Integration of Size and Binocular Disparity Visual Cues in Manual Depth-Control Tasks

Previous experiments have shown that V2 neurons respond to complex stimuli such as cyclopean edges (edges defined purely by binocular disparity), angles, and motion borders. It is currently unknown whether these responses are a simple consequence of converging inputs from a prior stage of processing (V1). Alternatively, they may identify edges in a way that is invariant across a range of visual cues defining the edge, in which case they could provide a neuronal substrate for scene segmentation. Here, we examine the ability of a simple feedforward model that combines two V1-like inputs to describe the responses of V2 neurons to cyclopean edges. A linear feedforward model was able to qualitatively reproduce the major patterns of response enhancement for cyclopean edges seen in V2. However, quantitative fitting revealed that this model usually predicts response suppression by some edge configurations and such suppression was rarely seen in the data. This problem was resolved by introducing a squaring nonlinearity at the output of the individual inputs prior to combination. The extended model produced extremely good fits to most of our data. We conclude that the responses of V2 neurons to complex stimuli such as cyclopean edges can be adequately explained by a simple convergence model and do not necessarily represent the development of sophisticated mechanisms that signal scene segmentation, although they probably constitute a step toward this goal.

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Relative contributions to vergence eye movements of two binocular cues for motion-in-depth

Scientific Reports ◽

10.1038/s41598-019-53902-y ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 1

Author(s):

Martin Giesel ◽

Alexandra Yakovleva ◽

Marina Bloj ◽

Alex R. Wade ◽

Anthony M. Norcia ◽

...

Keyword(s):

Eye Movements ◽

Eye Movement ◽

Visual Cues ◽

Binocular Disparity ◽

Stimulus Motion ◽

Sensory Control ◽

Motion In Depth ◽

Relative Contribution ◽

Control Signals

AbstractWhen we track an object moving in depth, our eyes rotate in opposite directions. This type of “disjunctive” eye movement is called horizontal vergence. The sensory control signals for vergence arise from multiple visual cues, two of which, changing binocular disparity (CD) and inter-ocular velocity differences (IOVD), are specifically binocular. While it is well known that the CD cue triggers horizontal vergence eye movements, the role of the IOVD cue has only recently been explored. To better understand the relative contribution of CD and IOVD cues in driving horizontal vergence, we recorded vergence eye movements from ten observers in response to four types of stimuli that isolated or combined the two cues to motion-in-depth, using stimulus conditions and CD/IOVD stimuli typical of behavioural motion-in-depth experiments. An analysis of the slopes of the vergence traces and the consistency of the directions of vergence and stimulus movements showed that under our conditions IOVD cues provided very little input to vergence mechanisms. The eye movements that did occur coinciding with the presentation of IOVD stimuli were likely not a response to stimulus motion, but a phoria initiated by the absence of a disparity signal.

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Processing of Shape Defined by Disparity in Monkey Inferior Temporal Cortex

Journal of Neurophysiology ◽

10.1152/jn.2001.85.2.735 ◽

2001 ◽

Vol 85 (2) ◽

pp. 735-744 ◽

Cited By ~ 46

Author(s):

Hiroki Tanaka ◽

Takanori Uka ◽

Kenji Yoshiyama ◽

Makoto Kato ◽

Ichiro Fujita

Keyword(s):

Visual Cues ◽

Binocular Disparity ◽

Temporal Cortex ◽

Inferior Temporal Cortex ◽

Response Modulation ◽

Random Dot Stereograms ◽

Fixation Task ◽

Per Se ◽

Extracellular Activity

Neurons in the monkey inferior temporal cortex (IT) have been shown to respond to shapes defined by luminance, texture, or motion. In the present study, we determined whether IT neurons respond to shapes defined solely by binocular disparity, and if so, whether signals of disparity and other visual cues to define shape converge on single IT neurons. We recorded extracellular activity from IT neurons while monkeys performed a fixation task. Among the neurons that responded to at least one of eight random-dot stereograms (RDSs) containing different disparity-defined shapes, 21% varied their responses to different RDSs. Responses of most of the neurons were positively correlated between two sets of RDSs, which consisted of different dot patterns but defined the same set of eight shapes, whereas responses to RDSs and their monocular images were not correlated. This indicates that the response modulation for the eight RDSs reflects selectivity for shapes (or their component contours) defined by disparity, although responses were also affected by dot patterns per se. Among the neurons that showed selectivity for shapes defined by luminance or disparity, 44% were activated by both cues. Responses of these neurons to luminance-defined shapes and those to disparity-defined shapes were often positively correlated to each other. Furthermore the stimulus rank, which was determined by the magnitude of responses to shapes, generally matched between these cues. The same held true between disparity and texture cues. The results suggest that the signals of disparity, luminance, and texture cues to define the shapes converge on a population of single IT neurons to produce the selectivity for shapes.

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Supporting the Use of Rudimentary Vocalizations

Perspectives on Augmentative and Alternative Communication ◽

10.1044/aac23.3.132 ◽

2014 ◽

Vol 23 (3) ◽

pp. 132-139 ◽

Cited By ~ 1

Author(s):

Lauren Zubow ◽

Richard Hurtig

Keyword(s):

Rett Syndrome ◽

Visual Cues ◽

Acoustic Analysis ◽

Eye Gaze ◽

Research Question ◽

Primary Research ◽

Multiple Modalities ◽

Face To Face ◽

Perceptual Judgments ◽

The Face

Children with Rett Syndrome (RS) are reported to use multiple modalities to communicate although their intentionality is often questioned (Bartolotta, Zipp, Simpkins, & Glazewski, 2011; Hetzroni & Rubin, 2006; Sigafoos et al., 2000; Sigafoos, Woodyatt, Tuckeer, Roberts-Pennell, & Pittendreigh, 2000). This paper will present results of a study analyzing the unconventional vocalizations of a child with RS. The primary research question addresses the ability of familiar and unfamiliar listeners to interpret unconventional vocalizations as “yes” or “no” responses. This paper will also address the acoustic analysis and perceptual judgments of these vocalizations. Pre-recorded isolated vocalizations of “yes” and “no” were presented to 5 listeners (mother, father, 1 unfamiliar, and 2 familiar clinicians) and the listeners were asked to rate the vocalizations as either “yes” or “no.” The ratings were compared to the original identification made by the child's mother during the face-to-face interaction from which the samples were drawn. Findings of this study suggest, in this case, the child's vocalizations were intentional and could be interpreted by familiar and unfamiliar listeners as either “yes” or “no” without contextual or visual cues. The results suggest that communication partners should be trained to attend to eye-gaze and vocalizations to ensure the child's intended choice is accurately understood.

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