Hemodynamic changes in the infant cortex during the processing of featural and spatiotemporal information

Abstract

Over the last 20 years neuroscientists have learned a great deal about the ventral and dorsal object processing pathways in the adult brain, yet little is known about the functional development of these pathways. The present research assessed the extent to which different patterns of neural activation, as measured by changes in blood volume and oxygenation, are observed in infant visual and temporal cortex in response to events that involve processing of featural differences or spatiotemporal discontinuities. Infants aged 6.5 months were tested. Increased neural activation was observed in visual cortex in response to a featural-difference and a spatiotemporal-discontinuity event. In addition, increased neural activation was observed in temporal cortex in response to the featuraldifference but not the spatiotemporal-discontinuity event. The outcome of this experiment reveals early functional specialization of temporal cortex and lays the foundation for future investigation of the maturation of object processing pathways in humans. Keywordsinfants; near-infrared spectroscopy; object processing; featural information; spatiotemporal information Over the last 20 years a great deal of research has been conducted on the neural basis of object processing. Early studies conducted with non-human primates suggested that there are two Address for correspondence: Teresa Wilcox, Department of Psychology, Texas A&M University, 4235 TAMU, College Station,; email: E-mail: tgw@psyc.tamu.edu). Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. NIH Public Access Author ManuscriptNeuropsychologia. Author manuscript; available in PMC 2010 February 1. (Livingstone & Hubel, 1988; De Yoe & Van Essen, 1988;Goodale & Milner, 1992;Mishkin, Ungerleider, & Macko, 1983;Ungerleider & Mishkin, 1982). The ventral route originates from the parvocellular layers of the lateral geniculate nucleus (LGN) and projects from the primary visual cortex to the temporal cortex and mediates processing of visual features important for the recognition and identification of objects. The dorsal route originates from the magnocellular layers of the LGN and projects from the primary visual cortex to the parietal cortex and is important for the analysis of motion, depth, and location. More recent studies with non-human (Orban, Van Essen, & Vanduffel, 2004;Tanaka, 2000;Tootell, Tsao, & Vanduffel, 2003; Tsunoda, Yamane, Nishkzaki, & Tanifuji, 2001;Wang, Tanifuji, & Tanaka, 1998;Wang, Tanaka, Tanifuji, 1996) and human (Bly & Kosslyn, 1997;Grill-Spector, Kourtzi, & Kanwisher, 2001;Grill-Spector et al., 1998;Haxby et al.,...

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

“…There are two major infant groupings according to Cristia et al 3 that have been most commonly studied: newborns and 4-to 8-month-old infants. Studies by other groups, [4][5][6][7][8][9][10] in the age range of 5 to 7 months similar to the age range in our study, focused on the occipital, temporal, and parietal cortices.…”

Role of Prefrontal Cortex in Learning and Generalizing Hierarchical Rules in 8-Month-Old Infants

“…Each block was preceded by a 10 s baseline interval to allow blood volume to return to baseline levels, during which time a black screen with a white fixation cross was presented. Previous studies indicate that 10 s is sufficient for blood volume to return to baseline levels (Wilcox et al, 2008(Wilcox et al, , 2009). The order of blocks was counterbalanced between participants.…”

Illuminating the developing brain: The past, present and future of functional near infrared spectroscopy

“…In an object processing study by Wilcox et al (2009), a differential change in HbO 2 concentration across regions, specific to a single experimental condition, was observed. Whereas the featural difference condition produced HbO 2 increases in both the temporal and occipital area, the spatiotemporal-discontinuity condition produced an increase in HbO 2 in the occipital area, and a decrease in HbO 2 in the temporal area.…”