Event-Related Electromagnetic Response

Event-related responses are spatial-temporal patterns of physiological responses associated with neural population activity, elicited by external or internal stimuli. Indeed the function of neural systems depends on dynamic spatial and temporal patterns of activation within linked networks of excitable cells. In the human brain, most purposeful function is mediated by correlated activity in substantial populations of neurons. The physical and physiological consequences of this activity can be detected with noninvasive measurement techniques, including electroencephalography (EEG) and magnetoencephalography (MEG). In the present article we will consider a range of methods, and the major focus will be on neural electromagnetic measurement (NEM) techniques (MEG and EEG) and noninvasive measurements of neural population responses. These methods have challenges and limitations for localizing the source of neural responses, but the excellent temporal resolution of these responses can be exploited by clever experimental paradigms to probe the dynamic interactions between multiple cortical regions. We underline that these interactions serve as the basis of information processing and control by the human brain.