Testing quasi-visual neurons in the monkey's frontal eye field with the triple-step paradigm

To look successively at sites where several spots of light have appeared in the dark, we cannot simply rely on the image left by these targets on our retina. Our brain has to update target coordinates by taking into account e ach gaze movement that has taken place. A par -ticular type of brain cell - the quasi-visual (QV) neuron - is assumed to play an important role in thi s updating by combining target coordinates and eye displacement signals. Ho wever, what is exactly this role? Is a QV neuron an element of a working me mory that encodes the location of a potential target, or is it pointing to the location of the single goal selected for the next saccade? The two role s theoretically correspond to successive stages of processing: the location s of the optional targets would be stored at one stage, whereas the locatio n of the next selected target would be stored at the subsequent stage. With a task that imposes a choice of goals - the triple-step paradigm - we foun d evidence that several groups of QV neurons can become simultaneously acti vated in the monkey's frontal eye field (FEF), suggesting that each group r epresents a different target location. This supports the hypothesis that th e FEF itself contains the spatial information about not yet selected target s.