Pharmacological treatment effects on eye movement control

The increasing use of eye movement paradigms to assess the functional integrity of brain systems involved in sensorimotor and cognitive processing in clinical disorders requires greater attention to effects of pharmacological treatments on these systems. This is needed to better differentiate disease and medication effects in clinical samples, to learn about neurochemical systems relevant for identified disturbances, and to facilitate identification of oculomotor biomarkers of pharmacological effects. In this review, studies of pharmacologic treatment effects on eye movements in healthy individuals are summarized and the sensitivity of eye movements to a variety of pharmacological manipulations is established. Primary findings from these studies of healthy individuals involving mainly acute effects indicate that: (i) the most consistent finding across several classes of drugs, including benzodiazepines, first- and second- generation antipsychotics, anticholinergic agents, and anticonvulsant/mood stabilizing medications is a decrease in saccade and smooth pursuit velocity (or increase in saccades during pursuit); (ii) these oculomotor effects largely reflect the general sedating effects of these medications on central nervous system functioning and are often dose-dependent; (iii) in many cases changes in oculomotor functioning are more sensitive indicators of pharmacological effects than other measures; and (iv) other agents, including the antidepressant class of serotonergic reuptake inhibitors, direct serotonergic agonists, and stimulants including amphetamine and nicotine, do not appear to adversely impact oculomotor functions in healthy individuals and may well enhance aspects of saccade and pursuit performance. Pharmacological treatment effects on eye movements across several clinical disorders including schizophrenia, affective disorders, attention deficit hyperactivity disorder, Parkinson’s disease, and Huntington’s disease are also reviewed. While greater recognition and investigation into pharmacological treatment effects in these disorders is needed, both beneficial and adverse drug effects are identified. This raises the important caveat for oculomotor studies of neuropsychiatric disorders that performance differences from healthy individuals cannot be attributed to illness effects alone. In final sections of this review, studies are presented that illustrate the utility of eye movements for use as potential biomarkers in pharmacodynamic and pharmacogenetic studies. While more systematic studies are needed, we conclude that eye movement measurements hold significant promise as tools to investigate treatment effects on cognitive and sensorimotor processes in clinical populations and that their use may be helpful in speeding the drug development pathway for drugs targeting specific neural systems and in individualizing pharmacological treatments.     

The neural basis of smooth pursuit eye movements in the rhesus monkey brain

Smooth pursuit eye movements are performed in order to prevent retinal image blur of a moving object. Rhesus monkeys are able to perform smooth pursuit eye movements quite similar as humans, even if the pursuit target does not consist in a simple moving dot. Therefore, the study of the neuronal responses as well as the consequences of micro-stimulation and lesions in trained monkeys performing smooth pursuit is a powerful approach to understand the human pursuit system. The processing of visual motion is achieved in the primary visual cortex and the middle temporal area. Further processing including the combination of retinal image motion signals with extra-retinal signals such as the ongoing eye and head movement occurs in subsequent cortical areas as the medial superior temporal area, the ventral intraparietal area and the frontal and supplementary eye field. The frontal eye field especially contributes anticipatory signals which have a substantial influence on the execution of smooth pursuit. All these cortical areas send information to the pontine nuclei, which in turn provide the input to the cerebellum. The cerebellum contains two pursuit representations: in the paraflocculus/flocculus region and in the posterior vermis. While the first representation is most likely involved in the coordination of pursuit and the vestibular-ocular reflex, the latter is involved in the precise adjustments of the eye movements such as adaptation of pursuit initiation. The output of the cerebellum is directed to the moto-neurons of the extra-ocular muscles in the brainstem.     

Is anyone looking at me? Direct gaze detection in children with and without autism

Atypical processing of eye contact is one of the significant characteristics of individuals with autism, but the mechanism underlying atypical direct gaze processing is still unclear. This study used a visual search paradigm to examine whether the facial context would affect direct gaze detection in children with autism. Participants were asked to detect target gazes presented among distracters with different gaze directions. The target gazes were either direct gaze or averted gaze, which were either presented alone (Experiment 1) or within facial context (Experiment 2). As with the typically developing children, the children with autism, were faster and more efficient to detect direct gaze than averted gaze, whether or not the eyes were presented alone or within faces. In addition, face inversion distorted efficient direct gaze detection in typically developing children, but not in children with autism. These results suggest that children with autism use featural information to detect direct gaze, whereas typically developing children use configural information to detect direct gaze.     

不同难度阅读材料对阅读知觉广度影响的眼动研究

采用经典的呈现随眼动变化技术,以Eyelink II眼动仪为工具,考察材料难度和窗口大小对中文句子阅读的影响.实验设计为2(材料难度:难,易)× 5(窗口大小:1个字,3个字,5个字,7个字和整行)被试内实验设计,被试为15名在校大学生.研究结果表明:(1)阅读容易材料时的知觉广度为5个字.(2)阅读困难材料时知觉广度为3-5个字.     

Coordinating cognition: the costs and benefits of shared gaze during collaborative search

Collaboration has its benefits, but coordination has its costs. We explored the potential for remotely located pairs of people to collaborate during visual search, using shared gaze and speech. Pairs of searchers wearing eyetrackers jointly performed an O-in-Qs search task alone, or in one of three collaboration conditions: shared gaze (with one searcher seeing a gaze-cursor indicating where the other was looking, and vice versa), shared-voice (by speaking to each other), and shared-gaze-plus-voice (by using both gaze-cursors and speech). Although collaborating pairs performed better than solitary searchers, search in the shared gaze condition was best of all: twice as fast and efficient as solitary search. People can successfully communicate and coordinate their searching labor using shared gaze alone. Strikingly, shared gaze search was even faster than shared-gaze-plus-voice search; speaking incurred substantial coordination costs. We conclude that shared gaze affords a highly efficient method of coordinating parallel activity in a time-critical spatial task.     

Crossmodal spatial attention shift produced by centrally presented gaze cues1

Abstract: Despite previous failures to identify visual‐upon‐auditory spatial‐cuing effects, recent studies have demonstrated that the abrupt onset of a lateralized visual stimulus triggers a shift of spatial attention in response to auditory judgment. Nevertheless, whether a centrally presented visual stimulus orients auditory attention remained unclear. The present study investigated whether centrally presented gaze cues trigger a reflexive shift of attention in response to auditory judgment. Participants fixated on a schematic face in which the eyes looked left or right (the cue). A target sound was then presented to the left or right of the cue. Participants judged the direction of the target as quickly as possible. Even though participants were told that the gaze direction did not predict the direction of the target, the response time was significantly faster when the gaze was in the target direction than when it was in the non‐target direction. These findings provide initial evidence for visual‐upon‐auditory spatial‐cuing effects produced by centrally presented cues, suggesting that a reflexive crossmodal shift of attention does occur with a centrally presented visual stimulus.     

中文阅读过程中的副中央凹预视效应

副中央凹预视效应指当读者正注视某个词(即位于中央凹的词n)时, 可以获得词n右侧词(即位于副中央凹词n+1或词n+2)的部分信息。在阅读过程中读者能否从副中央凹预视到信息, 会直接影响他们的阅读效率。因此, 探讨阅读过程中的副中央凹预视效应产生的条件、影响因素及机制, 成为阅读心理学需要解决的基本问题之一。本文系统总结了中外文阅读过程中副中央凹预视效应的研究进展, 包括副中央凹预视效应的研究范式, 中外文阅读过程中副中央凹预视的信息类型、不同类型信息预视加工的时间进程, 以及空间上获得预视信息的范围。最后提出中文阅读过程中副中央凹预视研究需要解决的几个关键问题。     

眼动交互中对象排列方式对作业绩效的影响

由于人眼注视的方位能够表达用户的兴趣中心等信息,使得基于眼动的用户界面备受关注,同时眼动也成为攫取当前认知加工过程的一个窗口。本研究采用２排列方式×６目标项位置的被试内设计,主要考察了眼动人机界面中交互对象的不同空间排列方式及目标项位置对选择工效的影响,以期为设计和优化基于视线追踪的人机交互界面的布局提供心理学依据。所获得的主要结论如下：（1）在基于视线追踪的人机交互中,对象水平排列方式优于垂直排列方式;（2）不同对象排列方式影响目标项位置对作业时间的效应模式,对象水平排列时,作业时间随着目标位置右移而线性递增;垂直排列时,作业时间随目标位置下移以非线性方式递增;（3）目标项位置仅影响目标定位时间,目标激活时间不受对象空间排列方式和目标项位置的影响;（4）基于视线追踪的人机交互系统其对象排列方式以水平方式为宜     

Continuous Dynamics in Real-Time Cognition

ABSTRACT— Real-time cognition is best described not as a sequence of logical operations performed on discrete symbols but as a continuously changing pattern of neuronal activity. The continuity in these dynamics indicates that, in between describable states of mind, mental activity does not lend itself to the linguistic labels relied on by much of psychology. We discuss eye-tracking and mouse-tracking evidence for this temporal continuity and provide geometric visualizations of mental activity, depicting it as a continuous trajectory through a state space (a multidimensional space in which locations correspond to mental states). When the state of the system travels toward a frequently visited region of that space, the destination may constitute recognition of a particular word or a particular object; but on the way there, the majority of the mental trajectory is in intermediate regions of that space, revealing graded mixtures of mental states.     

Eye movements during spoken word recognition in Russian children

This study explores incremental processing in spoken word recognition in Russian 5- and 6-year-olds and adults using free-viewing eye-tracking. Participants viewed scenes containing pictures of four familiar objects and clicked on a target embedded in a spoken instruction. In the cohort condition, two object names shared identical three-phoneme onsets. In the noncohort condition, all object names had unique onsets. Coarse-grain analyses of eye movements indicated that adults produced looks to the competitor on significantly more cohort trials than on noncohort trials, whereas children surprisingly failed to demonstrate cohort competition due to widespread exploratory eye movements across conditions. Fine-grain analyses, in contrast, showed a similar time course of eye movements across children and adults, but with cohort competition lingering more than 1s longer in children. The dissociation between coarse-grain and fine-grain eye movements indicates a need to consider multiple behavioral measures in making developmental comparisons in language processing.