Neural connections of the pontine reticular formation, which connects reciprocally with the nucleus prepositus hypoglossi in the rat

The pontine reticular formation connected with the nucleus prepositus hypog lossi was studied in the rat using anterograde and retrograde tracer techni ques. The area reciprocally connected with the nucleus prepositus hypogloss i was evident in the pontine reticular formation of the rat. The region had intensive reciprocal connections with the ipsilateral subthalamic region, the contralateral pontine reticular formation and the nucleus prepositus hy poglossi. Furthermore, it was confirmed that the region received cholinergi c projections mainly from the pedunculopontine tegmental nucleus and the la terodorsal tegmental nucleus, and aminergic projections from the dopaminerg ic cell groups A13 and A11, noradrenergic cell groups A7, A6 and A5, and th e serotoninergic B9 cell group. This region in the rat was considered to be the preoculomotor structure in the function of horizontal gaze corresponding to the paramedian pontine ret icular formation in other animals. (C) 1999 IBRO. Published by Elsevier Sci ence Ltd.