Saccadic and attentional abnormalities in patients with schizophrenia

1998 ◽  
Vol 28 (5) ◽  
pp. 1091-1100 ◽  
Author(s):  
P. MARUFF ◽  
J. DANCKERT ◽  
C. PANTELIS ◽  
J. CURRIE
Keyword(s):  
Chronic Schizophrenia ◽  
Stimulus Onset ◽  
Error Rates ◽  
Covert Attention ◽  
Visually Guided ◽  
Antisaccade Task ◽  
Attentional Shifts ◽  
Abnormal Performance ◽  
Onset Asynchrony ◽  
Normal Performance

Background. Abnormal performance on the antisaccade task suggests that patients with schizophrenia have difficulty with the inhibition of reflexive attentional shifts. The aim of the study was to investigate whether deficits in the inhibition of reflexive attentional shifts were specific to the oculomotor modality or whether they could also occur when attentional shifts were made without eye movements (e.g. covert attentional shifts).Methods. Fifteen medicated patients with chronic schizophrenia and 15 matched controls performed the antisaccade task and the covert orientating task (COVAT) where the probability of targets appearing at the same location of a peripheral cue was varied so that voluntary and reflexive orientating systems had the same goal (80% probability of target and cued condition) or opposite goals (20%probability of target at cued location). A condition where only reflexive orientating was initiated was also included (50% probability of target at cued location). For each of these conditions the stimulus onset asynchrony (SOA) varied between 150 and 350 ms.Results. Patients with schizophrenia showed normal latency and accuracy for visually guided saccades but increased error rates and latency on the antisaccade task. For the COVAT, patients with schizophrenia were unable to use voluntary orientating strategies to inhibit reflexive shifts of covert attention. On conditions where only reflexive orientating was required or when the goals of the reflexive and voluntary orientating systems were the same, patients with schizophrenia showed normal performance.Conclusions. These results suggest the reflexive orientating mode is normal in patients with chronic schizophrenia. However, these patients have a reduced ability to utilize the voluntary orientating mode to control or inhibit reflexive orientating. This impairment of voluntary control is evident for both overt and covert attentional shifts.

The Perception of Involuntary Prosaccades in an Antisaccade Task

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 275-275
Author(s):  
A Mokler ◽  
B Fischer
Keyword(s):  
Error Rate ◽  
Reaction Times ◽  
Stimulus Onset ◽  
Error Rates ◽  
Data Sets ◽  
Antisaccade Task ◽  
Key Press ◽  
Extra Peak ◽  
The Mean ◽  
Strong Mode

In an antisaccade task subjects are required to generate a voluntary saccade to the side opposite to a small visual stimulus. With fixation-point offset preceding stimulus onset (gap) subjects produce some involuntary saccades to the stimulus and correct them by a second saccade. We wanted to know whether the subjects recognised their errors and whether a recognised sequence (error followed by correction) is different from an unrecognised sequence. To test the access to the correction mechanism, subjects were asked in subsequent experiments to produce the error-correction sequence voluntarily (voluntary sequence). We used the gap = 200 ms condition. A valid cue was presented 100 ms before stimulus onset. This manipulation increased the error rate (Fischer and Weber, 1996 Experimental Brain Research109 507 – 512). Subjects indicated errors by key-press. The rate of recognised and unrecognised errors, saccadic size, reaction times (SRT), and correction times (CRT) were determined. Altogether 93 data sets (400 trials each) from 38 subjects were analysed. The mean error rate was 20%, of which 62% went unrecognised. In sessions with high error rates the fraction of unrecognised errors was high. The SRT of the errors ranged from 80 to 170 ms with a strong mode of express saccades at 100 ms. Both types of errors had the same mean SRT of 117 – 119 ms. The unrecognised errors were 0.4 deg smaller. They were corrected after a mean CRT of 95 ms. The recognised errors were corrected after 127 ms; in the voluntary sequence the correction occurred after 217 ms. The CRT distributions differ from each other with the unrecognised errors having an extra peak around 45 ms, suggesting different modes of correction, to which perception has different access. These results raise the question why the large and long-lasting changes of the retinal image escape the conscious perception so often.

Phonological and semantic activation in reading two-kanji compound words

2000 ◽  
Vol 21 (4) ◽  
pp. 487-503 ◽  
Author(s):  
AIKO MORITA ◽  
FUMIKO MATSUDA
Keyword(s):  
Stimulus Onset Asynchrony ◽  
Reaction Times ◽  
Stimulus Onset ◽  
Error Rates ◽  
Semantic Activation ◽  
Phonological Information ◽  
Semantic Interference ◽  
Compound Words ◽  
Phonological Interference ◽  
Onset Asynchrony

The purpose of this study was to examine whether phonological information was activated automatically in processing two-kanji compound words. In Experiment 1, 27 participants judged whether pairs of the words were homophones, while another 27 participants judged whether pairs were synonyms. Stimulus onset asynchrony (SOA) was 140 ms, 230 ms, or 320 ms. In Experiment 2, 36 participants were asked to make one of the two judgments, as in Experiment 1. SOA was determined individually. The following results were found. Reaction times showed semantic interference. Phonological interference was observed only under the shortest SOA in Experiment 2. Error rates showed phonological and semantic interferences even when SOA was the longest. These findings support the universal phonological principle.

Abnormalities of internally generated saccades in obsessive–compulsive disorder

1999 ◽  
Vol 29 (6) ◽  
pp. 1377-1385 ◽  
Author(s):  
P. MARUFF ◽  
R. PURCELL ◽  
P. TYLER ◽  
C. PANTELIS ◽  
J. CURRIE
Keyword(s):  
Obsessive Compulsive Disorder ◽  
Internal Representation ◽  
Error Rates ◽  
Visually Guided ◽  
Antisaccade Task ◽  
Obsessive Compulsive ◽  
Compulsive Disorder ◽  
Task Goal ◽  
Saccade Task ◽  
The Difference

Background. We aimed to utilize tests of saccadic function to investigate whether cognitive abnormalities in obsessive–compulsive disorder (OCD) arise from a dysfunction of inhibitory processes or whether they reflect a more general difficulty in guiding behaviour on the basis of an internal representation of task goal.Methods. Twelve patients with OCD and 12 matched controls performed a visually-guided saccade task, a volitional prosaccade task and an antisaccade task. The latency and gain of saccades was compared between groups for the three saccade tasks. The number of antisaccade errors was also calculated and compared between groups.Results. There was no difference for antisaccade error rates between the groups. The latency of visually guided saccades did not differ between groups, however the latency of both volitional prosaccades and antisaccades was significantly slower in the patients with OCD than in controls. The difference in latency between volitional prosacades and antisaccades, however, was equal between groups.Conclusions. These results suggest that patients with OCD have an abnormality in guiding behaviour on the basis of an internal representation of the task goal, rather than a problem with inhibiting reflexive behaviour.

Anchor Effects and Figural Aftereffects: A Comparative Psychophysical Investigation

1975 ◽  
Vol 41 (3) ◽  
pp. 791-796 ◽  
Author(s):  
Johannes Abresch ◽  
Viktor Sarris
Keyword(s):  
Stimulus Onset Asynchrony ◽  
Contrast Effect ◽  
Rating Scale ◽  
Stimulus Onset ◽  
Figural Aftereffect ◽  
Anchor Effect ◽  
Substantial Influence ◽  
Perceptual Contrast ◽  
Points Of View ◽  
Onset Asynchrony

Perceptual contrast effect was studied from two points of view, as a special anchor effect and as a special figural aftereffect. Two experiments were conducted to investigate the influence of stimulus onset asynchrony on contrast and assimilation effects, induced and measured by different psychophysical methods. Stimuli were circular beams of light projected on screens (Delboef type of illusion). When anchor and series stimuli were shown and the latter were judged by means of a rating scale, stimulus onset asychrony had no substantial influence on the contrast effect (Exp. I). When the constant method was applied, however, the asynchrony altered the shape of the contrast effect considerably (Exp. II).

Primed-lexical decision: The effect of varying the stimulus-onset asynchrony of prime and target

1986 ◽  
Vol 61 (1) ◽  
pp. 17-36 ◽  
Author(s):  
Annette M.B. de Groot ◽  
Arnold J.W.M. Thomassen ◽  
Patrick T.W. Hudson
Keyword(s):  
Lexical Decision ◽  
Stimulus Onset Asynchrony ◽  
Stimulus Onset ◽  
Onset Asynchrony

Sequential Stereotype Priming: A Meta-Analysis

2017 ◽  
Vol 22 (3) ◽  
pp. 199-227 ◽  
Author(s):  
Ciara K. Kidder ◽  
Katherine R. White ◽  
Michelle R. Hinojos ◽  
Mayra Sandoval ◽  
Stephen L. Crites
Keyword(s):  
Meta Analysis ◽  
Stimulus Onset ◽  
Future Research ◽  
Implicit Measures ◽  
Methodological Rigor ◽  
Priming Paradigm ◽  
Type Data ◽  
Onset Asynchrony ◽  
Stereotype Priming ◽  
Explicit Measures

Psychological interest in stereotype measurement has spanned nearly a century, with researchers adopting implicit measures in the 1980s to complement explicit measures. One of the most frequently used implicit measures of stereotypes is the sequential priming paradigm. The current meta-analysis examines stereotype priming, focusing specifically on this paradigm. To contribute to ongoing discussions regarding methodological rigor in social psychology, one primary goal was to identify methodological moderators of the stereotype priming effect—whether priming is due to a relation between the prime and target stimuli, the prime and target response, participant task, stereotype dimension, stimulus onset asynchrony (SOA), and stimuli type. Data from 39 studies yielded 87 individual effect sizes from 5,497 participants. Analyses revealed that stereotype priming is significantly moderated by the presence of prime–response relations, participant task, stereotype dimension, target stimulus type, SOA, and prime repetition. These results carry both practical and theoretical implications for future research on stereotype priming.

scholarly journals Contextual processing in unpredictable auditory environments: the limited resource model of auditory refractoriness in the rhesus

2016 ◽  
Vol 116 (5) ◽  
pp. 2125-2139 ◽  
Author(s):  
Tobias Teichert ◽  
Kate Gurnsey ◽  
Dean Salisbury ◽  
Robert A. Sweet
Keyword(s):  
Limited Resource ◽  
Stimulus Onset ◽  
Physiological Mechanisms ◽  
Contextual Processing ◽  
Targeted Interventions ◽  
Pharmacological Mechanism ◽  
Long Latency ◽  
Onset Asynchrony ◽  
Limited Resource Model ◽  
Gradual Decay

Auditory refractoriness refers to the finding of smaller electroencephalographic (EEG) responses to tones preceded by shorter periods of silence. To date, its physiological mechanisms remain unclear, limiting the insights gained from findings of abnormal refractoriness in individuals with schizophrenia. To resolve this roadblock, we studied auditory refractoriness in the rhesus, one of the most important animal models of auditory function, using grids of up to 32 chronically implanted cranial EEG electrodes. Four macaques passively listened to sounds whose identity and timing was random, thus preventing animals from forming valid predictions about upcoming sounds. Stimulus onset asynchrony ranged between 0.2 and 12.8 s, thus encompassing the clinically relevant timescale of refractoriness. Our results show refractoriness in all 8 previously identified middle- and long-latency components that peaked between 14 and 170 ms after tone onset. Refractoriness may reflect the formation and gradual decay of a basic sensory memory trace that may be mirrored by the expenditure and gradual recovery of a limited physiological resource that determines generator excitability. For all 8 components, results were consistent with the assumption that processing of each tone expends ∼65% of the available resource. Differences between components are caused by how quickly the resource recovers. Recovery time constants of different components ranged between 0.5 and 2 s. This work provides a solid conceptual, methodological, and computational foundation to dissect the physiological mechanisms of auditory refractoriness in the rhesus. Such knowledge may, in turn, help develop novel pharmacological, mechanism-targeted interventions.

scholarly journals A question of (perfect) timing: A preceding head turn increases the head-fake effect in basketball

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0251117
Author(s):  
Andrea Polzien ◽  
Iris Güldenpenning ◽  
Matthias Weigelt
Keyword(s):  
Stimulus Onset Asynchrony ◽  
Opposite Direction ◽  
Underlying Mechanism ◽  
Stimulus Onset ◽  
Basketball Player ◽  
Head Turn ◽  
Onset Asynchrony ◽  
Practical Implications ◽  
Head Fake

In many kinds of sports, deceptive actions are frequently used to hamper the anticipation of an opponent. The head fake in basketball is often applied to deceive an observer regarding the direction of a pass. To perform a head fake, a basketball player turns the head in one direction, but passes the ball to the opposite direction. Several studies showed that reactions to passes with head fakes are slower and more error-prone than to passes without head fakes (head-fake effect). The aim of a basketball player is to produce a head-fake effect for as large as possible in the opponent. The question if the timing of the deceptive action influences the size of the head-fake effect has not yet been examined systematically. The present study investigated if the head-fake effect depends on the temporal lag between the head turn and the passing movement. To this end, the stimulus onset asynchrony between head turn, and pass was varied between 0 and 800 ms. The results showed the largest effect when the head turn precedes the pass by 300 ms. This result can be explained better by facilitating the processing of passes without head fake than by making it more difficult to process passes with a head fake. This result is discussed regarding practical implications and conclusions about the underlying mechanism of the head–fake effect in basketball are drawn.

Multimodal Ternus: Visual, Tactile, and Visuo — Tactile Grouping in Apparent Motion

Perception ◽  
10.1068/p5844 ◽  
2007 ◽  
Vol 36 (10) ◽  
pp. 1455-1464 ◽  
Author(s):  
Vanessa Harrar ◽  
Laurence R Harris
Keyword(s):  
Stimulus Onset Asynchrony ◽  
Apparent Motion ◽  
Visual Stimuli ◽  
Stimulus Onset ◽  
Light Touch ◽  
Visual Group ◽  
Motion Stimulus ◽  
Group Motion ◽  
Onset Asynchrony

Gestalt rules that describe how visual stimuli are grouped also apply to sounds, but it is unknown if the Gestalt rules also apply to tactile or uniquely multimodal stimuli. To investigate these rules, we used lights, touches, and a combination of lights and touches, arranged in a classic Ternus configuration. Three stimuli (A, B, C) were arranged in a row across three fingers. A and B were presented for 50 ms and, after a delay, B and C were presented for 50 ms. Subjects were asked whether they perceived AB moving to BC (group motion) or A moving to C (element motion). For all three types of stimuli, at short delays, A to C dominated, while at longer delays AB to BC dominated. The critical delay, where perception changed from group to element motion, was significantly different for the visual Ternus (3 lights, 162 ms) and the tactile Ternus (3 touches, 195 ms). The critical delay for the multimodal Ternus (3 light – touch pairs, 161 ms) was not different from the visual or tactile Ternus effects. In a second experiment, subjects were exposed to 2.5 min of visual group motion (stimulus onset asynchrony = 300 ms). The exposure caused a shift in the critical delay of the visual Ternus, a trend in the same direction for the multimodal Ternus, but no shift in the tactile Ternus. These results suggest separate but similar grouping rules for visual, tactile, and multimodal stimuli.

Sign in / Sign up

Export Citation Format

Share Document