An event-related fNIRS investigation of Japanese word order.

Japanese is a free word-order language, and allows both subject-object-verb (SOV) and object-subject-verb (OSV) orders. Our previous study using near-infrared spectroscopy (NIRS) imaging revealed that OSV sentences induce more activation in the left frontal lobe than SOV sentences. The present study develops our previous experiment: (1) by adopting an event-related design, and (2) by using sentences involving the adverb naze 'why', which plays a prominent role in recent linguistic studies. The results of our new experiment indicated that the cerebral activation in O why SV sentences was significantly larger than that in S why OV sentences, in the right anterior prefrontal region, which is consistent with the assumption that O why SV order is derived from S why OV order. We speculate that the activation observed in the anterior prefrontal cortex during the processing of the sentences involving 'why' might be due to the processing of higher-order function in the cerebral cortex.

A functional near-infrared spectroscopy study on the basic word order in Japanese.

To determine the basic word order in Japanese, oxyhemoglobin concentration changes in the frontal region of 32 healthy men were measured by near-infrared spectroscopy. Our experiment used four types of sentences: (i) subject-object-verb (SOV), (ii) object-subject-verb (OSV), (iii) subject-naze (why)-object-verb (SwhyOV), and (iv) naze (why)-subject-object-verb (whySOV). The results have shown that although oxyhemoglobin changes in the OSV sentences were significantly larger than those in the SOV sentences in the left frontal lobe, such effects were not observed between SwhyOV sentences and whySOV sentences. These results are consistent with the view that both SwhyOV and whySOV are the basic, which suggests that neurolinguistic evidence has the potential to provide an important basis for determining the basic word order in a free word-order language.

Localization of ubiquitin C-terminal hydrolase L1 in mouse ova and its function in the plasma membrane to block polyspermy.

Protein degradation is essential for oogenesis and embryogenesis. The ubiquitin-proteasome system regulates many cellular processes via the rapid degradation of specific proteins. Ubiquitin carboxyl-terminal hydrolase L1 (UCH-L1) is exclusively expressed in neurons, testis, ovary, and placenta, each of which has unique biological activities. However, the functional role of UCH-L1 in mouse oocytes remains unknown. Here, we report the expression pattern of UCH-L1 and its isozyme UCH-L3 in mouse ovaries and embryos. Using immunocytochemistry, UCH-L1 was selectively detected on the plasma membrane, whereas UCH-L3 was mainly detected in the cytoplasm, suggesting that these isozymes have distinct functions in mouse eggs. To further investigate the functional role of UCH-L1 in mouse eggs, we analyzed the fertilization rate of UCH-L1-deficient ova of gad female mice. Female gad mice had a significantly increased rate of polyspermy in in vitro fertilization assays, although the rate of fertilization did not differ significantly from wild-type mice. In addition, the litter size of gad female mice was significantly reduced compared with wild-type mice. These results may identify UCH-L1 as a candidate for a sperm-oocyte interactive binding or fusion protein on the plasma membrane that functions during the block to polyspermy in mouse oocytes.