The multisensory representation of number in infancy

Kerry E. Jordan and Elizabeth M. Brannon

PNAS 103:3486-3489 (2006)

Human infants can discriminate visual and auditory stimuli solely on the basis of number, suggesting a developmental foundation for the nonverbal number representations of adult humans. Recent studies suggest that these language-independent number representations are multisensory in both adult human and nonhuman animals. Surprisingly, however, previous studies have yielded mixed evidence concerning whether nonverbal numerical representations independent of sensory modality are present early in human development. In this article, we use a paradigm that avoids stimulus confounds present in previous studies of cross-modal numerical mapping in infants. We show that 7-month-old infants preferentially attend to visual displays of adult humans that numerically match the number of adult humans they hear speaking. These data provide evidence that by 7 months of age, infants connect numerical representations across different sensory modalities when presented with human faces and voices. Results support the possibility of a shared system between preverbal infants and nonverbal animals for representing number.

Intellectual ability and cortical development in children and adolescents

P. Shaw, D. Greenstein, J. Lerch, L. Clasen, R. Lenroot, N. Gogtay, A. Evans, J. Rapoport, and J. Giedd

Nature 440:676-679 (2006)

Children who are adept at any one of the three academic ‘R’s (reading, writing and arithmetic) tend to be good at the others, and grow into adults who are similarly skilled at diverse intellectually demanding activities. Determining the neuroanatomical correlates of this relatively stable individual trait of general intelligence has proved difficult, particularly in the rapidly developing brains of children and adolescents. Here we demonstrate that the trajectory of change in the thickness of the cerebral cortex, rather than cortical thickness itself, is most closely related to level of intelligence. Using a longitudinal design, we find a marked developmental shift from a predominantly negative correlation between intelligence and cortical thickness in early childhood to a positive correlation in late childhood and beyond. Additionally, level of intelligence is associated with the trajectory of cortical development, primarily in frontal regions implicated in the maturation of intelligent activity. More intelligent children demonstrate a particularly plastic cortex, with an initial accelerated and prolonged phase of cortical increase, which yields to equally vigorous cortical thinning by early adolescence. This study indicates that the neuroanatomical expression of intelligence in children is dynamic.

A functional magnetic resonance imaging study of neural dissociations between brand and person judgments

Carolyn Yoon, Angela H. Gutchess, Fred Feinberg, and Thad A. Polk

Journal of Consumer Research 33:31-40 (2006)

Functional magnetic resonance imaging (fMRI) was used to investigate whether semantic judgments about products and persons are processed similarly. Our results suggest they are not: comparison of neural correlate of product versus human descriptor judgments indicated greater activation in the medial prefrontal cortex regions for persons; for products, activation was greater in the left inferior prefrontal cortex, an area known to be involved in object processing. These findings serve to challenge the view that processing of products and brands is akin to that of humans and set a precedent for the use of fMRI techniques in consumer neuroscience studies.

Neural correlates of culturally familiar brands of car manufacturers

Michael Schaefer, Harald Berens, Hans-Jochen Heinze, and Michael Rotte

Neuroimage 31:861-865 (2006)

Brands have a high impact on people’s economic decisions. People may prefer products of brands even among almost identical products. Brands can be defined as cultural-based symbols, which promise certain advantages of a product. Recent studies suggest that the prefrontal cortex may be crucial for the processing of brand knowledge. The aim of this study was to examine the neural correlates of culturally based brands. We confronted subjects with logos of car manufactures during an fMRI session and instructed them to imagine and use a car of these companies. As a control condition, we used graphically comparable logos of car manufacturers that were unfamiliar to the culture of the subjects participating in this study. If they did not know the logo of the brand, they were told to image and use a generic car. Results showed activation of a single region in the medial prefrontal cortex related to the logos of the culturally familiar brands. We discuss the results as self-relevant processing induced by the imagined use of cars of familiar brands and suggest that the prefrontal cortex plays a crucial role for processing culturally based brands.

Cortical signatures of noun and verb production

Kevin A. Shapiro, Lauren R. Moo and Alfonso Caramazza

PNAS 103:1644-1649 (2006)

Categories like “noun” and “verb” represent the basic units of grammar in all human languages, and the retrieval of categorical information associated with words is an essential step in the production of grammatical speech. Studies of brain-damaged patients suggest that knowledge of nouns and verbs can be spared or impaired selectively; however, the neuroanatomical correlates of this dissociation are not well understood. We used event-related functional MRI to identify cortical regions that were active when English-speaking subjects produced nouns or verbs in the context of short phrases. Two regions, in the left prefrontal cortex and left superior parietal lobule, were selectively activated for verb trials compared with noun trials; one region in the left inferior temporal lobe was more active during noun production than verb production. We proposed that these regions are involved in presenting core conceptual properties of nouns and verbs.