Blindsight Modulation of Motion Perception

2002 ◽  
Vol 14 (8) ◽  
pp. 1174-1183 ◽  
Author(s):  
James M. Intriligator ◽  
Ruiman Xie ◽  
Jason J. S. Barton
Keyword(s):  
Motion Perception ◽  
Optic Flow ◽  
Reaction Times ◽  
Similar Efficacy ◽  
Forced Choice ◽  
Flow Modulation ◽  
Residual Vision ◽  
Peripheral Cues ◽  
Residual Motion ◽  
Perceptual Abilities

Monkey data suggest that of all perceptual abilities, motion perception is the most likely to survive striate damage. The results of studies on motion blindsight in humans, though, are mixed. We used an indirect strategy to examine how responses to visible stimuli were modulated by blind-field stimuli. In a 26-year-old man with focal striate lesions, discrimination of visible optic flow was enhanced about 7% by blind-field flow, even though discrimination of optic flow in the blind field alone (the direct strategy) was at chance. Pursuit of an imagined target using peripheral cues showed reduced variance but not increased gain with blind-field cues. Preceding blind-field prompts shortened reaction times to visible targets by about 10 msec, but there was no attentional crowding of visible stimuli by blind-field distractors. A similar efficacy of indirect blind-field optic flow modulation was found in a second patient with residual vision after focal striate damage, but not in a third with more extensive medial occipito-temporal damage. We conclude that indirect modulatory strategies are more effective than direct forced-choice methods at revealing residual motion perception after focal striate lesions.

Covert orienting of attention in macaques. I. Effects of behavioral context

1993 ◽  
Vol 70 (1) ◽  
pp. 431-443 ◽  
Author(s):  
E. M. Bowman ◽  
V. J. Brown ◽  
C. Kertzman ◽  
U. Schwarz ◽  
D. L. Robinson
Keyword(s):  
Cognitive Processes ◽  
Reaction Times ◽  
Orienting Response ◽  
Validity Effect ◽  
Experimental Conditions ◽  
Covert Orienting ◽  
Cognitive Influences ◽  
Attentional Effect ◽  
Peripheral Cues ◽  
Neurophysiological Studies

1. A task was used by Posner (1980) to measure shifts of attention that occurred covertly, in the absence of an eye movement or other orienting response. This paradigm was used here to assess the nature of covert attentional orienting in monkeys to develop an animal model for neurophysiological studies. Shifts of attention were measurable in monkeys and were consistent across a variety of experimental conditions. 2. The paradigm required that monkeys fixate and release a bar at the appearance of a target, which was preceded by a cue. Reaction times to targets that followed peripheral cues at the same location (validly cued) were significantly faster than those that followed cues in the opposite visual field (invalidly cued). This difference was defined as the validity effect, which as in humans, is used as the measure of a covert attentional shift. 3. When the proportion of validly to invalidly cued targets was decreased, no change was seen in the validity effect of the monkeys. This is in contrast to humans, for whom the ratio of validly to invalidly cued targets affected the magnitude of the validity effect. When 80% of the targets were preceded by cues at the same location, the validity effect was greatest. The effect was reversed when the proportions were reversed. From this result, it is concluded that cognitive processes can affect covert orienting to peripheral cues in humans, whereas in trained monkeys, performance was automatic. 4. To test whether cognitive influences on attention could be demonstrated in the monkey, an animal was taught to use symbolic, foveal signals to covertly direct attention. The magnitude of this validity effect was greater than that obtained with peripheral cues. 5. The effects of motivational and perceptual processes were tested. Although overall reaction times could be modified, the facilitating effects of the cues persisted. This constancy across motivational and perceptual levels supports the notion that the monkeys were performing the task in an automatic way, under the exogenous control of peripheral cues. 6. Most visual cuing has been tested with visual landmarks at the locations of cues and targets. These monkeys were trained with such landmarks, and when tested without them, the attentional effect of the cues was nearly abolished. These data suggest that local visual features can be important for covert orienting. 7. To determine the spatial extent of the effect of the cue, monkeys and humans were tested with four cue-target distances (0-60 degrees).(ABSTRACT TRUNCATED AT 400 WORDS)

Man, Monkey, and Blindsight

1998 ◽  
Vol 4 (4) ◽  
pp. 227-230 ◽  
Author(s):  
Tirin Moore ◽  
Hillary R. Rodman ◽  
Charles G. Gross
Keyword(s):  
Visual Cortex ◽  
Visual System ◽  
Primary Visual Cortex ◽  
Visual Function ◽  
Forced Choice ◽  
Neural Mechanisms ◽  
Residual Vision ◽  
Choice Testing

The visual function that survives damage to the primary visual cortex (V1) in humans is often unaccompanied by awareness. This type of residual vision, called “blindsight,” has raised considerable interest because it implies a separation of conscious from unconscious vision mechanisms. The monkey visual system has proven to be a useful model in elucidating the possible neural mechanisms of residual vision and blindsight in humans. Clear similarities, however, between the phenomenology of human and monkey residual vision have only recently become evident. This article summarizes parallels between residual vision in monkeys and humans with damage to V1. These parallels Include the tendency of the remaining vision to require forced-choice testing and the fact that more robust residual vision remains when V1 damage is sustained early in life. NEUROSCIENTIST 4:227–230

A Neural Network for the Processing of Optic Flow from Ego-Motion in Man and Higher Mammals

1993 ◽  
Vol 5 (3) ◽  
pp. 374-391 ◽  
Author(s):  
Markus Lappe ◽  
Josef P. Rauschecker
Keyword(s):  
Neural Network ◽  
Motion Perception ◽  
Network Model ◽  
Neural Network Model ◽  
Optic Flow ◽  
Cortical Area ◽  
Visual Motion ◽  
Flow Fields ◽  
Subspace Algorithm ◽  
Motion Flow

Interest in the processing of optic flow has increased recently in both the neurophysiological and the psychophysical communities. We have designed a neural network model of the visual motion pathway in higher mammals that detects the direction of heading from optic flow. The model is a neural implementation of the subspace algorithm introduced by Heeger and Jepson (1990). We have tested the network in simulations that are closely related to psychophysical and neurophysiological experiments and show that our results are consistent with recent data from both fields. The network reproduces some key properties of human ego-motion perception. At the same time, it produces neurons that are selective for different components of ego-motion flow fields, such as expansions and rotations. These properties are reminiscent of a subclass of neurons in cortical area MSTd, the triple-component neurons. We propose that the output of such neurons could be used to generate a computational map of heading directions in or beyond MST.

Inhibition of Return, but Not Facilitation, Disappears Under Vigilance Decrease Due to Sleep Deprivation

2014 ◽  
Vol 61 (2) ◽  
pp. 99-109 ◽  
Author(s):  
Diana Martella ◽  
Andrea Marotta ◽  
Luis J. Fuentes ◽  
Maria Casagrande
Keyword(s):  
Sleep Deprivation ◽  
Inhibition Of Return ◽  
Target Location ◽  
Reaction Times ◽  
Attentional Orienting ◽  
Target Interval ◽  
Facilitation Effect ◽  
Peripheral Cues ◽  
Endogenous Component ◽  
Phasic Alerting

In this study, we assessed whether unspecific attention processes signaled by general reaction times (RTs), as well as specific facilitatory (validity or facilitation effect) and inhibitory (inhibition of return, IOR) effects involved in the attentional orienting network, are affected by low vigilance due to both circadian factors and sleep deprivation (SD). Eighteen male participants performed a cuing task in which peripheral cues were nonpredictive about the target location and the cue-target interval varied at three levels: 200 ms, 800 ms, and 1,100 ms. Facilitation with the shortest and IOR with the longest cue-target intervals were observed in the baseline session, thus replicating previous related studies. Under SD condition, RTs were generally slower, indicating a reduction in the participants’ arousal level. The inclusion of a phasic alerting tone in several trials partially compensated for the reduction in tonic alertness, but not with the longest cue-target interval. With regard to orienting, whereas the facilitation effect due to reflexive shifts of attention was preserved with sleep loss, the IOR was not observed. These results suggest that the decrease of vigilance produced by SD affects both the compensatory effects of phasic alerting and the endogenous component involved in disengaging attention from the cued location, a requisite for the IOR effect being observed.

Effect of Element Size on Stereoscopic Apparent Motion

2003 ◽  
Vol 96 (3_suppl) ◽  
pp. 1187-1193 ◽  
Author(s):  
Hiroyuki Ito
Keyword(s):  
Motion Perception ◽  
Apparent Motion ◽  
Forced Choice ◽  
Spatial Displacement ◽  
Motion Direction ◽  
Element Size ◽  
Random Dot Stereograms ◽  
Perceived Motion

Spatial displacement limits in stereoscopic (cyclopean) apparent motion were measured from sequentially presented two-frame random-depth configurations. Each depth configuration was defined by stereoscopically near or far elements of various sizes. The limits were compared with those in luminance-defined apparent motion. The subject's task was 2-alternative forced-choice of the perceived motion direction of the sequentially presented two-frame random-dot stereograms. The spatial displacement limit below which correct motion perception arose with stereoscopic configurations was larger in proportion to increases in size of elements. The values were almost consistent with those measured by luminance-defined configurations with the same element sizes. This result suggests that the strategy for discrimination of motion direction of random configurations is similar in both stereoscopic and luminance-defined apparent motion.

Novel two-alternative forced choice paradigm for bilateral vibrotactile whisker frequency discrimination in head-fixed mice and rats

2013 ◽  
Vol 109 (1) ◽  
pp. 273-284 ◽  
Author(s):  
Johannes M. Mayrhofer ◽  
Vida Skreb ◽  
Wolfger von der Behrens ◽  
Simon Musall ◽  
Bruno Weber ◽  
...  
Keyword(s):  
Reaction Times ◽  
Stimulus Presentation ◽  
Frequency Discrimination ◽  
Forced Choice ◽  
Peak Performance ◽  
Perceptual Decision Making ◽  
Learning Rates ◽  
Behavioral Paradigm ◽  
Mystacial Vibrissae ◽  
Rats And Mice

Rats and mice receive a constant bilateral stream of tactile information with their large mystacial vibrissae when navigating in their environment. In a two-alternative forced choice paradigm (2-AFC), head-fixed rats and mice learned to discriminate vibrotactile frequencies applied simultaneously to individual whiskers on the left and right sides of the snout. Mice and rats discriminated 90-Hz pulsatile stimuli from pulsatile stimuli with lower repetition frequencies (10–80 Hz) but with identical kinematic properties in each pulse. Psychometric curves displayed an average perceptual threshold of 50.6-Hz and 53.0-Hz frequency difference corresponding to Weber fractions of 0.56 and 0.58 in mice and rats, respectively. Both species performed >400 trials a day (>200 trials per session, 2 sessions/day), with a peak performance of >90% correct responses. In general, rats and mice trained in the identical task showed comparable psychometric curves. Behavioral readouts, such as reaction times, learning rates, trial omissions, and impulsivity, were also very similar in the two species. Furthermore, whisking of the animals before stimulus presentation reduced task performance. This behavioral paradigm, combined with whisker position tracking, allows precise stimulus control in the 2-AFC task for head-fixed rodents. It is compatible with state-of-the-art neurophysiological recording techniques, such as electrophysiology and two-photon imaging, and therefore represents a valuable framework for neurophysiological investigations of perceptual decision-making.

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