The one-trial passive avoidance task (OTPAT) and sickness-conditioned learning task (SCLT) models are widely used in studies on the mechanisms of learning and memory in day-old chicks and a numerous progress has been achieved. Previous findings have shown that the intermediate medial hyperstriatum ventrale (IMHV) and lobus parolfactorius (LPO) are principal structures involved in memory formation in the chick brain. In light of studies on the relevant molecular mechanisms, pharmacological experiments have discovered a number of medicines which may affect the memory formation at its different stages. As an example, noradrenalin may enhance and modulate the long-term memory. Since the principal structures and their functions in the avian brain are, to some extents, comparable to those in the mammal, the above-mentioned studies on chicks may provide important clues for exploring the learning and memory in human brain.