Dynamic Process of Visual Change Detection in Human Brain:an ERP Study / 中国心理卫生杂志

ABSTRACT

Objective:To explore the spatio-temporal dynamics of brain mechanisms in visual change detection by 256-channel event-related potential (ERP) and low-resolution electromagnetic tomography (LORETA) analyses.Methods：ERP were recorded in 12 healthy participants during performing an S1-S2 matching task.Visual stimuli defined by color and shape.Each trial consisted of two sequentially presented stimuli (S1 and S2),where S2 was either the same as S1,different from S1 in shape only,different in color only,or different in both color and shape.Subjects matched the stimuli according to task demands：attending to color and attending to shape.Result：Change condition elicited change-related positivity (CRP) ranging 135～165 ms.The estimated source regions contributing to CRP were lingual gyrus and cuneus of occipital lobe.N200 was elicited in no change and task-irrelevant change condition ranging 235～275 ms.The source for N200 was in the right temporal fusiform gyrus,middle temporal gyrus and parahippocampal gyrus.In the time window of 240～320 ms,N270 was elicited in all change conditions.The N270 source was localizable to the anterior cingulated cortex and amygdala.Conclusion：In the early stage,CRP reflects the preattentive processing of visual changes.The LORETA result confirms that CRP is generated in the early visual areas.N200 may be related to the active ignored processing of task-irrelevant change.The source for N200 is in the right temporal fusiform gyrus,middle temporal gyrus and parahippocampal gyrus.In the late stage,N270 reflects the advanced processing of visual change in the human brain.The N270 source may be in anterior cingulate cortex (ACC) and amygdala.