. Brain mechanisms and learning, a symposium. Psychophysiology; Learning, Psychology of. E. GARCIA-AUSTT, J. BOGACZ AND A. VANZULLI 609 more concentrated a few minutes after the beginning of the experiment when they were teehng more comfortable. Form afid frajiiciicy. During habituation the evoked potential had a tendency to become more complex and to present a greater number of waves (Fig. 2A). The waves multiplied progressively. This change was more noticeable in the fnst negative wave where a notch appeared which as it became deeper was transformed into a surface negative-positive- ncgativc
. Brain mechanisms and learning, a symposium. Psychophysiology; Learning, Psychology of. E. GARCIA-AUSTT, J. BOGACZ AND A. VANZULLI 609 more concentrated a few minutes after the beginning of the experiment when they were teehng more comfortable. Form afid frajiiciicy. During habituation the evoked potential had a tendency to become more complex and to present a greater number of waves (Fig. 2A). The waves multiplied progressively. This change was more noticeable in the fnst negative wave where a notch appeared which as it became deeper was transformed into a surface negative-positive- ncgativc wave. In some cases all the waves were multiplied, the evoked A B. ^ "^^'^'^-A /V^/>aA/V. i-V'^s/^'WA/*^ t ' â t ' ' t Fig. 2 Changes of the visual evoked response by effect of liabituatioii. Continuous flicker frequency, Stroboscope at 3 m. from the retina. Forty superimposed sweeps. Technique of Calvet and co-workers. Arrows indicate the stimulus. Lead 02-right mastoid. A, B, and C, experiments performed on different subjects. (1) at the beginning of the experiment; (2) when habituation was achieved. A, the initial component before habituation is constituted by three w-aves and after habituation the amplitude decreases and the waves become more numerous. B, with eyes open, after habituation the amplitude is reduced and a fast after-discharge of 22/scc. develops. C. with eyes closed, after habituation the amplitude docs not change and a slow after-discliargc of 14/sec. sets in. Calibration, 200 msec. potential being consticuted by a succession of 6 to 8 cycles of low amplitude. Occasionally the progressive reduction of the amplitude finally caused the disappearance of some waves, notably of the first negative wave which generally was of lesser magnitude than the following ones (Fig. i). Provided the flicker stimulation was a low frequency ( sec.) and that it was prolonged for a lengthy period, there constantly appeared in succession to the evoked response a regu
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