scholarly journals A comparison of the effects of spatial separation on apparent motion in the auditory and visual modalities

1990 ◽  
Vol 47 (5) ◽  
pp. 439-448 ◽  
Author(s):  
Thomas Z. Strybel ◽  
Carol L. Manligas ◽  
Ozzie Chan ◽  
David R. Perrott
Keyword(s):  
Apparent Motion ◽  
Spatial Separation

scholarly journals Comparison of the Spatial Limits on Direction Selectivity in Visual Areas MT and V1

2005 ◽  
Vol 93 (3) ◽  
pp. 1235-1245 ◽  
Author(s):  
Mark M. Churchland ◽  
Nicholas J. Priebe ◽  
Stephen G. Lisberger
Keyword(s):  
Apparent Motion ◽  
Great Majority ◽  
Spatial Separation ◽  
Direction Selectivity ◽  
Temporal Separation ◽  
Temporal Area ◽  
Mean Values ◽  
V1 Neurons ◽  
Preferred Direction ◽  
The Difference

We recorded responses to apparent motion from directionally selective neurons in primary visual cortex (V1) of anesthetized monkeys and middle temporal area (MT) of awake monkeys. Apparent motion consisted of multiple stationary stimulus flashes presented in sequence, characterized by their temporal separation (Δ t) and spatial separation (Δ x). Stimuli were 8° square patterns of 100% correlated random dots that moved at apparent speeds of 16 or 32°/s. For both V1 and MT, the difference between the response to the preferred and null directions declined with increasing flash separation. For each neuron, we estimated the maximum flash separation for which directionally selective responses were observed. For the range of speeds we used, Δ x provided a better description of the limitation on directional responses than did Δ t. When comparing MT and V1 neurons of similar preferred speed, there was no difference in the maximum Δ x between our samples from the two areas. In both V1 and MT, the great majority of neurons had maximal values of Δ x in the 0.25–1° range. Mean values were almost identical between the two areas. For most neurons, larger flash separations led to both weaker responses to the preferred direction and increased responses to the opposite direction. The former mechanism was slightly more dominant in MT and the latter slightly more dominant in V1. We conclude that V1 and MT neurons lose direction selectivity for similar values of Δ x, supporting the hypothesis that basic direction selectivity in MT is inherited from V1, at least over the range of stimulus speeds represented by both areas.

The Effect of Two-Dimensional and Three-Dimensional Distance on Apparent Motion

Perception ◽  
1983 ◽  
Vol 12 (3) ◽  
pp. 305-312 ◽  
Author(s):  
Kathleen Mutch ◽  
Isabel M Smith ◽  
Albert Yonas
Keyword(s):  
Motion Perception ◽  
Apparent Motion ◽  
Three Dimensional ◽  
Spatial Separation ◽  
Three Dimensions ◽  
Correspondence Problem ◽  
Two Dimensional ◽  
Motion Display ◽  
Specific Concern ◽  
Actual Depth

The problem of how the visual system matches corresponding inputs from one instant to the next to produce the perception of motion has been experimentally examined. The specific concern was whether this correspondence problem is solved prior to the interpretation of three-dimensional distance. Observers judged the degree of apparent motion between pairs of lights in a conflicting motion display. Spatial separation of the lights was varied in two and three dimensions in order to assess whether retinal distance, actual depth, or some combination of these provided critical information for correspondence. The results support Ullman's contention that only two-dimensional (retinal) distances are used in establishing correspondence in motion perception.

scholarly journals The effect of timing and spatial separation on the velocity of auditory apparent motion

1998 ◽  
Vol 60 (8) ◽  
pp. 1441-1451 ◽  
Author(s):  
Thomas Z. Strybel ◽  
Sherry A. Span ◽  
April M. Witty
Keyword(s):  
Apparent Motion ◽  
Spatial Separation

Two Dimensionality of the Correspondence Process in Apparent Motion

Perception ◽  
1978 ◽  
Vol 7 (6) ◽  
pp. 683-693 ◽  
Author(s):  
Shimon Ullman
Keyword(s):  
Motion Perception ◽  
Apparent Motion ◽  
Spatial Separation ◽  
Two Dimensional ◽  
Fundamental Process

A fundamental process underlying motion perception is the matching of corresponding elements in different views. In this correspondence process spatial separation between elements plays a major role. The relevant separation is shown by the current study to be the two-dimensional, uninterpreted distance, a finding that has an implication to the level at which the correspondence process is carried out. The current findings are compared with earlier results concerning ‘optimality’ of apparent motion to conclude that optimality cannot serve as a measure for the correspondence strength.

Space and Time: An Impact of Spatial Separation, Apparent Motion, and Perceptual Grouping on TOJ Performance

Perception ◽  
10.1068/p7401 ◽  
2013 ◽  
Vol 42 (5) ◽  
pp. 551-561 ◽  
Author(s):  
Orit Baruch ◽  
Yaffa Yeshurun ◽  
David I Shore
Keyword(s):  
Apparent Motion ◽  
Perceptual Grouping ◽  
Spatial Separation ◽  
Space And Time

Long-Range Apparent Motion as a Result of Perceptual Organisation

Perception ◽  
1994 ◽  
Vol 23 (3) ◽  
pp. 269-286 ◽  
Author(s):  
Tadasu Oyama ◽  
Katsuo Naito ◽  
Hiromi Naito
Keyword(s):  
Long Range ◽  
Apparent Motion ◽  
Spatial Separation ◽  
Stimulus Onset ◽  
Lateral Motion ◽  
Perceptual Constancy ◽  
Colour Difference ◽  
Relative Dominance ◽  
Onset Asynchrony ◽  
Shape And Size

Five kinds of percept have been found to occur when two different stimulus objects are simultaneously presented, exchanging positions with each other in successive exposures. These five percepts can be classified as follows: (i) Appearance—Disappearance (succession), (ii) Lateral Motion, (iii) Depth Motion, (iv) Transmutation (in colour, brightness, and/or shape), and (v) Overlapping (simultaneity). Results of three experiments indicate that relative dominance among these five percepts systematically depends upon differences between the two stimulus objects in colour, luminance, shape, and size. The relative dominance depended upon the stimulus onset asynchrony (SOA) between successive presentations and on the spatial separation between the two objects. Lateral Motion became more dominant as a result of (a) an increase in the number of stimulus attributes differing between the two objects, (b) an increase in the SOA, or (c) a decrease in the distance between the two objects. Colour difference, even without a luminance difference, was one of the determinants for Lateral Motion. Depth Motion frequently occurred when the two objects differed in size and the SOA and the distances between them were relatively great. Transmutation occurred when the objects differed in colour, luminance, or shape. Perceptual modes (ii) to (iv) can be understood as different results of perceptual organisation that always maintains perceptual identity of objects and maintains perceptual constancy of their attributes as much as possible. Long-range apparent motion could be a result of such perceptual organisation.

The Effect of Nonlinear Amplitude Growth on the Speech Perception Benefits Provided by a Single-Sided Vocoder

2019 ◽  
Vol 62 (3) ◽  
pp. 745-757 ◽  
Author(s):  
Jessica M. Wess ◽  
Joshua G. W. Bernstein
Keyword(s):  
Transfer Functions ◽  
Spatial Configuration ◽  
Free Field ◽  
Spatial Separation ◽  
Compression And Expansion ◽  
Interaural Difference ◽  
Interaural Differences ◽  
Single Sided Deafness ◽  
Perceptual Separation ◽  
Loudness Growth

PurposeFor listeners with single-sided deafness, a cochlear implant (CI) can improve speech understanding by giving the listener access to the ear with the better target-to-masker ratio (TMR; head shadow) or by providing interaural difference cues to facilitate the perceptual separation of concurrent talkers (squelch). CI simulations presented to listeners with normal hearing examined how these benefits could be affected by interaural differences in loudness growth in a speech-on-speech masking task.MethodExperiment 1 examined a target–masker spatial configuration where the vocoded ear had a poorer TMR than the nonvocoded ear. Experiment 2 examined the reverse configuration. Generic head-related transfer functions simulated free-field listening. Compression or expansion was applied independently to each vocoder channel (power-law exponents: 0.25, 0.5, 1, 1.5, or 2).ResultsCompression reduced the benefit provided by the vocoder ear in both experiments. There was some evidence that expansion increased squelch in Experiment 1 but reduced the benefit in Experiment 2 where the vocoder ear provided a combination of head-shadow and squelch benefits.ConclusionsThe effects of compression and expansion are interpreted in terms of envelope distortion and changes in the vocoded-ear TMR (for head shadow) or changes in perceived target–masker spatial separation (for squelch). The compression parameter is a candidate for clinical optimization to improve single-sided deafness CI outcomes.

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