ABSTRACT
Objective To investigate the brain mechanisms of aging of the visual attention. Methods Through the precue-target visual search paradigm using the event-related potentials technique,16 young and 16 elderly subjects participated the electrophysiological experiment.The background was comprised of three homocentric black circles and eight English capital letters consisted of each circle.The letter “T” was designed as the target stimulus.T was a target only when it located the circle clued to the same size of the precue.For example,when the cue was the “large”,“T” may appear within 3 circles.When the cue was the “median”,“T” may appear within either the median or small circles.When the cue was small,the target “T” may appear only within the small circle. Results The reaction time of the two groups of subjects became quick with the reduction of the cue scale,while the amplitudes of P1 and N1 components of event-related potentials increased with the decrease of the cue scale.Old subjects showed longer response time than did young subjects,and the posterior P1 component was enhanced significantly and N1 component was inhibited obviously.The P2 component was manifested as significantly inhibitory effect not only in the amplitude but also in the abnormal and unstable waveform.Conclusions The cognitive function of elderly subjects declines in the research of target stimuli,which suggests that the age-related changes could lead to deficit in the posterior area of the brain to visual spatial attention (involuntary attention).