Determination of average heart rate as a sign of the orienting response

The "O wave" is one component of minute EEG signals recorded from the scalp in response to external stimuli and is one sign of the "orienting response". The orienting response is a fundamental response in which attention is turned to fresh or important sources of information. The orienting response has many signs in the autonomic nervous system including changes in heart rate. Software was developed to track changes in heart rate as an additional sign of the orienting response. Instantaneous heart rate was determined by detecting R waves and calculating the interval between successive R waves. Segments of the instantaneous heart rate, time located to the occurrence of the stimuli, were averaged to produce an average heart rate during the time interval in which the stimuli occurred. Changes in the average heart rate where found to occur in time correspondence to the "O wave" in the EEG signal and thus provide an additional measure of the orienting response.