Abstract
The lateral intraparietal cortex (LIP) is thought to encode a salience map of the external environment that guides visual attention and gaze. There are, however, multiple factors that determine salience including visual properties, task relevance, Pavlovian reward associations and novelty/familiarity. Little is known about the mechanisms that draw attention based on these factors. We previously reported that visual salience is determined in part by Pavlovian associations, such that cues predicting reward attract attention while cues predicting no reward inhibit attention from their location, and these effects are automatic and independent of operant decisions (Peck, Jangraw et al., 2009). Here we extend these findings to examine the correlates of novelty-driven orienting. Two monkeys performed a task where a peripheral cue signaled the reward probability of a trial. To measure whether the cue attracted attention, we required monkeys to hold fixation for 600ms and then make a saccade to a separate target that appeared unpredictably at the same or opposite location as the cue. The cues were distinct colored patterns that could be novel or familiar and signal 100% or 0% probability of reward. Familiar cues had received prolonged training with consistent reward associations, while each novel cue was used for only a single session. Monkeys quickly learned the reward value of novel cues (shown by their anticipatory licking) and testing began after this learning was complete. Novelty produced a multiplicative enhancement of the LIP response, which persisted throughout a session (~30 cue presentations) and interacted linearly with the reward effect. This enhancement appeared within 100ms and was spatially specific, correlating with a rapid attentional capture produced by the novel cues. We suggest that LIP provides a short-latency signal that mediates fast visual orienting toward novel stimuli, which may precede recognition and interpretation of the reward properties of these stimuli.
Meeting abstract presented at VSS 2012