Melina R. Uncapher - US grants

[unreadable] DESCRIPTION (provided by applicant): The broad aim of the proposed research program is to investigate the relationship between neurocognitive mechanisms giving rise to a multidimensional perceptual experience, and those that encode the experience in long-term memory. A novel paradigm will be employed to examine how the constituent elements of an experience-processed by distinct neural mechanisms-converge to form a coherent percept, and are subsequently encoded as an enduring 'episodic' memory. While much evidence supports the dual ideas that the creation of a unified percept ('perceptual binding') relies on attentional mechanisms in posterior parietal cortex (PPC), and that the formation of an integrated episodic memory relies on medial temporal lobe (MTL) encoding mechanisms, little is known about functional interactions between these mechanisms. By one account, MIL acts indiscriminately on the information projected to it, as mediated by attentional mechanisms. To the extent that this accurately describes the interplay between such mechanisms, the question arises whether the extent to which the multiple elements of an episode are perceived coherently changes the nature of the input to the MTL, and thus the resultant episodic representation. The proposed research aims to programmatically address this question by employing a novel paradigm that allows the factors of attention, perceptual and episodic binding to be independently assessed and correlated with functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) measures of neural activity. Expt 1 will employ fMRI to directly investigate the extent to which episodic binding is contingent on attentionally-mediated perceptual binding. Expt 2 will examine, with conventional fMRI and effective connectivity analyses, how attention to the various elements of an episode determines which MTL encoding mechanisms are engaged, and thus the type of memory formed. Finally, Expt 3 will characterize the temporal dimension of these operations by examining cross-regional synchronous oscillations in EEG signal. Delineating the manner in which the nature of the attention brought to bear on an experience influences the nature of encoding mechanisms promises to advance mechanistic accounts of encoding. PUBLIC HEALTH RELEVANCE: The proposed research will use fMRI and EEG to examine functional interactions between mechanisms of attention, perceptual binding, and episodic encoding. Characterizing the role of attentionally-mediated perceptual binding in the formation of informationally-rich memories will be directly relevant to understanding mechanisms of prevalent neurological conditions involving impairments in these processes, such as schizophrenia, Alzheimer's disease, depression, and attention deficit disorder. [unreadable] [unreadable] [unreadable]

Abstract American youth spend more time with media than in any other activity. Almost a third of this time is spent simultaneously engaging with (or switching between) multiple media streams (`media multitasking'; MMT). The rapid rise in MMT has generated considerable scientific and societal interest in determining whether, and if so how, MMT impacts cognition, psychosocial health, academic achievement, and brain structure and function. Given the prevalence of MMT in children and young adults, there is urgency to understand the neurocognitive profiles of media multitaskers. Mounting evidence (including new behavioral and neural findings generated in our exploratory grant R21MH099812) points to consistent MMT-related differences in attention and memory, yet the nature and extent of these cognitive differences, their neural underpinnings, and their emergence across the lifespan remain largely unknown. The proposed multi-modal research program will examine the neurocognitive differences associated with chronic MMT, and will explore how and when differences onset. In young adults (18-24yr), we will leverage sensitive behavioral paradigms, scalp EEG, and concurrent EEG-fMRI to test hypotheses about the nature and neural underpinnings of MMT-related attention and memory differences, and we will relate these cognitive and task-based neural differences to functional and structural connectivity in frontoparietal networks of attention and cognitive control. In children (7-12yr), we will use a large-sample, longitudinal design and a novel multi-domain cognitive assessment tool to measure working memory (WM), selective and sustained attention, and inhibitory control; we will relate these cognitive measures to MMT behavior and to EEG measures of attention- and memory-related neural function. We also will obtain measures of academic achievement for both age groups. Our aims are to: (Aim 1) delineate the nature of the WM and long-term memory (LTM) decrements associated with heavier MMT, and (Aim 2) test the hypothesis that increased attentional lapses and diminished attentional control contribute to these decrements; (Aim 3) test the hypothesis that the large-scale frontoparietal structural and functional networks that support attention and cognitive control vary with MMT; and (Aim 4) determine how and when MMT-related cognitive and neural differences arise in children (7-12yr), at the time when younger populations begin to engage in MMT. The proposed research will (a) delineate how memory, attention, and cognitive control, and their underlying neural systems, vary with MMT and relate to academic achievement in young adults and children, as well as (b) begin to shed light on whether chronic MMT is a cause or consequence of neurocognitive differences. Moreover, by leveraging an individual differences approach, we will advance mechanistic understanding of the interactions between four R-DoC cognitive constructs (attention, cognitive control, WM, and declarative memory) and their dependence on large-scale frontoparietal structural and functional networks.