temporal order processing below the threshold for conscious perception

Correctly discriminating the order of events arising in our environment is a fundamental temporal process that allows us to better understand and interact with our dynamic world. However, if consecutive events are separated by an interval of less than 20-40 ms, we cannot consciously perceive their relative order. Nevertheless, indirect evidence suggests that the sequential order of events separated by less than 20 ms might still be processed subconsciously. In our study, we aimed to provide evidence that temporal order processing can occur below the threshold for conscious perception. We developed a novel paradigm in which participants were instructed that a visual cue, composed of two coloured stimuli appearing in a particular order, would allow them to predict the shape of a subsequent target. The interval between the two stimuli allowed temporal order to be consciously perceived (66 ms interval) or not (17 ms interval), as verified by performance on a separate temporal order judgment task. Performance was compared to a control condition that provided no predictive information. In both experiments, reaction times were faster in the order-cue conditions compared to the control condition, whether the SOA separating events was longer (66 ms) or shorter (17 ms) than the typical temporal order threshold. Therefore, even when participants could not consciously perceive the temporal order of two consecutive stimuli, the relative sequence of events was nevertheless processed and used to optimise performance. These results suggest that temporal order can be processed subconsciously.

A virus as an icon: the 2020 pandemic in images

The 2020 coronavirus pandemic is puzzling from a visual point of view. There are millions of photographs published about the crisis every day, yet we can see the key actor, the virus, only in artistic representations. Most of us also have very restricted access to central sites of the crisis, as intensive care units, nursing homes, meat packing plants and prisons are often not available for photographic representation. At the same time, we are oversupplied by other images that try to capture the "essence" of the moment. This article analyzes three prevalent visual genres in connection with the ongoing pandemic: abstract representations of the virus and public responses to it, images of heroes and sinners, and photographs of the "stage": the iconic spaces including empty public buildings and busy domestic spaces. All these iconic representations try to grasp the "deep meaning" of the crisis through a particular scene or moment. Their expressive surfaces have become our key sources to imagine the coronavirus crisis, and to socially connect in a time of painful and prolonged physical distance.

Correlations Between Audiovisual Temporal Processing and Sensory Responsiveness in Adolescents with Autistic Traits

Atypical sensory processing has recently gained much research interest as a key domain of autistic symptoms. Individuals with autism spectrum disorder (ASD) exhibit difficulties in processing the temporal aspects of sensory inputs, and show altered behavioural responses to sensory stimuli (i.e., sensory responsiveness). The present study examined the relation between sensory responsiveness (assessed by the Adult/Adolescent Sensory Profile) and audiovisual temporal integration (measured by unisensory temporal order judgement (TOJ) tasks and audiovisual simultaneity judgement (SJ) tasks) in typically-developing adolescents (n = 94). We found that adolescents with higher levels of autistic traits exhibited more difficulties in separating visual stimuli in time (i.e., larger visual TOJ threshold) and showed a stronger bias to perceive sound-leading audiovisual pairings as simultaneous. Regarding the associations between different measures of sensory function, reduced visual temporal acuity, but not auditory or multisensory temporal processing, was significantly correlated with more atypical patterns of sensory responsiveness. Furthermore, the positive correlation between visual TOJ thresholds and sensory avoidance was only found in adolescents with relatively high levels of autistic traits, but not in those with relatively low levels of autistic traits. These findings suggest that reduced visual temporal acuity may contribute to altered sensory experiences and may be linked to broader behavioural characteristics of ASD.

Characteristics of headaches among surgeons and associated factors: A cross-sectional study

BACKGROUND

Surgeons performing Minimally Invasive Surgery (MIS) report significant neck/shoulder problems and visual symptoms. Headache is another commonly reported symptom but publications about the characteristics and associated risk factors are limited.

PURPOSE OF THE STUDY

To determine the characteristics of headache among MIS surgeons and the associations of headache with neck/shoulder problems, visual symptoms and other associated factors.

DESIGN

A cross-sectional study.

METHODS

A comprehensive online survey was sent to MIS surgeons inclusive of 63 questions about individual and workplace physical factors, characteristics of headache, neck/shoulder problems and visual symptoms. Binary logistic regression models were conducted to determine the associations of the prevalence and severity of headache with risk factors.

THE MAIN FINDINGS

Headaches in the last 7 days were reported by 36% of surgeons, with 37% of these of moderate to severe intensity. Frequent intense headaches were often preceded by neck pain. Surgeons with headache were eight times more likely to also experience visual symptoms and four times more likely to experience neck/shoulder problems. Several factors (frequently adopting forward head movement, surgical specialty, sex and age) were significantly associated with headaches (p ≤ 0.05).

CONCLUSIONS

This study revealed headaches were present in one-third of MIS surgeons. During surgery, surgeons report adopting non-neutral neck/shoulder/head positions, which may explain headaches, neck/shoulder problems and visual symptoms. Evidence based strategies to assist surgeons better manage these symptoms are warranted.

A systematic review of ongoing clinical trials in optic pathway gliomas

INTRODUCTION

Optic pathway gliomas (OPGs), also known as Visual Pathway Gliomas, are insidious, debilitating tumours. They are most commonly WHO grade 1 pilocytic astrocytomas and frequently occur in patients with neurofibromatosis type 1. The location of OPGs within the optic pathway typically precludes complete resection or optimal radiation dosing, hence outcomes remain poor compared to many other low-grade gliomas. The aim of this systematic review was to formulate a comprehensive list of all current ongoing clinical trials that are specifically looking at clinical care of OPGs in order to identify trends in current research and provide an overview to guide future research efforts.

METHODS

This systematic review was conducted in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. The Cochrane Controlled Register of Trials (CENTRAL) and ClinicalTrials.gov were searched. Inclusion and exclusion criteria were applied and final results were reviewed.

RESULTS

501 clinical trials were identified with the search strategy. All were screened and eligible studies extracted and reviewed. This yielded 36 ongoing clinical trials, 27 of which were pharmacological agents in phase I-III. The remaining trials were a mixture of biological agents, radiation optimisation, diagnostic imaging, surgical intervention, and a social function analysis.

CONCLUSION

OPG is a complex multifaceted disease, and advances in care require ongoing research efforts across a spectrum of different research fields. This review provides an update on the current state of research in OPG and summarises ongoing trials.

Aberrant Cortical Ensembles and Schizophrenia-like Sensory Phenotypes in Setd1a+/- Mice

BACKGROUND

A breakdown of synchrony within neuronal ensembles leading to destabilization of network "attractors" could be a defining aspect of neuropsychiatric diseases such as schizophrenia, representing a common downstream convergence point for the diverse etiological pathways associated with the disease. Using a mouse genetic model, we demonstrated that altered ensembles are associated with pathological sensory cortical processing phenotypes resulting from loss of function mutations in the Setd1a gene, a recently identified rare risk genotype with very high penetrance for schizophrenia.

METHODS

We used fast two-photon calcium imaging of neuronal populations (calcium indicator GCaMP6s, 10 Hz, 100-250 cells, layer 2/3 of primary visual cortex, i.e., V1) in awake head-fixed mice (Setd1a^+/- vs. wild-type littermate control) during rest and visual stimulation with moving full-field square-wave gratings (0.04 cycles per degree, 2.0 cycles per second, 100% contrast, 12 directions). Multielectrode recordings were analyzed in the time-frequency domain to assess stimulus-induced oscillations and cross-layer phase synchrony.

RESULTS

Neuronal activity and orientation/direction selectivity were unaffected in Setd1a^+/- mice, but correlations between cell pairs in V1 showed altered distributions compared with wild-type mice, in both ongoing and visually evoked activity. Furthermore, population-wide "ensemble activations" in Setd1a^+/- mice were markedly less reliable over time during rest and visual stimulation, resulting in unstable encoding of basic visual information. This alteration of ensembles coincided with reductions in alpha and high-gamma band phase synchrony within and between cortical layers.

CONCLUSIONS

These results provide new evidence for an ensemble hypothesis of schizophrenia and highlight the utility of Setd1a^+/- mice for modeling sensory-processing phenotypes.