Olivia G. Calancie

Humans blink their eyes 16–20 times each minute to spread tear film on the cornea, representing a substantial amount of waking time when one's eyes are closed. These spontaneous blinks are strategically timed to prioritize the processing of important visual input, balancing both stimulus characteristics and personal goals. Until now, the learning process underlying blink timing has not been investigated in detail. Here, we present video-based eye-tracking data from 703 healthy participants (aged 5–91 years, 470 female) performing a structured interleaved prosaccade/antisaccade task, in which we previously found that blinks are suppressed in anticipation of visual stimulus appearance. Our goals are to understand (1) how participants modify their blink timing according to the temporal contingencies of the task, (2) whether the capacity to do so impacts performance, and (3) whether this pattern varies with age. We found evidence that participants quickly adapted their blink timing to minimize co-occurrence with task-relevant stimuli. Blink probability decreased in periods that would compromise antisaccade execution and increased when visual input was less critical. We also found significant differences in blink timing and in the rate of blink adaptation across the task for participants with low versus high error rates. Furthermore, the rate of blink adaptation increased gradually from childhood to early adulthood and then decreased with advanced age. This work supports a possible link between the regulation of blink behavior and lifespan changes in learning capacity and inhibitory control.

Humans blink their eyes 16-20 times each minute to spread tear film on the cornea, representing a substantial amount of waking time when one’s eyes are closed. These spontaneous blinks are strategically timed to prioritize the processing of important visual input, balancing both stimulus characteristics and personal goals. Until now, the learning process underlying optimal blink timing has not been investigated in detail. Here, we present video-based eye-tracking data from 703 healthy participants (aged 5-91 years, 470 female) performing a structured interleaved pro-/anti-saccade task, in which we previously found that blink suppression occurs in anticipation of visual stimulus appearance (Pitigoi et al., 2024). Our goals are to understand (1) how participants modify their blink timing according to the temporal contingencies of the task; (2) whether the capacity to optimize blink timing impacts performance; and (3) whether this pattern varies with age. We found that participants quickly and strategically modified their blink distribution to optimize task performance. Blink probability decreased in periods that would compromise anti-saccade execution and increased when visual input was less critical. We also found significant differences in blink patterns and adaptive ability based on cognitive control capacity (indicated by participants’ anti-saccade error rates). Furthermore, we demonstrated that blink optimization improves gradually from childhood to early adulthood, before declining with advanced age. This supports a possible link between regulation of blink behavior and age-related changes in learning capacity and inhibitory control across the lifespan.

Spontaneous eye blinking is gaining popularity as a proxy for higher cognitive functions, as it is readily modulated by both environmental demands and internal processes. Prior studies were impoverished in sample size, sex representation, and age distribution, making it difficult to establish a complete picture of the behavior. Here we present eye-tracking data from a large cohort of normative participants (n = 604; 393 F; aged 5–93 years) performing two tasks: one with structured, discrete trials (interleaved pro-/anti-saccade task, IPAST) and one with a less structured, continuous organization in which participants watch movies (free-viewing; FV). Sex- and age-based analyses revealed that females had higher blink rates between the ages of 22 and 58 years in the IPAST and 22 and 34 years in FV. We derived a continuous measure of blink probability to reveal behavioral changes driven by stimulus appearance in both paradigms. In the IPAST, blinks were suppressed near stimulus appearance, particularly on correct anti-saccade trials, which we attribute to the stronger inhibitory control required for anti-saccades compared with pro-saccades. In FV, blink suppression occurred immediately after scene changes, and the effect was sustained on scenes where gaze clustered among participants (indicating engagement of attention). Females were more likely than males to blink during appearance of novel stimuli in both tasks, but only within the age bin of 18–44 years. The consistency of blink patterns in each paradigm endorses blinking as a sensitive index for changes in visual processing and attention, while sex and age differences drive interindividual variability.

Shifting motor actions from reflexively reacting to an environmental stimulus to predicting it allows for smooth synchronization of behavior with the outside world. This shift relies on the identification of patterns within the stimulus – knowing when a stimulus is predictable and when it is not – and launching motor actions accordingly. Failure to identify predictable stimuli results in movement delays whereas failure to recognize unpredictable stimuli results in early movements with incomplete information that can result in errors. Here we used a metronome task, combined with video-based eye-tracking, to quantify temporal predictive learning and performance to regularly paced visual targets at 5 different interstimulus intervals (ISIs). We compared these results to the random task where the timing of the target was randomized at each target step. We completed these tasks in female pediatric psychiatry patients (age range: 11–18 years) with borderline personality disorder (BPD) symptoms, with (n = 22) and without (n = 23) a comorbid attention-deficit hyperactivity disorder (ADHD) diagnosis, against controls (n = 35). Compared to controls, BPD and ADHD/BPD cohorts showed no differences in their predictive saccade performance to metronome targets, however, when targets were random ADHD/BPD participants made significantly more anticipatory saccades (i.e., guesses of target arrival). The ADHD/BPD group also significantly increased their blink rate and pupil size when initiating movements to predictable versus unpredictable targets, likely a reflection of increased neural effort for motor synchronization. BPD and ADHD/BPD groups showed increased sympathetic tone evidenced by larger pupil sizes than controls. Together, these results support normal temporal motor prediction in BPD with and without ADHD, reduced response inhibition in BPD with comorbid ADHD, and increased pupil sizes in BPD patients. Further these results emphasize the importance of controlling for comorbid ADHD when querying BPD pathology.

When presented with a periodic stimulus, humans spontaneously adjust their movements from reacting to predicting the timing of its arrival, but little is known about how this sensorimotor adaptation changes across development. To investigate this, we analyzed saccade behavior in 114 healthy humans (ages 6–24 years) performing the visual metronome task, who were instructed to move their eyes in time with a visual target that alternated between two known locations at a fixed rate, and we compared their behavior to performance in a random task, where target onsets were randomized across five interstimulus intervals (ISIs) and thus the timing of appearance was unknown. Saccades initiated before registration of the visual target, thus in anticipation of its appearance, were labeled predictive [saccade reaction time (SRT) < 90 ms] and saccades that were made in reaction to its appearance were labeled reactive (SRT > 90 ms). Eye-tracking behavior including saccadic metrics (e.g., peak velocity, amplitude), pupil size following saccade to target, and blink behavior all varied as a function of predicting or reacting to periodic targets. Compared with reactive saccades, predictive saccades had a lower peak velocity, a hypometric amplitude, smaller pupil size, and a reduced probability of blink occurrence before target appearance. The percentage of predictive and reactive saccades changed inversely from ages 8–16, at which they reached adult-levels of behavior. Differences in predictive saccades for fast and slow target rates are interpreted by differential maturation of cerebellar-thalamic-striatal pathways.SIGNIFICANCE STATEMENTFrom the first moments of life, humans are exposed to rhythm (i.e., mother's heartbeatin utero), but the timeline of brain development to promote the identification and anticipation of a rhythmic stimulus, known as temporal prediction, remains unknown. Here, we used saccade reaction time (SRT) in the visual metronome task to differentiate between temporally predictive and reactive responses to a target that alternated at a fixed rate in humans aged 6–24. Periods of age-related change varied little by target rate, with matured predictive performance evident by mid-adolescence for fast and slow rates. A strong correlation among saccade, pupil, and blink responses during target prediction provides evidence of oculomotor coordination and dampened noradrenergic neuronal activity when generating rhythmic motor responses.

Eye movement desensitization and reprocessing (EMDR), a form of psychotherapy for individuals with post‐traumatic stress disorder (PTSD), has long been a controversial topic, hampered in part by a lack of understanding of the neural mechanisms that contribute to its remedial effect. Here, we review current theories describing EMDR's potential neurobiological mechanisms of action involving working memory, interhemispheric communication, de‐arousal, and memory reconsolidation. We then discuss recent studies describing the temporal and spatial aspects of smooth pursuit and predictive saccades, which resemble those made during EMDR, and their neural correlates within the default mode network (DMN) and cerebellum. We hypothesize that if the production of bilateral predictive eye movements is supportive of DMN and cerebellum activation, then therapies that shift the brain towards this state correspondingly would benefit the processes regulated by these structures (i.e., memory retrieval, relaxation, and associative learning), all of which are essential components for PTSD recovery. We propose that the timing of sensory stimulation may be relevant to treatment effect and could be adapted across different patients depending on their baseline saccade metrics. Empirical data in support of this model are reviewed and experimental predictions are discussed.

Adolescents with anxiety disorders often have low self-esteem, poor problem-solving, and a strong desire to be accepted. Combined, these qualities may predispose them to experience unique stressors when using social network sites (SNSs). Focus groups of adolescent Facebook users who have a primary anxiety diagnosis uncovered narratives describing individuals’ perspectives related to how Facebook can influence their anxiety. Qualitative analysis revealed six themes related to Facebook stressors: seeking approval, fearing judgment, escalating interpersonal issues, wanting privacy, negotiating self and social identity, and connecting & disconnecting. Many participants reported a fear of receiving negative comments online and discussed strategies to avoid them, such as posting less content (i.e., comments, photographs) than their peers. Some participants described feeling positive emotions when they received a “like” from a SNS user, however, they also tended to describe these positive emotions as “false”, “unreal” and “fleeting.” Notably, many participants reported comparing themselves to peers on Facebook, which increased feelings of anxiety, as well as compulsive checking behaviours, such as monitoring posted content and friend lists. These findings were coupled with discussions surrounding rumination, privacy, and elevated personal conflict due in part to the public nature of Facebook. The narratives from our exploratory study suggest there are various mechanisms through which Facebook may exacerbate anxiety in adolescents who have pre-existing anxiety disorders and thereby may make them vulnerable to negative online experiences. Understanding the underlying themes of this phenomenon can aid clinicians, school staff, and parents in identifying potential stressors for anxious adolescents who use SNSs, and provide strategies around social media use for this specific patient population. Future quantitative studies are recommended to further understand the relationships between Facebook stressors and expressed anxiety in clinical populations.

Background: Cognitive behavioral therapy (CBT) is found to be effective for common mental disorders and has been delivered in self-help and guided self-help formats. Crisis and transitional case management (TCM) services play a vital role in managing clients in acute mental health crises. It is, therefore, an appropriate setting to try CBT in guided self-help format. Methods: This was a preliminary evaluation of a formulation-driven cognitive behavioral guided self-help. Thirty-six (36) consenting participants with a diagnosis of nonpsychotic illness, attending crisis and the TCM services in Kingston, Canada, were recruited in this study. They were randomly assigned to the guided self-help plus treatment as usual (TAU) (treatment group) or to TAU alone (control group). The intervention was delivered over 8–12 weeks. Assessments were completed at baseline and 3 months after baseline. The primary outcome was a reduction in general psychopathology, and this was done using Clinical Outcomes in Routine Evaluation – Outcome Measure. The secondary outcomes included a reduction in depression, measured using the Hospital Anxiety and Depression Scale, and reduction in disability, measured using the World Health Organization Disability Assessment Schedule 2.0. Findings: Participants in the treatment group showed statistically significant improvement in overall psychopathology (PPPConclusion: A formulation-driven cognitive behavioral guided self-help was feasible for the crisis and TCM clients and can be effective in improving mental health, when compared with TAU. This is the first report of a trial of guided self-help for clients attending crisis and TCM services.