Perception Precedes Computation: Can Familiarity Preferences Explain Apparent Calculation by Human Babies?

Two studies of 5-month-old infants explored whether a phenomenon reported by K. Wynn (1992) reflects a familiarity preference instead of a mathematical competence. Experiment 1 was a conceptual replication of Wynn\u27s study. When data were analyzed with the relatively liberal statistical approach used by Wynn, the original phenomenon was replicated. However, an analysis of variance revealed that girls and boys behaved in different ways, and that boys did not behave as Wynn would have predicted. Experiment 2 was identical to Experiment 1, with one exception that should not have influenced computation: Infants in this study were completely familiarized with the test displays before testing. Again, the data revealed an interaction involving sex: Boys tended to be influenced by their familiarity with the test displays, whereas girls tended to behave as Wynn would have predicted. These findings are discussed with reference to the literature on sex differences--specifically the finding that male infants are typically immature relative to their female peers--as well as to articles that have been critical or supportive of Wynn\u27s conclusions

Pax6 Is Required at the Telencephalic Pallial-Subpallial Boundary for the Generation of Neuronal Diversity in the Postnatal Limbic System

During embryogenesis, the pallial-subpallial boundary (PSB) divides the two main progenitor domains in the telencephalon: the pallium, the major source of excitatory neurons, and the subpallium, the major source of inhibitory neurons. The PSB is formed at the molecular interface between the pallial (high Pax6+) and subpallial (high Gsx2+) ventricular zone (VZ) compartments. Initially, the PSB contains cells that express both Pax6 and Gsx2, but during later stages of development this boundary is largely refined into two separate compartments. In this study we examined the developmental mechanisms underlying PSB boundary formation and the postnatal consequences of conditional loss of Pax6 function at the PSB on neuronal fate in the amygdala and olfactory bulb, two targets of PSB-derived migratory populations. Our cell fate and time-lapse imaging analyses reveal that the sorting of Pax6+ and Gsx2+ progenitors during embryogenesis is the result of a combination of changes in gene expression and cell movements. Interestingly, we find that in addition to giving rise to inhibitory neurons in the amygdala and olfactory bulb, Gsx2+ progenitors generate a subpopulation of amygdala excitatory neurons. Consistent with this finding, targeted conditional ablation of Pax6 in Gsx2+ progenitors results in discrete local embryonic patterning defects that are linked to changes in the generation of subsets of postnatal excitatory and inhibitory neurons in the amygdala and inhibitory neurons in the olfactory bulb. Thus, in PSB progenitors, Pax6 plays an important role in the generation of multiple subtypes of neurons that contribute to the amygdala and olfactory bulb

Identification of distinct telencephalic progenitor pools for neuronal diversity in the amygdala

The development of the amygdala, a central structure of the limbic system, remains poorly understood. We found that two spatially distinct and early-specified telencephalic progenitor pools marked by the homeodomain transcription factor Dbx1 are major sources of neuronal cell diversity in the mature mouse amygdala. We found that Dbx1-positive cells of the ventral pallium generate the excitatory neurons of the basolateral complex and cortical amygdala nuclei. Moreover, Dbx1-derived cells comprise a previously unknown migratory stream that emanates from the preoptic area (POA), a ventral telencephalic domain adjacent to the diencephalic border. The Dbx1-positive, POA-derived population migrated specifically to the amygdala and, as defined by both immunochemical and electrophysiological criteria, generated a unique subclass of inhibitory neurons in the medial amygdala nucleus. Thus, this POA-derived population represents a previously unknown progenitor pool dedicated to the limbic system.Fil: Hirata, Tsutomu. Children’s National Medical Center. Center for Neuroscience Research; Estados UnidosFil: Li, Peijun. University Of Georgetown; Estados UnidosFil: Lanuza, Guillermo Marcos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Cocas, Laura A.. Children’s National Medical Center. Center for Neuroscience Research; Estados Unidos. University Of Georgetown; Estados UnidosFil: Huntsman, Molly M.. University Of Georgetown; Estados UnidosFil: Corbin, Joshua G.. Children’s National Medical Center. Center for Neuroscience Research; Estados Unido