Infant fMRI: A Model System for Cognitive Neuroscience

Abstract

Our understanding of the typical human brain has benefitted greatly from studying different kinds of brains and their associated behavioral repertoires, including animal models and neuropsychological patients. This same comparative perspective can be applied to early development - the environment, behavior, and brains of infants provide a model system for understanding how the mature brain works. This approach requires noninvasive methods for measuring brain function in awake, behaving infants. fMRI is becoming increasingly viable for this purpose, with the unique ability to precisely measure the entire brain, including both cortical and subcortical structures. Here we discuss potential lessons from infant fMRI for several domains of adult cognition and consider the challenges of conducting such research and how they might be mitigated.

Keywords: attention; cognitive development; memory systems; neuroimaging; perception.

Figure 1. Approximate Developmental Trajectories for Certain Neural, Cognitive, and Behavioral Systems from 0 to 8 Years of Age

(A) Language acquisition reflected in the size of spoken vocabulary [105]. (B) The development of memory span up to adult capacity [106]. (C) The amount of myelination across development relative to adults [107, 108]. (D) The visual acuity of children relative to adults [8]. (E) Changes in speech prosody from child- to adult-directed speech [11, 12]. Abbreviation: CDS, child-directed speech. Subpanels were adapted from figures in cited sources.

Figure 2

Different types of contrasts across three cognitive domains for which quasi-experiments with infant fMRI may be informative about adult cognitive neuroscience. Neural contrast in memory: infants may not need a dedicated memory system for rapid learning (the hippocampus) because there is less risk of catastrophic interference to stable prior knowledge (in neocortex). Cognitive contrast in attention: infant deficits in goal-directed attention may reflect impoverished goal representations and help isolate behaviors and brain networks associated with stimulus-driven attention. Experiential contrast in perception: infants have much less sensory experience and thus every new experience may lead to more substantial perceptual changes than adults and a greater ability to tease apart proposed theoretical explanations of such learning.