Contextual Effects on Choice Reaction Time and Accuracy in Acute and Chronic Schizophrenics Impairment in Selective Attention or in the Influence of Prior Learning?

1991 ◽  
Vol 159 (3) ◽  
pp. 415-421 ◽  
Author(s):  
Steven H. Jones ◽  
David R. Hemsley ◽  
Jeffrey A. Gray
Keyword(s):  
Reaction Time ◽  
Selective Attention ◽  
Choice Reaction Time ◽  
Contextual Effects ◽  
Error Rates ◽  
Prior Learning ◽  
Left Hand ◽  
Cue Validity ◽  
Chronic Schizophrenics ◽  
Normal Controls

Two hypotheses were tested concerning the nature of the cognitive dysfunction in schizophrenia: (a) that there is a broadening of selective attention; and (b) that there is an impairment in associational learning. RDC-diagnosed acute and chronic schizophrenics and normal controls carried out a choice reaction time (RT) task in which conflict between the correct response to a target (a letter in the centre of a computer screen) and that cued by simultaneously presented flankers (two letters either side of the target) increased RT. For 80 (‘valid’) trials, flankers and targets were consistent in the response cued (pressing a button with either left or right hand); on 8 (‘invalid’) trials they conflicted. On invalid trials there was a slowing of RT, and an increase of errors for left-hand responses. Chronic schizophrenics showed the same reactions to cue validity as normal controls, both groups differing significantly from acute schizophrenics. For the latter, the RT data supported hypothesis (b), but the error rates appeared to support hypothesis (a).

Effects of certainty, modality shift and guess outcome on evoked potentials and reaction times in chronic schizophrenics

1978 ◽  
Vol 8 (1) ◽  
pp. 81-93 ◽  
Author(s):  
Rolf Verleger ◽  
Rudolf Cohen
Keyword(s):  
Reaction Time ◽  
Evoked Potentials ◽  
Reaction Times ◽  
Random Order ◽  
Verbal Information ◽  
Group Interactions ◽  
Chronic Schizophrenics ◽  
Modality Shift ◽  
Normal Controls

SynopsisEvoked potentials and reaction times were obtained from chronic schizophrenics and normal controls to light and sound stimuli presented in random order. In the ‘ certain’ condition subjects were told what the next stimulus would be, in the ‘uncertain’ condition they were asked to guess. Amplitudes were usually larger for normals than for schizophrenics, for ‘uncertain’ than for ‘certain’ conditions, and in cross- than in ipsimodal stimulus-sequences. The effect of certainty was stronger in normals across 4 leads; so was the effect of modality shift at vertex. While these findings replicate earlier results from acute schizophrenics, no condition x group interactions could be found in the reaction time measures.Two additional results were interpreted as showing basically different attitudes with respect to the predictability of events: (1) there was a slow positivity between the verbal information and the following stimuli which was largest for schizophrenics in the conditions of certainty; (2) while normals showed long-term habituation only in N1- but not in P3-amplitudes, the reverse was true for schizophrenics.

scholarly journals Simultaneous transcranial and transcutaneous spinal direct current stimulation to enhance athletic performance outcome in experienced boxers

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ali-Mohammad Kamali ◽  
Milad Kazemiha ◽  
Behnam Keshtkarhesamabadi ◽  
Mohsan Daneshvari ◽  
Asadollah Zarifkar ◽  
...  
Keyword(s):  
Reaction Time ◽  
Selective Attention ◽  
Direct Current ◽  
Cognitive Functions ◽  
Athletic Performance ◽  
Primary Motor Cortex ◽  
Left Hand ◽  
Direct Current Stimulation ◽  
Corticomotoneuronal Cells ◽  
The Impact

AbstractTranscranial direct current stimulation (tDCS) is among the rapidly growing experimental approaches to enhance athletic performance. Likewise, novel investigations have recently addressed the effects of transcutaneous spinal Direct Current Stimulation (tsDCS) on motor functions such as reduced reaction time. The impact of tDCS, and tsDCS might be attributed to altered spontaneous neural activity and membrane potentials of cortical and corticomotoneuronal cells, respectively. Given the paucity of empirical research in non-invasive brain stimulation in sports neuroscience, especially in boxing, the present investigation studied the effects of neuromodulation on motor and cognitive functions of professional boxers. The study sample comprised 14 experienced male boxers who received random sequential real or sham direct current stimulation over the primary motor cortex (M1) and paraspinal region (corresponding to the hand area) in two sessions with a 72-h interval. Unlike sham stimulation, real stimulation improved selective attention and reaction time of the experienced boxers [enhanced selective attention (p < 0.0003), diminished right hand (p < 0.0001) and left hand reaction time (p < 0.0006)]. Meanwhile, the intervention left no impact on the participants’ cognitive functions (p > 0.05). We demonstrated that simultaneous stimulation of the spinal cord and M1 can improve the performance of experienced boxers through neuromodulation. The present study design may be extended to examine the role of neurostimulation in other sport fields.

The Effect of Part Proliferation on Assembly Line Operators' Decision Making Capabilities

1979 ◽  
Vol 23 (1) ◽  
pp. 169-173
Author(s):  
Susanne M. Gatchell
Keyword(s):  
Decision Making ◽  
Reaction Time ◽  
Choice Reaction Time ◽  
Assembly Line ◽  
Research Study ◽  
Reaction Times ◽  
Decision Time ◽  
Error Rates

In order to quantify the effects of part proliferation on assembly line operators' decision making capabilities, a research study was conducted. Using a Choice Reaction Time technique, 16 operators were tested to determine their reaction times and error rates when selecting parts. These operators were from four training levels (trained, relief, untrained/job and untrained/plant) and had to decide between 4, 7 or 10 major parts. Results show that operators with 10 parts made 46% more errors and needed 13% more decision time than operators with 4 parts. Furthermore, the relief and untrained/job operators made three times more errors than the trained operators. The untrained/plant operators had over five times more errors than the trained operators. These results indicate that all operators could make a selection when working with 10 major parts. However, their reaction times and error rates increased as the number or parts increased from 4 to 10.

Analysis of Task Difficulty under Varying Conditions of Induced Stress

1970 ◽  
Vol 31 (2) ◽  
pp. 343-348 ◽  
Author(s):  
Jerry W. Thornton ◽  
Paul D. Jacobs
Keyword(s):  
Reaction Time ◽  
Choice Reaction Time ◽  
Reaction Time Task ◽  
Simple Reaction Time Task ◽  
Simple Task ◽  
Practical Applications ◽  
Time Task ◽  
Significant Difference ◽  
Task Relatedness ◽  
Related Stress

Two tasks (simple and choice reaction time) were examined while varying three types of stressors (shock, threat of shock, and noise) and the stressor task relationship (i.e., task-related stress, task-unrelated stress, and no-stress). Four specific hypotheses were tested and 3 were supported in the simple reaction-time task. There were no significant differences among stressors for either task, although greater differences were reported in the simple than in the choice reaction-time task. A significant difference between the “task-relatedness” of stress levels in the simple task was interpreted as possibly due to a “coping” or “protective adaptive mechanism” in which increases in performance serve to reduce stress. Practical applications were examined.

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