COMPARISON OF AVERAGE EVOKED POTENTIALS BY MEANS OF A GENERALIZED T2 TEST . APPLICATION TO PROBLEM OF INTERFERENCE OF SUCCESSIVE VISUAL EVOKED RESPONSES

The generalized T2 test makes it possible to compare the forms of waves and to decide if they are similar or not, with a given probability of error. This test has been applied to the problem of the interference of successive visual evoked potentials. It showed that for stimulus intervals greater than 400 msec there was an algebraic addition of the tails of the evoked responses; the visual system would thus behave in a purely passive and linear fashion throughout the whole of the tail of the evoked response. On the other hand, for stimulus intervals of less than 150 msec this hypothesis must be rejected; consequently, immediately after a stimulus the visual system is in an active state and it responds in a non-linear fashion. In the range of intervals between 150 and 400 msec this system passes from a definitely non-linear to a definitely linear state. © 1969.