MOTION EVOKED BRAIN POTENTIALS PARALLEL THE CONSISTENCY OF COHERENT MOTION PERCEPTION IN HUMANS

The perception of global coherent motion perception in complex motion patterns containing different direction vectors was investigated. Rand om dot kinematograms (RDK), plaids and fragmented plaid pattern were p resented in which direction vectors of the moving elements were varied . In order to elicit coherent motion perception, all elements were dis placed in the same direction (Delta 0 degrees). In a second condition, fifty percent of the elements were moved diagonally downwards to the left, with the remaining elements moving orthogonally (Delta 90 degree s). Simultaneously with psychophysical judgements on the perceived mot ion direction, visual evoked potentials (VEPs) were recorded at occipi tal electrode positions. Onset of a global coherent motion was associa ted with a VEP negativity occuring at about 200 ms. The amplitude of t his component was clearly reduced when local ambiguous signals could n ot be integrated to produce the perception of global coherent motion. (C) 1998 Elsevier Science Ireland Ltd.