Raymond M. Klein

Bio: Raymond M. Klein is an academic researcher from Dalhousie University. The author has contributed to research in topics: Inhibition of return & Eye movement. The author has an hindex of 4, co-authored 14 publications receiving 39 citations.

Inhibition of return: An information processing theory of its natures and significance

Abstract: Inhibition of return (IOR) is an inhibitory aftereffect of visuospatial orienting, typically resulting in slower responses to targets presented in an area that has been recently attended. Since its discovery, myriad research has sought to explain the causes and effects underlying this phenomenon. Here, we briefly summarize the history of the phenomenon, and describe the early work supporting the functional significance of IOR as a foraging facilitator. We then shine a light on the discordance in the literature with respect to mechanism—in particular the lack of theoretical constructs that can consistently explain innumerable dissociations. We then describe three diagnostics (central arrow targets, locus of slack logic and the psychological refractory period, and performance in speed-accuracy space) used to support our theory that there are two forms of inhibition of return—the form which is manifest being contingent upon the activation state of the reflexive oculomotor system. The input form, which operates to decrease the salience of inputs, is generated when the reflexive oculomotor system is suppressed; the output form, which operates to bias responding, is generated when the reflexive oculomotor system is not suppressed. Then, we subject a published data set, wherein inhibitory effects had been generated while the reflexive oculomotor system was either active or suppressed, to diffusion modelling. As we hypothesized, based on the aforementioned theory, the effects of the two forms of IOR were best accounted for by different drift diffusion parameters. The paper ends with a variety of suggestions for further research.

On the origins and evolution of the Attention Network Tests.

Abstract: Attention is a pivotal cognitive function and efforts to understand its properties and operations are fundamental. Building upon the best known taxonomy of attention put forward by Posner and colleagues, the Attention Network Test (ANT) was designed to efficiently provide scores that reflect the efficacy of alerting, orienting and executive control. The ANT has not only been very widely adopted by scholars around the world, it has inspired a wide range of variants, the ANTs, - each with its own purpose. This review will describe the origin of the ANT in the taxonomic contributions of Posner and the evolution of the ANTs with some discussion of the nature and rationale for each major variant described here. We briefly allude to minor modifications of the ANT and present some suggestions related to data reporting and data analysis. We end with some projections about the future use of the original ANT and its notable variants.

What Neuroscientific Studies Tell Us about Inhibition of Return.

Abstract: An inhibitory aftermath of orienting, inhibition of return (IOR), has intrigued scholars since its discovery about 40 years ago. Since then, the phenomenon has been subjected to a wide range of neuroscientific methods and the results of these are reviewed in this paper. These include direct manipulations of brain structures (which occur naturally in brain damage and disease or experimentally as in TMS and lesion studies) and measurements of brain activity (in humans using EEG and fMRI and in animals using single unit recording). A variety of less direct methods (e.g., computational modeling, developmental studies, etc.) have also been used. The findings from this wide range of methods support the critical role of subcortical and cortical oculomotor pathways in the generation and nature of IOR.

Spatial gradients of oculomotor inhibition of return in deaf and normal adults.

Abstract: We explored the effect of deafness on the spatial (gradient) and temporal (decay) properties of oculomotor inhibition of return (IOR) using a task developed by Vaughan (Theoretical and applied aspects of eye movement research. Elsevier, North Holland, pp 143-150, 1984) in which participants made a sequence of saccades to carefully placed targets . Unlike IOR tasks in which ignored cues are used to explore the aftereffects of covert orienting, this task better approximates real-world behavior in which participants are free to make eye movements to potentially relevant inputs. Because IOR is a bias against returning attention and gaze to a previously attended location, we expected to find, and we did find, slower saccades toward previously fixated locations. Replicating Vaughan, a gradient of inhibition around a previously fixated location was observed and this inhibition began to decay after 1200 ms. Importantly, there were no significant differences between the deaf and the normal hearing subjects, on neither the magnitude of oculomotor IOR, nor its decay over time, nor its gradient around the previously fixated location .

Is covert spatial orienting embodied or disembodied cognition? A historical review.

Abstract: The possible relations between eye movements and shifts of attention are considered in the context of the contemporary proposal of embodied cognition. The focus of this historical review is Klein's oculomotor readiness hypothesis for how visuospatial attention might be allocated when under endogenous control. When eye movements are actually executed, attention shifts in advance of these movements. But when eye movements are prepared but not executed, shifts of attention are not observed. Conversely, when attention is allocated endogenously and covertly to a location in space, eye movements to that location are not prepared. These findings suggest that covert spatial orienting when under endogenous control is more dis-embodied than embodied cognition.

The intersection between the oculomotor and hippocampal memory systems: empirical developments and clinical implications

Abstract: Decades of cognitive neuroscience research has shown that where we look is intimately connected to what we remember. In this article, we review findings from human and nonhuman animals, using behavioral, neuropsychological, neuroimaging, and computational modeling methods, to show that the oculomotor and hippocampal memory systems interact in a reciprocal manner, on a moment-to-moment basis, mediated by a vast structural and functional network. Visual exploration serves to efficiently gather information from the environment for the purpose of creating new memories, updating existing memories, and reconstructing the rich, vivid details from memory. Conversely, memory increases the efficiency of visual exploration. We call for models of oculomotor control to consider the influence of the hippocampal memory system on the cognitive control of eye movements, and for models of hippocampal and broader medial temporal lobe function to consider the influence of the oculomotor system on the development and expression of memory. We describe eye movement-based applications for the detection of neurodegeneration and delivery of therapeutic interventions for mental health disorders for which the hippocampus is implicated and memory dysfunctions are at the forefront.

Salience Models: A Computational Cognitive Neuroscience Review.

Abstract: The seminal model by Laurent Itti and Cristoph Koch demonstrated that we can compute the entire flow of visual processing from input to resulting fixations. Despite many replications and follow-ups, few have matched the impact of the original model-so what made this model so groundbreaking? We have selected five key contributions that distinguish the original salience model by Itti and Koch; namely, its contribution to our theoretical, neural, and computational understanding of visual processing, as well as the spatial and temporal predictions for fixation distributions. During the last 20 years, advances in the field have brought up various techniques and approaches to salience modelling, many of which tried to improve or add to the initial Itti and Koch model. One of the most recent trends has been to adopt the computational power of deep learning neural networks; however, this has also shifted their primary focus to spatial classification. We present a review of recent approaches to modelling salience, starting from direct variations of the Itti and Koch salience model to sophisticated deep-learning architectures, and discuss the models from the point of view of their contribution to computational cognitive neuroscience.

Endogenous orienting in the archer fish.

Abstract: Significance Volitional orienting, most commonly explored in humans using the classic Posner endogenous cuing task, is often linked to neocortical regions. We applied this task in a species lacking a neocortex (i.e., archer fish). Our study provides a demonstration of facilitation and inhibition of return as a result of a purely endogenous (centrally presented, informative, and symbolic) cue. The results have major implications for our understanding of the evolution of orienting (reflexive and volitional), and for the paradigms used to study “volitional” processes. The literature has long emphasized the neocortex’s role in volitional processes. In this work, we examined endogenous orienting in an evolutionarily older species, the archer fish, which lacks neocortex-like cells. We used Posner’s classic endogenous cuing task, in which a centrally presented, spatially informative cue is followed by a target. The fish responded to the target by shooting a stream of water at it. Interestingly, the fish demonstrated a human-like “volitional” facilitation effect: their reaction times to targets that appeared on the side indicated by the precue were faster than their reaction times to targets on the opposite side. The fish also exhibited inhibition of return, an aftermath of orienting that commonly emerges only in reflexive orienting tasks in human participants. We believe that this pattern demonstrates the acquisition of an arbitrary connection between spatial orienting and a nonspatial feature of a centrally presented stimulus in nonprimate species. In the literature on human attention, orienting in response to such contingencies has been strongly associated with volitional control. We discuss the implications of these results for the evolution of orienting, and for the study of volitional processes in all species, including humans.