Interfield Differences in Reaction Times to Lateralised Visual Stimuli in Normal Subjects

1979 ◽  
pp. 390-399 ◽  
Author(s):  
G. Rizzolatti
Keyword(s):  
Visual Stimuli ◽  
Reaction Times ◽  
Normal Subjects

Abnormal Emotional Responses to Pleasant and Unpleasant Visual Stimuli in First Episode Schizophrenia: f-MRI Investigation

2009 ◽  
Vol 24 (S1) ◽  
pp. 1-1
Author(s):  
M. Casacchia ◽  
M. Mazza ◽  
A. Catalucci ◽  
R. Pollice ◽  
M. Gallucci ◽  
...  
Keyword(s):  
Negative Symptoms ◽  
Psychiatric Service ◽  
Visual Stimuli ◽  
Chronic Schizophrenia ◽  
Normal Subjects ◽  
Blood Oxygenation ◽  
First Episode ◽  
Affective Deficits ◽  
Oxygenation Level ◽  
Mri Study

Aims:Affective deficits (flat affect, a diminished expression of emotion, anhedonia, and lowered ability to experience pleasure) are very common in schizophrenia. In emotion feeling, the crucial role of the insula, rather than of the primary somatosensory cortices, strongly suggests that the neural substrate for emotions is not merely sensorial. It is more likely that the activation of the insula representation of the viscero-motor activity is responsible for feeling of disgust. A recent MRI study demonstrated specific left anterior insular volume reduction in chronic schizophrenia patients: sustainable is the suggestion that emotion of disgust or of taste may be related to the experience of pleasure, which probably is compromise in schizophrenics.We investigated fMRI brain activations in first episode schizophrenic subjects with negative symptoms and in healthy subjects elicited by pleasant and unpleasant visual stimuli.Method:Ten first-episode schizophrenic subjects with normal IQ were recruited from the psychiatric service “SMILE” of San Salvatore Hospital and 10 healthy volunteers matched for age and education were scanned during observation of pleasant and unpleasant visual stimuli. Functional images were acquired with a 1.5T MRI scanner. Blood oxygenation level dependent (BOLD) contrast was obtained using EPI T2* weighted images.Results:The most important result of the study was the demonstration that anterior insula was activated by the exposure to disgusting stimula in normal subjects but not in schizophrenic subjects.Conclusion:This failure of the neural systems used to support emotional attribution is consistent with pervasive problems in experiencing emotions by schizophrenics.

Some Factors Affecting Reaction Times to Auditory Stimuli in Mental Patients

1954 ◽  
Vol 100 (419) ◽  
pp. 462-477 ◽  
Author(s):  
K. R. L. Hall ◽  
E. Stride
Keyword(s):  
Reaction Time ◽  
Visual Perception ◽  
Visual Stimuli ◽  
Reaction Times ◽  
Auditory Stimuli ◽  
Factors Affecting ◽  
Mental Patients ◽  
Personal Equation ◽  
Work Up

A number of studies on reaction time (R.T.) latency to visual and auditory stimuli in psychotic patients has been reported since the first investigations on the personal equation were carried out. The general trends from the work up to 1943 are well summarized by Hunt (1944), while Granger's (1953) review of “Personality and visual perception” contains a summary of the studies on R.T. to visual stimuli.

Use of Magnitude-Estimation Scaling for Predicting Hemispheric Processing of Lexical Decisions

1993 ◽  
Vol 76 (3_suppl) ◽  
pp. 1147-1152 ◽  
Author(s):  
Lee W. Ellis ◽  
Joan N. Kaderavek ◽  
Michael P. Rastatter
Keyword(s):  
Reaction Time ◽  
Lexical Decision ◽  
Analysis Of Variance ◽  
Magnitude Estimation ◽  
Reaction Times ◽  
Normal Subjects ◽  
Hemispheric Processing ◽  
Lexical Decisions ◽  
Significant Magnitude ◽  
Abstract Words

The purpose of this study was to evaluate the usefulness and validity of magnitude-estimation scaling as an alternative to a traditional, somewhat more cumbersome reaction-time procedure in the assessment of hemispheric processing asymmetry. Lexical decision vocal reaction times and magnitude-estimation scaling values were obtained for 16 normal subjects to tachistoscopically presented concrete and abstract words. Analysis of variance showed identical interactions of field x stimuli for each dependent variable while all pair-wise correlations between these measures were significant. Magnitude-estimation scaling may be a sensitive measure of visual psychophysical differences in hemispheric processing and may circumvent problems with variance of latencies associated with disordered populations.

scholarly journals Comparative analysis of reactions to visual and auditory stimuli in research on EEG evoked potentials

2018 ◽  
Vol 7 ◽  
pp. 172-177
Author(s):  
Łukasz Tyburcy ◽  
Małgorzata Plechawska-Wójcik
Keyword(s):  
Comparative Analysis ◽  
Evoked Potentials ◽  
Auditory Stimulus ◽  
Visual Stimulus ◽  
Visual Stimuli ◽  
Reaction Times ◽  
Auditory Stimuli

The paper describes results of comparison of reactions times to visual and auditory stimuli using EEG evoked potentials. Two experiments were used to applied. The first one explored reaction times to visual stimulus and the second one to auditory stimulus. After conducting an analysis of data, received results enable determining that visual stimuli evoke faster reactions than auditory stimuli.

Mapping of Extracorporeal Space by Vibrotactile Reaction Times: A Far-Left-Side Disadvantage

Perception ◽  
1987 ◽  
Vol 16 (3) ◽  
pp. 283-290 ◽  
Author(s):  
Jane M Pierson-Savage ◽  
John L Bradshaw
Keyword(s):  
Clinical Symptoms ◽  
Reaction Times ◽  
Normal Subjects ◽  
The Other ◽  
Covert Attention ◽  
Left Part ◽  
Left And Right

Vibrotactile reaction times in normal dextrals were measured for the two hands separately when either hand was located at each of seven possible positions: 90°, 45°, and 15° to the left and right of the chest midline, and at the midline itself (0°). Reaction times for the two hands did not differ and there was no Hand by Position interaction. At 90° left, reaction times were significantly slower than at any other position except 45° right. However, none of the other positions, including 45° right, differed from each other. Performance in this task, therefore, was relatively uniform from 90° right to 45° left, but markedly slower at 90° left. This far-left-side disadvantage may reflect a difficulty (for dextrals) in focussing covert attention in the far-left part of space for a block of trials. Since vibrotactile reaction times are sensitive to attentional factors in normal subjects, the paradigm should allow quantification of the clinical symptoms of the hemineglect syndrome; some preliminary observations of this syndrome with another vibrotactile design are reported.

Vocal Reaction Times to Tachistoscopically Presented High- and Low-Frequency Verbs: Some Evidence for Selective Minor Hemisphere Linguistic Analysis

1988 ◽  
Vol 66 (3) ◽  
pp. 803-810 ◽  
Author(s):  
Michael P. Rastatter ◽  
Catherine Loren
Keyword(s):  
Visual Field ◽  
High Frequency ◽  
Right Hemisphere ◽  
Visual Fields ◽  
Reaction Times ◽  
Low Frequency ◽  
Normal Subjects ◽  
Right Visual Field ◽  
Intact Brain ◽  
The Right

The current study investigated the capacity of the right hemisphere to process verbs using a paradigm proven reliable for predicting differential, minor hemisphere lexical analysis in the normal, intact brain. Vocal reaction times of normal subjects were measured to unilaterally presented verbs of high and of low frequency. A significant interaction was noted between the stimulus items and visual fields. Post hoc tests showed that vocal reaction times to verbs of high frequency were significantly faster following right visual-field presentations (right hemisphere). No significant differences in vocal reaction time occurred between the two visual fields for the verbs of low frequency. Also, significant differences were observed between the two types of verbs following left visual-field presentation but not the right. These results were interpreted to suggest that right-hemispheric analysis was restricted to the verbs of high frequency in the presence of a dominant left hemisphere.

Relationships of Auditory and Visual Reaction Times to Reading Achievement

1968 ◽  
Vol 27 (2) ◽  
pp. 447-450 ◽  
Author(s):  
Walter A. Busby ◽  
Donald E. Hurd
Keyword(s):  
Reaction Time ◽  
Reading Achievement ◽  
Single Channel ◽  
Visual Stimuli ◽  
Green Light ◽  
Reaction Times ◽  
Perceptual Field ◽  
Visual Channel ◽  
Visual Reaction ◽  
Low Tone

To determine the relationship between reading achievement and the reaction time of an individual responding to auditory and visual stimuli present in his perceptual field Ss were selected at random from Grades 2, 4 and 6. S lifted his finger from a key as rapidly as possible at the onset of any one of four stimuli (red or green light, high or low tone). Shifting reaction time was not independent of reaction time in either the auditory or visual channel. Hence, the possibility that relative perceptual difficulties could exist in shifting behavior while no defect existed in either single channel was not supported. Perception defined as the reaction time of an individual responding to auditory and visual stimuli was not significantly related to reading achievement.

SIMPLE REACTION TIMES OF IPSILATERAL AND CONTRALATERAL HAND TO LATERALIZED VISUAL STIMULI

Brain ◽  
1971 ◽  
Vol 94 (3) ◽  
pp. 419-430 ◽  
Author(s):  
G. BERLUCCHI ◽  
W. HERON ◽  
R. HYMAN ◽  
G. RIZZOLATTI ◽  
C. UMILTÀ
Keyword(s):  
Visual Stimuli ◽  
Reaction Times ◽  
Simple Reaction ◽  
Contralateral Hand

Cardiac Cycle Phase and Movement and Reaction Times

1976 ◽  
Vol 42 (3) ◽  
pp. 767-770 ◽  
Author(s):  
Matti J. Saari ◽  
Bruce A. Pappas
Keyword(s):  
Reaction Time ◽  
Cardiac Cycle ◽  
Visual Stimuli ◽  
Reaction Times ◽  
Reaction Time Task ◽  
Stimulus Presentation ◽  
Stimulus Onset ◽  
Cycle Phase ◽  
Second Phase ◽  
Time Task

The EKG was recorded while Ss differentially responded to auditory or visual stimuli in a reaction time task. The EKG record was analyzed by dividing each R-R interval encompassing a stimulus presentation into 9 equal phases. Reaction times were determined as a function of the phase encompassing stimulus onset while movement times were determined for the phase in which the response was initiated. Only reaction time significantly varied with cardiac cycle, with reactions during the second phase being slower than later phases.

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