Processing Of Sensory Information Research Articles

Vasopressin as Possible Treatment Option in Autism Spectrum Disorder.

Autism spectrum disorder (ASD) is rather common, presenting with prevalent early problems in social communication and accompanied by repetitive behavior. As vasopressin was implicated not only in salt-water homeostasis and stress-axis regulation, but also in social behavior, its role in the development of ASD might be suggested. In this review, we summarized a wide range of problems associated with ASD to which vasopressin might contribute, from social skills to communication, motor function problems, autonomous nervous system alterations as well as sleep disturbances, and altered sensory information processing. Beside functional connections between vasopressin and ASD, we draw attention to the anatomical background, highlighting several brain areas, including the paraventricular nucleus of the hypothalamus, medial preoptic area, lateral septum, bed nucleus of stria terminalis, amygdala, hippocampus, olfactory bulb and even the cerebellum, either producing vasopressin or containing vasopressinergic receptors (presumably V1a). Sex differences in the vasopressinergic system might underline the male prevalence of ASD. Moreover, vasopressin might contribute to the effectiveness of available off-label therapies as well as serve as a possible target for intervention. In this sense, vasopressin, but paradoxically also V1a receptor antagonist, were found to be effective in some clinical trials. We concluded that although vasopressin might be an effective candidate for ASD treatment, we might assume that only a subgroup (e.g., with stress-axis disturbances), a certain sex (most probably males) and a certain brain area (targeting by means of virus vectors) would benefit from this therapy.

Network Model of Nociceptive Processing in the Superficial Spinal Dorsal Horn Reveals Mechanisms of Hyperalgesia, Allodynia, and Spinal Cord Stimulation.

The spinal dorsal horn (DH) processes sensory information and plays a key role in transmitting nociception to supraspinal centers. Loss of DH inhibition during neuropathic pain unmasks a pathway from non-nociceptive Aβ-afferent inputs to superficial dorsal horn (SDH) nociceptive-specific (NS) projection neurons, and this change may contribute to hyperalgesia and allodynia. We developed and validated a computational model of SDH neuronal circuitry that linked non-nociceptive Aβ-afferent inputs in lamina II/III to a NS projection neuron in lamina I via a network of excitatory interneurons. The excitatory pathway and the NS projection neuron were in turn gated by inhibitory interneurons with connections based on prior patch clamp recordings. Changing synaptic weights in the computational model to replicate neuropathic pain states unmasked a low-threshold excitatory pathway to NS neurons similar to experimental recordings. Spinal cord stimulation (SCS) is an effective therapy for neuropathic pain, and accumulating experimental evidence indicates that NS neurons in the SDH also respond to SCS. Accounting for these responses may inform therapeutic improvements, and we quantified responses to SCS in the SDH network model and examined the role of different modes of inhibitory control in modulating NS neuron responses to SCS. We combined the SDH network model with a previously published model of the deep dorsal horn (DDH) and identified optimal stimulation frequencies across different neuropathic pain conditions. Finally, we found that SCS-generated inhibition did not completely suppress model NS activity during simulated pinch inputs, providing an explanation of why SCS does not eliminate acute pain.

The systemic effects of the enriched environment on the conditioned fear reaction.

In this review, a hypothesis is proposed to explain the beneficial effect of an enriched environment (EE) on the conditioned fear reaction (CFR) from the perspective of a functional system of behavioral control. According to the hypothesis, the EE affects all behavioral act components, including the processing of sensory information, memory, motivational and reinforcing systems, and motor activities, which weakens the CFR. Animals raised in the EE have effects that are comparable to those of context (CTX) and CS pre-exposures at latent inhibition. An abundance of stimuli in the EE and constant contact with them provide the formation of CS-noUS and CTX-noUS connections that later, during CFR learning, slow down and diminish fear. The EE also contributes to faster processing of information and habituation to it. As a result, many stimuli in the context lose their significance, and subjects simply ignore them. And finally, the EE affects the motivational and reinforcing brain mechanisms, induces an impairment of search activity, and worsens memory consolidation, which leads to a reduction of CFR.

Structural changes in the thalamus and its subregions in regulating different symptoms of posttraumatic stress disorder

As a key center for sensory information processing and transmission, the thalamus plays a crucial role in the development of posttraumatic stress disorder (PTSD). However, the changes in the thalamus and its role in regulating different PTSD symptoms remain unclear. In this study, fourteen PTSD patients and eighteen healthy controls (HCs) were recruited. All subjects underwent whole-brain T1-weighted three-dimensional Magnetization Prepared Rapid Gradient Echo Imaging scans. Gray matter volume (GMV) in the thalamus and its subregions were estimated using voxel-based morphometry (VBM). Compared to HCs, PTSD patients exhibited significant GMV reduction in the left thalamus and its subregions, including anterior, mediodorsal, ventral-lateral-dorsal (VLD), ventral-anterior, and ventral-lateral-ventral (VLV). Among the significantly reduced thalamic subregions, we found positive correlations between the GMV values of the left VLD and VLV and the re-experiencing symptoms score, arousal symptoms score, and total CAPS score. When using the symptom-related GMV values of left VLV and VLD in combination as a predictor, receiver operating characteristic (ROC) analysis revealed that the area under the curve (AUC) for binary classification reached 0.813. This study highlights the neurobiological mechanisms of PTSD related to thalamic changes and may provide potential imaging markers for diagnosis and therapy targets.

Muscular reflex gains reflect changes of mind in reaching.

Decisions for action are accompanied with a continual processing of sensory information, sometimes resulting in a revision of the initial choice, called a change of mind (CoM). While the motor system is tuned during the formation of a reach decision, it is unclear whether its preparatory state differs between CoM and non-CoM decisions. To test this, participants (n=14) viewed a random dot motion (RDM) stimulus of various coherence levels for a random viewing duration. At the onset of a mechanical perturbation, which rapidly stretched the pectoralis muscle, they indicated the perceived motion direction by making a reaching movement to one of two targets. Using electromyography (EMG), we quantified the reflex gains of the pectoralis and posterior deltoid muscle. Results show that reflex gains scaled with both the coherence level and viewing duration of the stimulus. We fit a drift diffusion model (DDM) to the behavioral choices. The decision variable (DV), derived from the DDM, correlated well with the measured reflex gain at the single trial level. However, when matched on DV magnitude, reflex gains were significantly lower in CoM than non-CoM trials. We conclude that the internal state of the motor system, as measured by the spinal reflexes, reflects the continual deliberation on sensory evidence for action selection, including the post-decisional evidence that can lead to a change of mind.

Multisensory integration in the mammalian brain: diversity and flexibility in health and disease.

Multisensory integration (MSI) occurs in a variety of brain areas, spanning cortical and subcortical regions. In traditional studies on sensory processing, the sensory cortices have been considered for processing sensory information in a modality-specific manner. The sensory cortices, however, send the information to other cortical and subcortical areas, including the higher association cortices and the other sensory cortices, where the multiple modality inputs converge and integrate to generate a meaningful percept. This integration process is neither simple nor fixed because these brain areas interact with each other via complicated circuits, which can be modulated by numerous internal and external conditions. As a result, dynamic MSI makes multisensory decisions flexible and adaptive in behaving animals. Impairments in MSI occur in many psychiatric disorders, which may result in an altered perception of the multisensory stimuli and an abnormal reaction to them. This review discusses the diversity and flexibility of MSI in mammals, including humans, primates and rodents, as well as the brain areas involved. It further explains how such flexibility influences perceptual experiences in behaving animals in both health and disease. This article is part of the theme issue 'Decision and control processes in multisensory perception'.

Astrocytes adjust the dynamic range of cortical network activity to control modality-specific sensory information processing

Cortical neuron-astrocyte communication in response to peripheral sensory stimulation occurs in a topographic-, frequency-, and intensity-dependent manner. However, the contribution of this functional interaction to the processing of sensory inputs and consequent behavior remains unclear. We investigate the role of astrocytes in sensory information processing at circuit and behavioral levels by monitoring and manipulating astrocytic activity invivo. We show that astrocytes control the dynamic range of the cortical network activity, optimizing its responsiveness to incoming sensory inputs. The astrocytic modulation of sensory processing contributes to setting the detection threshold for tactile and thermal behavior responses. The mechanism of such astrocytic control is mediated through modulation of inhibitory transmission to adjust the gain and sensitivity of responding networks. These results uncover a role for astrocytes in maintaining the cortical network activity in an optimal range to control behavior associated with specific sensory modalities.

Barriers and needs in mental healthcare of adults with autism spectrum disorder in Germany: a qualitative study in autistic adults, relatives, and healthcare providers

BackgroundAutism refers to a neurodevelopmental condition with characteristic impairments in social interaction and communication, restrictive and repetitive behaviors, as well as difficulties in sensory information processing and daily living skills. Even though symptoms persist from early childhood throughout the lifespan and often require long-term support, there is a lack of mental health services that sufficiently meet the needs of autistic adults. Previous evidence suggested individual, professional and structural barriers to healthcare for autistic adults. Here, using a peer research approach, we sought to systematically investigate barriers and needs in mental healthcare of autistic adults in Germany at the three relevant levels (individual, professional, structural) and from three relevant perspectives (autistic adults, relatives and healthcare providers), in order to obtain specific recommendations for optimized healthcare.MethodsMaximum variation sampling was used to account for the complexity of the research field. Semi-structured, open-ended interviews were conducted with autistic adults (n = 15) and focus groups with relatives/partners (n = 12), and healthcare providers of several professions (n = 15). Data analysis was performed using the codebook approach of thematic analysis.ResultsPoor mental healthcare of autistic adults in Germany was characterized by six central and overarching themes: (i) lack of knowledge about autism, (ii) a need for increased participation/involvement, (iii) consideration of autism-specific needs in treatment, (iv) lack of services, (v) limited access to services, and (vi) improvement of stakeholder collaboration. Themes were similarly reported across participants, emphasizing dissatisfaction in all stakeholders.ConclusionsWe identified major barriers to mental healthcare for autistic adults in Germany that affect autistic adults, but are also of concern to relatives and healthcare providers. Our results point to specific and generic areas for improvement, independent of stakeholder perspectives, which could guide future development of needs- and evidence-based services, recommendations and guidelines of mental healthcare for people with autism across the lifespan.Trial registrationThis study protocol was preregistered at the Open Science Framework (https://osf.io/5x8pg).

TMS-induced inhibition of the left premotor cortex modulates illusory social perception

Communicative actions from one person are used to predict another person's response. However, in some cases, these predictions can outweigh the processing of sensory information and lead to illusory social perception such as seeing two people interact, although only one is present (i.e., seeing a Bayesian ghost). We applied either inhibitory brain stimulation over the left premotor cortex (i.e., real TMS) or sham TMS. Then, participants indicated the presence or absence of a masked agent that followed a communicative or individual gesture of another agent. As expected, participants had more false alarms in the communicative (i.e., Bayesian ghosts) than individual condition in the sham TMS session and this difference between conditions vanished after real TMS. In contrast to our hypothesis, the number of false alarms increased (rather than decreased) after real TMS. These pre-registered findings confirm the significance of the premotor cortex for social action predictions and illusory social perception.

Children at Familial High risk of Schizophrenia and Bipolar Disorder Exhibit Altered Connectivity Patterns During Pre-attentive Processing of an Auditory Prediction Error.

Individuals with schizophrenia or bipolar disorder have attenuated auditory mismatch negativity (MMN) responses, indicating impaired sensory information processing. Computational models of effective connectivity between brain areas underlying MMN responses show reduced connectivity between fronto-temporal areas in individuals with schizophrenia. Here we ask whether children at familial high risk (FHR) of developing a serious mental disorder show similar alterations. We recruited 67 children at FHR for schizophrenia, 47 children at FHR for bipolar disorder as well as 59 matched population-based controls from the Danish High Risk and Resilience study. The 11-12-year-old participants engaged in a classical auditory MMN paradigm with deviations in frequency, duration, or frequency and duration, while we recorded their EEG. We used dynamic causal modeling (DCM) to infer on the effective connectivity between brain areas underlying MMN. DCM yielded strong evidence for differences in effective connectivity among groups in connections from right inferior frontal gyrus (IFG) to right superior temporal gyrus (STG), along with differences in intrinsic connectivity within primary auditory cortex (A1). Critically, the 2 high-risk groups differed in intrinsic connectivity in left STG and IFG as well as effective connectivity from right A1 to right STG. Results persisted even when controlling for past or present psychiatric diagnoses. We provide novel evidence that connectivity underlying MMN responses in children at FHR for schizophrenia and bipolar disorder is altered at the age of 11-12, echoing findings that have been found in individuals with manifest schizophrenia.

Effect of teeth clenching on handgrip force in adult men: role of periodontal mechanoreceptors.

Voluntary teeth clenching is shown to increase the strength of muscle reflexes contributing to the improvement of postural stability. However, the interaction between the handgrip strength and teeth clenching is not yet understood. In this study, we aimed to evaluate the change in handgrip force in response to voluntary teeth clenching, and its relation to the peripheral receptors that play a central role in the control of mastication. Thirty-six healthy men were divided into two groups: aged 50-59years, no dental prosthesis, and 53-62years with total dental prosthesis. Each individual was given handgrip and teeth clenching instructions for five experiments: only handgrip, teeth clenching followed by handgrip without teeth clenching, teeth clenching followed by handgrip with teeth clenching, and the repetition of the last two instructions while wearing mouth guards. Our findings showed that maximum handgrip force decreased and the resistance to fatigue increased in complete edentulous individuals using appropriate prostheses. Also, the significantly lower maximum handgrip force and higher resistance to fatigue values of the participants with dental prosthesis using a mouth guard while teeth clenching, revealed the central roles of periodontal mechanoreceptors. Decreases in masticatory sensory information processes influence handgrip force values which is the most important indicator of motor function. The lack of periodontal mechanoreceptors associated with dental prosthesis usage may lead to a loss in muscle strength.

Does Binaural Stimulation Enhance Temporal Processing in Young Children?

Background and objective Temporal processing abilities help perceive signal changes over time. Efficient temporal processing is necessary for pitch perception, voice identification, and speech perception. It plays a significant role in language development. Internal redundancy of the central auditory nervous plays a role in processing sensory information. There is a need to gain more insights into the maturation of neural hardwiring that supports binaural temporal processing at a young age. The purpose of the present study was to evaluate the difference between monaural and binaural temporal processing in children aged 7-11 years. Methods Temporal processing was assessed using gap detection and temporal modulation transfer function (TMTF) tests. The tests were administered in 40 typically developing children with normal clinical auditory sensitivity. The maximum likelihood procedure (MLP), a MATLAB toolbox, was employed to deliver the stimulus. A multivariate analysis followed by post hoc analysis was performed to analyze the data. Results There was a significant difference between binaural and monoaural stimulation in children aged 7-11 years. However, there was no statistically significant difference between the right and left ears for gap detection threshold (GDT) and TMTF across all test frequencies. Conclusion Based on our findings, binaural stimulation enhances temporal processing in young children.

Visual Information Is Predictively Encoded in Occipital Alpha/Low-Beta Oscillations.

Hierarchical predictive coding networks are a general model of sensory processing in the brain. Under neural delays, these networks have been suggested to naturally generate oscillatory activity in approximately the α frequency range (∼8-12 Hz). This suggests that α oscillations, a prominent feature of EEG recordings, may be a spectral "fingerprint" of predictive sensory processing. Here, we probed this possibility by investigating whether oscillations over the visual cortex predictively encode visual information. Specifically, we examined whether their power carries information about the position of a moving stimulus, in a temporally predictive fashion. In two experiments (N = 32, 18 female; N = 34, 17 female), participants viewed an apparent-motion stimulus moving along a circular path while EEG was recorded. To investigate the encoding of stimulus-position information, we developed a method of deriving probabilistic spatial maps from oscillatory power estimates. With this method, we demonstrate that it is possible to reconstruct the trajectory of a moving stimulus from α/low-β oscillations, tracking its position even across unexpected motion reversals. We also show that future position representations are activated in the absence of direct visual input, demonstrating that temporally predictive mechanisms manifest in α/β band oscillations. In a second experiment, we replicate these findings and show that the encoding of information in this range is not driven by visual entrainment. By demonstrating that occipital α/β oscillations carry stimulus-related information, in a temporally predictive fashion, we provide empirical evidence of these rhythms as a spectral "fingerprint" of hierarchical predictive processing in the human visual system.SIGNIFICANCE STATEMENT "Hierarchical predictive coding" is a general model of sensory information processing in the brain. When in silico predictive coding models are constrained by neural transmission delays, their activity naturally oscillates in roughly the α range (∼8-12 Hz). Using time-resolved EEG decoding, we show that neural rhythms in this approximate range (α/low-β) over the human visual cortex predictively encode the position of a moving stimulus. From the amplitude of these oscillations, we are able to reconstruct the stimulus' trajectory, revealing signatures of temporally predictive processing. This provides direct neural evidence linking occipital α/β rhythms to predictive visual processing, supporting the emerging view of such oscillations as a potential spectral "fingerprint" of hierarchical predictive processing in the human visual system.

Attention is required for canonical brain signature of prediction error despite early encoding of the stimuli.

Prediction error is a basic component of predictive-coding theory of brain processing. According to the theory, each stage of brain processing of sensory information generates a model of the current sensory input; subsequent input is compared against the model and only if there is a mismatch, a prediction error, is further processing performed. Recently, Smout and colleagues found that a signature of prediction error, the visual (v) mismatch negativity (MMN), for a fundamental property of visual input-its orientation-was absent without endogenous attention on the stimuli. This is remarkable because the weight of evidence for MMNs from audition and vision is that they occur without endogenous attention. To resolve this discrepancy, we conducted an experiment addressing 2 alternative explanations for Smout and colleagues' finding: that it was from a lack of reproducibility or that participants' visual systems did not encode the stimuli when attention was on something else. We conducted a similar experiment to that of Smout and colleagues. We showed 21 participants sequences of identically oriented Gabor patches, standards, and, unpredictably, otherwise identical, Gabor patches differing in orientation by ±15°, ±30°, and ±60°, deviants. To test whether participants encoded the orientation of the standards, we varied the number of standards preceding a deviant, allowing us to search for a decrease in activity with the number of repetitions of standards-repetition suppression. We diverted participants' attention from the oriented stimuli with a central, letter-detection task. We reproduced Smout and colleagues' finding of no vMMN without endogenous attention, strengthening their finding. We found that our participants showed repetition suppression: They did encode the stimuli preattentively. We also found early processing of deviants. We discuss various explanations why the earlier processing did not extend into the vMMN time window, including low precision of prediction.

SoundFields: A Virtual Reality Home-Based Intervention for Auditory Hypersensitivity Experienced by Autistic Children

Previous studies have shown that autistic people often display atypical responses when processing sensory information, with particular prevalence within the auditory domain. Often provoked by common everyday sounds, auditory hypersensitivity can result in self-regulatory fear responses. This can be potentially harmful to autistic individuals and the people around them and is associated with greater occurrence of anxiety, depression, and poorer overall quality of life in the autistic population. Rather than a physiological causation, the literature suggests that hypersensitivity to sound is likely to be caused by how auditory stimuli are processed in the brain. This paper reports a home-based digital intervention aimed to address auditory hypersensitivity in autistic children. Developed as an interactive virtual reality game, the system integrates exposure-based therapy techniques into game mechanics and delivers target auditory stimuli to the player rendered via binaural-based spatial audio. The performance of the platform was evaluated in a 10-week feasibility study, during which children (n = 7) engaged weekly with the game during a 30 min session. Following this period, a comparison of pre- and post-study measurements showed a decrease in sensitivity for five participants, with qualitative feedback highlighting an increase in tolerance towards real-world stimuli and challenging environments. These results provide initial support for SoundFields as a home-based intervention targeting auditory hypersensitivity experienced by autistic children.

Prestimulus α/β power in temporal-order judgments: individuals differ in direction of modulation but show consistency over auditory and visual tasks.

The processing of incoming sensory information can be differentially affected by varying levels of α-power in the electroencephalogram (EEG). A prominent hypothesis is that relatively low prestimulus α-power is associated with improved perceptual performance. However, there are studies in the literature that do not fit easily into this picture, and the reasons for this are poorly understood and rarely discussed. To evaluate the robustness of previous findings and to better understand the overall mixed results, we used a spatial TOJ task in which we presented auditory and visual stimulus pairs in random order while recording EEG. For veridical and non-veridical TOJs, we calculated the power spectral density (PSD) for 3 frequencies (5 Hz steps: 10, 15, and 20 Hz). We found on the group level: (1) Veridical auditory TOJs, relative to non-veridical, were associated with higher β-band (20 Hz) power over central electrodes. (2) Veridical visual TOJs showed higher β-band (10, 15 Hz) power over parieto-occipital electrodes (3) Electrode site interacted with TOJ condition in the β-band: For auditory TOJs, PSD over central electrodes was higher for veridical than non-veridical and over parieto-occipital electrodes was lower for veridical than non-veridical trials, while the latter pattern was reversed for visual TOJs. While our group-level result showed a clear direction of prestimulus modulation, the individual-level modulation pattern was variable and included activations opposite to the group mean. Interestingly, our results at the individual-level mirror the situation in the literature, where reports of group-level prestimulus modulation were found in either direction. Because the direction of individual activation of electrodes over auditory brain regions and parieto-occipital electrodes was always negatively correlated in the respective TOJ conditions, this activation opposite to the group mean cannot be easily dismissed as noise. The consistency of the individual-level data cautions against premature generalization of group-effects and suggests different strategies that participants initially adopted and then consistently followed. We discuss our results in light of probabilistic information processing and complex system properties, and suggest that a general description of brain activity must account for variability in modulation directions at both the group and individual levels.

Social odor discrimination and its enhancement by associative learning in the hippocampal CA2 region

Although the hippocampus is crucial for social memory, how social sensory information is combined with contextual information to form episodic social memories remains unknown. Here, we investigated the mechanisms for social sensory information processing using two-photon calcium imaging from hippocampal CA2 pyramidal neurons (PNs)-which are crucial for social memory-in awake head-fixed mice exposed to social and non-social odors. We found that CA2 PNs represent social odors of individual conspecifics and that these representations are refined during associative social odor-reward learning to enhance the discrimination of rewarded compared with unrewarded odors. Moreover, the structure of the CA2 PN population activity enables CA2 to generalize along categories of rewarded versus unrewarded and social versus non-social odor stimuli. Finally, we found that CA2 is important for learning social but not non-social odor-reward associations. These properties of CA2 odor representations provide a likely substrate for the encoding of episodic social memory.

Влияние осложненных родов на развитие высших психических функций детей 7-8 лет (на примере первоклассников г. Архангельска)

Unfavourable course of labour is one of the most significant factors of perinatal dysontogenesis that have a negative impact on the development of the central nervous system in children. The purpose of this article was to assess the effects of complicated birth on the development of higher mental functions in children aged 7–8 years. Materials and methods. The study was conducted in October 2017 and involved 86 first-formers (48 boys and 38 girls) studying in primary schools of the city of Arkhangelsk. Based on the results of parent surveys, two comparison groups were formed. The main group included 18 first-formers (7 boys and 11 girls) who were born as a result of complicated delivery. The control group included 30 children (18 boys and 12 girls) with a favourable course of the perinatal period. To assess higher mental functions, we determined the level of short-term memory development, intelligence, and adjustment of the pace of activity. Results. The study showed that first-formers born as a result of complicated delivery have certain psychophysiological features that can cause difficulties in schooling. In particular, they have a lower rate of operational activity (p = 0.026), which may be evidence of problems with sensory information processing and immaturity of the control functions of the brain. In addition, these children differ significantly from their peers in terms of the development of verbal intelligence (p = 0.001), which indicates particular vulnerability of the child’s speech functions to the factors of perinatal dysontogenesis.

Quantifying body ownership information processing and perceptual bias in the rubber hand illusion

Bodily illusions have fascinated humankind for centuries, and researchers have studied them to learn about the perceptual and neural processes that underpin multisensory channels of bodily awareness. The influential rubber hand illusion (RHI) has been used to study changes in the sense of body ownership — that is, how a limb is perceived to belong to one's body, which is a fundamental building block in many theories of bodily awareness, self-consciousness, embodiment, and self-representation. However, the methods used to quantify perceptual changes in bodily illusions, including the RHI, have mainly relied on subjective questionnaires and rating scales, and the degree to which such illusory sensations depend on sensory information processing has been difficult to test directly. Here, we introduce a signal detection theory (SDT) framework to study the sense of body ownership in the RHI. We provide evidence that the illusion is associated with changes in body ownership sensitivity that depend on the information carried in the degree of asynchrony of correlated visual and tactile signals, as well as with perceptual bias and sensitivity that reflect the distance between the rubber hand and the participant's body. We found that the illusion's sensitivity to asynchrony is remarkably precise; even a 50 ms visuotactile delay significantly affected body ownership information processing. Our findings conclusively link changes in a complex bodily experience such as body ownership to basic sensory information processing and provide a proof of concept that SDT can be used to study bodily illusions.

Visual velocity perception dysfunction in Parkinson’s disease

ObjectiveCompared with motor deficits, sensory information processing in Parkinson’s disease (PD) is relatively unexplored. While there is increasing interest in understanding the sensory manifestations of PD, the extent of sensory abnormality in PD has remained relatively unexplored. Furthermore, most investigations on the sensory aspects of PD involve motor aspects, causing confounding results. As sensory deficits often arise in early PD development stages, they present a potential technological target for diagnosis and disease monitoring that is affordable and accessible. Considering this, the current study’s aim is to assess visual spatiotemporal perception independent of goal directed movements in PD by designing and using a scalable computational tool. MethodsA flexible 2-D virtual reality environment was created to evaluate various cases of visual perception. Using the tool, an experimental task quantifying the visual perception of velocity was tested on 37 individuals with PD and 17 age-matched control participants. Results: PD patients, both ON and OFF PD therapy, displayed perceptual impairments (p = 0.001 and p = 0.008, respectively) at slower tested velocity magnitudes. These impairments were even observed in early stages of PD (p = 0.015). ConclusionVisual velocity perception is impaired in PD patients, which suggests impairments in visual spatiotemporal processing occur in PD and provides a promising modality to be used with disease monitoring software. SignificanceVisual velocity perception shows high sensitivity to PD at all stages of the disease. Dysfunction in visual velocity perception may contribute to observed motor dysfunction in PD.