Visual category-selectivity for faces, places and objects emerges along different developmental trajectories

The organization of category-selective regions in ventral visual cortex is well characterized in human adults. We investigated a crucial, previously unaddressed, question about how this organization emerges developmentally. We contrasted the developmental trajectories for face-, object-, and place-selective activation in the ventral visual cortex in children, adolescents, and adults. Although children demonstrated adult-like organization in object- and place-related cortex, as a group they failed to show consistent face-selective activation in classical face regions. The lack of a consistent neural signature for faces was attributable to (1) reduced face-selectivity and extent of activation within the regions that will become the FFA, OFA, and STS in adults, and (2) smaller volumes and considerable variability in the locus of face-selective activation in individual children. In contrast, adolescents showed an adult-like pattern of face-selective activation, although it was more right-lateralized. These findings reveal critical age-related differences in the emergence of category-specific functional organization in the visual cortex and support a model of brain development in which specialization emerges from interactions between experience-dependent learning and the maturing brain.     

Preserved Implicit Knowledge of a Forgotten Childhood Language

ABSTRACT— Previous research suggests that a language learned during early childhood is completely forgotten when contact to that language is severed. In contrast with these findings, we report leftover traces of early language exposure in individuals in their adult years, despite a complete absence of explicit memory for the language. Specifically, native English individuals under age 40 selectively relearned subtle Hindi or Zulu sound contrasts that they once knew. However, individuals over 40 failed to show any relearning, and young control participants with no previous exposure to Hindi or Zulu showed no learning. This research highlights the lasting impact of early language experience in shaping speech perception, and the value of exposing children to foreign languages even if such exposure does not continue into adulthood.     

Sensitivity to syntax in visual cortex

One of the most intriguing findings on language comprehension is that violations of syntactic predictions can affect event-related potentials as early as 120 ms, in the same time-window as early sensory processing. This effect, the so-called early left-anterior negativity (ELAN), has been argued to reflect word category access and initial syntactic structure building (Friederici, 2002). In two experiments, we used magnetoencephalography to investigate whether (a) rapid word category identification relies on overt category-marking closed-class morphemes and (b) whether violations of word category predictions affect modality-specific sensory responses. Participants read sentences containing violations of word category predictions. Unexpected items varied in whether or not their word category was marked by an overt function morpheme. In Experiment 1, the amplitude of the visual evoked M100 component was increased for unexpected items, but only when word category was overtly marked by a function morpheme. Dipole modeling localized the generator of this effect to the occipital cortex. Experiment 2 replicated the main results of Experiment 1 and eliminated two non-morphology-related explanations of the M100 contrast we observed between targets containing overt category-marking and targets that lacked such morphology. Our results show that during reading, syntactically relevant cues in the input can affect activity in occipital regions at around 125 ms, a finding that may shed new light on the remarkable rapidity of language processing.     

A preliminary investigation of within-year growth patterns in reading and mathematics curriculum-based measures

This study examined patterns of growth across benchmark assessments for curriculum-based measures (CBM) over 2 academic years, with the twofold purpose of replicating earlier findings of growth patterns on R-CBM and conducting a preliminary investigation of growth patterns on M-CBM and CBM-Maze. The sample included 898 cases from 3rd through 5th grade over 2 academic years from one elementary school in the rural Midwest. All students participated in tri-annual benchmark assessments in which they were administered R-CBM, CBM-Maze, and M-CBM. Repeated measures analysis of variance was used to examine patterns of growth for all three measures. Students demonstrated greater R-CBM weekly growth during winter-to-spring than fall-to-winter across grade levels. Patterns for CBM-Maze and M-CBM were somewhat inconsistent across school years and grade levels. Results are discussed in terms of contextual variables that may impact within-year growth patterns and technical characteristics of CBM slopes.     

Perception,meaning, and mind

Earlier versions of this paper were read in the Philosophy department at the University of Helsinki, in the Institute for Advanced Studies in the Humanities at the University of Edinburgh, at Vanderbilt University, at the Indiana Philosophical Association, and at the Institute for Logic and Cognitive Science at the University of Houston. I am grateful for very helpful comments on each of these occasions, and I am especially appreciative to John Haugeland, Mark Johnson, and George McClure for their comments and suggestions. Thanks, too, to Robert Solomon who urged me to amplify my claims about perceptual meaning.