| Budget Amount *help |
¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 1987: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1986: ¥2,000,000 (Direct Cost: ¥2,000,000)
|
|---|
| Research Abstract |
An eye movement record shows step-like pattern consisting of saccades and fixation pauses.In previors studies,we found that the polyphasic potentials,which had been called the lambda responses,appeared at onset of saccadic fixation pauses.The lambda responses can be obtained wiht averaging EEG at onset of fixation pauses.The purpose of this project was to examine the lambda responses during some cognitive tasks. This project consisted of three experimental studies.Preceding the first experiment,a processing system and computer programs were developed to analyze the brain potentials associated with fixation pauses.
In Experiment 1,the relationship between the lambda responses and characteristics of visual stimuli (the contrast and the spatial frequency) was examined.As a result,the higher spatial frequency and the stronger contrast of visual stimuli caused larger lambda responses in amplitude. In Experiment 2,lambda responses recorded from the left and the right hemispheres were compared during the verbal task and the pattern task. Amplitudes of the lambda responses at the left parietal region were larger in the verbal task than those in the pattern task.
In Experiment 3,the lambda responses during the signal detection task were recorded.The large positive potentials with latency about 300 msec following the lambda responses were elicited,when eyes paused at signals which were detected,
These results showed that the lambda response might be a kind of visual evoked potentials (VEP).The movement of eyes are usually very restricted in measuring VEP.The lambda responses are of great advantage to measure visral cognitive processes rather than VEP,because the lambda response is applicable in eye movement situations.
|
