Lost time: Perception of events timeline affected by the COVID pandemic.

The need to remember when a past event occurred, is often an everyday necessity. However, placing events in a timeline is seldom accurate and although to some extent modulated by event saliency, on average we are less accurate in remembering a timeline for events happening in the distant past compared to more recent events. 277 participants took part in an online study during May 2022 in which they were asked to state the year in which a number of events took place. The events' occurrences ranged from 2017 to 2021, with participants choosing one date from the 2016-2022 range. In addition, they completed 4 questionnaires aimed at quantifying their State Boredom; Depression, Anxiety & stress; resilience; and level of activity during the lockdown periods of the COVID pandemic. As expected, the findings showed more errors for distant events than those in 2020, but surprisingly we found a large error for estimating the timing of events that occurred in 2021 matching in the extent to those 3 to 4 years earlier. The findings show that participants were less able to recall the timeline of very recent events coinciding with COVID lockdowns. This increased error in perception of event timeline correlated positively with reported levels of depression & anxiety as well as physical and mental demands during the pandemic, but negatively correlated with measures of resilience. Although measures of boredom showed significant correlations with reported depression & anxiety and physical/mental load, they did not correlate with errors in the perception of the event timeline for 2021. The findings are consistent with poor perception of event timeline reported previously in prison inmates. It is likely that an accurate perception of an event timeline relies on a collection of life events such as birthdays, holidays, travels, etc., anchoring our experiences in the time domain, which was largely absent during COVID restrictions.

Phasic Alertness and Multisensory Integration Contribute to Visual Awareness of Weak Visual Targets in Audio-Visual Stimulation under Continuous Flash Suppression.

Multisensory stimulation is associated with behavioural benefits, including faster processing speed, higher detection accuracy, and increased subjective awareness. These effects are most likely explained by multisensory integration, alertness, or a combination of the two. To examine changes in subjective awareness under multisensory stimulation, we conducted three experiments in which we used Continuous Flash Suppression to mask subthreshold visual targets for healthy observers. Using the Perceptual Awareness Scale, participants reported their level of awareness of the visual target on a trial-by-trial basis. The first experiment had an audio-visual Redundant Signal Effect paradigm, in which we found faster reaction times in the audio-visual condition compared to responses to auditory or visual signals alone. In two following experiments, we separated the auditory and visual signals, first spatially (experiment 2) and then temporally (experiment 3), to test whether the behavioural benefits in our multisensory stimulation paradigm could best be explained by multisensory integration or increased phasic alerting. Based on the findings, we conclude that the largest contributing factor to increased awareness of visual stimuli accompanied by auditory tones is a rise in phasic alertness and a reduction in temporal uncertainty with a small but significant contribution of multisensory integration.

More or less of me and you: self-relevance augments the effects of item probability on stimulus prioritization.

Self-relevance exerts a powerful influence on information processing. Compared to material associated with other people, personally meaningful stimuli are prioritized during decision-making. Further exploring the character of this effect, here we considered the extent to which stimulus enhancement is impacted by the frequency of self-relevant versus friend-relevant material. In a matching task, participants reported whether shape-label stimulus pairs corresponded to previously learned associations (e.g., triangle = self, square = friend). Crucially however, before the task commenced, stimulus-based expectancies were provided indicating the probability with which both self- and friend-related shapes would be encountered. The results revealed that task performance was impacted by the frequency of stimulus presentation in combination with the personal relevance of the items. When self- and friend-related shapes appeared with equal frequencies, a self-prioritization effect emerged (Expt. 1). Additionally, in both confirmatory (Expt. 2) and dis-confirmatory (Expt. 3) task contexts, stimuli that were encountered frequently (vs. infrequently) were prioritized, an effect that was most pronounced for self-relevant (vs. friend-relevant) items. Further computational analyses indicated that, in each of the reported experiments, differences in performance were underpinned by variation in the rate of information uptake, with evidence extracted more rapidly from self-relevant compared to friend-relevant stimuli. These findings advance our understanding of the emergence and origin of stimulus-prioritization effects during decisional processing.

Increased Visual Sensitivity and Occipital Activity in Patients With Hemianopia Following Vision Rehabilitation.

Hemianopia, loss of vision in half of the visual field, results from damage to the visual pathway posterior to the optic chiasm. Despite negative effects on quality of life, few rehabilitation options are currently available. Recently, several long-term training programs have been developed that show visual improvement within the blind field. Little is known of the underlying neural changes. Here, we have investigated functional and structural changes in the brain associated with visual rehabilitation. Seven human participants with occipital lobe damage enrolled in a visual training program to distinguish which of two intervals contained a drifting Gabor patch presented within the blind field. Participants performed ∼25 min of training each day for 3-6 months and undertook psychophysical tests and an magnetic resonance imaging scan before and after training. A control group undertook psychophysical tests before and after an equivalent period without training. Participants who were not at ceiling on baseline tests showed on average 9.6% improvement in Gabor detection, 8.3% in detection of moving dots, and 9.9% improvement in direction discrimination after training. Importantly, psychophysical improvement only correlated with improvement in Humphrey perimetry in the trained region of the visual field. Whole-brain analysis showed an increased neural response to moving stimuli in the blind visual field in motion area V5/hMT. Using a region-of-interest approach, training had a significant effect on the blood oxygenation level-dependent signal compared with baseline. Moreover, baseline V5/hMT activity was correlated to the amount of improvement in visual sensitivity using psychophysical and perimetry tests. This study, identifying a critical role for V5/hMT in boosting visual function, may allow us to identify which patients may benefit most from training and design adjunct intervention to increase training effects.SIGNIFICANCE STATEMENTHomonymous visual field loss is a common consequence of brain injury and is estimated to affect more than 230,000 people in the United Kingdom. Despite its high prevalence and well-described impact on quality of life, treatments to improve visual sensitivity remain experimental, and deficits are considered permanent after 6 months. Our study shows that behavioral changes following vision rehabilitation are associated with enhanced visual-evoked occipital activity to stimuli in the blind visual field. Unlike previous behavioral studies, we observe clinical changes that are specific to the trained region of vision. This lends significant weight to such training paradigms and offers a mechanism by which visual function can be improved despite damage to the primary visual pathway.

Conscious awareness modulates processing speed in the redundant signal effect.

Evidence for the influence of unaware signals on behaviour has been reported in both patient groups and healthy observers using the Redundant Signal Effect (RSE). The RSE refers to faster manual reaction times to the onset of multiple simultaneously presented target than those to a single stimulus. These findings are robust and apply to unimodal and multi-modal sensory inputs. A number of studies on neurologically impaired cases have demonstrated that RSE can be found even in the absence of conscious experience of the redundant signals. Here, we investigated behavioural changes associated with awareness in healthy observers by using Continuous Flash Suppression to render observers unaware of redundant targets. Across three experiments, we found an association between reaction times to the onset of a consciously perceived target and the reported level of visual awareness of the redundant target, with higher awareness being associated with faster reaction times. However, in the absence of any awareness of the redundant target, we found no evidence for speeded reaction times and even weak evidence for an inhibitory effect (slowing down of reaction times) on response to the seen target. These findings reveal marked differences between healthy observers and blindsight patients in how aware and unaware information from different locations is integrated in the RSE.

Self-relevance enhances evidence gathering during decision-making.

Despite repeated demonstrations that self-relevant material is prioritized during stimulus appraisal, a number of unresolved issues remain. In particular, it is unclear if self-relevance facilitates task performance when stimuli are encountered under challenging processing conditions. To explore this issue, using a backward masking procedure, here participants were required to report if briefly presented objects (pencils and pens) had previously been assigned to the self or a best friend (i.e., object-ownership task). The results yielded a standard self-ownership effect, such that responses were faster and more accurate to self-owned (vs. friend-owned) objects. In addition, a drift diffusion model analysis indicated that this effect was underpinned by a stimulus bias. Specifically, evidence was accumulated more rapidly from self-owned compared to friend-owned stimuli. These findings further elucidate the extent and origin of self-prioritization during decisional processing.

Efficacy and predictors of recovery of function after eye movement training in 296 hemianopic patients.

Compensatory approaches to rehabilitation of vision loss as a result of brain injury are aimed at improving the efficacy of eye movements, enabling patients to bring the otherwise unseen stimuli into their sighted field. Eye movement training has shown promise in a large number of studies in small clinical populations. Nevertheless, there remain two problems; standardisation and wide accessibility. NeuroEyeCoach™ (NEC) has been developed to address both. The therapy is based on the visual search approach and is adaptive to the patient's level of disability and the task difficulty is varied systematically through a combination of set-size and target/distractor similarity. Importantly, the therapy can be accessed online or in clinical settings, to enhance accessibility. Here we have reported on the findings from the first 296 consecutive cases who have accessed and completed NEC online, the largest cohort of patients studied to date. Patients' performance on two objective (visual search times and errors) and one subjective (self-reported disability) measures of performance were assessed before and after therapy. The findings showed that patients improved in search time, had less errors and improved disability scores in 87% (255/294), 80% (236/294) and 66% (167/254) of all cases respectively. We examined factors age, sex, side of blindness, age at the onset of brain injury, and time elapsed between the brain injury and start of therapy as predictors of both objective and subjective measures of improvements. Age was a significant predictor of improved search errors with older patients showing larger improvements. Time between brain injury and intervention negatively influenced search reaction time, however, none of the factors could predict improved subjective reports of disability.

Practice-related changes in eye movement strategy in healthy adults with simulated hemianopia.

The impact of visual field deficits such as hemianopia can be mitigated by eye movements that position the visual image within the intact visual field. Effective eye movement strategies are not observed in all patients, however, and it is not known whether persistent deficits are due to injury or to pre-existing individual differences. Here we examined whether repeated exposure to a search task with rewards for good performance would lead to better eye movement strategies in healthy individuals. Participants were exposed to simulated hemianopia during a search task in five testing sessions over five consecutive days and received monetary payment for improvements in search times. With practice, most participants made saccades that went further into the blind field earlier in search, specifically under conditions where little information about the target location would be gained by inspecting the sighted field. These changes in search strategy were correlated with reduced search times. This strategy improvement also generalised to a novel task, with better performance in naming objects in a photograph under conditions of simulated hemianopia after practice with visual search compared to a control group. However, even after five days, eye movements in most participants remained far from optimal. The results demonstrate the benefits, and limitations, of practice and reward in the development of effective coping strategies for visual field deficits.

Self-prioritization and perceptual matching: The effects of temporal construal.

Recent research has revealed that self-referential processing enhances perceptual judgments - the so-called self-prioritization effect. The extent and origin of this effect remains unknown, however. Noting the multifaceted nature of the self, here we hypothesized that temporal influences on self-construal (i.e., past/future-self continuity) may serve as an important determinant of stimulus prioritization. Specifically, as representations of the self increase in abstraction as a function of temporal distance (i.e., distance from now), self-prioritization may only emerge when stimuli are associated with the current self. The results of three experiments supported this prediction. Self-relevance only enhanced performance in a standard perceptual-matching task when stimuli (i.e., geometric shapes) were connected with the current self; representations of the self in the future (Expts. 1 & 2) and past (Expt. 3) failed to facilitate decision making. To identify the processes underlying task performance, data were interrogated using a hierarchical drift diffusion model (HDDM) approach. Results of these analyses revealed that self-prioritization was underpinned by a stimulus bias (i.e., rate of information uptake). Collectively, these findings elucidate when and how self-relevance influences decisional processing.

Self-relevance prioritizes access to visual awareness.

As we are cognizant of only a fraction of the available visual inputs at any given time, how is information selected for access to consciousness? In particular, does the personal significance of stimuli influence perceptual selection? Given that self-relevant information is prioritized during various stages of processing, here we hypothesized that self-association may privilege access to awareness under continuous flash suppression (CFS). The results supported this prediction. Compared with geometric shapes referenced to either a friend or stranger, those previously associated with self were prioritized in visual awareness. To establish the basis of this effect, the processes underlying task performance were investigated using a hierarchical drift diffusion model approach. These analyses showed that self-prioritization mapped onto both the decisional (i.e., starting value, z) and nondecisional (i.e., t0) parameters of the diffusion model. The implications of these findings are considered. (PsycINFO Database Record

Use of NeuroEyeCoach™ to Improve Eye Movement Efficacy in Patients with Homonymous Visual Field Loss.

Visual field deficits are common in patients with damaged retinogeniculostriate pathways. The patient's eye movements are often affected leading to inefficient visual search. Systematic eye movement training also called compensatory therapy is needed to allow patients to develop effective coping strategies. There is a lack of evidence-based, clinical gold-standard registered medical device accessible to patients at home or in clinical settings and NeuroEyeCoach (NEC) is developed to address this need. In three experiments, we report on performance of patients on NEC compared to the data obtained previously on the earlier versions of the search task (n = 32); we assessed whether the self-administered computerised tasks can be used to monitor the progress (n = 24) and compared the findings in a subgroup of patients to a healthy control group. Performance on cancellation tasks, simple visual search, and self-reported responses on activities of daily living was compared, before and after training. Patients performed similarly well on NEC as on previous versions of the therapy; the inbuilt functionality for pre- and postevaluation functions was sensitive to allowing assessment of improvements; and improvements in patients were significantly greater than those in a group of healthy adults. In conclusion, NeuroEyeCoach can be used as an effective rehabilitation tool to develop compensatory strategies in patients with visual field deficits after brain injury.

Inefficient search strategies in simulated hemianopia.

We investigated whether healthy participants can spontaneously adopt effective eye movement strategies to compensate for information loss similar to that experienced by patients with damage to visual cortex (hemianopia). Visual information in 1 hemifield was removed or degraded while participants searched for an emotional face among neutral faces or a line tilted 45° to the right among lines of varying degree of tilt. A bias to direct saccades toward the sighted field was observed across all 4 experiments. The proportion of saccades directed toward the "blind" field increased with the amount of information available in that field, suggesting fixations are driven toward salient visual stimuli rather than toward locations that maximize information gain. In Experiments 1 and 2, the sighted-field bias had a minimal impact on search efficiency, because the target was difficult to find. However, the sighted-field bias persisted even when the target was visually distinct from the distractors and could easily be detected in the periphery (Experiments 3 and 4). This surprisingly inefficient search behavior suggests that eye movements are biased to salient visual stimuli even when it comes at a clear cost to search efficiency, and efficient strategies to compensate for visual deficits are not spontaneously adopted by healthy participants. (PsycINFO Database Record

Redundancy gain in binocular rivalry.

A behavioural advantage is found across a wide range of stimuli when two targets are presented in opposite hemifields compared with those targets being presented together in one hemifield, or one target being presented alone. This advantage for responses to multiple targets versus a single target is often termed redundancy gain. Here we report on the findings of two experiments investigating redundancy gain in binocular rivalry. Experiment 1 presented a rival pair in one hemifield with an additional image presented to both eyes in the opposite hemifield. There was a weak effect of this stable image on the perceived dominance of the images within the rival pair. Experiment 2 presented a second rival pair in either the same or opposite hemifield and showed that instances of joint predominance were greater when the two pairs were presented in opposite hemifields than within the same hemifield. Therefore, the findings suggest that redundancy gain may be extended to stimuli presented under binocular rivalry conditions.

Pupil response as a predictor of blindsight in hemianopia.

Significantly above-chance detection of stimuli presented within the field defect of patients with postgeniculate lesions is termed "blindsight." It has been proposed that those with blindsight are more likely to benefit from visual rehabilitation by repeated stimulation, leading to increased visual sensitivity within their field defect. Establishing the incidence of blindsight and developing an objective and reliable method for its detection are of great interest. Sudden onsets of a grating pattern in the absence of any change in light flux result in a transient constriction of the pupil, termed "pupil grating response." The existence of pupil grating responses for stimuli presented within the blindfield has previously been reported in a hemianopic patient and two monkeys with removal of the primary visual cortex unilaterally. Here, we have systematically investigated the presence of a spatial channel of processing at a range of spatial frequencies using a psychophysical forced-choice technique and obtained the corresponding pupil responses in the blindfield of 19 hemianopic patients. In addition, in 13 cases we determined the pupil responses in a sighted field location that matched the blindfield eccentricities. Our findings demonstrate that blindfield pupil responses are similar to those for the sighted field, but attenuated in amplitude. Pupillometry correctly characterized the presence or absence of a significant psychophysical response and thus is worth measuring in the cortically blindfields as a predictor of intact psychophysical capacity. The incidence of blindsight where detection performance had been investigated psychophysically over a range of spatial frequencies was 70%.

Eye rivalry and object rivalry in the intact and split-brain.

Both the eye of origin and the images themselves have been found to rival during binocular rivalry. We presented traditional binocular rivalry stimuli (face to one eye, house to the other) and Diaz-Caneja stimuli (half of each image to each eye) centrally to both a split-brain participant and a control group. With traditional rivalry stimuli both the split-brain participant and age-matched controls perceived more coherent percepts (synchronised across the hemifields) than non-synchrony, but our split-brain participant perceived more non-synchrony than our controls. For rival stimuli in the Diaz-Caneja presentation condition, object rivalry gave way to eye rivalry with all participants reporting more non-synchrony than coherent percepts. We have shown that splitting the stimuli across the hemifields between the eyes leads to greater eye than object rivalry, but that when traditional rival stimuli are split as the result of the severed corpus callosum, traditional rivalry persists but to a lesser extent than in the intact brain. These results suggest that communication between the early visual areas is not essential for synchrony in traditional rivalry stimuli, and that other routes for interhemispheric interactions such as subcortical connections may mediate rivalry in a traditional binocular rivalry condition.

The continuum of detection and awareness of visual stimuli within the blindfield: from blindsight to the sighted-sight.

PURPOSE: We investigated systematically the effect of repeated exposure on detection and reported awareness of visual stimuli presented deep within the field defect of 5 hemianopic patients. METHODS: An objective measure of sensitivity (detection in a temporal two-alternative forced-choice paradigm) and subjective reports of awareness were recorded on trial by trial bases. Visual stimulus to be detected was a temporally modulated (10 Hz) circular patch (6° diameter) of vertical grating (1 c/°). Hemianopic patients took part in the study 8 to 15 months after injury, so that the findings could not be attributed to spontaneous recovery. RESULTS: Initially, high contrast (90%) target stimuli were detected at or near chance level with little reported awareness. In 4 of 5 cases, repeated stimulation led to improved sensitivity, indicated by increased detection scores and higher incidence of awareness. In a fifth case, there was no change in sensitivity despite extensive exposure (>22,000 trials). CONCLUSIONS: At retinal locations deep within the field defect, repeated stimulation can lead to blindsight performance (type I detection without awareness), followed by detection with reported awareness (type II blindsight), and eventual reported visual experiences. The findings indicate that conscious awareness of stimuli lies on a continuous spectrum and repeated systematic training can lead to improved visual sensitivity.

Saccadic latency is modulated by emotional content of spatially filtered face stimuli.

Models of attention and emotion assign a special status to the processing of threat. While evidence for threat-related attentional bias in highly anxious individuals is robust, effects in the normal population are mixed. An important explanation for the absence of threat-related attentional bias in nonanxious individuals may relate to the spatial frequency components of stimuli. Here we report behavioral data from two experiments examining the relationship between spatial frequency components of emotional and neutral faces and fast saccadic orienting behavior. In Experiment 1 participants had to saccade toward a single face, filtered to include mostly low, high or broad spatial frequencies (LSF, HSF or BSF), posing a fearful, happy or neutral expression presented for 20 ms in the periphery. At BSF a general emotional effect was found whereby saccadic responses were faster for fearful and happy faces relative to neutral, with no significant differences between fearful and happy faces. At LSF both fearful and happy faces had shorter saccadic latencies in comparison to neutral, demonstrating an emotional bias consistent with the BSF data. However, at LSF fearful faces resulted in significantly faster saccades than happy faces indicating that this bias was stronger for threat-related faces. There was no difference in saccadic responses between any emotions at HSF. Experiment 2 showed that the emotional bias diminished for inverted stimuli suggesting that the results were not attributable to low-level image properties. The findings suggest an overall advantage in the oculomotor system for orientation to emotional stimuli and at LSF in particular, a significantly faster localization of threat conveyed by the face stimuli in all individuals.

Emotional stimuli capture spatial attention but do not modulate spatial memory.

There is evidence that emotional stimuli capture spatial attention and that visual memory is enhanced for emotional content. Here we examine the relationship between emotional content of stimuli and interactions with spatial memory. To assess spatial memory, a modified version of the Corsi Blocks Task (CBT), utilising emotional stimuli, was employed. In the CBT a series of spatial positions are highlighted and the participant has to repeat these in the order in which they were produced. Results showed that presenting more meaningful stimuli, such as emotional faces (e.g. angry or happy) at the spatial locations in the CBT did not enhance spatial memory span relative to the presentation of neutral stimuli (e.g. neutral faces) or non-image stimuli signified by a change in the luminance of the blocks. In addition, saccadic eye movements performed during retention disrupted spatial memory for all items. This occurred irrespective of whether the item to be remembered was a face, a luminance-defined stimulus or whether the face carried emotional significance. The results were not related to the visibility of the test stimuli as participants recognised the emotion displayed by the faces significantly above chance and rated emotional faces as being more arousing than neutral faces. Changes in the type of emotional stimulus (e.g. fearful faces, emotional schematic faces, spiders or flowers) or encoding (short vs. long) duration did not alter the pattern of results. These findings demonstrate an important dissociation between spatial capture and memory. Although emotional content can modulate orienting behaviour, it appears to be of limited effect on spatial memory.

Evidence for perceptual learning with repeated stimulation after partial and total cortical blindness.

Lesions of occipital cortex result in loss of sight in the corresponding regions of visual fields. The traditional view that, apart from some spontaneous recovery in the acute phase, field defects remain permanently and irreversibly blind, has been challenged. In patients with partial field loss, a range of residual visual abilities in the absence of conscious perception (blindsight) has been demonstrated (Weiskrantz, 1986). Recent findings (Sahraie et al., 2006, 2010) have also demonstrated increased visual sensitivity in the field defect following repeated stimulation. We aimed to extend these findings by systematically exploring whether repeated stimulation can also lead to increased visual sensitivity in two cases with total (bilateral) cortical blindness. In addition, for a case of partial blindness, we examined the extent of the recovery as a function of stimulated region of the visual field, over extended periods of visual training. Positive auditory feedback was provided during the training task for correct detection of a spatial grating pattern presented at specific retinotopic locations using a temporal two alternative forced-choice paradigm (Neuro-Eye Therapy). All three cases showed improved visual sensitivity with repeated stimulation. The findings indicate that perceptual learning can occur through systematic visual field stimulation even in cases of bilateral cortical blindness.

Trans-saccadic priming in hemianopia: sighted-field sensitivity is boosted by a blind-field prime.

We experience visual stability despite shifts of the visual array across the retina produced by eye movements. A process known as remapping is thought to keep track of the spatial locations of objects as they move on the retina. We explored remapping in damaged visual cortex by presenting a stimulus in the blind field of two patients with hemianopia. When they executed a saccadic eye movement that would bring the stimulated location into the sighted field, reported awareness of the stimulus increased, even though the stimulus was removed before the saccade began and so never actually fell in the sighted field. Moreover, when a location was primed by a blind-field stimulus and then brought into the sighted field by a saccade, detection sensitivity for near-threshold targets appearing at this location increased dramatically. The results demonstrate that brain areas supporting conscious vision are not necessary for remapping, and suggest visual stability is maintained for salient objects even when they are not consciously perceived.