Cortical activation to object shape and speed of motion during the first year

Abstract

A great deal is known about the functional organization of cortical networks that mediate visual object processing in the adult. The current research is part of a growing effort to identify the functional maturation of these pathways in the developing brain. The current research used near-infrared spectroscopy to investigate functional activation of the infant cortex during the processing of featural information (shape) and spatiotemporal information (speed of motion) during the first year of life. Our investigation focused on two areas that were implicated in previous studies: anterior temporal cortex and posterior parietal cortex. Neuroimaging data were collected with 207 infants across three age groups: 3 to 6 months (Experiment 1), 7 to 8 months (Experiment 2), and 10 to 12 months (Experiments 3 and 4). The neuroimaging data revealed age-related changes in patterns of activation to shape and speed information, mostly involving posterior parietal areas, some of which were predicted and others that were not. We suggest that these changes reflect age-related differences in the perceptual and/or cognitive processes engaged during the task.

Object processing in the infant: lessons from neuroscience

“…fNIRS studies have revealed that activation is obtained in the anterior temporal cortex to events in which spatiotemporal discontinuities (e.g., discontinuities in path or speed of motion) signal the presence of distinct objects. Control events (like that in Figure 2A) do not elicit activation in the anterior temporal cortex [49, 51]. This confirms and extends the individuation-by-feature results by revealing that the anterior temporal cortex is activated regardless of how the objects were individuated (e.g., on the basis of featural or spatiotemporal information).…”

“…However, posterior temporal responses change markedly during the first year. Regardless of event condition, by 7 months activation in posterior temporal areas wane, and by 12 months is no longer observed for this task [50,51]. These results suggest a functional reorganization of the ventral object-processing network during the second half of the first year.…”

“…To identify the neural basis of infants’ emerging capacity for individuation-by-feature, a series of fNIRS studies were conducted with infants between 3 and 12 months of age [49–51]. Infants viewed shape-difference, color-difference, or control events similar to those used in previous behavioral studies (Figure 2A).…”

“…That is, behavioral responses should be reflected in patterns of cortical activation. Indeed, across studies, activation was obtained in the anterior temporal cortex only in response to events in which infants individuate by feature [13,49–51]. For example, infants 3 to 9 months, who use shape but not color information to individuate objects [39], show anterior temporal activation when viewing the shape-difference but not the color-difference or control event.…”

Methodology for high-yield acquisition of functional near-infrared spectroscopy data from alert, upright infants

“…There is considerable interest in using functional near-infared spectroscopy (fNIRS) to study infants with more recent studies (since July 2012) covering its broad potential as a noninvasive tool to study infant cognition, 10 typical and atypical development, 11 and, more specifically, to study face recognition, [12][13][14] shape processing, and motion 15,16 and color priming. 17 Despite the rapid growth in the number of infant fNIRS publications in recent years, this number is relatively low when compared to that of adult studies.…”