April A Benasich, Ph.D. - US grants

The study of early infant behaviors and their relation to later cognitive and linguistic competence has been an enduring research focus in the investigation of human development. Research which aims to predict cognitive and linguistic abilities in later childhood based on early infant behavior, implicate infant perceptual-cognitive abilities as likely analogs for childhood information-processing skills. The primary aim of this study is to examine the specific relationship between early perceptual-cognitive abilities (as indexed by habituation, recognition memory, and auditory temporal processing) and later cognitive and linguistic development Speed of encoding appears to be the critical factor in differential performance on perceptual-cognitive tasks. Measures of perceptual- cognitive abilities in infancy, such as habituation decrement and recognition memory, are in turn related to performance on childhood linguistic and cognitive tasks. Similarly, studies with language impaired children implicate a specific deficit in rate of sensory and perceptual information processing. Previous research has found auditory temporal processing and memory deficits to be highly predictive of developmental speech and language impairment We propose to bring together two promising lines of research which, to our knowledge, have not previously been integrated, in order to directly examine the role of speed of encoding in infant perceptual-cognitive abilities and its subsequent impact on later cognitive and language outcomes. We will pursue these goals in two ways. First, by continuing to develop and refine our infant operant conditioning paradigm that facilitates assessment of auditory temporal processing (ATP) in the first year of life and collecting cross-sectional, normative data on ATP for infants 4- to 9- months-of-age. Second, by examining prospectively the developmental course of early perceptual memory, information processing, and temporal processing in three infant populations expected to differ in the course of language development and the incidence of specific language impairment: normal term infants, preterm very low-birth-weight (VLBW) infants, and infants from families with a positive history of specific language impairment (LI). The primary rationale for the proposed research is to address and integrate existing theories of early perceptual, cognitive and language development. Ultimately, these studies may lead to the development of specific measures which may provide for earlier prediction of subsequent cognitive and/or language disorders.

Project Summary: The exploratory research proposed here addresses the critical issue of understanding both macrostructure and microstructure of infant sleep as well as the role of sleep as a facilitator of brain maturation and cognitive outcomes. Although extensive research has been conducted on sleep in animal models, in adults and in premature neonates, very little is known about the neurophysiology of sleep in healthy human infants. Current research suggests that alterations in sleep pattern or duration play a role in almost all known psychiatric disorders and further, that many of the mechanisms governing developmental plasticity also mediate plasticity in the adult brain. Variability in sleep patterns is also gaining attention as a possible early biomarker for a number of neurodevelopmental disorders. Identification of reliable biomarkers could lead to targeted diagnostic tools that would be useful in diagnosing a number of developmental disorders. We will examine infant daytime sleep in a rarely studied age group (3, 6 and 9 months), using advanced dense-array EEG recording (dEEG) and analytic techniques seldom used in sleep studies, in combination with concurrent assessment of infant cognition and information processing. Thus, the aims of this application include: (1) characterizing the topographical spectral composition and network connectivity of non-rapid eye movement sleep (NREMS) and rapid eye movement sleep (REMS) in typically developing, napping infants, at 3, 6, and 9 months; and (2) testing the hypothesis that neurophysiological measures of topographical electrophysiology (microstructure) and temporal global functional networks (microstates) during NREMS are associated with cognitive measures. We propose to achieve these aims using dEEG data and characterizing spectral power, coherence, and network connectivity of NREMS and REMS as well as the morphology, topography, and developmental trajectories of two prominent NREMS waveforms (i.e. sleep spindles and slow waves), which are hypothesized to be critical to infant brain development. Finally we will use standardized cognitive scales and auditory and visual habituation/recognition-memory tasks to assess infants? cognitive development levels as well as working memory and attention. We anticipate that the outcomes of this study will accelerate our understanding of infant brain development across the first year of life, delineating the emergence, function and maturation of changing oscillatory sleep patterns, while simultaneously facilitating future translational approaches (e.g. interventional strategies for slow wave and spindle enhancement) targeting developmental sleep as it relates to the prevention of neuropsychiatric disorders.