Visual consciousness dynamics in adults with and without autism

The role of pattern coherence in interocular grouping during binocular rivalry: Insights from individual differences

Interocular grouping during binocular rivalry occurs when two images presented to each eye combine into a coherent pattern. The experience of interocular grouping is thought to be influenced by both eye-of-origin, which involves excitatory lateral connections among monocular neurons, and pattern coherence, which results from top-down intervention from higher visual areas. However, it remains unclear which factor plays a more significant role in the interocularly-grouped percepts during binocular rivalry. The current study employed an individual difference approach to investigate whether grouping dynamics are mainly determined by eye-of-origin or pattern coherence. We found that participants who perceived interocularly-driven coherent percepts for a longer duration also tended to experience longer periods of monocularly-driven coherent percepts. In contrast, participants who experienced non-coherent piecemeal percepts for an extended duration in conventional rivalry also had longer duration of non-coherent percepts in the interocular coherence setting. This individual differences in experiencing interocular grouping suggest that pattern coherence exerts a stronger influence on grouping dynamics during binocular rivalry compared to eye-of-origin factors.

State-dependent alterations of implicit emotional dominance during binocular rivalry in subthreshold depression

Binocular rivalry, a visual perception phenomenon where two or more percepts alternate every few seconds when distinct stimuli are presented to the two eyes, has been reported as a biomarker in several psychiatric disorders. It is unclear whether abnormalities of binocular rivalry in depression could occur when emotional rivaling stimuli are used, and if so, whether an emotional binocular rivalry test could provide a trait-dependent or state-dependent biomarker. In the current study, 34 individuals with subthreshold depression and 31 non-depressed individuals performed a binocular rivalry task associated with implicit emotional processing. Participants were required to report their perceived orientations of the rival gratings in the foreground and to neglect emotional face stimuli in the background. The participants were retested after an approximately 4-month time interval. Compared to the non-depressed group, the subthreshold depression group showed significantly longer perceptual dominance durations of the grating with emotional faces as the background (i.e., implicit emotional dominance) at the initial assessment. However, the abnormality was not found at the follow-up assessment. More importantly, we found smaller changes in depressive severity at the follow-up assessment for individuals displaying longer emotional dominance at the initial assessment than for individuals with weaker emotional dominance. The current emotional binocular rivalry test may provide an objective, state-dependent biomarker for distinguishing individuals with subthreshold depression from non-depressed individuals.

Effects of interocular grouping demands on binocular rivalry

Binocular rivalry (BR) is a visual phenomenon in which perception alternates between two non-fusible images presented to each eye. Transition periods between dominant and suppressed images are marked by mixed percepts, where participants report fragments of each image being dynamically perceived. Interestingly, BR remains robust even when typical images are subdivided and presented in complementary patches to each eye, a phenomenon termed interocular grouping (IOG). The objective of the present study was to determine if increasing grouping demand in the context of BR changes the perceptual experience of rivalry. In 48 subjects with normal vision, mean dominant and mixed percept durations were recorded for classic BR and IOG conditions with increasing grouping demands from two, four, and six patches. We found that, as grouping demands increased, the duration of mixed periods increased. Indeed, durations of dominant and mixed percepts, as well as percentage of time spent in dominant or mixed state, differed significantly across conditions. However, durations of global dominant percepts remained relatively stable and saturated at about 1.5 seconds, despite the exponential increase in possible mixed combinations. Evidence shows that this saturation followed a nonlinear trend. The data also indicate that grouping across the vertical meridian is slightly more stable than for the horizontal meridian. Finally, individual differences in speed of alternation identified during BR were maintained in all interocular grouping conditions. These results provide new information about binocular visual spatial integration and will be useful for future studies of the underlying neural substrates and models of binocular vision.

Binocular rivalry in autistic and socially anxious adults

Background

Social anxiousness is a pervasive symptom in both social anxiety disorder and autism spectrum conditions. Binocular rivalry, which occurs when different images are presented to each eye, has been used to explore how visual and cognitive processing differs across various clinical diagnoses. Previous studies have separately explored whether individuals with autism or anxiety experience binocular rivalry in ways that are different from neurotypical individuals.

Methods

We applied rivalry paradigms that are similar to those used in previous studies of autism and general anxiety to individuals experiencing symptoms of social anxiousness at clinical or subclinical levels. We also incorporated rivalrous stimuli featuring neutral and emotional facial valances to explore potential overlap of social processing components in social anxiety and autism.

Results

We hypothesized that higher levels of social anxiousness would increase binocular rivalry switch rates and that higher levels of autistic traits would decrease switch rates. However, stimulus condition did not affect switch rates in either diagnostic group, and switch rate was not significantly predictive of dimensional measures of either autism or social anxiety.

Discussion

This may suggest a common mechanism for atypical visual cognition styles previously associated with social anxiety and autism. Alternatively, differences in switch rates may only emerge at higher trait levels than reported by the participants in our studies. Furthermore, these findings may be influenced by sex differences in our unique sample.

A theory of autism bringing across levels of description

Autism impacts a wide range of behaviors and neural functions. As such, theories of autism spectrum disorder (ASD) are numerous and span different levels of description, from neurocognitive to molecular. We propose how existent behavioral, computational, algorithmic, and neural accounts of ASD may relate to one another. Specifically, we argue that ASD may be cast as a disorder of causal inference (computational level). This computation relies on marginalization, which is thought to be subserved by divisive normalization (algorithmic level). In turn, divisive normalization may be impaired by excitatory-to-inhibitory imbalances (neural implementation level). We also discuss ASD within similar frameworks, those of predictive coding and circular inference. Together, we hope to motivate work unifying the different accounts of ASD.

InFoRM (Indicate-Follow-Replay-Me): A novel method to measure perceptual multistability dynamics using continuous data tracking and validated estimates of visual introspection

Perceptual multistability, e.g. Binocular Rivalry, has been intensively used as a tool to study visual consciousness. Current methods to assess multistability do not capture all potentially occurring perceptual states, provide no estimate of introspection, and lack continuous, high-temporal resolution to resolve perceptual changes between states and within mixed perceptual states. We introduce InFoRM (Indicate-Follow-Replay-Me), a four-phase method that (1) trains a participant to self-generate estimates of perceptual introspection-maps that are (2) validated during a physical mimic task, (3) gathers perceptual multistability data, and (4) confirms their validity during a physical replay. 28 condition-blinded adults performed InFoRM while experiencing binocular rivalry evoked with orthogonal sinusoidal gratings. A 60 Hz joystick (3600 data samples/minute) was used to indicate continuously changes across six perceptual states within each 1 min trial. A polarized monitor system was used to present the stimuli dichoptically. Three contrast conditions were investigated: low vs low, high vs high, and low vs high. InFoRM replicates standard outcome measures, i.e. alternation rate, mean and relative proportions of perception, and distribution of exclusive percepts that are well fitted with gamma functions. Furthermore, InFoRM generates novel outcomes that deliver new insights in visual cognition via estimates of introspection maps, in ocular dominance via perceptual-state-specific dominance scores, in transitory dynamics between and within perceptual states, via techniques adopted from eye-tracking, and in rivalry-zone-size estimates utilizing InFoRM's ability to simulate piecemeal perception. The replay phase (physical replay of perceptual rivalry) confirmed good overall agreement (73% ±5 standard deviation). InFoRM can be applied to other multistable paradigms and can be used to study visual consciousness in typical and neuro-atypical populations.

Microglia dynamics in aging-related neurobehavioral and neuroinflammatory diseases

Microglia represent the first line of immune feedback in the brain. Beyond immune surveillance, they are essential for maintaining brain homeostasis. Recent research has revealed the microglial cells' spatiotemporal heterogeneity based on their local and time-based functions in brain trauma or disease when homeostasis is disrupted. Distinct "microglial signatures" have been recorded in physiological states and brain injuries, with discrete or sometimes overlapping pro- and anti-inflammatory functions. Microglia are involved in the neurological repair processes, such as neurovascular unit restoration and synaptic plasticity, and manage the extent of the damage due to their phenotype switching. The versatility of cellular phenotypes beyond the classical M1/M2 classification, as well as the double-edge actions of microglia in neurodegeneration, indicate the need for further exploration of microglial cell dynamics and their contribution to neurodegenerative processes. This review discusses the homeostatic functions of different microglial subsets focusing on neuropathological conditions. Also, we address the feasibility of targeting microglia as a therapeutic strategy in neurodegenerative diseases.

Exploring the Relationship Between Binocular Imbalance and Myopia: Refraction with a Virtual Reality Platform

To explore the relationship between binocular imbalance (BI) and the abnormal development of binocular refraction. BI data were collected by enrolling the first 1,000 adolescents and children aged 6-18 years in Shenzhen Eye Hospital from April 2020 to January 2021. In this cross-sectional study, the imbalance value (IV) did not show a statistical correlation with the spherical equivalent (SE) (oculus dexter [OD]: r = 0.022, p = 0.586; oculus sinister [OS]: r = -0.021, p = 0.606), and had little correlation with the uncorrected visual acuity (VA) (OD: r = -0.084, p = 0.039; OS: r = -0.034, p = 0.408). The proportion of binocular contrast imbalance (BCI) (the absolute value) maintained the highest level (from 54.42 to 79.17 percent) with the increase of bilateral SE difference in the four subcategories (binocular balance, monocular suppression, binocular rivalry, and BCI). From -100 to +100 of IV, the SE of the left eye tends to increase negatively when compared with the right eye (from -95 < IV ≦ -80, SE difference = -0.83 ± 1.58, to -20 < IV ≦ -10, SE difference = -0.14 ± 0.61; from 10 ≦ IV <20, SE difference = -0.05 ± 0.80, to 80 ≦ IV <95, SE difference = 1.48 ± 2.77). BI widely exists within the general pediatric population. The BI did not show significant correlation with the unilateral eye refractive state and the VA. However, the BI may be accompanied by imbalanced development of the eye refractive system. Furthermore, the SE of the dominant eye (from the prospective of BI) tends to be more negative than that of the opposite eye as the value increases. Clinical Trial Registration number: ChiCTR2100045457.