Kelly Snyder - US grants

DESCRIPTION (provided by applicant): Preferential looking paradigms have been used for almost 50 years to study detection and discrimination of stimuli, categorization, memory, concept formation, and individual differences in infant cognition. Yet, relatively little is known about the nature of the representations which mediate novelty preferences. The general aim of this research is to investigate the neural correlates of novelty preferences during the first year of life in order to elucidate the nature of the representation reflected in an infant's differential attention to a novel stimulus. To accomplish this goal, two experiments are proposed. Experiment 1 will employ a cross-sectional design in order to allow the evaluation of differences in infant electroencephalogram (EEG) and event-related potentials (ERPs) which predict novelty preferences across the first year of life. One goal of this research is to evaluate infant novelty preferences against an adult model of dissociable memory systems. In order to investigate this, the effect of retention interval on infant memory will be assessed by two different tasks: preferential looking and priming. ERPs will be recorded while infants participate in these tasks to assess the extent to which different neural circuits may dissociate performance on the tasks, whether there is a difference in the pattern of brain activity which predicts immediate vs delayed recognition memory, and whether there is a difference in the pattern of brain activity during familiarization across the first year of life. Experiment 2 will investigate the effect of experience on novelty preferences in infancy. This will be accomplished b manipulating infants' experience with a particular class of stimuli, and testing infants before and after this experience. The goal of this study are to assess whether experience with a particular class of stimuli effects performance on preferential looking task whether this experience effects brain re-organization of memory systems with respect to the stimuli, and whether such reorganization, if it is found, persists over time even when the stimuli are removed from the environment.

Description (provided by applicant): Preferential-looking paradigms rely on an infant's inherent "preference" for viewing novel stimuli (i.e., novelty preferences) to provide evidence for memory or discrimination. Our long-term goal is to elucidate the neural mechanisms underlying performance on preferential-looking tasks in order to advance our knowledge about the functional neurobiology and development of visual attention and memory. Such knowledge has important implications for understanding cognitive development in general, and will ultimately help to inform our understanding of how disruptions in the development of these systems may give rise to developmental disorders. The specific hypothesis behind the proposed research is that preferential-looking primarily reflects the incidental encoding of the visual scene into a perceptual store vs. the recollection or recognition of information. The specific aims of this proposal are to: 1. Investigate whether novelty and familiarity preferences are associated with the same or different cognitive processes. The processes underlying novelty and familiarity preferences will be investigated by examining he relation between preferential-looking in the visual-paired comparison (VPC) and subsequent processing of the familiar stimulus via ERPs. Differences in the topography of ERP components can be inferred to reflect differences in the underlying neural circuits, and hence cognitive processes. 2. Dissociate processes related to recognition vs. priming. This will be accomplished by examining the relation between novelty preferences in the VPC and subsequent ERP differences during the processing of familiar and novel stimuli. 3. Dissociate processes related to familiarity vs. recency. This will be accomplished by investigating the effects of repetition of novel and familiar stimuli on ERPs in 6-month olds, focusing in particular on components that have been related to performance on preferential-looking tasks in previous work.