I attached the image related to your concerned question.
In theory, the part of the brain that is responsible for the sleep wake cycle is the hypothalamus; specifically, the ventrolateral preoptic nucleus of the hypothalamus. In the image, the location of the hypothalamus is pointed by the green square.
In theory, the part of the brain that is responsible for the sleep wake cycle is the hypothalamus; specifically, the ventrolateral preoptic nucleus of the hypothalamus. In the image, the location of the hypothalamus is pointed by the green square.