The level of autonomic activity as well as the magnitude of response to stimulation must be taken into consideration in evaluating autonomic effects on the electroencephalogram. Reaction to stimulation involving an altered 'level of excitation' has repeatedly been studied both as 'blocking effect' on the EEG (i, 4, 5, 6, 58, 59, 84, 85) and as blocking with co'ncomitarit autonomic reactions (6, 23, 28, 36, 35, 48, 63v 64), such as changes in heart rate (HR) or as the galvanic skin response (GSR). Identity of blocking conditions (i, 5) for the EEG with the 'intention,' 'attention,' 'alertness,' and apprehension which are recognized (15, 84,85) as precipitating conditions for the GSR has been noted by Jasper (53). When protracted into a chronic state these conditions have been identified psychologically and psychiatrically as 'tension' or 'anxiety' and have been found often associated with low potential fast activity in the EEG (9, 24, 45, 56, 62, 80) and with low palmar resistance (high conductance, sweating) in the GSR (16, 29), and both have been associated with increased tenvperaturfc or metabolism (4-1, 56, 51, 54, 63). Such persisting states or levels of excitation have been referred to neurophysiologically as 'the central excitatory state' or as 'excitation background' (17*32,53).Because EEG potentials are reduced as cerebral activity is increased the correlations with bodily changes under conditions of excitation tend to be negative. The relation of EEG to levels of physiological function in the absence of central excitation, on the other hand, has been less frequently studied. Of particular interest is Hadley's (47) finding among a •group of individuals of a positive correlation of r => .33 between levels of resting heart rate and occipital EEG potential. This is the opposite relation to that where heart
