The effects of age and hearing impairment on the time course of backward masking

1998 ◽  
Vol 103 (5) ◽  
pp. 3051-3051
Author(s):  
Sara Elizabeth Gehr ◽  
Mitchell Sommers
Keyword(s):  
Hearing Impairment ◽  
Time Course ◽  
Backward Masking

The Temporal Course of Visual Pattern Encoding: Effects of Pattern Goodness

1983 ◽  
Vol 35 (4) ◽  
pp. 607-633 ◽  
Author(s):  
Edmund S. Howe ◽  
Cynthia J. Brandau
Keyword(s):  
Processing Time ◽  
Time Course ◽  
Short Term Memory ◽  
Experimental Situation ◽  
Stimulus Display ◽  
Backward Masking ◽  
Display Time ◽  
Pattern Goodness ◽  
Temporal Course ◽  
Encoding Effects

Subjects typically display superior reproduction of good (redundant, symmetrical) visual patterns compared with poor ones. This pattern goodness effect could conceivably involve encoding processes, short-term memory processes, or response processes. The present experiments explored the time course of wholistic encoding of Garner dot patterns as a function of tachistoscopic exposure time, delay of backward masking, and post-mask shadowing. Within the specific framework of additive factors theory, Experiment I showed: (a) equal rates of encoding for all patterns since comparable slopes were obtained for the recall X processing time functions; and (b) superior absolute recall for good patterns since different intercepts were obtained. Experiment II demonstrated that when degree of encoding was initially equalized for all patterns, the rate of extraction of further information remained constant over available processing time and was unaffected by pattern goodness, slopes and intercepts for good versus poor patterns then being equal. Experiment III confirmed that, given some fixed duration of available processing time, information is abstracted at the same rate for all pattern regardless of the ratio stimulus display time to delay of mask onset. Experiment IV indicated that maintenance rehearsal normally occurs in the present experimental situation, and that very good patterns are somewhat less disrupted by shadowing over a three-second interval. While STM is thus implicated in the pattern goodness effect it does not follow that STM constitutes a complete explanation of the intercept differences reported here. Empirical evidence of response bias toward production of good patterns, however, was not found. It was shown that very good patterns are highly familiar and nameable, and proposed that they do consequently have an early encoding advantage.

Differential Controls Over Tactile Detection in Humans by Motor Commands and Peripheral Reafference

2006 ◽  
Vol 96 (3) ◽  
pp. 1664-1675 ◽  
Author(s):  
C. Elaine Chapman ◽  
Evelyne Beauchamp
Keyword(s):  
Time Course ◽  
Index Finger ◽  
Motor Command ◽  
Electromyographic Activity ◽  
Backward Masking ◽  
Motor Tasks ◽  
Motor Commands ◽  
Tactile Stimuli ◽  
Tactile Detection ◽  
Electrical Stimuli

The purpose of this study was to determine the extent to which motor commands and peripheral reafference differentially control the detection of near-threshold, tactile stimuli. Detection of weak electrical stimuli applied to the index finger (D2) was evaluated with two bias-free measures of sensory detection, the index of detectability ( d′) and the proportion of stimuli detected. Stimuli were presented at different delays prior to and during two motor tasks, D2 abduction, and elbow extension; both tasks were tested in two modes, active and passive. For both active tasks, the peak decrease in tactile suppression occurred at the onset of electromyographic activity. The time course for the suppression of detection during active and passive D2 abduction was identical, and preceded the onset of movement (respectively, −35 and −47 ms). These results suggest that movement reafference alone, acting through a mechanism of backward masking, could explain the modulation seen with D2 movement. In contrast, tactile suppression was significantly earlier for active elbow movements (−59 ms) as compared with passive (−21 ms), an observation consistent with both the motor command and peripheral reafference contributing to the suppression of detection of stimuli applied to D2 during movements about a proximal joint. A role for the motor command in tactile gating during distal movements cannot be discounted, however, because differences in the strength and distribution of the peripheral reafference may also have contributed to the proximo-distal differences in the timing of the suppression.

scholarly journals Saccadic suppression in schizophrenia

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rebekka Lencer ◽  
Inga Meyhöfer ◽  
Janina Triebsch ◽  
Karen Rolfes ◽  
Markus Lappe ◽  
...  
Keyword(s):  
Time Course ◽  
Visual Disturbance ◽  
Efference Copy ◽  
Visual Sensitivity ◽  
Saccadic Suppression ◽  
Backward Masking ◽  
Control Task ◽  
Saccade Onset ◽  
Saccade Control ◽  
Visual Disturbances

AbstractAbout 40% of schizophrenia patients report discrete visual disturbances which could occur if saccadic suppression, the decrease of visual sensitivity around saccade onset, is impaired. Two mechanisms contribute to saccadic suppression: efference copy processing and backwards masking. Both are reportedly altered in schizophrenia. However, saccadic suppression has not been investigated in schizophrenia. 17 schizophrenia patients and 18 healthy controls performed a saccadic suppression task using a Gabor stimulus with individually adjusted contrast, which was presented within an interval 300 ms around saccade onset. Visual disturbance scores were higher in patients than controls, but saccadic suppression strength and time course were similar in both groups with lower saccadic suppression rates being similarly related to smaller saccade amplitudes. Saccade amplitudes in the saccadic suppression task were reduced in patients, in contrast to unaltered amplitudes during a saccade control task. Notably, smaller saccade amplitudes were related to higher visual disturbances scores in patients. Saccadic suppression performance was unrelated to symptom expression and antipsychotic medication. Unaltered saccadic suppression in patients suggests sufficiently intact efference copy processing and backward masking as required for this task. Instead, visual disturbances in patients may be related to restricted saccadic amplitudes arising from cognitive load while completing a task.

scholarly journals The time course of visual processing: Backward masking and natural scene categorisation

2005 ◽  
Vol 45 (11) ◽  
pp. 1459-1469 ◽  
Author(s):  
Nadège Bacon-Macé ◽  
Marc J.-M. Macé ◽  
Michèle Fabre-Thorpe ◽  
Simon J. Thorpe
Keyword(s):  
Visual Processing ◽  
Time Course ◽  
Backward Masking ◽  
Natural Scene

Investigating the Time-Course of Task-Dependent Perceptual Grouping

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 148-148
Author(s):  
E D Freeman
Keyword(s):  
Perceptual Grouping ◽  
Time Course ◽  
Shape Matching ◽  
Early Stage ◽  
Backward Masking ◽  
Task Context ◽  
Visual Processes ◽  
Task Experience ◽  
Selection Of ◽  
And Task

At what stage do factors such as task experience and expectation interact with the perception of whole objects? Recent work (Freeman, 1995 Perception24 Supplement, 134; 1996 Perception25 Supplement, 51) suggests that perceptual grouping of ambiguous 1-Whole/2-Wholes stimuli is dependent upon learning and task predictability, as inferred from changes in performance in a Whole - Whole/Whole - Part shape matching paradigm. Thus, subjects seemed able to offset the effect of a stimulus parameter known to influence perceived grouping, in order to see the grouping they had been trained to see or were expecting to see. In the present research the timing of these interactive processes was investigated, with the use of backward masking to take a snapshot of visual processes at different stages in their development. Stimulus and task-context factors were found to interact even at the shortest masking interval (50 ms), suggesting that top - down knowledge constrains perceptual grouping processes from an early stage onwards. A simple model of the development of 1-Whole and 2-Whole percepts implies two further conclusions. First, task and stimulus factors both seem to work by modifying the rate of development of the alternative percepts. Second, and counter-intuitively, it appears that, given the appropriate task-context and stimuli, it is possible to group the stimulus in several different ways at once. These results shed light on issues concerning the nature of perceptual grouping, and the process by which our experience of objects is brought to bear on our selection of functional perceptual groups.

What Is Shaping RT and Accuracy Distributions? Active and Selective Response Inhibition Causes the Negative Compatibility Effect

2016 ◽  
Vol 28 (11) ◽  
pp. 1651-1671 ◽  
Author(s):  
Sven Panis ◽  
Thomas Schmidt
Keyword(s):  
Response Inhibition ◽  
Compatibility Effect ◽  
Time Course ◽  
Selective Inhibition ◽  
Masked Priming ◽  
Backward Masking ◽  
Hazard Functions ◽  
Negative Compatibility Effect ◽  
Priming Paradigm ◽  
Prime Target

Inhibitory control such as active selective response inhibition is currently a major topic in cognitive neuroscience. Here we analyze the shape of behavioral RT and accuracy distributions in a visual masked priming paradigm. We employ discrete time hazard functions of response occurrence and conditional accuracy functions to study what causes the negative compatibility effect (NCE)—faster responses and less errors in inconsistent than in consistent prime target conditions—during the time course of a trial. Experiment 1 compares different mask types to find out whether response-relevant mask features are necessary for the NCE. After ruling out this explanation, Experiment 2 manipulates prime mask and mask target intervals to find out whether the NCE is time-locked to the prime or to the mask. We find that (a) response conflicts in inconsistent prime target conditions are locked to target onset, (b) positive priming effects are locked to prime onset whereas the NCE is locked to mask onset, (c) active response inhibition is selective for the primed response, and (d) the type of mask has only modulating effects. We conclude that the NCE is neither caused by automatic self-inhibition of the primed response due to backward masking nor by updating response-relevant features of the mask, but by active mask-triggered selective inhibition of the primed response. We discuss our results in light of a recent computational model of the role of the BG in response gating and executive control.

Time Course and Magnitude of Movement-Related Gating of Tactile Detection in Humans. III. Effect of Motor Tasks

2002 ◽  
Vol 88 (4) ◽  
pp. 1968-1979 ◽  
Author(s):  
Stephan R. Williams ◽  
C. Elaine Chapman
Keyword(s):  
Time Course ◽  
Motor Command ◽  
Passive Movement ◽  
Emg Activity ◽  
Active Movement ◽  
Potential Contribution ◽  
Backward Masking ◽  
Movement Onset ◽  
Tactile Stimuli ◽  
Tactile Detection

This study investigated the relative importance of central and peripheral signals for movement-related gating by comparing the time course and magnitude of movement-related decreases in tactile detection during a reference motor task, active isotonic digit 2 (D2) abduction, with that seen during three test tasks: a comparison with active isometric D2 abduction (movement vs. no movement) evaluated the contribution of peripheral reafference generated by the movement to gating; a comparison with passive D2 abduction (motor command vs. no motor command; movement generated by an external agent) allowed us to evaluate the contribution of the central motor command to tactile gating; and finally, the inclusion of an active “no apparatus,” or freehand, D2 abduction task allowed us to evaluate the potential contribution of incidental peripheral reafference generated by the position detecting apparatus to the results (apparatus vs. no apparatus). Weak electrical stimuli (2-ms pulse; intensity, 90% detected at rest) were applied to D2 at different delays before and after movement onset or electromyographic (EMG) activity onset. Significant time-dependent movement-related decreases in detection were obtained with all tasks. When the results obtained during the active isotonic movement task were compared with those obtained in the three test tasks, no significant differences in the functions describing detection performance over time were seen. The results obtained with the isometric D2 abduction task show that actual movement of a body part is not necessary to diminish detection of tactile stimuli in a manner similar to the decrease produced by isotonic, active movement. In the passive test task, the peak decrease in detection clearly preceded the onset of passive movement (by 38 ms) despite the lack of a motor command and, presumably, no movement-related peripheral reafference. A slightly but not significantly earlier decrease was obtained with active movement (49 ms before movement onset). Expectation of movement likely did not contribute to the results because stimulus detection during sham passive movement trials (subjects expected but did not receive a passive movement) was not different from performance at rest (no movement). The results obtained with passive movement are best explained by invoking backward masking of the test stimuli by movement-related reafference and demonstrate that movement-related reafference is sufficient to produce decreases in detection with a time course and amplitude not significantly different from that produced by active movement.

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