The hypothalamus is the primary brain region that responds to leptin, sending a signal that curbs appetite.
下丘脑是对瘦素起反应的最主要的大脑区域，通过传递信号来抑制食欲。
2
Speech recognition, which focuses on speech as object, is an important research direction of speech signal processing and a primary technology to realize the communication between human and machines.
语音识别是以语音为研究对象，是语音信号处理的一个重要研究方向，是实现人机通信的主要技术。
3
This is used to set the record's primary key and it serves as a signal to Doctrine that the record being processed already exists in the database.