This transgenic mice express a fusion gene, APTTC, consisting of the truncated human placental alkaline phosphatase with TTC (Tetanus toxin C fragment). This strain can be used to make an inducible expression of APTTC as a retrograde transynaptic genetic tracer crossing with the genetically-engineered mice that have a tetracycline-controlled transactivator (tTA) in any specific neurons. (J:337810)