Gain control of saccadic eye movements is probabilistic

Saccades are rapid eye movements that orient the visual axis toward objects of interest to allow their processing by the central, highacuity retina. Our ability to collect visual information efficiently relies on saccadic accuracy, which is limited by a combination of uncertainty in the location of the target and motor noise. It has been observed that saccades have a systematic tendency to fall short of their intended targets, and it has been suggested that this bias originates from a cost function that overly penalizes hypermetric errors. Here we tested this hypothesis by systematically manipulating the positional uncertainty of saccadic targets. We found that increasing uncertainty produced not only a larger spread of the saccadic endpoints but also more hypometric errors and a systematic bias toward the average of target locations in a given block, revealing that prior knowledge was integrated into saccadic planning. Moreover, by examining how variability and bias co-varied across conditions, we estimated the asymmetry of the cost function and found that it was related to individual differences in the additional time needed to program secondary saccades for correcting hypermetric errors, relative to hypometric ones. Taken together, these findings reveal that the saccadic system uses a probabilistic-Bayesian control strategy to compensate for uncertainty in a statistically principled way and to minimize the expected cost of saccadic errors

Infant attentional markers studied with eye-tracking as possible predictors of toddler age adaptive behavior

Objectives: Early recognition of developmental challenges in infancy is central for being able to start interventions earlier with possible better outcomes. The aim of this study was to investigate the potential of using eye-tracking at seven months to predict adaptive behavior outcomes at two years. Adaptive behavior implies the child's adaptation to their specific living environment and it includes aspects of conceptual, social and practical adaptation. Here, I studied several eye-tracking based markers of visual attention in infancy for their possible association with adaptive behavior at two years, such as saccadic reaction time (SRT) and measures of attentional preference for faces and emotional facial expressions. SRT has been shown to be a general attentional marker in infancy associated with many developmental and clinical aspects while attentional preference for faces and emotional facial expressions are pronounced at seven months and have been hypothesized to play a role in socio-emotional development. Infants were also studied with respect to attentional behavioral tendencies based on their SRT measures. Methods: This study employed material from the Toibilas-study at BABA center at Helsinki University Hospital. The study consisted of 45 children of either typical development (n=26) or children of high developmental risk (n=19) due to their prior treatment at the neonatal intensive care unit. The high-risk group was assumed to increase variability of the sample. Infants participated in eye-tracking measurements at seven months old using two different eye-tracking paradigms; a SRT task and a task measuring attentional bias for facial vs. non-facial as well as emotional facial expressions vs. neutral facial expressions. The same children were assessed for adaptive behavior at two years of age by a parent filled-questionnaire. Associations between attentional behavioral markers at seven months and adaptive behavior at two years were analyzed using linear models. The models also accounted for behavioral attentional tendency as identified from a set of SRT measures. Results and conclusions: A bigger attentional preference for faces compared to non-faces was associated with better overall adaptive behavior score as well as adaptive behavior composites for conceptual and practical adaptive behavior. This is in line with the hypothesis that attentional bias for faces is important for socio-emotional development. A significant association between identified behavioral attentional tendencies and the conceptual composite score of adaptive behavior was found. This finding suggests that recognizing attentional tendency may be useful for predicting later developmental trajectories. The present work provides preliminary evidence for the proof of principle that eye-tracking based metrics may provide clinically relevant predictions in infants, however novel prospective datasets are needed for clinical validation.Målsättning: Identifiering av utvecklingsmässiga utmaningar redan i spädbarnsåldern är viktigt för att ha möjlighet att inleda tidiga interventioner och därmed potentiellt öka interventionernas effektivitet. Målsättningen för den här studien var att utreda användbarheten av ögonrörelsemätning (eye-tracking) i sju månaders ålder för att förutspå adaptivt beteende i två års ålder. Adaptivt beteende beskriver barnets anpassning till hans eller hennes specifika livsmiljö och innehåller begreppsmässig, social och praktisk anpassning. I den här studien har jag använt flera markörer för visuell uppmärksamhet mätta i spädbarns åldern m.hj.a ögonrörelsemätning; sackadiska ögonrörelsers reaktionshastighet (SRT) samt preferens att rikta uppmärksamhet mot ansikten och emotionella ansiktsuttryck. Jag har undersökt de olika markörernas association till adaptivt beteende vid två års ålder. SRT är ett allmänt mått för visuell uppmärksamhet i spädbarnsåldern och har förknippats med flera utvecklingsmässiga och kliniska aspekter medan uppmärksamhetsmässig preferens för ansikten och emotionella ansiktsuttryck är markant vid sju månaders ålder och har föreslagits ha en roll i socio-emotionell utveckling. Möjlig association mellan spädbarnens tendenser för uppmärksamhetsbeteende, identifierat m. hj. a. flera olika SRT-mått, och adaptivt beteende undersöktes också. Metoder: Den här studien använde sig av material från Toibilas-studien vid BABA-center, Helsingfors Universitets Sjukhus. Studien innefattade 45 barn, både barn utan identifierade utvecklingsmässiga risker (n=26) och barn tillhörande en hög-risk grupp (n=19) p.g.a. deras tidigare vårdperiod vid neonatal intensivvård avdelningen. Vid sju månaders ålder deltog spädbarnen i en ögonrörelsemätning med två olika uppgifter; en SRT-uppgift och en uppgift som mätte skillnaden i uppmärksamhet gentemot ansikten jämfört med annat visuellt stimulus samt emotionella ansiktsuttryck jämfört med neutrala ansiktsuttryck. Samma barns adaptiva beteende utvärderades vid två års ålder med ett frågeformulär ifyllt av en förälder. Associationen mellan markörer för visuell uppmärksamhet, barnens tendenser för uppmärksamhetsbeteende i spädbarnsåldern och adaptivt beteende i två års ålder undersöktes med lineära modeller. Resultat och slutsatser: Större preferens för ansikten jämfört med annat visuellt stimulus vid sju månaders ålder var förknippat med bättre adaptivt beteende vid två års ålder. Upptäckten stöder hypotesen att preferensen för uppmärksamhet riktad mot ansikten är viktig för den socio-emotionella utvecklingen. En signifikant association mellan spädbarnets tendenser för uppmärksamhetsbeteende och begreppsmässigt adaptivt beteende kunde konstateras. Detta fynd tyder på att identifikation av spädbarnets tendenser för uppmärksamhetsbeteende kunde vara nyttigt för att förutspå senare utveckling. Denna studie ger preliminära bevis för principen att ögonrörelsemätning i spädbarnsåldern kunde ge kliniskt relevant infromation som förutspår utveckling, men upprepning av resultaten och framtida forskning för klinisk verifiering är av yttersta vikt

Inside the brain of an elite athlete: The neural processes that support high achievement in sports

Events like the World Championships in athletics and the Olympic Games raise the public profile of competitive sports. They may also leave us wondering what sets the competitors in these events apart from those of us who simply watch. Here we attempt to link neural and cognitive processes that have been found to be important for elite performance with computational and physiological theories inspired by much simpler laboratory tasks. In this way we hope to inspire neuroscientists to consider how their basic research might help to explain sporting skill at the highest levels of performance

Saccade Landing Point Prediction Based on Fine-Grained Learning Method

The landing point of a saccade defines the new fixation region, the new region of interest. We asked whether it was possible to predict the saccade landing point early in this very fast eye movement. This work proposes a new algorithm based on LSTM networks and a fine-grained loss function for saccade landing point prediction in real-world scenarios. Predicting the landing point is a critical milestone toward reducing the problems caused by display-update latency in gaze-contingent systems that make real-time changes in the display based on eye tracking. Saccadic eye movements are some of the fastest human neuro-motor activities with angular velocities of up to 1,000°/s. We present a comprehensive analysis of the performance of our method using a database with almost 220,000 saccades from 75 participants captured during natural viewing of videos. We include a comparison with state-of-the-art saccade landing point prediction algorithms. The results obtained using our proposed method outperformed existing approaches with improvements of up to 50% error reduction. Finally, we analyzed some factors that affected prediction errors including duration, length, age, and user intrinsic characteristics.This work was supported in part by the Project BIBECA through MINECO/FEDER under Grant RTI2018-101248-B-100, in part by the Jose Castillejo Program through MINECO under Grant CAS17/00117, and in part by the National Institutes of Health (NIH) under Grant P30EY003790 and Grant R21EY023724

Eye movement patterns during the recognition of three-dimensional objects: Preferential fixation of concave surface curvature minima

This study used eye movement patterns to examine how high-level shape information is used during 3D object recognition. Eye movements were recorded while observers either actively memorized or passively viewed sets of novel objects, and then during a subsequent recognition memory task. Fixation data were contrasted against different algorithmically generated models of shape analysis based on: (1) regions of internal concave or (2) convex surface curvature discontinuity or (3) external bounding contour. The results showed a preference for fixation at regions of internal local features during both active memorization and passive viewing but also for regions of concave surface curvature during the recognition task. These findings provide new evidence supporting the special functional status of local concave discontinuities in recognition and show how studies of eye movement patterns can elucidate shape information processing in human vision

Recent Saccadic Eye Movement Research Uncovers Patterns of Cognitive Dysfunction in Schizophrenia.

The frontal cortex and the subcortical areas of the brain play a major role in the control of thought and action. Eye movements are increasingly used in neuropsychological research to explore the executive and sensorimotor functions of such neural networks. This interface links the control of action, at the fundamental levels of neurophysiological and neurochemical processes, with the high-level cognitive operations that underlie visual orienting. Patients with schizophrenia have neurocognitive impairments that can be readily investigated with novel saccadic eye movement paradigms. Animal, human lesion, and neuroimaging studies have identified the cerebral centers that underlie saccadic eye movements. The areas of the prefrontal cortex include the dorsolateral prefrontal cortex, the frontal eye fields, the supplementary eye fields, and the anterior cingulate gyrus. Pathology of saccadic eye movements therefore provides information on the functional status of the underlying neural circuitry in brain disorders such as schizophrenia