BRIDGING THE GAP BETWEEN MONKEY NEUROPHYSIOLOGY AND HUMAN PERCEPTION - AN AMBIGUITY RESOLUTION THEORY OF VISUAL SELECTIVE ATTENTION

When the visual system must process multiple objects simultaneously, a s in the visual search paradigm, the neural coding of individual objec ts can become ambiguous due to the visual system's extensive use of co arse coding and distributed representations. Here we propose that the primary role of visual selective attention within the ventral object r ecognition pathway is to resolve these ambiguities. We begin by review ing previous studies of the effects of attention on neural responses i n monkeys, which provide the basis for this hypothesis, and then descr ibe a new set of experiments showing that similar attentional mechanis ms operate in the human brain. In these new experiments, event-related potentials (ERPs) were recorded from normal human observers while the y performed tasks analogous to those used previously in monkeys. The c entral finding was that an attention-related ERP wave called the ''N2p c component'' was present under the same conditions that led to attent ional modulations of neural responses in monkey visual cortex. These h uman electrophysiological results provide a bridge between cognitive-l evel theories of visual attention and the behavior of individual neuro ns in visual cortex. (C) 1997 Academic Press.