Ramp-to-threshold dynamics in a hindbrain population controls the timing of spontaneous saccades.

Organisms have the capacity to make decisions based solely on internal drives. However, it is unclear how neural circuits form decisions in the absence of sensory stimuli. Here we provide a comprehensive map of the activity patterns underlying the generation of saccades made in the absence of visual stimuli. We perform calcium imaging in the larval zebrafish to discover a range of responses surrounding spontaneous saccades, from cells that display tonic discharge only during fixations to neurons whose activity rises in advance of saccades by multiple seconds. When we lesion cells in these populations we find that ablation of neurons with pre-saccadic rise delays saccade initiation. We analyze spontaneous saccade initiation using a ramp-to-threshold model and are able to predict the times of upcoming saccades using pre-saccadic activity. These findings suggest that ramping of neuronal activity to a bound is a critical component of self-initiated saccadic movements.

Associations of prenatal exposure to phthalates with measures of cognition in 7.5-month-old infants.

BACKGROUND: Phthalates are endocrine disrupting chemicals that have been associated with adverse neurobehavior, but little is known about their influence on infant cognition. METHODS: A visual recognition memory task was used to assess cognition in 244 7-8-month-old infants (121 females; 123 males) from a prospective cohort study. Phthalate metabolites were quantified in maternal urines pooled from across pregnancy. The task included familiarization trials (infant shown 2 identical faces) and test trials (infant shown the now familiar face paired with a novel one). Half of the infants saw one set of faces as familiar (set 1) and half saw the other set as familiar (set 2). During familiarization trials, average run duration (time looking at stimuli before looking away, measure of processing speed), and time to familiarization (time to reach 20 s looking at the stimuli, measure of attention) were assessed. During test trials, novelty preference (proportion of time looking at the novel face, measure of recognition memory) was assessed. Multivariable generalized linear models were used to assess associations of monoethyl phthalate (MEP), sum of di(2-ethylhexyl) phthalate metabolites (ΣDEHP), sum of di(isononyl) phthalate metabolites (ΣDINP), and sum of anti-androgenic phthalate metabolites (ΣAA) with each outcome. RESULTS: Mothers were mostly white and college educated, and urine phthalate concentrations were similar to those in reproductive age women in the U.S. POPULATION: All phthalate exposure biomarkers, except MEP, were associated with increases in average run duration. However, depending on the phthalate, associations were only in males or infants who saw the set 2 stimuli as familiar. Unexpectedly, ΣAA was associated with a shorter time to reach familiarization. Phthalate biomarkers also were associated with modest decrements in novelty preference, but these associations were nonsignificant. CONCLUSION: Prenatal exposure to phthalates may be related to slower information processing and poorer recognition memory in infants.

Using head-mounted eye tracking to examine visual and manual exploration during naturalistic toy play in children with and without autism spectrum disorder.

Multimodal exploration of objects during toy play is important for a child's development and is suggested to be abnormal in children with autism spectrum disorder (ASD) due to either atypical attention or atypical action. However, little is known about how children with ASD coordinate their visual attention and manual actions during toy play. The current study aims to understand if and in what ways children with ASD generate exploratory behaviors to toys in natural, unconstrained contexts by utilizing head-mounted eye tracking to quantify moment-by-moment attention. We found no differences in how 24- to 48-mo children with and without ASD distribute their visual attention, generate manual action, or coordinate their visual and manual behaviors during toy play with a parent. Our findings suggest an intact ability and willingness of children with ASD to explore toys and suggest that context is important when studying child behavior.

An experimental eye-tracking study of text adaptation for readers with dyslexia: effects of visual support and word frequency.

Easy-to-read guidelines recommend visual support and lexical simplification to facilitate text processing, but few empirical studies confirm a positive effect from these recommendations in individuals with dyslexia. This study examined the influence of the visual support and lexical simplification on sentence processing through eye movements at both the text- and word-level, and the differences between readers with and without dyslexia. Furthermore, we explored the influence of reading experience and vocabulary, as control variables. We tested 20 young adults with dyslexia and 20 chronological age-matched controls. Participants read 60 sentences in total. Half the sentences contained an image and the other half did not, and half contained a low-frequency word and half a high-frequency word. Results showed that visual support and lexical simplification facilitated sentence processing, potentially by jointly facilitating lexical semantic access. We also found that participants with lower print exposure and lower vocabulary benefited more from word-level lexical simplification. We conclude that both adaptations could benefit readers with low print exposure and smaller vocabularies, and therefore, to many dyslexic readers who show these characteristics.

Visual Attention Preference for Intermediate Predictability in Young Children.

How do children allocate their attention? There is too much information in the world to encode it all, so children must pick and choose. How do they organize their sampling to make the most of the learning opportunities that surround them? Previous work shows infants actively seek intermediately predictable information. Here we employ eye-tracking and computational modeling to examine the impact of stimulus predictability across early childhood (ages 3-6 years, n = 72, predominantly Non-Hispanic White, middle- to upper-middle-income), by chronological age and cognitive ability. Results indicated that children prefer attending to stimuli of intermediate predictability, with no differences in this pattern based on age or cognitive ability. The consistency may suggest a robust general information-processing mechanism that operates across the lifespan.

Avoidance of tobacco health warnings? An eye-tracking approach.

AIMS: Among three eye-tracking studies, we examined how cigarette pack features affected visual attention and self-reported avoidance of and reactance to warnings. DESIGN: Study 1: smoking status × warning immediacy (short-term versus long-term health consequences) × warning location (top versus bottom of pack). Study 2: smoking status × warning framing (gain-framed versus loss-framed) × warning format (text-only versus pictorial). Study 3: smoking status × warning severity (highly severe versus moderately severe consequences of smoking). SETTING: University of Bristol, UK, eye-tracking laboratory. PARTICIPANTS: Study 1: non-smokers (n = 25), weekly smokers (n = 25) and daily smokers (n = 25). Study 2: non-smokers (n = 37), smokers contemplating quitting (n = 37) and smokers not contemplating quitting (n = 43). Study 3: non-smokers (n = 27), weekly smokers (n = 26) and daily smokers (n = 26). MEASUREMENTS: For all studies: visual attention, measured as the ratio of the number of fixations to the warning versus the branding, self-reported predicted avoidance of and reactance to warnings and for study 3, effect of warning on quitting motivation. FINDINGS: Study 1: greater self-reported avoidance [mean difference (MD) = 1.14; 95% confidence interval (CI) = 0.94, 1.35, P < 0.001, ηp2  = 0.64] and visual attention (MD = 0.89, 95% CI = 0.09, 1.68, P = 0.03, ηp2  = 0.06) to long-term warnings, but not for reactance (MD = 0.14, 95% CI = -0.04, 0.32, P = 0.12, ηp2  = 0.03). Increased visual attention to warnings on the upper versus lower half of the pack (MD = 1.8; 95% CI = 0.33, 3.26, P = 0.02, ηp2  = 0.08). Study 2: higher self-reported avoidance of (MD = 0.70; 95% CI = 0.59,0.80, P < 0.001, ηp2  = 0.61) and reactance to (MD = 0.37; 95% CI = 0.27, 0.47, P < 0.001, ηp2  = 0.34) loss-framed warnings but little evidence of a difference for visual attention (MD = 0.52; 95% CI = -0.54, 1.58, P = 0.30, ηp2  = 0.01). Greater visual attention, avoidance and reactance to pictorial versus text-only warnings (all Ps < 0.001, ηp2  > 0.25). Study 3: greater self-reported avoidance of (MD = 0.37; 95% CI = 0.25, 0.48, P < 0.001, ηp2  = 0.33) and reactance to (MD = 0.14; 95% CI = 0.05, 0.23, P = 0.003, ηp2  = 0.11) highly severe warnings but findings were inconclusive as to whether there was a difference in visual attention (MD = -0.55; 95% CI = -1.5, 0.41, P = 0.24, ηp2  = 0.02). CONCLUSIONS: Subjective and objective (eye-tracking) measures of avoidance of health warnings on cigarette packs produce different results, suggesting these measure different constructs. Visual avoidance of warnings indicates low-level disengagement with warnings, while self-reported predicted avoidance reflects higher-level engagement with warnings.

Structural and Contextual Cues in Third-Person Pronoun Interpretation by Children with Autism Spectrum Disorder and Their Neurotypical Peers.

This study investigates the use of structural and discourse contextual cues in the interpretation of third-person pronouns by children and adolescents with autism and their neurotypical peers. Results show that referent-biasing contextual information influences pronominal interpretation and modulates looking patterns in both groups compared to a context-neutral condition. These results go against the predictions of Weak Central Coherence and the notion that pragmatics in general is impaired in ASD, since the ASD group was able to use details in discourse context to influence the pronominal interpretation process. However, although discourse context influenced looking patterns in both groups, the groups nevertheless diverged in the nature of these patterns, suggesting that behavioral differences may emerge in more complicated discourse tasks.

Short-term noise annoyance and electrodermal response as a function of sound-pressure level, cognitive task load, and noise sensitivity.

INTRODUCTION: Two aspects of noise annoyance were addressed in the present laboratory study: (1) the disturbance produced by vehicle pass-by noise while engaging in a challenging non-auditory task, and (2) the evaluative response elicited by the same sounds while imagining to relax at home in the absence of a primary activity. METHODS AND MATERIAL: In Experiment 1, N = 29 participants were exposed to short (3-6 s) pass-by recordings presented at graded levels between 50 and 70 dB(A). Concurrent with each sound presentation, they performed a visual multiple-object tracking task, and subsequently rated the annoyance of the sounds on a VAS scale. In Experiment 2, N = 30 participants judged the sounds while imagining to relax, without such a cognitive task. RESULTS AND DISCUSSION: Annoyance was reduced when participants were engaged in the cognitively demanding task, in Experiment 1. Furthermore, when occupied with the task, annoyance slightly, but significantly increased with task load. Across both experiments, the magnitude of simultaneously recorded skin conductance responses in the first 1-4 s after the onset of stimulation increased significantly with sound pressure level. Annoyance ratings tended to be elevated across all sound levels, though significantly only in Experiment 2, in participants classified as noise sensitive based on a 52-item questionnaire. CONCLUSIONS: The results suggest that noise annoyance depends on the primary activity the listener is engaged in. They demonstrate that phasic skin conductance responses may serve as an objective correlate of the degree of annoyance experienced. Finally, noise sensitivity is once more shown to augment annoyance ratings in an additive fashion.

Exploring Social Biomarkers in High-Functioning Adults with Autism and Asperger's Versus Healthy Controls: A Cross-Sectional Analysis.

Biomarkers for autism spectrum disorder (ASD) are lacking but would facilitate drug development for the core deficits of the disorder. We evaluated markers proposed for characterization of differences in social communication and interaction in adults with ASD versus healthy controls (HC) for utility as biomarkers. Data pooled from an observational study and baseline data from a placebo-controlled study were analyzed. Between-group differences were observed in eye-tracking tasks for activity monitoring, biomotion, human activity preference, composite score (p = 0.0001-0.037) and pupillometry (various tasks, p = 0.017-0.05). Impaired olfaction was more common in the ASD sample versus HC (p = 0.018). Our preliminary results suggest the potential use for stratification and response sub-analyses outcome-prediction of specific eye-tracking tasks, pupillometry and olfaction tests in ASD trials.

The relationship between dispositional attention to feelings and visual attention to emotion.

Attention to feelings is a core dimension of individual differences in the perception of one's emotions. It concerns the frequency with which own emotions are attended to. The aim of the present eye-tracking investigation was to examine the relationship of dispositional attention to feelings with early and late attentional processes in the visual perception of emotional information. Attentional orientation was assessed in a sample of healthy women (N = 91) using eye-tracking during a free viewing task in which images with positive, negative and neutral content were shown simultaneously. Pictures were taken from the Besançon Affective Picture Set. State and trait affect, depression, and intelligence of participants were controlled. In our sample, attention to feelings was not related to positive affect, negative affect, depression or intelligence. Attention to feelings was negatively correlated with entry times for all emotional picture types. Moreover, attention to feelings was positively correlated with dwell time on positive images and negatively correlated with dwell time on neutral images. Our data indicate that devoting habitually attention to one's feelings is linked to an enhanced initial orientation of attention towards emotional scenes, irrespective of affective valence. Dispositional attention to feelings might also be associated with an attentional preference for emotional over neutral visual stimuli. The present findings on general individual differences in attention to feelings could have important implications for future clinical research on attentional biases.

Smile judgment in substance use disorders and its relationship to interpersonal and emotional functioning: An eye-tracking investigation.

The current study explored the judgments individuals with Substance Use Disorders (SUDs) make regarding the authenticity of enjoyment smiles and masking smiles containing traces of negative emotions. Accuracy at identifying the masked negative emotions were also examined. Eye-movements were recorded to observe relationships between attentional processes and smile judgment. Additionally, the relationships between smile judgment, emotion dysregulation, and interpersonal problems were investigated. Twenty individuals with SUDs and twenty individuals matched on gender/age participated in the smile judgment task. Results indicated that individuals with SUDs were no different in their categorization of smiles. However, the results showed that individuals with SUDs were significantly more likely to report the presence of negative emotions in the expressions. They were also more often incorrect in their identification of the masked emotions. No link was observed between smile judgment and attentional processes. Emotional and interpersonal functioning were related more to the ability to distinguish smile authenticity than the ability to identify masked emotions.

A novel eye-tracking paradigm for indexing social avoidance-related behavior in fragile X syndrome.

Fragile X syndrome (FXS) is characterized by hallmark features of gaze avoidance, reduced social approach, and social anxiety. The development of therapeutics to manage these symptoms has been hindered, in part, by the lack of sensitive outcome measures. This study investigated the utility of a novel eye-tracking paradigm for indexing social avoidance-related phenotypes. Adolescent/young adult-aged males with FXS (n = 24) and typical development (n = 23) participated in the study. Participants viewed faces displaying direct or averted gaze and the first fixation duration on the eyes was recorded as an index of initial stimulus registration. Fixation durations did not differ across the direction of gaze conditions in either group, although the control group showed longer initial fixations on the eyes relative to the FXS group. Shorter initial fixation on averted gaze in males with FXS was a robust predictor of the severity of their social avoidance behavior exhibited during a social greeting context, whereas parent-reported social avoidance symptoms were not related to performance in the semi-naturalistic context. This eye-tracking paradigm may represent a promising outcome measure for FXS clinical trials because it provides a quantitative index that closely maps onto core social avoidance phenotypes of FXS, can be completed in less than 20 min, and is suitable for use with individuals with low IQ.

Zoned in or zoned out? Investigating immersion in slot machine gambling using mobile eye-tracking.

BACKGROUND AND AIMS: Immersion during slot machine gambling has been linked to disordered gambling. Current conceptualizations of immersion (namely dissociation, flow and the machine zone) make contrasting predictions as to whether gamblers are captivated by the game per se ('zoned in') or motivated by the escape that immersion provides ('zoned out'). We examined whether selected eye-movement metrics can distinguish between these predictions. DESIGN AND SETTING: Pre-registered, correlational analysis in a laboratory setting. Participants gambled on a genuine slot machine for 20 minutes while wearing eye-tracking glasses. PARTICIPANTS: Fifty-three adult slot machine gamblers who were not high-risk problem gamblers. MEASUREMENTS: We examined self-reported immersion during the gambling session and eye movements at different areas of the slot machine screen (the reels, the credit window, etc.). We further explored these variables' relationships with saccade count and amplitude. FINDINGS: The ratio of dwell time on the game's credit window relative to the game's reels was positively associated with immersion (t(51)  = 1.68, P = 0.049 one-tailed, R2  = 0.05). Follow-up analyses described event-related changes in these patterns following different spin outcomes. CONCLUSIONS: Immersion while gambling on a slot machine appears to be associated with active scanning of the game and a focus on the game's credit window. These results are more consistent with a 'zoned in' account of immersion aligned with flow theory than a 'zoned out' account based on escape.