Modulation of hippocampal dentate gyrus (DG) excitability regulates anxiety. In the DG, glutamatergic mossy cells (MCs) receive the excitatory drive from principal granule cells (GCs) and mediate the feedback excitation and inhibition of GCs. However, the circuit mechanism by which MCs regulate anxiety-related information routing through hippocampal circuits remains unclear. Moreover, the correlation between MC activity and anxiety states is unclear. In this study, we first demonstrate, by means of calcium fiber photometry, that MC activity in the ventral hippocampus (vHPC) of mice increases while they explore anxiogenic environments. Next, juxtacellular recordings reveal that optogenetic activation of MCs preferentially recruits GABAergic neurons, thereby suppressing GCs and ventral CA1 neurons. Finally, chemogenetic excitation of MCs in the vHPC reduces avoidance behaviors in both healthy and anxious mice. These results not only indicate an anxiolytic role of MCs but also suggest that MCs may be a potential therapeutic target for anxiety disorders.

The Hong Kong Cantonese variety of Chinese (hereafter "Cantonese") poses an interesting challenge for prosodic typology and transcription for three closely interrelated reasons. First, compared to the Mandarin varieties of Chinese, Cantonese has far fewer polysyllabic wordforms. The majority of the syllables are potentially free-standing morphemes, and there is no contrast between "stressed" syllables and reduced ("neutral-tone") syllables. Second, there is an extremely dense syntagmatic specification of tone. Every syllable in an utterance has a lexical tone, even if it is a grammatical morpheme or pragmatic particle, and there is a rich inventory of non-segmental pragmatic morphemes ("boundary tones")

The problem of word segmentation affects all aspects of Chinese language processing, including the development of text-to-speech synthesis systems. In synthesizing a Hong Kong Cantonese text, for example, words must be identified in order to model fusion of coda [p] with initial [h], and other similar effects that differentiate word-internal syllable boundaries from syllable edges that begin or end words. Accurate segmentation is necessary also for developing any list of words large enough to identify the wordinternal cross-syllable sequences that must be recorded to model such effects using concatenated synthesis units. This paper describes our use of the Segmentation Corpus to constrain such units.

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