Bone morphogenetic protein (BMP) 15 and growth differentiation factor (GDF) 9 are oocyte-secreted growth factors that are critical local regulators of ovarian function and may be involved in preovulatory cumulus expansion. As cumulus expansion occurs in response to the ovulatory surge, the present study was designed: 1) to investigate whether GDF9 and BMP15 are regulated by gonadotropins in the mouse ovary; and 2) to visualize changes in both GDF9 and BMP15 immunostaining in response to gonadotropins. Immature 21-day-old mice were sequentially treated with recombinant human FSH (r-hFSH), 5 IU daily, at Days 21, 22, and 23 of life, then injected with 5 IU hCG at Day 24 of life. In response to r-hFSH, steady-state Bmp15 mRNA expression levels increased in both total ovaries and cumulusoocyte complexes, whereas Gdf 9 mRNA levels did not. In addition, BMP15 protein levels increased in total ovaries. The GDF9 immunostaining was exclusively seen in growing oocytes in both control and gonadotropin-treated mice, whereas that of BMP15, which was also primarily seen in growing oocytes, exhibited important changes in response to gonadotropins. Strong BMP15 immunostaining was observed in the follicular fluid of atretic antral follicles after FSH treatment and in expanded, but not in compact, cumulus cells after hCG. The present results show for the first time that BMP15 levels increase during gonadotropininduced follicular development, in parallel with oocyte maturation, and that this local factor is likely involved in cumulus expansion as previously suggested by studies in Bmp15-null mice.cumulus cells, follicle-stimulating hormone, growth factors, oocyte development, ovary

We examined the effect of stimulus complexity and frequency on infants' attention responses during an auditory habituation procedure. Five stimuli of different complexity and frequency were presented repeatedly to 80 5-month-old infants. Quicker attention-getting and longer attention-holding responses were obtained with the more complex stimuli. Furthermore, a progressive decrease in attention-holding, but not in attentiongetting, was observed across trials. The findings are similar to those well established in the visual modality [e.g., Cohen et al. showing that auditory complexity is an important variable in attracting and maintaining infant attention, and that only attention-holding is subject to habituation. Although the complex stimulus contained higher frequencies than the simple or intermediate stimuli, our results further showed that stimulus frequency alone had no significant effect on attention-getting or attention-holding, which strengthens our claim that complexity preference during habituation can be generalized to the auditory modality.

The Ebbinghaus illusion was used to study size estimation as influenced by salient features of the central figure. Two groups of fourth graders, 9 boys and 11 girls, and two groups of seventh graders, 9 boys and 9 girls, judged the size of two central figures (an Oreo cookie or a black cardboard disc) with small and large black cardboard disc inducers. Responding showed the Oreo cookie was consistently perceived as larger than the cardboard disc when surrounded by the large inducing figures. The results are discussed in terms of an interaction between the geometric properties and salience of the central figure with the surrounds. This Oreo effect is not predicted by a strict version of the token-value hypothesis and differs from explanations based on contrast and conceptual similarity.

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