scholarly journals Effect of central and surrounding gratings of test stimulus on appearance of motion aftereffect

2002 ◽  
Vol 73 (1) ◽  
pp. 71-77
Author(s):  
Isao Watanabe ◽  
Shinya Fukuura ◽  
Hiroyuki Ito
Keyword(s):  
Test Stimulus ◽  
Motion Aftereffect

scholarly journals The tactile motion aftereffect suggests an intensive code for speed in neurons sensitive to both speed and direction of motion

2016 ◽  
Vol 115 (3) ◽  
pp. 1703-1712 ◽  
Author(s):  
S. McIntyre ◽  
I. Birznieks ◽  
R. M. Vickery ◽  
A. O. Holcombe ◽  
T. Seizova-Cajic
Keyword(s):  
Test Stimulus ◽  
Dynamic Test ◽  
Human Perception ◽  
Motion Aftereffect ◽  
Object Motion ◽  
Motion Processing ◽  
Motion Direction ◽  
Test Speed ◽  
Neurophysiological Studies ◽  
Tactile Motion Aftereffect

Neurophysiological studies in primates have found that direction-sensitive neurons in the primary somatosensory cortex (SI) generally increase their response rate with increasing speed of object motion across the skin and show little evidence of speed tuning. We employed psychophysics to determine whether human perception of motion direction could be explained by features of such neurons and whether evidence can be found for a speed-tuned process. After adaptation to motion across the skin, a subsequently presented dynamic test stimulus yields an impression of motion in the opposite direction. We measured the strength of this tactile motion aftereffect (tMAE) induced with different combinations of adapting and test speeds. Distal-to-proximal or proximal-to-distal adapting motion was applied to participants' index fingers using a tactile array, after which participants reported the perceived direction of a bidirectional test stimulus. An intensive code for speed, like that observed in SI neurons, predicts greater adaptation (and a stronger tMAE) the faster the adapting speed, regardless of the test speed. In contrast, speed tuning of direction-sensitive neurons predicts the greatest tMAE when the adapting and test stimuli have matching speeds. We found that the strength of the tMAE increased monotonically with adapting speed, regardless of the test speed, showing no evidence of speed tuning. Our data are consistent with neurophysiological findings that suggest an intensive code for speed along the motion processing pathways comprising neurons sensitive both to speed and direction of motion.

Difference of Spatial Frequency Selectivity between Static and Flicker Motion Aftereffects

Perception ◽  
1994 ◽  
Vol 23 (11) ◽  
pp. 1313-1320 ◽  
Author(s):  
Hiroshi Ashida ◽  
Naoyuki Osaka
Keyword(s):  
Spatial Frequency ◽  
Test Stimulus ◽  
Motion Aftereffect ◽  
Frequency Selectivity ◽  
Spatial Frequencies ◽  
Sinusoidal Gratings ◽  
Early Processing ◽  
Motion Aftereffects

The strength of motion aftereffect (MAE) was measured with the use of sinusoidal gratings of several spatial frequencies, to examine the spatial frequency selectivity of two types of MAE. With ordinary static grating as a test stimulus, to measure ‘static MAE’, the maximum aftereffect for each adapting spatial frequency was obtained at the testing stimuli of the same spatial frequency, showing spatial frequency selectivity. However, in the case when the sinusoidally flickering grating was used as a test stimulus, to measure ‘flicker MAE’, no spatial frequency selectivity was observed. The two types of MAE were considered to be based on different mechanisms. Static MAE is thought to depend on the spatiotemporal channel mechanism in the early processing stages, whereas flicker MAE might reflect higher-level processes which might occur at the extrastriate regions.

PATHS OF SEEN MOTION AND MOTION AFTEREFFECT

1966 ◽  
Vol 23 (3) ◽  
pp. 1003-1008 ◽  
Author(s):  
SHIGEMASA SUMI
Keyword(s):  
Motion Aftereffect

scholarly journals Through the Neural Magnifying Glass: Visual Acuity and Motion-Aftereffect

i-Perception ◽  
10.1068/ii48 ◽  
2014 ◽  
Vol 5 (5) ◽  
pp. 479-479
Author(s):  
S.C Boyle ◽  
R Jenkins ◽  
M Lages
Keyword(s):  
Visual Acuity ◽  
Motion Aftereffect

Apparent Velocity of Motion Aftereffects in Central and Peripheral Vision

Perception ◽  
1986 ◽  
Vol 15 (5) ◽  
pp. 603-612 ◽  
Author(s):  
Michael J Wright
Keyword(s):  
Visual Field ◽  
Time Course ◽  
Peripheral Vision ◽  
Temporal Frequency ◽  
Motion Aftereffect ◽  
Apparent Velocity ◽  
Real Motion ◽  
Temporal Decay ◽  
Spatial Grain ◽  
Motion Aftereffects

Adapting to a drifting grating (temporal frequency 4 Hz, contrast 0.4) in the periphery gave rise to a motion aftereffect (MAE) when the grating was stopped. A standard unadapted foveal grating was matched to the apparent velocity of the MAE, and the matching velocity was approximately constant regardless of the visual field position and spatial frequency of the adapting grating. On the other hand, when the MAE was measured by nulling with real motion of the test grating, nulling velocity was found to increase with eccentricity. The nulling velocity was constant when scaled to compensate for changes in the spatial ‘grain’ of the visual field. Thus apparent velocity of MAE is constant across the visual field, but requires a greater velocity of real motion to cancel it in the periphery. This confirms that the mechanism underlying MAE is spatially-scaled with eccentricity, but temporally homogeneous. A further indication of temporal homogeneity is that when MAE is tracked, by matching or by nulling, the time course of temporal decay of the aftereffect is similar for central and for peripheral stimuli.

The Effect of Set on the Two-Point Tactual Threshold

1966 ◽  
Vol 18 (2) ◽  
pp. 169-174 ◽  
Author(s):  
Anima Sen
Keyword(s):  
University Students ◽  
Test Stimulus ◽  
Opposite Direction ◽  
Adaptation Level ◽  
Critical Stimulus ◽  
Positive Direction ◽  
Control Series ◽  
Longitudinal Line ◽  
Adaptation Level Theory ◽  
The Right

This experiment studies the influence of set on the two-point tactual threshold. The two-point limen (critical stimulus) was determined along the mid-longitudinal line of both volar and dorsal surfaces of the right forearms of seven university students. Test-stimuli were selected at 3 mm. steps both up and down from each of the critical stimuli. Each of these test-stimuli was presented separately, the critical stimulus being interpolated 30 times in each test of the series. The proportions of two-point and one-point responses to the critical stimulus were then determined again in a control series. It was found that, as the test-stimulus deviated in the positive direction from the critical stimulus, the proportion of two-point responses to the critical stimulus increased, reached a maximum and then began to decline. A similar rise and fall in one-point responses were found in the opposite direction. The results were explained by Adaptation Level Theory.

scholarly journals Mental Rotation Meets the Motion Aftereffect: The Role of hV5/MT+ in Visual Mental Imagery

2011 ◽  
Vol 23 (6) ◽  
pp. 1395-1404 ◽  
Author(s):  
Ruth Seurinck ◽  
Floris P. de Lange ◽  
Erik Achten ◽  
Guy Vingerhoets
Keyword(s):  
Mental Rotation ◽  
Mental Imagery ◽  
Parietal Cortex ◽  
Neural Activity ◽  
Posterior Parietal Cortex ◽  
Visual Motion ◽  
Motion Aftereffect ◽  
Mental Rotation Task ◽  
Behavioral Performance ◽  
Visual Mental Imagery

A growing number of studies show that visual mental imagery recruits the same brain areas as visual perception. Although the necessity of hV5/MT+ for motion perception has been revealed by means of TMS, its relevance for motion imagery remains unclear. We induced a direction-selective adaptation in hV5/MT+ by means of an MAE while subjects performed a mental rotation task that elicits imagined motion. We concurrently measured behavioral performance and neural activity with fMRI, enabling us to directly assess the effect of a perturbation of hV5/MT+ on other cortical areas involved in the mental rotation task. The activity in hV5/MT+ increased as more mental rotation was required, and the perturbation of hV5/MT+ affected behavioral performance as well as the neural activity in this area. Moreover, several regions in the posterior parietal cortex were also affected by this perturbation. Our results show that hV5/MT+ is required for imagined visual motion and engages in an interaction with parietal cortex during this cognitive process.

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